- new

[packages/kernel.git] / kernel-aufs.patch

diff -urN linux/fs/aufs/aufs.h linux-aufs/fs/aufs/aufs.h
--- linux/fs/aufs/aufs.h        1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/aufs.h   2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,70 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * main header files
+ *
+ * $Id$
+ */
+
+#ifndef __AUFS_H__
+#define __AUFS_H__
+
+#ifdef __KERNEL__
+
+#include <linux/version.h>
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 25)
+#error you got wrong version
+#endif
+
+/* introduced in linux-2.6.27 */
+#include <linux/bug.h>
+#ifndef WARN_ONCE
+#define WARN_ONCE(cond, fmt ...) WARN_ON(cond)
+#endif
+
+/* ---------------------------------------------------------------------- */
+
+#include "debug.h"
+
+#include "branch.h"
+#include "cpup.h"
+#include "dcsub.h"
+#include "dentry.h"
+#include "dir.h"
+#include "file.h"
+#include "hinode.h"
+#include "inode.h"
+#include "misc.h"
+#include "module.h"
+#include "opts.h"
+#include "super.h"
+#include "sysaufs.h"
+#include "vfsub.h"
+#include "whout.h"
+#include "wkq.h"
+/* reserved for future use */
+/* #include "xattr.h" */
+
+#ifdef AuNoInlineForStack
+#undef noinline_for_stack
+#define noinline_for_stack /* */
+#endif
+
+#endif /* __KERNEL__ */
+#endif /* __AUFS_H__ */
diff -urN linux/fs/aufs/branch.c linux-aufs/fs/aufs/branch.c
--- linux/fs/aufs/branch.c      1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/branch.c 2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,1038 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * branch management
+ *
+ * $Id$
+ */
+
+#include <linux/iso_fs.h>
+#include <linux/loop.h>
+#include <linux/romfs_fs.h>
+#include <linux/smp_lock.h>
+#include "aufs.h"
+
+static void au_br_do_free(struct au_branch *br)
+{
+       int i;
+       struct au_wbr *wbr;
+
+       AuTraceEnter();
+
+       if (br->br_xino.xi_file)
+               fput(br->br_xino.xi_file);
+       mutex_destroy(&br->br_xino.xi_nondir_mtx);
+       wbr = br->br_wbr;
+       if (wbr)
+               for (i = 0; i < AuBrWh_Last; i++)
+                       dput(wbr->wbr_wh[i]);
+       /* do not call au_br_nfs_lockdep_off() here */
+       if (br->br_mnt && !au_test_nfs(br->br_mnt->mnt_sb))
+               mntput(br->br_mnt);
+       else {
+               lockdep_off();
+               mntput(br->br_mnt);
+               lockdep_on();
+       }
+       AuDebugOn(au_br_count(br));
+       if (wbr) {
+               AuDebugOn(atomic_read(&wbr->wbr_wh_running));
+               au_rwsem_destroy(&wbr->wbr_wh_rwsem);
+       }
+       kfree(wbr);
+       kfree(br);
+}
+
+/*
+ * frees all branches
+ */
+void au_br_free(struct au_sbinfo *sbinfo)
+{
+       aufs_bindex_t bmax;
+       struct au_branch **br;
+
+       AuTraceEnter();
+       bmax = sbinfo->si_bend + 1;
+       br = sbinfo->si_branch;
+       while (bmax--)
+               au_br_do_free(*br++);
+}
+
+/*
+ * find the index of a branch which is specified by @br_id.
+ */
+int au_br_index(struct super_block *sb, aufs_bindex_t br_id)
+{
+       aufs_bindex_t bindex, bend;
+
+       AuTraceEnter();
+
+       bend = au_sbend(sb);
+       for (bindex = 0; bindex <= bend; bindex++)
+               if (au_sbr_id(sb, bindex) == br_id)
+                       return bindex;
+       return -1;
+}
+
+/*
+ * test if the @h_sb is real-readonly.
+ */
+int au_test_def_rr(struct super_block *h_sb)
+{
+       switch (h_sb->s_magic) {
+#ifdef CONFIG_AUFS_RR_SQUASHFS
+       case SQUASHFS_MAGIC_LZMA:
+       case SQUASHFS_MAGIC:
+       case SQUASHFS_MAGIC_LZMA_SWAP:
+       case SQUASHFS_MAGIC_SWAP:
+               return 1; /* real readonly */
+#endif
+
+#if defined(CONFIG_ISO9660_FS) || defined(CONFIG_ISO9660_FS_MODULE)
+       case ISOFS_SUPER_MAGIC:
+               return 1;
+#endif
+
+#if defined(CONFIG_CRAMFS) || defined(CONFIG_CRAMFS_MODULE)
+       case CRAMFS_MAGIC:
+               return 1;
+#endif
+
+#if defined(CONFIG_ROMFS_FS) || defined(CONFIG_ROMFS_FS_MODULE)
+       case ROMFS_MAGIC:
+               return 1;
+#endif
+
+       default:
+               return 0;
+       }
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * test if two hidden_dentries have overlapping branches.
+ */
+static int do_test_overlap(struct super_block *sb, struct dentry *h_d1,
+                          struct dentry *h_d2)
+{
+       struct dentry *d;
+
+       LKTRTrace("%.*s, %.*s\n", AuDLNPair(h_d1), AuDLNPair(h_d2));
+
+       d = au_test_subdir(h_d1, h_d2);
+       if (unlikely(d)) {
+               AuDbgDentry(h_d1);
+               AuDbgDentry(h_d2);
+       }
+       return !!d;
+}
+
+static int test_overlap_loopback(struct super_block *sb, struct dentry *h_d1,
+                                struct dentry *h_d2)
+{
+#if defined(CONFIG_BLK_DEV_LOOP) || defined(CONFIG_BLK_DEV_LOOP_MODULE)
+       struct inode *h_inode;
+       struct loop_device *l;
+
+       LKTRTrace("%.*s, %.*s\n", AuDLNPair(h_d1), AuDLNPair(h_d2));
+       AuDbgDentry(h_d1);
+       AuDbgDentry(h_d2);
+       AuDbgSb(h_d1->d_sb);
+       AuDbgSb(h_d2->d_sb);
+
+       h_inode = h_d1->d_inode;
+       if (MAJOR(h_inode->i_sb->s_dev) != LOOP_MAJOR)
+               return 0;
+
+       l = h_inode->i_sb->s_bdev->bd_disk->private_data;
+       h_d1 = l->lo_backing_file->f_dentry;
+       /* h_d1 can be local NFS. in this case aufs cannot detect the loop */
+       AuDbgDentry(h_d1);
+       AuDbgDentry(h_d2);
+       AuDbgSb(h_d1->d_sb);
+       AuDbgSb(h_d2->d_sb);
+       if (unlikely(h_d1->d_sb == sb))
+               return 1;
+       return do_test_overlap(sb, h_d1, h_d2);
+#else
+       return 0;
+#endif
+}
+
+static int test_overlap(struct super_block *sb, struct dentry *h_d1,
+                       struct dentry *h_d2)
+{
+       LKTRTrace("d1 %.*s, d2 %.*s\n", AuDLNPair(h_d1), AuDLNPair(h_d2));
+
+       if (unlikely(h_d1 == h_d2)) {
+               AuDbgDentry(h_d1);
+               AuDbgDentry(h_d2);
+               return 1;
+       }
+       return do_test_overlap(sb, h_d1, h_d2)
+               || do_test_overlap(sb, h_d2, h_d1)
+               || test_overlap_loopback(sb, h_d1, h_d2)
+               || test_overlap_loopback(sb, h_d2, h_d1);
+}
+
+/* ---------------------------------------------------------------------- */
+
+static int au_br_init_wh(struct super_block *sb, aufs_bindex_t bindex,
+                        struct au_branch *br, int new_perm,
+                        struct dentry *h_root, struct vfsmount *h_mnt)
+{
+       int err, old_perm;
+       struct inode *h_dir;
+       struct au_wbr *wbr;
+
+       LKTRTrace("b%d, new_perm %d\n", bindex, new_perm);
+       SiMustWriteLock(sb);
+
+       wbr = br->br_wbr;
+       h_dir = h_root->d_inode;
+       old_perm = br->br_perm;
+       mutex_lock_nested(&h_dir->i_mutex, AuLsc_I_PARENT);
+       if (wbr)
+               wbr_wh_write_lock(wbr);
+       br->br_perm = new_perm;
+       err = au_wh_init(h_root, br, h_mnt, sb, bindex);
+       br->br_perm = old_perm;
+       if (wbr)
+               wbr_wh_write_unlock(wbr);
+       mutex_unlock(&h_dir->i_mutex);
+       if (!err && wbr && !au_br_writable(new_perm)) {
+               AuDebugOn(wbr->wbr_whbase);
+               AuDebugOn(wbr->wbr_plink);
+               AuDebugOn(wbr->wbr_tmp);
+               kfree(wbr);
+               br->br_wbr = NULL;
+       }
+
+       AuTraceErr(err);
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * returns a newly allocated branch. @new_nbranch is a number of branches
+ * after adding a branch.
+ */
+static struct au_branch *alloc_addbr(struct super_block *sb, int new_nbranch,
+                                    int perm)
+{
+       struct au_branch **branchp, *add_branch;
+       int sz;
+       void *p;
+       struct dentry *root;
+       struct inode *inode;
+       struct au_hinode *hinodep;
+       struct au_hdentry *hdentryp;
+
+       LKTRTrace("new_nbranch %d\n", new_nbranch);
+       SiMustWriteLock(sb);
+       root = sb->s_root;
+       DiMustWriteLock(root);
+       inode = root->d_inode;
+       IiMustWriteLock(inode);
+
+       add_branch = kmalloc(sizeof(*add_branch), GFP_NOFS);
+       if (unlikely(!add_branch))
+               goto out;
+       add_branch->br_wbr = NULL;
+       if (au_br_writable(perm)) {
+               add_branch->br_wbr = kmalloc(sizeof(*add_branch->br_wbr),
+                                            GFP_NOFS);
+               if (unlikely(!add_branch->br_wbr))
+                       goto out_br;
+       }
+
+       sz = sizeof(*branchp) * (new_nbranch - 1);
+       if (unlikely(!sz))
+               sz = sizeof(*branchp);
+       p = au_sbi(sb)->si_branch;
+       branchp = au_kzrealloc(p, sz, sizeof(*branchp) * new_nbranch, GFP_NOFS);
+       if (unlikely(!branchp))
+               goto out_wbr;
+       au_sbi(sb)->si_branch = branchp;
+
+       sz = sizeof(*hdentryp) * (new_nbranch - 1);
+       if (unlikely(!sz))
+               sz = sizeof(*hdentryp);
+       p = au_di(root)->di_hdentry;
+       hdentryp = au_kzrealloc(p, sz, sizeof(*hdentryp) * new_nbranch,
+                               GFP_NOFS);
+       if (unlikely(!hdentryp))
+               goto out_wbr;
+       au_di(root)->di_hdentry = hdentryp;
+
+       sz = sizeof(*hinodep) * (new_nbranch - 1);
+       if (unlikely(!sz))
+               sz = sizeof(*hinodep);
+       p = au_ii(inode)->ii_hinode;
+       hinodep = au_kzrealloc(p, sz, sizeof(*hinodep) * new_nbranch, GFP_NOFS);
+       if (unlikely(!hinodep))
+               goto out_wbr;
+       au_ii(inode)->ii_hinode = hinodep;
+       return add_branch; /* success */
+
+ out_wbr:
+       kfree(add_branch->br_wbr);
+ out_br:
+       kfree(add_branch);
+ out:
+       AuTraceErr(-ENOMEM);
+       return ERR_PTR(-ENOMEM);
+}
+
+/*
+ * test if the branch permission is legal or not.
+ */
+static int test_br(struct super_block *sb, struct inode *inode, int brperm,
+                  char *path)
+{
+       int err;
+
+       err = 0;
+       if (unlikely(au_br_writable(brperm) && IS_RDONLY(inode))) {
+               AuErr("write permission for readonly fs or inode, %s\n", path);
+               err = -EINVAL;
+       }
+
+       AuTraceErr(err);
+       return err;
+}
+
+static int au_unsupported_fs(struct super_block *sb)
+{
+       return sb->s_magic == PROC_SUPER_MAGIC
+#ifdef SYSFS_MAGIC
+               || sb->s_magic == SYSFS_MAGIC
+#endif
+               || !strcmp(au_sbtype(sb), "unionfs");
+}
+
+/*
+ * returns:
+ * 0: success, the caller will add it
+ * plus: success, it is already unified, the caller should ignore it
+ * minus: error
+ */
+static int test_add(struct super_block *sb, struct au_opt_add *add, int remount)
+{
+       int err;
+       struct dentry *root;
+       struct inode *inode, *h_inode;
+       aufs_bindex_t bend, bindex;
+
+       LKTRTrace("%s, remo%d\n", add->path, remount);
+
+       root = sb->s_root;
+       bend = au_sbend(sb);
+       if (unlikely(bend >= 0
+                    && au_find_dbindex(root, add->nd.path.dentry) >= 0)) {
+               err = 1;
+               if (!remount) {
+                       err = -EINVAL;
+                       AuErr("%s duplicated\n", add->path);
+               }
+               goto out;
+       }
+
+       err = -ENOSPC; /* -E2BIG; */
+       if (unlikely(AUFS_BRANCH_MAX <= add->bindex
+                    || AUFS_BRANCH_MAX - 1 <= bend)) {
+               AuErr("number of branches exceeded %s\n", add->path);
+               goto out;
+       }
+
+       err = -EDOM;
+       if (unlikely(add->bindex < 0 || bend + 1 < add->bindex)) {
+               AuErr("bad index %d\n", add->bindex);
+               goto out;
+       }
+
+       inode = add->nd.path.dentry->d_inode;
+       AuDebugOn(!inode || !S_ISDIR(inode->i_mode));
+       err = -ENOENT;
+       if (unlikely(!inode->i_nlink)) {
+               AuErr("no existence %s\n", add->path);
+               goto out;
+       }
+
+       err = -EINVAL;
+       if (unlikely(inode->i_sb == sb)) {
+               AuErr("%s must be outside\n", add->path);
+               goto out;
+       }
+
+       if (unlikely(au_test_nested(inode->i_sb))) {
+               AuErr("nested " AUFS_NAME " %s\n", add->path);
+               goto out;
+       }
+
+       if (unlikely(au_unsupported_fs(inode->i_sb))) {
+               AuErr("unsupported filesystem, %s\n", add->path);
+               goto out;
+       }
+
+       if (unlikely(au_test_unsupported_nfs(inode->i_sb))) {
+               AuErr(AuNoNfsBranchMsg " %s\n", add->path);
+               goto out;
+       }
+
+       if (unlikely(au_test_unsupported_nfs4(inode->i_sb))) {
+               AuErr(AuNoNfsv4BranchMsg " %s\n", add->path);
+               goto out;
+       }
+
+       err = test_br(sb, add->nd.path.dentry->d_inode, add->perm, add->path);
+       if (unlikely(err))
+               goto out;
+
+       if (bend < 0)
+               return 0; /* success */
+
+       err = -EINVAL;
+       for (bindex = 0; bindex <= bend; bindex++)
+               if (unlikely(test_overlap(sb, add->nd.path.dentry,
+                                         au_h_dptr(root, bindex)))) {
+                       AuErr("%s is overlapped\n", add->path);
+                       goto out;
+               }
+
+       err = 0;
+       h_inode = au_h_dptr(root, 0)->d_inode;
+       if (unlikely(au_opt_test(au_mntflags(sb), WARN_PERM)
+                    && ((h_inode->i_mode & S_IALLUGO)
+                        != (inode->i_mode & S_IALLUGO)
+                        || h_inode->i_uid != inode->i_uid
+                        || h_inode->i_gid != inode->i_gid)))
+               AuWarn("uid/gid/perm %s %u/%u/0%o, %u/%u/0%o\n",
+                      add->path,
+                      inode->i_uid, inode->i_gid, (inode->i_mode & S_IALLUGO),
+                      h_inode->i_uid, h_inode->i_gid,
+                      (h_inode->i_mode & S_IALLUGO));
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+static int au_wbr_init(struct au_branch *br, struct super_block *sb,
+                      int perm, struct path *path)
+{
+       int err;
+       struct au_wbr *wbr;
+
+       AuTraceEnter();
+       wbr = br->br_wbr;
+       AuDebugOn(!wbr);
+
+       au_rw_init_nolock(&wbr->wbr_wh_rwsem);
+       memset(wbr->wbr_wh, 0, sizeof(wbr->wbr_wh));
+       atomic_set(&wbr->wbr_wh_running, 0);
+       wbr->wbr_bytes = 0;
+
+       err = au_br_init_wh(sb, /*bindex*/-1, br, perm,
+                           path->dentry, path->mnt);
+
+       AuTraceErr(err);
+       return err;
+}
+
+static int au_br_init(struct au_branch *br, struct super_block *sb,
+                     struct au_opt_add *add)
+{
+       int err;
+       unsigned int mnt_flags;
+
+       AuTraceEnter();
+
+       err = 0;
+       br->br_mnt = NULL;
+       br->br_xino.xi_file = NULL;
+       mutex_init(&br->br_xino.xi_nondir_mtx);
+       atomic_set(&br->br_xino_running, 0);
+       atomic_set(&br->br_count, 0);
+
+       if (au_br_writable(add->perm)) {
+               err = au_wbr_init(br, sb, add->perm, &add->nd.path);
+               if (unlikely(err))
+                       goto out;
+       }
+
+       br->br_mnt = mntget(add->nd.path.mnt);
+       mnt_flags = au_mntflags(sb);
+       if (au_opt_test(mnt_flags, XINO)) {
+               err = au_xino_br(sb, br, add->nd.path.dentry->d_inode->i_ino,
+                                au_sbr(sb, 0)->br_xino.xi_file, /*do_test*/1);
+               if (unlikely(err)) {
+                       AuDebugOn(br->br_xino.xi_file);
+                       goto out;
+               }
+#if 0 /* reserved for future use */
+       } else if (au_opt_test(mnt_flags, XINODIR)) {
+               err = au_xinodir_br(sb, br, add->nd.path.dentry->d_inode->i_ino,
+                                   /*do_test*/1);
+               if (unlikely(err)) {
+                       AuDebugOn(br->br_xino.xi_file);
+                       goto out;
+               }
+#endif
+       }
+
+       br->br_id = au_new_br_id(sb);
+       br->br_perm = add->perm;
+       br->br_xino_upper = AUFS_XINO_TRUNC_INIT;
+       sysaufs_br_init(br);
+       br->br_generation = au_sigen(sb);
+       /* smp_mb(); */ /* atomic_set */
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+int au_br_add(struct super_block *sb, struct au_opt_add *add, int remount)
+{
+       int err, amount;
+       aufs_bindex_t bend, add_bindex;
+       struct dentry *root, *dentry;
+       struct au_iinfo *iinfo;
+       struct au_sbinfo *sbinfo;
+       struct au_dinfo *dinfo;
+       struct inode *root_inode;
+       unsigned long long maxb;
+       struct au_branch **branchp, *add_branch;
+       struct au_hdentry *hdentryp;
+       struct au_hinode *hinodep;
+
+       dentry = add->nd.path.dentry;
+       LKTRTrace("b%d, %s, 0x%x, %.*s\n",
+                 add->bindex, add->path, add->perm, AuDLNPair(dentry));
+       SiMustWriteLock(sb);
+       root = sb->s_root;
+       DiMustWriteLock(root);
+       root_inode = root->d_inode;
+       IMustLock(root_inode);
+       IiMustWriteLock(root_inode);
+
+       err = test_add(sb, add, remount);
+       if (unlikely(err < 0))
+               goto out;
+       if (err) {
+               err = 0;
+               goto out; /* success */
+       }
+
+       bend = au_sbend(sb);
+       add_branch = alloc_addbr(sb, bend + 2, add->perm);
+       err = PTR_ERR(add_branch);
+       if (IS_ERR(add_branch))
+               goto out;
+       err = au_br_init(add_branch, sb, add);
+       if (unlikely(err)) {
+               au_br_do_free(add_branch);
+               goto out;
+       }
+
+       add_bindex = add->bindex;
+       if (remount)
+               sysaufs_brs_del(sb, add_bindex);
+
+       sbinfo = au_sbi(sb);
+       dinfo = au_di(root);
+       iinfo = au_ii(root_inode);
+
+       amount = bend + 1 - add_bindex;
+       branchp = sbinfo->si_branch + add_bindex;
+       memmove(branchp + 1, branchp, sizeof(*branchp) * amount);
+       *branchp = add_branch;
+       hdentryp = dinfo->di_hdentry + add_bindex;
+       memmove(hdentryp + 1, hdentryp, sizeof(*hdentryp) * amount);
+       au_h_dentry_init(hdentryp);
+       hinodep = iinfo->ii_hinode + add_bindex;
+       memmove(hinodep + 1, hinodep, sizeof(*hinodep) * amount);
+       hinodep->hi_inode = NULL;
+       au_hin_init(hinodep, NULL);
+
+       sbinfo->si_bend++;
+       dinfo->di_bend++;
+       iinfo->ii_bend++;
+       if (unlikely(bend < 0)) {
+               sbinfo->si_bend = 0;
+               dinfo->di_bstart = 0;
+               iinfo->ii_bstart = 0;
+       }
+       au_set_h_dptr(root, add_bindex, dget(dentry));
+       au_set_h_iptr(root_inode, add_bindex, au_igrab(dentry->d_inode), 0);
+       if (remount)
+               sysaufs_brs_add(sb, add_bindex);
+
+       if (!add_bindex)
+               au_cpup_attr_all(root_inode, /*force*/1);
+       else
+               au_add_nlink(root_inode, dentry->d_inode);
+       maxb = dentry->d_sb->s_maxbytes;
+       if (sb->s_maxbytes < maxb)
+               sb->s_maxbytes = maxb;
+
+       /* safe d_parent reference */
+       if (!au_xino_def_br(sbinfo)
+           && add_branch->br_xino.xi_file
+           && add_branch->br_xino.xi_file->f_dentry->d_parent == dentry)
+               au_xino_def_br_set(add_branch, sbinfo);
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+#define AuVerbose(do_info, fmt, args...) do { \
+       if (!do_info) \
+               LKTRTrace(fmt, ##args); \
+       else \
+               AuInfo(fmt, ##args); \
+} while (0)
+
+/*
+ * test if the branch is deletable or not.
+ */
+static int test_dentry_busy(struct dentry *root, aufs_bindex_t bindex,
+                           au_gen_t sigen)
+{
+       int err, i, j, ndentry;
+       struct au_dcsub_pages dpages;
+       struct au_dpage *dpage;
+       struct dentry *d;
+       aufs_bindex_t bstart, bend;
+       unsigned char verbose;
+       struct inode *inode;
+
+       LKTRTrace("b%d, gen%d\n", bindex, sigen);
+       SiMustWriteLock(root->d_sb);
+
+       err = au_dpages_init(&dpages, GFP_NOFS);
+       if (unlikely(err))
+               goto out;
+       err = au_dcsub_pages(&dpages, root, NULL, NULL);
+       if (unlikely(err))
+               goto out_dpages;
+
+       verbose = !!au_opt_test(au_mntflags(root->d_sb), VERBOSE);
+       for (i = 0; !err && i < dpages.ndpage; i++) {
+               dpage = dpages.dpages + i;
+               ndentry = dpage->ndentry;
+               for (j = 0; !err && j < ndentry; j++) {
+                       d = dpage->dentries[j];
+                       AuDebugOn(!atomic_read(&d->d_count));
+                       inode = d->d_inode;
+                       AuDebugOn(!inode);
+                       if (au_digen(d) == sigen
+                           && au_iigen(inode) == sigen)
+                               di_read_lock_child(d, AuLock_IR);
+                       else {
+                               di_write_lock_child(d);
+                               err = au_reval_dpath(d, sigen);
+                               if (!err)
+                                       di_downgrade_lock(d, AuLock_IR);
+                               else {
+                                       di_write_unlock(d);
+                                       break;
+                               }
+                       }
+
+                       bstart = au_dbstart(d);
+                       bend = au_dbend(d);
+                       if (bstart <= bindex
+                           && bindex <= bend
+                           && au_h_dptr(d, bindex)
+                           && (!S_ISDIR(d->d_inode->i_mode)
+                               || bstart == bend)) {
+                               err = -EBUSY;
+                               AuVerbose(verbose, "busy %.*s\n", AuDLNPair(d));
+                       }
+                       di_read_unlock(d, AuLock_IR);
+               }
+       }
+
+ out_dpages:
+       au_dpages_free(&dpages);
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+static int test_inode_busy(struct super_block *sb, aufs_bindex_t bindex,
+                          au_gen_t sigen)
+{
+       int err;
+       struct inode *i;
+       aufs_bindex_t bstart, bend;
+       unsigned char verbose;
+
+       LKTRTrace("b%d, gen%d\n", bindex, sigen);
+       SiMustWriteLock(sb);
+
+       err = 0;
+       verbose = !!au_opt_test(au_mntflags(sb), VERBOSE);
+       list_for_each_entry(i, &sb->s_inodes, i_sb_list) {
+               AuDebugOn(!atomic_read(&i->i_count));
+               if (!list_empty(&i->i_dentry))
+                       continue;
+
+               if (au_iigen(i) == sigen)
+                       ii_read_lock_child(i);
+               else {
+                       ii_write_lock_child(i);
+                       err = au_refresh_hinode_self(i);
+                       if (!err)
+                               ii_downgrade_lock(i);
+                       else {
+                               ii_write_unlock(i);
+                               break;
+                       }
+               }
+
+               bstart = au_ibstart(i);
+               bend = au_ibend(i);
+               if (bstart <= bindex
+                   && bindex <= bend
+                   && au_h_iptr(i, bindex)
+                   && (!S_ISDIR(i->i_mode) || bstart == bend)) {
+                       err = -EBUSY;
+                       AuVerbose(verbose, "busy i%lu\n", i->i_ino);
+                       ii_read_unlock(i);
+                       break;
+               }
+               ii_read_unlock(i);
+       }
+
+       AuTraceErr(err);
+       return err;
+}
+
+static int test_children_busy(struct dentry *root, aufs_bindex_t bindex)
+{
+       int err;
+       au_gen_t sigen;
+
+       LKTRTrace("b%d\n", bindex);
+       SiMustWriteLock(root->d_sb);
+       DiMustWriteLock(root);
+       /* dont trust BKL */
+       AuDebugOn(!kernel_locked());
+
+       sigen = au_sigen(root->d_sb);
+       DiMustNoWaiters(root);
+       IiMustNoWaiters(root->d_inode);
+       di_write_unlock(root);
+       err = test_dentry_busy(root, bindex, sigen);
+       if (!err)
+               err = test_inode_busy(root->d_sb, bindex, sigen);
+       di_write_lock_child(root); /* aufs_write_lock() calls ..._child() */
+
+       AuTraceErr(err);
+       return err;
+}
+
+int au_br_del(struct super_block *sb, struct au_opt_del *del, int remount)
+{
+       int err, rerr, i;
+       aufs_bindex_t bindex, bend, br_id;
+       unsigned char do_wh, verbose;
+       struct au_sbinfo *sbinfo;
+       struct au_dinfo *dinfo;
+       struct au_iinfo *iinfo;
+       struct au_branch *br, **brp;
+       struct au_wbr *wbr;
+       struct au_hdentry *hdp;
+       struct au_hinode *hip;
+
+       LKTRTrace("%s, %.*s\n", del->path, AuDLNPair(del->h_root));
+       SiMustWriteLock(sb);
+       DiMustWriteLock(sb->s_root);
+       IiMustWriteLock(sb->s_root->d_inode);
+
+       err = 0;
+       bindex = au_find_dbindex(sb->s_root, del->h_root);
+       if (bindex < 0) {
+               if (remount)
+                       goto out; /* success */
+               err = -ENOENT;
+               AuErr("%s no such branch\n", del->path);
+               goto out;
+       }
+       LKTRTrace("bindex b%d\n", bindex);
+
+       err = -EBUSY;
+       verbose = !!au_opt_test(au_mntflags(sb), VERBOSE);
+       bend = au_sbend(sb);
+       if (unlikely(!bend)) {
+               AuVerbose(verbose, "no more branches left\n");
+               goto out;
+       }
+       br = au_sbr(sb, bindex);
+       if (unlikely(au_br_count(br))) {
+               AuVerbose(verbose, "%d file(s) opened\n", au_br_count(br));
+               goto out;
+       }
+
+       wbr = br->br_wbr;
+       do_wh = wbr && (wbr->wbr_whbase || wbr->wbr_plink || wbr->wbr_tmp);
+       if (do_wh) {
+#if 0 /* reserved for future use */
+               /* remove whiteout base */
+               err = au_br_init_wh(sb, bindex, br, AuBr_RO, del->h_root,
+                                   br->br_mnt);
+               if (unlikely(err))
+                       goto out;
+#else
+               for (i = 0; i < AuBrWh_Last; i++) {
+                       dput(wbr->wbr_wh[i]);
+                       wbr->wbr_wh[i] = NULL;
+               }
+#endif
+       }
+
+       err = test_children_busy(sb->s_root, bindex);
+       if (unlikely(err)) {
+               if (do_wh)
+                       goto out_wh;
+               goto out;
+       }
+
+       err = 0;
+       if (remount)
+               sysaufs_brs_del(sb, bindex);
+       sbinfo = au_sbi(sb);
+       dinfo = au_di(sb->s_root);
+       iinfo = au_ii(sb->s_root->d_inode);
+
+       dput(au_h_dptr(sb->s_root, bindex));
+       au_hiput(iinfo->ii_hinode + bindex);
+       br_id = br->br_id;
+       au_br_do_free(br);
+
+       /* todo: realloc and shrink memory? */
+       if (bindex < bend) {
+               const aufs_bindex_t n = bend - bindex;
+
+               brp = sbinfo->si_branch + bindex;
+               memmove(brp, brp + 1, sizeof(*brp) * n);
+               hdp = dinfo->di_hdentry + bindex;
+               memmove(hdp, hdp + 1, sizeof(*hdp) * n);
+               hip = iinfo->ii_hinode + bindex;
+               memmove(hip, hip + 1, sizeof(*hip) * n);
+       }
+       sbinfo->si_branch[0 + bend] = NULL;
+       dinfo->di_hdentry[0 + bend].hd_dentry = NULL;
+       iinfo->ii_hinode[0 + bend].hi_inode = NULL;
+       au_hin_init(iinfo->ii_hinode + bend, NULL);
+
+       sbinfo->si_bend--;
+       dinfo->di_bend--;
+       iinfo->ii_bend--;
+       if (remount)
+               sysaufs_brs_add(sb, bindex);
+
+       if (!bindex)
+               au_cpup_attr_all(sb->s_root->d_inode, /*force*/1);
+       else
+               au_sub_nlink(sb->s_root->d_inode, del->h_root->d_inode);
+       if (au_opt_test(au_mntflags(sb), PLINK))
+               au_plink_half_refresh(sb, br_id);
+
+       if (sb->s_maxbytes == del->h_root->d_sb->s_maxbytes) {
+               bend--;
+               sb->s_maxbytes = 0;
+               for (bindex = 0; bindex <= bend; bindex++) {
+                       unsigned long long maxb;
+                       maxb = au_sbr_sb(sb, bindex)->s_maxbytes;
+                       if (sb->s_maxbytes < maxb)
+                               sb->s_maxbytes = maxb;
+               }
+       }
+
+       if (au_xino_def_br(sbinfo) == br)
+               au_xino_def_br_set(NULL, sbinfo);
+       goto out; /* success */
+
+ out_wh:
+       /* revert */
+       rerr = au_br_init_wh(sb, bindex, br, br->br_perm, del->h_root,
+                            br->br_mnt);
+       if (rerr)
+               AuWarn("failed re-creating base whiteout, %s. (%d)\n",
+                      del->path, rerr);
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+static int do_need_sigen_inc(int a, int b)
+{
+       return au_br_whable(a) && !au_br_whable(b);
+}
+
+static int need_sigen_inc(int old, int new)
+{
+       return do_need_sigen_inc(old, new)
+               || do_need_sigen_inc(new, old);
+}
+
+static int au_br_mod_files_ro(struct super_block *sb, aufs_bindex_t bindex)
+{
+       int err;
+       struct file *file, *hf;
+
+       AuTraceEnter();
+       SiMustWriteLock(sb);
+
+       /* no need file_list_lock() since sbinfo is locked */
+       err = 0;
+       list_for_each_entry(file, &sb->s_files, f_u.fu_list) {
+               LKTRTrace("%.*s\n", AuDLNPair(file->f_dentry));
+               if (!au_test_aufs_file(file))
+                       continue;
+
+               fi_read_lock(file);
+               if (!S_ISREG(file->f_dentry->d_inode->i_mode)
+                   || !(file->f_mode & FMODE_WRITE)
+                   || au_fbstart(file) != bindex) {
+                       FiMustNoWaiters(file);
+                       fi_read_unlock(file);
+                       continue;
+               }
+
+               if (unlikely(au_test_mmapped(file))) {
+                       err = -EBUSY;
+                       FiMustNoWaiters(file);
+                       fi_read_unlock(file);
+                       break;
+               }
+
+               /* todo: already flushed? */
+               hf = au_h_fptr(file, au_fbstart(file));
+               hf->f_flags = au_file_roflags(hf->f_flags);
+               hf->f_mode &= ~FMODE_WRITE;
+               put_write_access(hf->f_dentry->d_inode);
+               FiMustNoWaiters(file);
+               fi_read_unlock(file);
+       }
+
+       AuTraceErr(err);
+       return err;
+}
+
+int au_br_mod(struct super_block *sb, struct au_opt_mod *mod, int remount,
+             int *do_update)
+{
+       int err;
+       struct dentry *root;
+       aufs_bindex_t bindex;
+       struct au_branch *br;
+       struct inode *hidden_dir;
+
+       LKTRTrace("%s, %.*s, 0x%x\n",
+                 mod->path, AuDLNPair(mod->h_root), mod->perm);
+       SiMustWriteLock(sb);
+       root = sb->s_root;
+       DiMustWriteLock(root);
+       IiMustWriteLock(root->d_inode);
+
+       bindex = au_find_dbindex(root, mod->h_root);
+       if (bindex < 0) {
+               if (remount)
+                       return 0; /* success */
+               err = -ENOENT;
+               AuErr("%s no such branch\n", mod->path);
+               goto out;
+       }
+       LKTRTrace("bindex b%d\n", bindex);
+
+       hidden_dir = mod->h_root->d_inode;
+       err = test_br(sb, hidden_dir, mod->perm, mod->path);
+       if (unlikely(err))
+               goto out;
+
+       br = au_sbr(sb, bindex);
+       if (br->br_perm == mod->perm)
+               return 0; /* success */
+
+       if (au_br_writable(br->br_perm)) {
+#if 1
+               /* remove whiteout base */
+               err = au_br_init_wh(sb, bindex, br, mod->perm, mod->h_root,
+                                   br->br_mnt);
+               if (unlikely(err))
+                       goto out;
+#else /* reserved for future use */
+               struct au_wbr *wbr;
+               wbr = br->wbr;
+               if (wbr)
+                       for (i = 0; i < AuBrWh_Last; i++) {
+                               dput(wbr->wbr_wh[i]);
+                               wbr->wbr_wh[i] = NULL;
+                       }
+#endif
+
+               if (!au_br_writable(mod->perm)) {
+                       /* rw --> ro, file might be mmapped */
+
+#if 1 /* todo: test more? */
+                       DiMustNoWaiters(root);
+                       IiMustNoWaiters(root->d_inode);
+                       di_write_unlock(root);
+                       err = au_br_mod_files_ro(sb, bindex);
+                       /* aufs_write_lock() calls ..._child() */
+                       di_write_lock_child(root);
+#endif
+               }
+       } else if (au_br_writable(mod->perm)) {
+               /* ro --> rw */
+               err = -ENOMEM;
+               br->br_wbr = kmalloc(sizeof(*br->br_wbr), GFP_NOFS);
+               if (br->br_wbr) {
+                       struct path path = {
+                               .mnt    = br->br_mnt,
+                               .dentry = mod->h_root
+                       };
+
+                       err = au_wbr_init(br, sb, mod->perm, &path);
+                       if (unlikely(err)) {
+                               kfree(br->br_wbr);
+                               br->br_wbr = NULL;
+                       }
+               }
+       }
+
+       if (!err) {
+               *do_update |= need_sigen_inc(br->br_perm, mod->perm);
+               br->br_perm = mod->perm;
+       }
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
diff -urN linux/fs/aufs/branch.h linux-aufs/fs/aufs/branch.h
--- linux/fs/aufs/branch.h      1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/branch.h 2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,437 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * branch filesystems and xino for them
+ *
+ * $Id$
+ */
+
+#ifndef __AUFS_BRANCH_H__
+#define __AUFS_BRANCH_H__
+
+#ifdef __KERNEL__
+
+#include <linux/fs.h>
+#include <linux/mount.h>
+#include <linux/sysfs.h>
+#include <linux/aufs_type.h>
+#include "misc.h"
+#include "super.h"
+
+/* ---------------------------------------------------------------------- */
+
+/* an entry in a xino file */
+struct au_xino_entry {
+       ino_t ino;
+       /* __u32 h_gen; */ /* reserved for future use */
+} __packed;
+
+/* reserved for future use */
+/* #define AuXino_INVALID_HGEN (-1) */
+
+/* a xino file */
+struct au_xino_file {
+       struct file             *xi_file;
+       struct mutex            xi_nondir_mtx;
+
+       /* reserved for future use */
+#if 0
+       struct file             **xi_file;
+
+       /* array management */
+       unsigned long long      xi_limit;       /* Max xino file size */
+       unsigned long long      xi_size;         /* s_maxbytes */
+
+       /* truncation */
+       unsigned long long      xi_upper;       /* watermark in bytes */
+       unsigned long long      xi_step;        /* to next watermark in bytes */
+
+       /* truncation */
+       blkcnt_t                xi_upper;       /* watermark in blocks */
+       atomic_t                xi_running;
+#endif
+};
+
+/* members for writable branch only */
+enum {AuBrWh_BASE, AuBrWh_PLINK, AuBrWh_TMP, AuBrWh_Last};
+struct au_wbr {
+       struct au_rwsem         wbr_wh_rwsem;
+       struct dentry           *wbr_wh[AuBrWh_Last];
+       atomic_t                wbr_wh_running;
+#define wbr_whbase             wbr_wh[AuBrWh_BASE]     /* whiteout base */
+#define wbr_plink              wbr_wh[AuBrWh_PLINK]    /* pseudo-link dir */
+#define wbr_tmp                        wbr_wh[AuBrWh_TMP]      /* temporary dir */
+
+       /* mfs mode */
+       unsigned long long      wbr_bytes;
+};
+
+/* protected by superblock rwsem */
+struct au_branch {
+       struct au_xino_file     br_xino;
+
+       aufs_bindex_t           br_id;
+
+       int                     br_perm;
+       struct vfsmount         *br_mnt;
+       atomic_t                br_count;
+
+       struct au_wbr           *br_wbr;
+
+#if 1 /* reserved for future use */
+       /* xino truncation */
+       blkcnt_t                br_xino_upper;  /* watermark in blocks */
+       atomic_t                br_xino_running;
+#endif
+
+#ifdef CONFIG_SYSFS
+       /* an entry under sysfs per mount-point */
+       char                    br_name[8];
+       struct attribute        br_attr;
+#endif
+
+       au_gen_t                br_generation;
+};
+
+/* ---------------------------------------------------------------------- */
+
+/* branch permission and attribute */
+enum {
+       AuBrPerm_RW,            /* writable, linkable wh */
+       AuBrPerm_RO,            /* readonly, no wh */
+       AuBrPerm_RR,            /* natively readonly, no wh */
+
+       AuBrPerm_RWNoLinkWH,    /* un-linkable whiteouts */
+
+       AuBrPerm_ROWH,
+       AuBrPerm_RRWH,          /* whiteout-able */
+
+       AuBrPerm_Last
+};
+
+static inline int au_br_writable(int brperm)
+{
+       return brperm == AuBrPerm_RW || brperm == AuBrPerm_RWNoLinkWH;
+}
+
+static inline int au_br_whable(int brperm)
+{
+       return brperm == AuBrPerm_RW
+               || brperm == AuBrPerm_ROWH
+               || brperm == AuBrPerm_RRWH;
+}
+
+#if 0 /* reserved for future use */
+static inline int au_br_linkable_wh(int brperm)
+{
+       return brperm == AuBrPerm_RW;
+}
+#endif
+
+static inline int au_br_hinotifyable(int brperm)
+{
+#ifdef CONFIG_AUFS_HINOTIFY
+       return brperm != AuBrPerm_RR && brperm != AuBrPerm_RRWH;
+#else
+       return 0;
+#endif
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* branch.c */
+struct au_sbinfo;
+void au_br_free(struct au_sbinfo *sinfo);
+int au_test_def_rr(struct super_block *h_sb);
+int au_br_index(struct super_block *sb, aufs_bindex_t br_id);
+struct au_opt_add;
+int au_br_add(struct super_block *sb, struct au_opt_add *add, int remount);
+struct au_opt_del;
+int au_br_del(struct super_block *sb, struct au_opt_del *del, int remount);
+struct au_opt_mod;
+int au_br_mod(struct super_block *sb, struct au_opt_mod *mod, int remount,
+             int *do_update);
+
+/* xino.c */
+#define Au_LOFF_MAX    ((loff_t)LLONG_MAX)
+int au_xib_trunc(struct super_block *sb);
+ssize_t xino_fread(au_readf_t func, struct file *file, void *buf, size_t size,
+                  loff_t *pos);
+ssize_t xino_fwrite(au_writef_t func, struct file *file, void *buf, size_t size,
+                   loff_t *pos);
+struct file *au_xino_create(struct super_block *sb, char *fname, int silent);
+struct file *au_xino_create2(struct super_block *sb, struct file *base_file,
+                            struct file *copy_src);
+ino_t au_xino_new_ino(struct super_block *sb);
+int au_xino_write0(struct super_block *sb, aufs_bindex_t bindex, ino_t h_ino,
+                  ino_t ino);
+int au_xino_write(struct super_block *sb, aufs_bindex_t bindex, ino_t h_ino,
+                 struct au_xino_entry *xinoe);
+int au_xino_read(struct super_block *sb, aufs_bindex_t bindex, ino_t h_ino,
+                struct au_xino_entry *xinoe);
+int au_xino_br(struct super_block *sb, struct au_branch *br, ino_t hino,
+              struct file *base_file, int do_test);
+int au_xino_trunc(struct super_block *sb, aufs_bindex_t bindex);
+
+struct au_opt_xino;
+int au_xino_set(struct super_block *sb, struct au_opt_xino *xino, int remount);
+void au_xino_clr(struct super_block *sb);
+struct file *au_xino_def(struct super_block *sb);
+
+struct au_opt_xinodir;
+#if 0 /* def CONFIG_AUFS_EXPORT */ /* reserved for future use */
+/* export.c */
+int au_xinodir_br(struct super_block *sb, struct au_branch *br, ino_t hino,
+                 int do_test);
+int au_xinodir_set(struct super_block *sb, struct au_opt_xinodir *xinodir,
+                  int remount);
+#else
+static inline
+int au_xinodir_br(struct super_block *sb, struct au_branch *br, ino_t hino,
+                 int do_test)
+{
+       return 0;
+}
+
+static inline
+int au_xinodir_set(struct super_block *sb, struct au_opt_xinodir *xinodir,
+                  int remount)
+{
+       return 0;
+}
+#endif
+
+/* ---------------------------------------------------------------------- */
+
+/* todo: memory barrier? */
+static inline int au_br_count(struct au_branch *br)
+{
+       return atomic_read(&br->br_count);
+}
+
+static inline int au_br_get(struct au_branch *br)
+{
+       return atomic_inc_return(&br->br_count);
+}
+
+static inline int au_br_put(struct au_branch *br)
+{
+       return atomic_dec_return(&br->br_count);
+}
+
+static inline au_gen_t au_br_gen(struct au_branch *br)
+{
+       return br->br_generation;
+}
+
+/*
+ * test if the @br is readonly or not.
+ */
+static inline int au_br_rdonly(struct au_branch *br)
+{
+       return ((br->br_mnt->mnt_sb->s_flags & MS_RDONLY)
+               || !au_br_writable(br->br_perm))
+               ? -EROFS : 0;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* Superblock to branch */
+static inline
+aufs_bindex_t au_sbr_id(struct super_block *sb, aufs_bindex_t bindex)
+{
+       return au_sbr(sb, bindex)->br_id;
+}
+
+static inline
+struct vfsmount *au_sbr_mnt(struct super_block *sb, aufs_bindex_t bindex)
+{
+       return au_sbr(sb, bindex)->br_mnt;
+}
+
+static inline
+struct super_block *au_sbr_sb(struct super_block *sb, aufs_bindex_t bindex)
+{
+       return au_sbr_mnt(sb, bindex)->mnt_sb;
+}
+
+#if 0 /* reserved for future use */
+static inline int au_sbr_count(struct super_block *sb, aufs_bindex_t bindex)
+{
+       return au_br_count(au_sbr(sb, bindex));
+}
+
+static inline void au_sbr_get(struct super_block *sb, aufs_bindex_t bindex)
+{
+       au_br_get(au_sbr(sb, bindex));
+}
+#endif
+
+static inline void au_sbr_put(struct super_block *sb, aufs_bindex_t bindex)
+{
+       au_br_put(au_sbr(sb, bindex));
+}
+
+static inline int au_sbr_perm(struct super_block *sb, aufs_bindex_t bindex)
+{
+       return au_sbr(sb, bindex)->br_perm;
+}
+
+static inline int au_sbr_whable(struct super_block *sb, aufs_bindex_t bindex)
+{
+       return au_br_whable(au_sbr_perm(sb, bindex));
+}
+
+static inline int au_br_want_write(struct au_branch *br)
+{
+       int err;
+
+       AuDebugOn(!au_br_writable(br->br_perm));
+       err = au_mnt_want_write(br->br_mnt);
+       AuTraceErr(err);
+       return err;
+}
+
+static inline void au_br_drop_write(struct au_branch *br)
+{
+       AuDebugOn(!au_br_writable(br->br_perm));
+       au_mnt_drop_write(br->br_mnt);
+}
+
+static inline int au_test_trunc_xino(struct super_block *sb)
+{
+       return au_test_tmpfs(sb);
+}
+
+/* temporary support for i#1 in cramfs */
+static inline int au_test_unique_ino(struct dentry *h_dentry, ino_t h_ino)
+{
+#if defined(CONFIG_CRAMFS) || defined(CONFIG_CRAMFS_MODULE)
+       if (unlikely(h_dentry->d_sb->s_magic == CRAMFS_MAGIC))
+               return h_ino != 1;
+#endif
+       return 1;
+}
+
+static inline struct vfsmount *au_do_nfsmnt(struct vfsmount *h_mnt)
+{
+       if (!au_test_nfs(h_mnt->mnt_sb)
+           && !au_test_ecryptfs(h_mnt->mnt_sb))
+               return NULL;
+       return h_mnt;
+}
+
+static inline void au_br_nfs_lockdep_off(struct super_block *sb)
+{
+       if (au_test_nfs(sb))
+               lockdep_off();
+}
+
+static inline void au_br_nfs_lockdep_on(struct super_block *sb)
+{
+       /* hoping this condition will be optimized... */
+       if (au_test_nfs(sb))
+               lockdep_on();
+}
+
+#ifdef CONFIG_AUFS_BR_NFS
+static inline int au_test_unsupported_nfs(struct super_block *h_sb)
+{
+       return 0;
+}
+
+/* it doesn't mntget() */
+static inline
+struct vfsmount *au_nfsmnt(struct super_block *sb, aufs_bindex_t bindex)
+{
+       return au_do_nfsmnt(au_sbr_mnt(sb, bindex));
+}
+
+#define AuNoNfsBranchMsg "dummy"
+
+#else
+static inline int au_test_unsupported_nfs(struct super_block *h_sb)
+{
+       return h_sb->s_magic == NFS_SUPER_MAGIC;
+}
+
+/* it doesn't mntget() */
+static inline
+struct vfsmount *au_nfsmnt(struct super_block *sb, aufs_bindex_t bindex)
+{
+       return NULL;
+}
+
+#define AuNoNfsBranchMsg "NFS branch is not supported" \
+       ", try some configurations and patches included in aufs source CVS."
+
+#endif /* CONFIG_AUFS_BR_NFS */
+
+#ifdef CONFIG_AUFS_BR_NFS_V4
+static inline int au_test_unsupported_nfs4(struct super_block *h_sb)
+{
+       return 0;
+}
+
+#define AuNoNfsv4BranchMsg "dummy"
+
+#else
+static inline int au_test_unsupported_nfs4(struct super_block *h_sb)
+{
+       return h_sb->s_magic == NFS_SUPER_MAGIC
+               && !strcmp(h_sb->s_type->name, "nfs4");
+}
+
+#define AuNoNfsv4BranchMsg "NFSv4 branch is not supported" \
+       ", try some configurations and patches included in aufs source CVS."
+
+#endif /* CONFIG_AUFS_BR_NFS_v4 */
+
+/* support atomic open */
+static inline int au_test_fs_intent(struct super_block *h_sb)
+{
+       return au_test_nfs4(h_sb) /*|| au_test_fuse(h_sb)*/;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * br_wh_read_lock, br_wh_write_lock
+ * br_wh_read_unlock, br_wh_write_unlock, br_wh_downgrade_lock
+ */
+AuSimpleRwsemFuncs(wbr_wh, struct au_wbr *wbr, wbr->wbr_wh_rwsem);
+
+/* to debug easier, do not make them inlined functions */
+#define WbrWhMustReadLock(wbr) do { \
+       /* SiMustAnyLock(sb); */ \
+       AuRwMustReadLock(&(wbr)->wbr_wh_rwsem); \
+} while (0)
+
+#define WbrWhMustWriteLock(wbr) do { \
+       /* SiMustAnyLock(sb); */ \
+       AuRwMustWriteLock(&(wbr)->wbr_wh_rwsem); \
+} while (0)
+
+#define WbrWhMustAnyLock(br) do { \
+       /* SiMustAnyLock(sb); */ \
+       AuRwMustAnyLock(&(wbr)->wbr_wh_rwsem); \
+} while (0)
+
+#endif /* __KERNEL__ */
+#endif /* __AUFS_BRANCH_H__ */
diff -urN linux/fs/aufs/br_fuse.c linux-aufs/fs/aufs/br_fuse.c
--- linux/fs/aufs/br_fuse.c     1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/br_fuse.c        2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,80 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * special handling for inode attributes on FUSE branch
+ *
+ * $Id$
+ */
+
+#include "aufs.h"
+
+/* h_mnt can be NULL, is it safe? */
+int au_update_fuse_h_inode(struct vfsmount *h_mnt, struct dentry *h_dentry)
+{
+       int err;
+       struct kstat st;
+
+       LKTRTrace("%.*s\n", AuDLNPair(h_dentry));
+
+       err = 0;
+       if (h_dentry->d_inode
+           /* && atomic_read(&h_dentry->d_inode->i_count) */
+           && au_test_fuse(h_dentry->d_sb)) {
+               err = vfsub_getattr(h_mnt, h_dentry, &st, /*dlgt*/0);
+               if (unlikely(err)) {
+                       AuDbg("err %d\n", err);
+                       au_debug_on();
+                       AuDbgDentry(h_dentry);
+                       au_debug_off();
+                       WARN_ON(err);
+               }
+       }
+       return err;
+}
+
+#if 0 /* temp */
+/*
+ * This function was born after a discussion with the FUSE developer.
+ * The inode attributes on a filesystem who defines i_op->getattr()
+ * is unreliable since such fs may not maintain the attributes at lookup.
+ * This function doesn't want the result of stat, instead wants the side-effect
+ * which refreshes the attributes.
+ * Hmm, there seems to be no such filesystem except fuse.
+ */
+int vfsub_i_attr(struct vfsmount *mnt, struct dentry *dentry, int dlgt)
+{
+       int err;
+       struct inode *inode;
+       struct inode_operations *op;
+       struct kstat st;
+
+       inode = dentry->d_inode;
+       AuDebugOn(!inode);
+
+       err = 0;
+       op = inode->i_op;
+       if (op && op->getattr && !au_test_aufs(dentry->d_sb)) {
+               err = security_inode_getattr(mnt, dentry);
+               if (!err)
+                       err = op->getattr(mnt, dentry, &st);
+       }
+       AuTraceErr(err);
+       return err;
+}
+#endif
diff -urN linux/fs/aufs/br_nfs.c linux-aufs/fs/aufs/br_nfs.c
--- linux/fs/aufs/br_nfs.c      1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/br_nfs.c 2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,356 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * lookup functions for NFS branch in linux-2.6.19 and later
+ *
+ * $Id$
+ */
+
+#include "aufs.h"
+
+static struct file *au_find_h_intent(struct au_hdentry *hd, struct file *file)
+{
+       struct file *h_file, *hf;
+       struct au_hdintent *hdi, *tmp, *do_free;
+
+       LKTRTrace("%.*s\n", AuDLNPair(hd->hd_dentry));
+
+       h_file = NULL;
+       do_free = NULL;
+       spin_lock(&hd->hd_lock);
+       list_for_each_entry_safe(hdi, tmp, hd->hd_intent_list, hdi_list) {
+               hf = hdi->hdi_file[AuIntent_BRANCH];
+               if (hdi->hdi_file[AuIntent_AUFS] == file
+                   && hf->f_dentry == hd->hd_dentry) {
+                       h_file = hf;
+                       do_free = hdi;
+                       list_del(&hdi->hdi_list);
+                       break;
+               }
+       }
+       spin_unlock(&hd->hd_lock);
+       kfree(do_free);
+
+       return h_file;
+}
+
+struct file *au_h_intent(struct dentry *dentry, aufs_bindex_t bindex,
+                        struct file *file)
+{
+       struct file *h_file;
+       struct au_hdentry *hd = au_di(dentry)->di_hdentry + bindex;
+
+       LKTRTrace("%.*s, b%d, f %p\n", AuDLNPair(dentry), bindex, file);
+       DiMustAnyLock(dentry);
+       AuDebugOn(bindex < au_di(dentry)->di_bstart
+                 || bindex > au_di(dentry)->di_bend);
+
+       h_file = NULL;
+       if (!hd->hd_intent_list || !file)
+               return h_file; /* success */
+
+       /* AuDebugOn(au_test_wkq(current)); */
+       h_file = au_find_h_intent(hd, file);
+       return h_file;
+}
+
+static int au_set_h_intent(struct dentry *dentry, aufs_bindex_t bindex,
+                          struct file *file, struct file *h_file)
+{
+       int err;
+       struct au_hdentry *hd = au_di(dentry)->di_hdentry + bindex;
+       struct au_hdintent *hdi;
+       struct file *hf;
+
+       LKTRTrace("%.*s, b%d, f %p\n", AuDLNPair(dentry), bindex, file);
+       /* d_revalidate() holds read_lock */
+       /* DiMustWriteLock(dentry); */
+       AuDebugOn(bindex < au_di(dentry)->di_bstart
+                 || bindex > au_di(dentry)->di_bend
+                 || !file
+                 || !h_file
+                 /* || au_test_wkq(current) */);
+
+       err = -ENOMEM;
+       if (hd->hd_intent_list) {
+               while (1) {
+                       hf = au_find_h_intent(hd, file);
+                       if (!hf)
+                               break;
+                       fput(hf);
+                       AuWarn("freed hfile %.*s b%d left\n",
+                              AuDLNPair(dentry), bindex);
+               }
+       } else {
+               spin_lock(&hd->hd_lock);
+               if (!hd->hd_intent_list) {
+                       hd->hd_intent_list
+                               = kmalloc(sizeof(*hd->hd_intent_list),
+                                         GFP_ATOMIC);
+                       if (unlikely(!hd->hd_intent_list)) {
+                               spin_unlock(&hd->hd_lock);
+                               goto out;
+                       }
+                       INIT_LIST_HEAD(hd->hd_intent_list);
+               }
+               spin_unlock(&hd->hd_lock);
+       }
+
+       hdi = kmalloc(sizeof(*hdi), GFP_NOFS);
+       if (unlikely(!hdi))
+               goto out;
+
+       err = 0;
+       /* hdi->hdi_pid = current->pid; */
+       hdi->hdi_file[AuIntent_AUFS] = file;
+       hdi->hdi_file[AuIntent_BRANCH] = h_file;
+       spin_lock(&hd->hd_lock);
+       list_add(&hdi->hdi_list, hd->hd_intent_list);
+       spin_unlock(&hd->hd_lock);
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+int au_br_nfs_h_intent(struct file *nd_file, struct dentry *dentry,
+                      aufs_bindex_t bindex, struct nameidata *nd)
+{
+       int err;
+
+       AuTraceEnter();
+
+       err = 0;
+       if (!nd_file)
+               goto out;
+
+       AuDebugOn(!nd);
+       err = au_set_h_intent(dentry, bindex, nd->intent.open.file, nd_file);
+       if (unlikely(err)) {
+               fput(nd_file);
+               au_set_h_dptr(dentry, bindex, NULL);
+               /* todo: update bstart and bend? */
+       }
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+void au_hintent_put(struct au_hdentry *hd, int do_free)
+{
+       struct au_hdintent *hdi, *tmp;
+       struct file *hf;
+
+       if (hd->hd_intent_list) {
+               /* no spin lock */
+               list_for_each_entry_safe(hdi, tmp, hd->hd_intent_list,
+                                        hdi_list) {
+                       LKTRTrace("hdi %p\n", hdi);
+                       hf = hdi->hdi_file[AuIntent_BRANCH];
+                       if (hf)
+                               fput(hf);
+                       /* list_del(&hdi->hdi_list); */
+                       kfree(hdi);
+               }
+               if (do_free)
+                       kfree(hd->hd_intent_list);
+       }
+}
+
+/* ---------------------------------------------------------------------- */
+
+int au_fake_intent(/* struct au_ndsub *save,  */struct nameidata *nd,
+                  struct au_branch *br)
+{
+       int err;
+
+       LKTRTrace("perm %d\n", br->br_perm);
+
+       err = 0;
+       nd->intent.open.file = NULL;
+       if (nd->flags & LOOKUP_OPEN) {
+               if (au_test_fs_intent(br->br_mnt->mnt_sb)) {
+                       err = -ENFILE;
+                       nd->intent.open.file = get_empty_filp();
+                       if (unlikely(!nd->intent.open.file))
+                               goto out;
+                       err = 0;
+               }
+               if (!au_br_writable(br->br_perm)) {
+                       nd->intent.open.flags = FMODE_READ
+                               | au_file_roflags(nd->intent.open.flags);
+                       nd->flags &= ~LOOKUP_CREATE;
+               }
+       }
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+static void au_put_filp(struct file *file)
+{
+#if !defined(CONFIG_AUFS_MODULE) || defined(CONFIG_AUFS_PUT_FILP_PATCH)
+       if (unlikely(file))
+               put_filp(file);
+#else
+       WARN_ONCE(file, "unexpected put_fillp() call");
+#endif
+}
+
+int au_hin_after_reval(struct nameidata *nd, struct dentry *dentry,
+                      aufs_bindex_t bindex, struct file *file)
+{
+       int err;
+
+       LKTRTrace("nd %p, %.*s, b%d, f %d\n",
+                 nd, AuDLNPair(dentry), bindex, !!file);
+
+       err = 0;
+       if ((nd->flags & LOOKUP_OPEN)
+           && nd->intent.open.file
+           && !IS_ERR(nd->intent.open.file)) {
+               if (nd->intent.open.file->f_dentry) {
+                       err = au_set_h_intent(dentry, bindex, file,
+                                             nd->intent.open.file);
+                       if (!err)
+                               nd->intent.open.file = NULL;
+               }
+               au_put_filp(nd->intent.open.file);
+       }
+
+       return err;
+}
+
+#ifdef CONFIG_AUFS_DLGT
+struct au_lookup_hash_args {
+       struct dentry **errp;
+       struct qstr *name;
+       struct dentry *base;
+       struct nameidata *nd;
+};
+
+static void au_call_lookup_hash(void *args)
+{
+       struct au_lookup_hash_args *a = args;
+       *a->errp = vfsub__lookup_hash(a->name, a->base, a->nd);
+}
+
+static struct dentry *
+au_lkup_hash_dlgt(struct qstr *this, struct dentry *parent,
+                 struct nameidata *nd, unsigned int flags)
+{
+       struct dentry *dentry;
+       int dirperm1;
+
+       dirperm1 = au_ftest_ndx(flags, DIRPERM1);
+       if (!dirperm1 && !au_ftest_ndx(flags, DLGT))
+               dentry = vfsub__lookup_hash(this, parent, nd);
+       else {
+               int wkq_err;
+               struct au_lookup_hash_args args = {
+                       .errp   = &dentry,
+                       .name   = this,
+                       .base   = parent,
+                       .nd     = nd
+               };
+               wkq_err = au_wkq_wait(au_call_lookup_hash, &args,
+                                     /*dlgt*/!dirperm1);
+               if (unlikely(wkq_err))
+                       dentry = ERR_PTR(wkq_err);
+       }
+
+       AuTraceErrPtr(dentry);
+       return dentry;
+}
+#else
+static struct dentry *
+au_lkup_hash_dlgt(struct qstr *this, struct dentry *parent,
+                 struct nameidata *nd, unsigned int flags)
+{
+       return vfsub__lookup_hash(this, parent, nd);
+}
+#endif /* CONFIG_AUFS_DLGT */
+
+struct dentry *au_lkup_hash(const char *name, struct dentry *parent,
+                           int len, struct au_ndx *ndx)
+{
+       struct dentry *dentry;
+       char *p;
+       unsigned long hash;
+       struct qstr this;
+       unsigned int c;
+       struct nameidata tmp_nd, *ndo;
+       int err;
+
+       LKTRTrace("%.*s/%.*s\n", AuDLNPair(parent), len, name);
+
+       /* todo: export and call __lookup_one_len() in fs/namei.c? */
+       dentry = ERR_PTR(-EACCES);
+       this.name = name;
+       this.len = len;
+       if (unlikely(!len))
+               goto out;
+
+       p = (void *)name;
+       hash = init_name_hash();
+       while (len--) {
+               c = *p++;
+               if (unlikely(c == '/' || c == '\0'))
+                       goto out;
+               hash = partial_name_hash(c, hash);
+       }
+       this.hash = end_name_hash(hash);
+
+       ndo = ndx->nd;
+       if (ndo) {
+               tmp_nd = *ndo;
+               err = au_fake_intent(&tmp_nd, ndx->br);
+               dentry = ERR_PTR(err);
+               if (unlikely(err))
+                       goto out_intent;
+       } else
+               memset(&tmp_nd, 0, sizeof(tmp_nd));
+
+       tmp_nd.path.dentry = parent;
+       tmp_nd.path.mnt = ndx->nfsmnt;
+       path_get(&tmp_nd.path);
+       dentry = au_lkup_hash_dlgt(&this, parent, &tmp_nd, ndx->flags);
+       if (!IS_ERR(dentry)) {
+               /* why negative dentry for a new dir was unhashed? */
+               if (unlikely(d_unhashed(dentry)))
+                       d_rehash(dentry);
+               if (tmp_nd.intent.open.file
+                   && tmp_nd.intent.open.file->f_dentry) {
+                       ndx->nd_file = tmp_nd.intent.open.file;
+                       tmp_nd.intent.open.file = NULL;
+                       /* au_br_get(ndx->br); */
+               }
+       }
+       path_put(&tmp_nd.path);
+
+ out_intent:
+       au_put_filp(tmp_nd.intent.open.file);
+ out:
+       AuTraceErrPtr(dentry);
+       return dentry;
+}
diff -urN linux/fs/aufs/br_xfs.c linux-aufs/fs/aufs/br_xfs.c
--- linux/fs/aufs/br_xfs.c      1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/br_xfs.c 2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,69 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * special handling inode attributes on XFS branch in linux-2.6.24 and later
+ *
+ * $Id$
+ */
+
+#include "aufs.h"
+
+/* h_mnt can be NULL, is it safe? */
+dev_t au_h_rdev(struct inode *h_inode, struct vfsmount *h_mnt,
+               struct dentry *h_dentry)
+{
+       dev_t rdev;
+       int err;
+       struct kstat st;
+
+       LKTRTrace("hi%lu\n", h_inode->i_ino);
+       if (h_dentry)
+               LKTRTrace("%.*s\n", AuDLNPair(h_dentry));
+
+       rdev = h_inode->i_rdev;
+       if (!rdev || !au_test_xfs(h_inode->i_sb))
+               goto out;
+
+       rdev = 0;
+       if (!h_dentry) {
+               err = 0;
+               h_dentry = d_find_alias(h_inode);
+               if (unlikely(!h_dentry))
+                       goto failure;
+               err = PTR_ERR(h_dentry);
+               if (IS_ERR(h_dentry)) {
+                       h_dentry = NULL;
+                       goto failure;
+               }
+               LKTRTrace("%.*s\n", AuDLNPair(h_dentry));
+       } else
+               dget(h_dentry);
+
+       err = vfsub_getattr(h_mnt, h_dentry, &st, /*dlgt*/0);
+       dput(h_dentry);
+       if (!err) {
+               rdev = st.rdev;
+               goto out; /* success */
+       }
+
+ failure:
+       AuIOErr("failed rdev for XFS inode, hi%lu, %d\n", h_inode->i_ino, err);
+ out:
+       return rdev;
+}
diff -urN linux/fs/aufs/cpup.c linux-aufs/fs/aufs/cpup.c
--- linux/fs/aufs/cpup.c        1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/cpup.c   2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,1132 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * copy-up functions, see wbr_policy.c for copy-down
+ *
+ * $Id$
+ */
+
+#include <linux/fs_stack.h>
+#include <linux/uaccess.h>
+#include "aufs.h"
+
+/* todo? violent cpup_attr_*() functions don't care inode lock */
+
+void au_cpup_attr_timesizes(struct inode *inode)
+{
+       struct inode *h_inode;
+
+       LKTRTrace("i%lu\n", inode->i_ino);
+       /* todo? IMustLock(inode); */
+       h_inode = au_h_iptr(inode, au_ibstart(inode));
+       AuDebugOn(!h_inode);
+       /* todo? IMustLock(!h_inode); */
+
+       fsstack_copy_attr_times(inode, h_inode);
+       vfsub_copy_inode_size(inode, h_inode);
+}
+
+void au_cpup_attr_nlink(struct inode *inode, int force)
+{
+       struct inode *h_inode;
+       struct super_block *sb;
+       aufs_bindex_t bindex, bend;
+
+       LKTRTrace("i%lu\n", inode->i_ino);
+       /* todo? IMustLock(inode); */
+       AuDebugOn(!inode->i_mode);
+
+       sb = inode->i_sb;
+       bindex = au_ibstart(inode);
+       h_inode = au_h_iptr(inode, bindex);
+
+       if (!force
+           && !S_ISDIR(h_inode->i_mode)
+           && au_opt_test(au_mntflags(sb), PLINK)
+           && au_plink_test(sb, inode))
+               return;
+
+       inode->i_nlink = h_inode->i_nlink;
+
+       /*
+        * fewer nlink makes find(1) noisy, but larger nlink doesn't.
+        * it may includes whplink directory.
+        */
+       if (S_ISDIR(h_inode->i_mode)) {
+               bend = au_ibend(inode);
+               for (bindex++; bindex <= bend; bindex++) {
+                       h_inode = au_h_iptr(inode, bindex);
+                       if (h_inode)
+                               au_add_nlink(inode, h_inode);
+               }
+       }
+}
+
+void au_cpup_attr_changeable(struct inode *inode)
+{
+       struct inode *h_inode;
+
+       LKTRTrace("i%lu\n", inode->i_ino);
+       /* todo? IMustLock(inode); */
+       h_inode = au_h_iptr(inode, au_ibstart(inode));
+       AuDebugOn(!h_inode);
+
+       inode->i_mode = h_inode->i_mode;
+       inode->i_uid = h_inode->i_uid;
+       inode->i_gid = h_inode->i_gid;
+       au_cpup_attr_timesizes(inode);
+       au_cpup_attr_flags(inode, h_inode);
+}
+
+void au_cpup_igen(struct inode *inode, struct inode *h_inode)
+{
+       struct au_iinfo *iinfo = au_ii(inode);
+       iinfo->ii_higen = h_inode->i_generation;
+       iinfo->ii_hsb1 = h_inode->i_sb;
+}
+
+void au_cpup_attr_all(struct inode *inode, int force)
+{
+       struct inode *h_inode;
+
+       LKTRTrace("i%lu\n", inode->i_ino);
+       /* todo? IMustLock(inode); */
+       h_inode = au_h_iptr(inode, au_ibstart(inode));
+       AuDebugOn(!h_inode);
+
+       au_cpup_attr_changeable(inode);
+       if (inode->i_nlink > 0)
+               au_cpup_attr_nlink(inode, force);
+
+       switch (inode->i_mode & S_IFMT) {
+       case S_IFBLK:
+       case S_IFCHR:
+               inode->i_rdev = au_h_rdev(h_inode, /*h_mnt*/NULL,
+                                         /*h_dentry*/NULL);
+       }
+       inode->i_blkbits = h_inode->i_blkbits;
+       au_cpup_igen(inode, h_inode);
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* Note: dt_dentry and dt_hidden_dentry are not dget/dput-ed */
+
+/* keep the timestamps of the parent dir when cpup */
+void au_dtime_store(struct au_dtime *dt, struct dentry *dentry,
+                   struct dentry *h_dentry, struct au_hinode *hinode,
+                   struct au_hinode *hdir)
+{
+       struct inode *h_inode;
+
+       LKTRTrace("%.*s, hdir %d\n", AuDLNPair(dentry), !!hdir);
+       AuDebugOn(!dentry || !h_dentry || !h_dentry->d_inode);
+
+       dt->dt_dentry = dentry;
+       dt->dt_h_dentry = h_dentry;
+       dt->dt_hinode = hinode;
+       dt->dt_hdir = hdir;
+       h_inode = h_dentry->d_inode;
+       dt->dt_atime = h_inode->i_atime;
+       dt->dt_mtime = h_inode->i_mtime;
+       /* smp_mb(); */
+}
+
+void au_dtime_revert(struct au_dtime *dt)
+{
+       struct iattr attr;
+       int err;
+       struct au_hin_ignore ign[2];
+       struct vfsub_args vargs;
+
+       LKTRTrace("%.*s\n", AuDLNPair(dt->dt_dentry));
+
+       attr.ia_atime = dt->dt_atime;
+       attr.ia_mtime = dt->dt_mtime;
+       attr.ia_valid = ATTR_FORCE | ATTR_MTIME | ATTR_MTIME_SET
+               | ATTR_ATIME | ATTR_ATIME_SET;
+
+       vfsub_args_init(&vargs, ign,
+                       au_test_dlgt(au_mntflags(dt->dt_dentry->d_sb)), 0);
+       /*
+        * IN_ATTRIB should be divided into
+        * IN_ATTRIB_ATIME, IN_ATTRIB_MTIME ...,
+        * and define all ORed new IN_ATTRIB macro.
+        */
+       vfsub_ign_hinode(&vargs, IN_ATTRIB, dt->dt_hinode);
+       vfsub_ign_hinode(&vargs, IN_ATTRIB, dt->dt_hdir);
+       err = vfsub_notify_change(dt->dt_h_dentry, &attr, &vargs);
+       if (unlikely(err))
+               AuWarn("restoring timestamps failed(%d). ignored\n", err);
+}
+
+/* ---------------------------------------------------------------------- */
+
+static noinline_for_stack
+int cpup_iattr(struct dentry *dst, aufs_bindex_t bindex, struct dentry *h_src,
+              struct au_hinode *hdir, struct vfsub_args *vargs)
+{
+       int err, sbits;
+       struct dentry *h_dst;
+       struct iattr ia;
+       struct inode *h_isrc, *h_idst;
+
+       h_dst = au_h_dptr(dst, bindex);
+       LKTRTrace("%.*s\n", AuDLNPair(h_dst));
+       h_idst = h_dst->d_inode;
+       /* todo? IMustLock(h_idst); */
+       h_isrc = h_src->d_inode;
+       /* todo? IMustLock(h_isrc); */
+
+       ia.ia_valid = ATTR_FORCE | ATTR_MODE | ATTR_UID | ATTR_GID
+               | ATTR_ATIME | ATTR_MTIME
+               | ATTR_ATIME_SET | ATTR_MTIME_SET;
+       ia.ia_mode = h_isrc->i_mode;
+       ia.ia_uid = h_isrc->i_uid;
+       ia.ia_gid = h_isrc->i_gid;
+       ia.ia_atime = h_isrc->i_atime;
+       ia.ia_mtime = h_isrc->i_mtime;
+       sbits = !!(ia.ia_mode & (S_ISUID | S_ISGID));
+       au_cpup_attr_flags(h_idst, h_isrc);
+
+       vfsub_args_reinit(vargs);
+       vfsub_ign_hinode(vargs, IN_ATTRIB, hdir);
+       err = vfsub_notify_change(h_dst, &ia, vargs);
+
+       /* is this nfs only? */
+       if (!err && sbits && au_test_nfs(h_dst->d_sb)) {
+               ia.ia_valid = ATTR_FORCE | ATTR_MODE;
+               ia.ia_mode = h_isrc->i_mode;
+               vfsub_args_reinit(vargs);
+               vfsub_ign_hinode(vargs, IN_ATTRIB, hdir);
+               err = vfsub_notify_change(h_dst, &ia, vargs);
+       }
+
+       AuTraceErr(err);
+       return err;
+}
+
+/*
+ * to support a sparse file which is opened with O_APPEND,
+ * we need to close the file.
+ */
+static noinline_for_stack
+int cpup_regular(struct dentry *dentry, aufs_bindex_t bdst, aufs_bindex_t bsrc,
+                loff_t len, struct au_hinode *hdir, struct vfsub_args *vargs)
+{
+       int err, i;
+       struct super_block *sb;
+       struct inode *h_inode;
+       enum { SRC, DST };
+       struct {
+               aufs_bindex_t bindex;
+               unsigned int flags;
+               struct dentry *dentry;
+               struct file *file;
+               void *label, *label_file;
+       } *h, hidden[] = {
+               {
+                       .bindex = bsrc,
+                       .flags = O_RDONLY | O_NOATIME | O_LARGEFILE,
+                       .file = NULL,
+                       .label = &&out,
+                       .label_file = &&out_src_file
+               },
+               {
+                       .bindex = bdst,
+                       .flags = O_WRONLY | O_NOATIME | O_LARGEFILE,
+                       .file = NULL,
+                       .label = &&out_src_file,
+                       .label_file = &&out_dst_file
+               }
+       };
+
+       LKTRTrace("dentry %.*s, bdst %d, bsrc %d, len %lld\n",
+                 AuDLNPair(dentry), bdst, bsrc, len);
+       AuDebugOn(bsrc <= bdst);
+       AuDebugOn(!len);
+       sb = dentry->d_sb;
+       AuDebugOn(au_test_ro(sb, bdst, dentry->d_inode));
+       /* bsrc branch can be ro/rw. */
+
+       h = hidden;
+       for (i = 0; i < 2; i++, h++) {
+               h->dentry = au_h_dptr(dentry, h->bindex);
+               AuDebugOn(!h->dentry);
+               h_inode = h->dentry->d_inode;
+               AuDebugOn(!h_inode || !S_ISREG(h_inode->i_mode));
+               h->file = au_h_open(dentry, h->bindex, h->flags, /*file*/NULL);
+               err = PTR_ERR(h->file);
+               if (IS_ERR(h->file))
+                       goto *h->label;
+               err = -EINVAL;
+               if (unlikely(!h->file->f_op))
+                       goto *h->label_file;
+       }
+
+       /* stop updating while we copyup */
+       IMustLock(hidden[SRC].dentry->d_inode);
+       err = au_copy_file(hidden[DST].file, hidden[SRC].file, len, hdir, sb,
+                          vargs);
+
+ out_dst_file:
+       fput(hidden[DST].file);
+       au_sbr_put(sb, hidden[DST].bindex);
+ out_src_file:
+       fput(hidden[SRC].file);
+       au_sbr_put(sb, hidden[SRC].bindex);
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+static int au_do_cpup_regular(struct dentry *dentry, aufs_bindex_t bdst,
+                             aufs_bindex_t bsrc, loff_t len,
+                             struct au_hinode *hdir, struct dentry *h_dst,
+                             struct vfsub_args *vargs)
+{
+       int err, rerr;
+       loff_t l;
+
+       AuTraceEnter();
+
+       err = 0;
+       l = i_size_read(au_h_iptr(dentry->d_inode, bsrc));
+       if (len == -1 || l < len)
+               len = l;
+       if (len)
+               err = cpup_regular(dentry, bdst, bsrc, len, hdir, vargs);
+       if (!err)
+               goto out; /* success */
+
+       vfsub_args_reinit(vargs);
+       vfsub_ign_hinode(vargs, IN_DELETE, hdir);
+       rerr = vfsub_unlink(hdir->hi_inode, h_dst, vargs);
+       if (rerr) {
+               AuIOErr("failed unlinking cpup-ed %.*s(%d, %d)\n",
+                       AuDLNPair(h_dst), err, rerr);
+               err = -EIO;
+       }
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+static int au_do_cpup_symlink(struct dentry *h_dst, struct dentry *h_src,
+                             struct inode *h_dir, umode_t mode,
+                             struct vfsub_args *vargs)
+{
+       int err, symlen;
+       char *sym;
+       mm_segment_t old_fs;
+
+       AuTraceEnter();
+
+       err = -ENOMEM;
+       sym = __getname();
+       if (unlikely(!sym))
+               goto out;
+
+       old_fs = get_fs();
+       set_fs(KERNEL_DS);
+       symlen = h_src->d_inode->i_op->readlink(h_src, (char __user *)sym,
+                                               PATH_MAX);
+       err = symlen;
+       set_fs(old_fs);
+
+       if (symlen > 0) {
+               sym[symlen] = 0;
+               err = vfsub_symlink(h_dir, h_dst, sym, mode, vargs);
+       }
+       __putname(sym);
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+/* return with hidden dst inode is locked */
+static noinline_for_stack
+int cpup_entry(struct dentry *dentry, aufs_bindex_t bdst, aufs_bindex_t bsrc,
+              loff_t len, unsigned int flags, struct dentry *dst_parent,
+              struct vfsub_args *vargs)
+{
+       int err;
+       unsigned char isdir, hinotify;
+       struct dentry *h_src, *h_dst, *h_parent, *gparent;
+       struct inode *h_inode, *h_dir;
+       struct au_dtime dt;
+       umode_t mode;
+       struct super_block *sb;
+       struct au_hinode *hgdir, *hdir;
+       unsigned int mnt_flags;
+       const int do_dt = au_ftest_cpup(flags, DTIME);
+
+       LKTRTrace("%.*s, i%lu, bdst %d, bsrc %d, len %lld, dtime %u\n",
+                 AuDLNPair(dentry), dentry->d_inode->i_ino, bdst, bsrc, len,
+                 do_dt);
+       sb = dentry->d_sb;
+       AuDebugOn(bdst >= bsrc || au_test_ro(sb, bdst, NULL));
+       /* bsrc branch can be ro/rw. */
+
+       h_src = au_h_dptr(dentry, bsrc);
+       AuDebugOn(!h_src);
+       h_inode = h_src->d_inode;
+       AuDebugOn(!h_inode);
+       AuDebugOn(h_inode != au_h_iptr(dentry->d_inode, bsrc));
+
+       /* stop referencing while we are creating */
+       h_dst = au_h_dptr(dentry, bdst);
+       AuDebugOn(h_dst && h_dst->d_inode);
+       h_parent = h_dst->d_parent; /* dir inode is locked */
+       h_dir = h_parent->d_inode;
+       IMustLock(h_dir);
+       AuDebugOn(h_parent != h_dst->d_parent);
+
+       hdir = NULL;
+       mnt_flags = au_mntflags(sb);
+       hinotify = !!au_opt_test(mnt_flags, UDBA_INOTIFY);
+       if (hinotify) {
+               hdir = au_hi(dst_parent->d_inode, bdst);
+               AuDebugOn(hdir->hi_inode != h_dir);
+       }
+
+       if (do_dt) {
+               hgdir = NULL;
+               if (hinotify && !IS_ROOT(dst_parent)) {
+                       gparent = dget_parent(dst_parent);
+                       hgdir = au_hi(gparent->d_inode, bdst);
+                       IMustLock(hgdir->hi_inode);
+                       dput(gparent);
+               }
+               au_dtime_store(&dt, dst_parent, h_parent, hdir, hgdir);
+       }
+
+       isdir = 0;
+       vfsub_args_reinit(vargs);
+       vfsub_ign_hinode(vargs, IN_CREATE, hdir);
+       mode = h_inode->i_mode;
+       switch (mode & S_IFMT) {
+       case S_IFREG:
+               /* stop updating while we are referencing */
+               IMustLock(h_inode);
+               err = au_h_create(h_dir, h_dst, mode | S_IWUSR, vargs, NULL,
+                                 au_nfsmnt(sb, bdst));
+               if (!err)
+                       err = au_do_cpup_regular(dentry, bdst, bsrc, len,
+                                                hdir, h_dst, vargs);
+               break;
+       case S_IFDIR:
+               isdir = 1;
+               err = vfsub_mkdir(h_dir, h_dst, mode, vargs);
+               if (!err) {
+                       /* setattr case: dir is not locked */
+                       if (0 && au_ibstart(dst_parent->d_inode) == bdst)
+                               au_cpup_attr_nlink(dst_parent->d_inode,
+                                                  /*force*/1);
+                       au_cpup_attr_nlink(dentry->d_inode, /*force*/1);
+               }
+               break;
+       case S_IFLNK:
+               err = au_do_cpup_symlink(h_dst, h_src, h_dir, mode, vargs);
+               break;
+       case S_IFCHR:
+       case S_IFBLK:
+               AuDebugOn(!capable(CAP_MKNOD));
+               /*FALLTHROUGH*/
+       case S_IFIFO:
+       case S_IFSOCK:
+               err = vfsub_mknod(h_dir, h_dst, mode,
+                                 au_h_rdev(h_inode, /*h_mnt*/NULL, h_src),
+                                 vargs);
+               break;
+       default:
+               AuIOErr("Unknown inode type 0%o\n", mode);
+               err = -EIO;
+       }
+
+       if (hinotify
+           && !isdir
+           && au_opt_test_xino(mnt_flags)
+           && h_inode->i_nlink == 1
+           /* todo: unnecessary? */
+           /* && dentry->d_inode->i_nlink == 1 */
+           && bdst < bsrc
+           && !au_ftest_cpup(flags, KEEPLINO))
+               au_xino_write0(sb, bsrc, h_inode->i_ino, /*ino*/0);
+               /* ignore this error */
+
+       if (do_dt)
+               au_dtime_revert(&dt);
+       AuTraceErr(err);
+       return err;
+}
+
+/*
+ * copyup the @dentry from @bsrc to @bdst.
+ * the caller must set the both of hidden dentries.
+ * @len is for truncating when it is -1 copyup the entire file.
+ */
+static int au_cpup_single(struct dentry *dentry, aufs_bindex_t bdst,
+                         aufs_bindex_t bsrc, loff_t len, unsigned int flags,
+                         struct dentry *dst_parent, struct vfsub_args *vargs)
+{
+       int err, rerr;
+       unsigned int mnt_flags;
+       aufs_bindex_t old_ibstart;
+       unsigned char isdir, plink, hinotify;
+       struct au_dtime dt;
+       struct dentry *h_src, *h_dst, *h_parent, *gparent;
+       struct inode *dst_inode, *h_dir, *inode;
+       struct super_block *sb;
+       struct au_hinode *hgdir, *hdir;
+
+       LKTRTrace("%.*s, i%lu, bdst %d, bsrc %d, len %lld, flags 0x%x\n",
+                 AuDLNPair(dentry), dentry->d_inode->i_ino, bdst, bsrc, len,
+                 flags);
+       sb = dentry->d_sb;
+       AuDebugOn(bsrc <= bdst);
+       h_dst = au_h_dptr(dentry, bdst);
+       AuDebugOn(!h_dst || h_dst->d_inode);
+       h_parent = h_dst->d_parent; /* dir inode is locked */
+       h_dir = h_parent->d_inode;
+       IMustLock(h_dir);
+       h_src = au_h_dptr(dentry, bsrc);
+       AuDebugOn(!h_src || !h_src->d_inode);
+       inode = dentry->d_inode;
+       IiMustWriteLock(inode);
+       if (!dst_parent)
+               dst_parent = dget_parent(dentry);
+       else
+               dget(dst_parent);
+
+       mnt_flags = au_mntflags(sb);
+       plink = !!au_opt_test(mnt_flags, PLINK);
+       hinotify = !!au_opt_test(mnt_flags, UDBA_INOTIFY);
+       hdir = NULL;
+       if (hinotify)
+               hdir = au_hi(dst_parent->d_inode, bdst);
+       dst_inode = au_h_iptr(inode, bdst);
+       if (dst_inode) {
+               if (unlikely(!plink)) {
+                       err = -EIO;
+                       AuIOErr("i%lu exists on a upper branch "
+                               "but plink is disabled\n", inode->i_ino);
+                       goto out;
+               }
+
+               if (dst_inode->i_nlink) {
+                       const int do_dt = au_ftest_cpup(flags, DTIME);
+
+                       h_src = au_plink_lkup(sb, bdst, inode);
+                       err = PTR_ERR(h_src);
+                       if (IS_ERR(h_src))
+                               goto out;
+                       if (unlikely(!h_src->d_inode)) {
+                               err = -EIO;
+                               AuIOErr("i%lu exists on a upper branch "
+                                       "but plink is broken\n", inode->i_ino);
+                               dput(h_src);
+                               goto out;
+                       }
+
+                       if (do_dt) {
+                               hgdir = NULL;
+                               if (hinotify && !IS_ROOT(dst_parent)) {
+                                       gparent = dget_parent(dst_parent);
+                                       hgdir = au_hi(gparent->d_inode, bdst);
+                                       IMustLock(hgdir->hi_inode);
+                                       dput(gparent);
+                               }
+                               au_dtime_store(&dt, dst_parent, h_parent, hdir,
+                                              hgdir);
+                       }
+                       vfsub_args_reinit(vargs);
+                       vfsub_ign_hinode(vargs, IN_CREATE, hdir);
+                       err = vfsub_link(h_src, h_dir, h_dst, vargs);
+                       if (do_dt)
+                               au_dtime_revert(&dt);
+                       dput(h_src);
+                       goto out;
+               } else
+                       /* todo: cpup_wh_file? */
+                       /* udba work */
+                       au_update_brange(inode, 1);
+       }
+
+       old_ibstart = au_ibstart(inode);
+       err = cpup_entry(dentry, bdst, bsrc, len, flags, dst_parent, vargs);
+       if (unlikely(err))
+               goto out;
+       dst_inode = h_dst->d_inode;
+       mutex_lock_nested(&dst_inode->i_mutex, AuLsc_I_CHILD2);
+
+       /* todo: test dlgt? */
+       err = cpup_iattr(dentry, bdst, h_src, hdir, vargs);
+#if 0 /* reserved for future use */
+       if (0 && !err)
+               err = cpup_xattrs(h_src, h_dst);
+#endif
+       isdir = S_ISDIR(dst_inode->i_mode);
+       if (!err) {
+               if (bdst < old_ibstart)
+                       au_set_ibstart(inode, bdst);
+               au_set_h_iptr(inode, bdst, au_igrab(dst_inode),
+                             au_hi_flags(inode, isdir));
+               mutex_unlock(&dst_inode->i_mutex);
+               if (!isdir
+                   && h_src->d_inode->i_nlink > 1
+                   && plink)
+                       au_plink_append(sb, inode, h_dst, bdst);
+               goto out; /* success */
+       }
+
+       /* revert */
+       mutex_unlock(&dst_inode->i_mutex);
+       hgdir = NULL;
+       if (au_opt_test(mnt_flags, UDBA_INOTIFY) && !IS_ROOT(dst_parent)) {
+               gparent = dget_parent(dst_parent);
+               hgdir = au_hi(gparent->d_inode, bdst);
+               dput(gparent);
+       }
+       au_dtime_store(&dt, dst_parent, h_parent, hdir, hgdir);
+       vfsub_args_reinit(vargs);
+       vfsub_ign_hinode(vargs, IN_DELETE, hdir);
+       if (!isdir)
+               rerr = vfsub_unlink(h_dir, h_dst, vargs);
+       else
+               rerr = vfsub_rmdir(h_dir, h_dst, vargs);
+       au_dtime_revert(&dt);
+       if (rerr) {
+               AuIOErr("failed removing broken entry(%d, %d)\n", err, rerr);
+               err = -EIO;
+       }
+
+ out:
+       dput(dst_parent);
+       AuTraceErr(err);
+       return err;
+}
+
+struct au_cpup_single_args {
+       int *errp;
+       struct dentry *dentry;
+       aufs_bindex_t bdst, bsrc;
+       loff_t len;
+       unsigned int flags;
+       struct dentry *dst_parent;
+       struct vfsub_args *vargs;
+};
+
+static void au_call_cpup_single(void *args)
+{
+       struct au_cpup_single_args *a = args;
+       *a->errp = au_cpup_single(a->dentry, a->bdst, a->bsrc, a->len,
+                                 a->flags, a->dst_parent, a->vargs);
+}
+
+int au_sio_cpup_single(struct dentry *dentry, aufs_bindex_t bdst,
+                      aufs_bindex_t bsrc, loff_t len, unsigned int flags,
+                      struct dentry *dst_parent)
+{
+       int err, wkq_err;
+       struct dentry *h_dentry;
+       umode_t mode;
+       struct au_hin_ignore ign;
+       struct vfsub_args vargs;
+
+       LKTRTrace("%.*s, i%lu, bdst %d, bsrc %d, len %lld, flags 0x%x\n",
+                 AuDLNPair(dentry), dentry->d_inode->i_ino, bdst, bsrc, len,
+                 flags);
+
+       vfsub_args_init(&vargs, &ign, au_test_dlgt(au_mntflags(dentry->d_sb)),
+                       /*force_unlink*/0);
+       h_dentry = au_h_dptr(dentry, bsrc);
+       mode = h_dentry->d_inode->i_mode & S_IFMT;
+       if ((mode != S_IFCHR && mode != S_IFBLK)
+           || capable(CAP_MKNOD))
+               err = au_cpup_single(dentry, bdst, bsrc, len, flags,
+                                    dst_parent, &vargs);
+       else {
+               struct au_cpup_single_args args = {
+                       .errp           = &err,
+                       .dentry         = dentry,
+                       .bdst           = bdst,
+                       .bsrc           = bsrc,
+                       .len            = len,
+                       .flags          = flags,
+                       .dst_parent     = dst_parent,
+                       .vargs          = &vargs
+               };
+               vfsub_fclr(vargs.flags, DLGT);
+               wkq_err = au_wkq_wait(au_call_cpup_single, &args, /*dlgt*/0);
+               if (unlikely(wkq_err))
+                       err = wkq_err;
+       }
+
+       AuTraceErr(err);
+       return err;
+}
+
+/*
+ * copyup the @dentry from the first active hidden branch to @bdst,
+ * using au_cpup_single().
+ */
+static int au_cpup_simple(struct dentry *dentry, aufs_bindex_t bdst, loff_t len,
+                         unsigned int flags, struct vfsub_args *vargs)
+{
+       int err;
+       struct inode *inode;
+       aufs_bindex_t bsrc, bend;
+
+       LKTRTrace("%.*s, bdst %d, len %lld, flags 0x%x\n",
+                 AuDLNPair(dentry), bdst, len, flags);
+       inode = dentry->d_inode;
+       AuDebugOn(!S_ISDIR(inode->i_mode) && au_dbstart(dentry) < bdst);
+
+       bend = au_dbend(dentry);
+       for (bsrc = bdst + 1; bsrc <= bend; bsrc++)
+               if (au_h_dptr(dentry, bsrc))
+                       break;
+       AuDebugOn(!au_h_dptr(dentry, bsrc));
+
+       err = au_lkup_neg(dentry, bdst);
+       if (!err) {
+               err = au_cpup_single(dentry, bdst, bsrc, len, flags, NULL,
+                                    vargs);
+               if (!err)
+                       return 0; /* success */
+
+               /* revert */
+               au_set_h_dptr(dentry, bdst, NULL);
+               au_set_dbstart(dentry, bsrc);
+       }
+
+       AuTraceErr(err);
+       return err;
+}
+
+struct au_cpup_simple_args {
+       int *errp;
+       struct dentry *dentry;
+       aufs_bindex_t bdst;
+       loff_t len;
+       unsigned int flags;
+       struct vfsub_args *vargs;
+};
+
+static void au_call_cpup_simple(void *args)
+{
+       struct au_cpup_simple_args *a = args;
+       *a->errp = au_cpup_simple(a->dentry, a->bdst, a->len, a->flags,
+                                 a->vargs);
+}
+
+int au_sio_cpup_simple(struct dentry *dentry, aufs_bindex_t bdst, loff_t len,
+                      unsigned int flags)
+{
+       int err, wkq_err;
+       unsigned char do_sio, dlgt;
+       struct dentry *parent;
+       struct inode *h_dir, *dir;
+       struct au_hin_ignore ign;
+       struct vfsub_args vargs;
+
+       LKTRTrace("%.*s, b%d, len %lld, flags 0x%x\n",
+                 AuDLNPair(dentry), bdst, len, flags);
+
+       parent = dget_parent(dentry);
+       dir = parent->d_inode;
+       h_dir = au_h_iptr(dir, bdst);
+       dlgt = !!au_test_dlgt(au_mntflags(dir->i_sb));
+       do_sio = !!au_test_h_perm_sio(h_dir, MAY_EXEC | MAY_WRITE, dlgt);
+       if (!do_sio) {
+               /*
+                * testing CAP_MKNOD is for generic fs,
+                * but CAP_FSETID is for xfs only, currently.
+                */
+               umode_t mode = dentry->d_inode->i_mode;
+               do_sio = (((mode & (S_IFCHR | S_IFBLK))
+                          && !capable(CAP_MKNOD))
+                         || ((mode & (S_ISUID | S_ISGID))
+                             && !capable(CAP_FSETID)));
+       }
+       vfsub_args_init(&vargs, &ign, dlgt, /*force_unlink*/0);
+       if (!do_sio)
+               err = au_cpup_simple(dentry, bdst, len, flags, &vargs);
+       else {
+               struct au_cpup_simple_args args = {
+                       .errp           = &err,
+                       .dentry         = dentry,
+                       .bdst           = bdst,
+                       .len            = len,
+                       .flags          = flags,
+                       .vargs          = &vargs
+               };
+               vfsub_fclr(vargs.flags, DLGT);
+               wkq_err = au_wkq_wait(au_call_cpup_simple, &args, /*dlgt*/0);
+               if (unlikely(wkq_err))
+                       err = wkq_err;
+       }
+
+       dput(parent);
+       AuTraceErr(err);
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static int au_do_cpup_wh(struct dentry *dentry, aufs_bindex_t bdst,
+                        struct dentry *wh_dentry, struct file *file,
+                        loff_t len, struct vfsub_args *vargs)
+{
+       int err;
+       struct au_dinfo *dinfo;
+       aufs_bindex_t bstart;
+       struct dentry *h_d_bdst, *h_d_bstart;
+
+       AuTraceEnter();
+
+       dinfo = au_di(dentry);
+       bstart = dinfo->di_bstart;
+       h_d_bdst = dinfo->di_hdentry[0 + bdst].hd_dentry;
+       dinfo->di_bstart = bdst;
+       dinfo->di_hdentry[0 + bdst].hd_dentry = wh_dentry;
+       h_d_bstart = dinfo->di_hdentry[0 + bstart].hd_dentry;
+       if (file)
+               dinfo->di_hdentry[0 + bstart].hd_dentry
+                       = au_h_fptr(file, au_fbstart(file))->f_dentry;
+       err = au_cpup_single(dentry, bdst, bstart, len, !AuCpup_DTIME,
+                            /*h_parent*/NULL, vargs);
+       if (!err && file) {
+               err = au_reopen_nondir(file);
+               dinfo->di_hdentry[0 + bstart].hd_dentry = h_d_bstart;
+       }
+       dinfo->di_hdentry[0 + bdst].hd_dentry = h_d_bdst;
+       dinfo->di_bstart = bstart;
+
+       AuTraceErr(err);
+       return err;
+}
+
+/*
+ * copyup the deleted file for writing.
+ */
+static int au_cpup_wh(struct dentry *dentry, aufs_bindex_t bdst, loff_t len,
+                     struct file *file)
+{
+       int err;
+       unsigned char dlgt;
+       struct dentry *parent, *h_parent, *wh_dentry;
+       struct super_block *sb;
+       unsigned int mnt_flags;
+       struct au_dtime dt;
+       struct au_hin_ignore ign;
+       struct vfsub_args vargs;
+       struct au_hinode *hgdir, *hdir;
+       struct au_ndx ndx = {
+               .nd     = NULL,
+               .flags  = 0,
+               /* .br  = NULL */
+       };
+
+       LKTRTrace("%.*s, bdst %d, len %llu\n", AuDLNPair(dentry), bdst, len);
+       AuDebugOn(S_ISDIR(dentry->d_inode->i_mode)
+                 || (file && !(file->f_mode & FMODE_WRITE)));
+       DiMustWriteLock(dentry);
+
+       parent = dget_parent(dentry);
+       IiMustAnyLock(parent->d_inode);
+       h_parent = au_h_dptr(parent, bdst);
+       AuDebugOn(!h_parent);
+
+       sb = parent->d_sb;
+       mnt_flags = au_mntflags(sb);
+       dlgt = 0;
+       ndx.nfsmnt = au_nfsmnt(sb, bdst);
+       if (au_test_dlgt(mnt_flags)) {
+               dlgt = 1;
+               au_fset_ndx(ndx.flags, DLGT);
+       }
+       wh_dentry = au_whtmp_lkup(h_parent, &dentry->d_name, &ndx);
+       err = PTR_ERR(wh_dentry);
+       if (IS_ERR(wh_dentry))
+               goto out;
+
+       hdir = NULL;
+       hgdir = NULL;
+       if (au_opt_test(mnt_flags, UDBA_INOTIFY)) {
+               hdir = au_hi(parent->d_inode, bdst);
+               if (!IS_ROOT(parent)) {
+                       struct dentry *gparent;
+                       gparent = dget_parent(parent);
+                       hgdir = au_hi(gparent->d_inode, bdst);
+                       dput(gparent);
+               }
+       }
+       au_dtime_store(&dt, parent, h_parent, hdir, hgdir);
+       vfsub_args_init(&vargs, &ign, dlgt, /*force_unlink*/0);
+       err = au_do_cpup_wh(dentry, bdst, wh_dentry, file, len, &vargs);
+       if (unlikely(err))
+               goto out_wh;
+
+       AuDebugOn(!d_unhashed(dentry));
+       /* dget first to force sillyrename on nfs */
+       dget(wh_dentry);
+       vfsub_args_reinit(&vargs);
+       vfsub_ign_hinode(&vargs, IN_DELETE, hdir);
+       err = vfsub_unlink(h_parent->d_inode, wh_dentry, &vargs);
+       if (unlikely(err)) {
+               AuIOErr("failed remove copied-up tmp file %.*s(%d)\n",
+                       AuDLNPair(wh_dentry), err);
+               err = -EIO;
+       }
+       au_dtime_revert(&dt);
+       au_set_hi_wh(dentry->d_inode, bdst, wh_dentry);
+
+ out_wh:
+       dput(wh_dentry);
+ out:
+       dput(parent);
+       AuTraceErr(err);
+       return err;
+}
+
+struct au_cpup_wh_args {
+       int *errp;
+       struct dentry *dentry;
+       aufs_bindex_t bdst;
+       loff_t len;
+       struct file *file;
+};
+
+static void au_call_cpup_wh(void *args)
+{
+       struct au_cpup_wh_args *a = args;
+       *a->errp = au_cpup_wh(a->dentry, a->bdst, a->len, a->file);
+}
+
+int au_sio_cpup_wh(struct dentry *dentry, aufs_bindex_t bdst, loff_t len,
+                  struct file *file)
+{
+       int err, wkq_err;
+       struct dentry *parent, *h_tmp, *h_parent, *h_dentry;
+       struct inode *dir, *h_dir, *h_tmpdir, *h_inode;
+       struct au_wbr *wbr;
+
+       AuTraceEnter();
+       parent = dget_parent(dentry);
+       dir = parent->d_inode;
+       IiMustAnyLock(dir);
+
+       h_tmp = NULL;
+       h_parent = NULL;
+       h_dir = au_igrab(au_h_iptr(dir, bdst));
+       h_tmpdir = h_dir;
+       if (!h_dir->i_nlink) {
+               DiMustWriteLock(parent);
+               wbr = au_sbr(dentry->d_sb, bdst)->br_wbr;
+               AuDebugOn(!wbr);
+               h_tmp = wbr->wbr_tmp;
+
+               h_parent = dget(au_h_dptr(parent, bdst));
+               au_set_h_dptr(parent, bdst, NULL);
+               au_set_h_dptr(parent, bdst, dget(h_tmp));
+               h_tmpdir = h_tmp->d_inode;
+               au_set_h_iptr(dir, bdst, NULL, 0);
+               au_set_h_iptr(dir, bdst, au_igrab(h_tmpdir), /*flags*/0);
+
+               /* this temporary unlock is safe */
+               if (file)
+                       h_dentry = au_h_fptr(file, au_fbstart(file))->f_dentry;
+               else
+                       h_dentry = au_h_dptr(dentry, au_dbstart(dentry));
+               h_inode = h_dentry->d_inode;
+               IMustLock(h_inode);
+               mutex_unlock(&h_inode->i_mutex);
+               mutex_lock_nested(&h_tmpdir->i_mutex, AuLsc_I_PARENT3);
+               mutex_lock_nested(&h_inode->i_mutex, AuLsc_I_CHILD);
+       }
+
+       if (!au_test_h_perm_sio
+           (h_tmpdir, MAY_EXEC | MAY_WRITE,
+            au_test_dlgt(au_mntflags(dentry->d_sb))))
+               err = au_cpup_wh(dentry, bdst, len, file);
+       else {
+               struct au_cpup_wh_args args = {
+                       .errp   = &err,
+                       .dentry = dentry,
+                       .bdst   = bdst,
+                       .len    = len,
+                       .file   = file
+               };
+               wkq_err = au_wkq_wait(au_call_cpup_wh, &args, /*dlgt*/0);
+               if (unlikely(wkq_err))
+                       err = wkq_err;
+       }
+
+       /* todo: is this restore safe? */
+       if (h_tmp) {
+               mutex_unlock(&h_tmpdir->i_mutex);
+               au_set_h_iptr(dir, bdst, NULL, 0);
+               au_set_h_iptr(dir, bdst, au_igrab(h_dir), /*flags*/0);
+               au_set_h_dptr(parent, bdst, NULL);
+               au_set_h_dptr(parent, bdst, h_parent);
+       }
+       iput(h_dir);
+       dput(parent);
+
+       AuTraceErr(err);
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * generic routine for both of copy-up and copy-down.
+ * Although I've tried building a path by dcsub, I gave up this approach.
+ * Since the ancestor directory may be moved/renamed during copy.
+ */
+/* cf. revalidate function in file.c */
+int au_cp_dirs(struct dentry *dentry, aufs_bindex_t bdst,
+              int (*cp)(struct dentry *dentry, aufs_bindex_t bdst,
+                        struct dentry *h_parent, void *arg),
+              void *arg)
+{
+       int err;
+       unsigned char pin_flags;
+       struct au_pin pin;
+       struct super_block *sb;
+       struct dentry *d, *parent, *h_parent, *real_parent;
+
+       LKTRTrace("%.*s, b%d, parent i%lu\n",
+                 AuDLNPair(dentry), bdst, (unsigned long)parent_ino(dentry));
+       sb = dentry->d_sb;
+       AuDebugOn(au_test_ro(sb, bdst, NULL));
+       err = 0;
+       parent = dget_parent(dentry);
+       IiMustWriteLock(parent->d_inode);
+       if (IS_ROOT(parent))
+               goto out;
+
+       pin_flags = AuPin_MNT_WRITE;
+       if (au_opt_test(au_mntflags(sb), UDBA_INOTIFY))
+               au_fset_pin(pin_flags, DO_GPARENT);
+       au_pin_init(&pin, dentry, bdst, AuLsc_DI_PARENT3, AuLsc_I_PARENT2,
+                   pin_flags);
+
+       /* do not use au_dpage */
+       real_parent = parent;
+       while (1) {
+               dput(parent);
+               parent = dget_parent(dentry);
+               h_parent = au_h_dptr(parent, bdst);
+               if (h_parent)
+                       goto out; /* success */
+
+               /* find top dir which is needed to cpup */
+               do {
+                       d = parent;
+                       dput(parent);
+                       parent = dget_parent(d);
+                       di_read_lock_parent3(parent, !AuLock_IR);
+                       h_parent = au_h_dptr(parent, bdst);
+                       di_read_unlock(parent, !AuLock_IR);
+               } while (!h_parent);
+
+               if (d != real_parent)
+                       di_write_lock_child3(d);
+
+               /* somebody else might create while we were sleeping */
+               if (!au_h_dptr(d, bdst) || !au_h_dptr(d, bdst)->d_inode) {
+                       if (au_h_dptr(d, bdst))
+                               au_update_dbstart(d);
+
+                       au_pin_do_set_dentry(pin.pin  + AuPin_PARENT, d);
+                       err = au_do_pin(pin.pin + AuPin_PARENT,
+                                       au_pin_gp(&pin));
+                       if (!err) {
+                               err = cp(d, bdst, h_parent, arg);
+                               au_unpin(&pin);
+                       }
+               }
+
+               if (d != real_parent)
+                       di_write_unlock(d);
+               if (unlikely(err))
+                       break;
+       }
+
+ out:
+       dput(parent);
+       AuTraceErr(err);
+       return err;
+}
+
+static int au_cpup_dir(struct dentry *dentry, aufs_bindex_t bdst,
+                      struct dentry *h_parent, void *arg)
+{
+       int err;
+
+       err = au_sio_cpup_simple(dentry, bdst, -1, AuCpup_DTIME);
+
+       AuTraceErr(err);
+       return err;
+}
+
+int au_cpup_dirs(struct dentry *dentry, aufs_bindex_t bdst)
+{
+       int err;
+
+       err = au_cp_dirs(dentry, bdst, au_cpup_dir, NULL);
+
+       AuTraceErr(err);
+       return err;
+}
+
+int au_test_and_cpup_dirs(struct dentry *dentry, aufs_bindex_t bdst)
+{
+       int err;
+       struct dentry *parent;
+       struct inode *dir;
+
+       parent = dget_parent(dentry);
+       dir = parent->d_inode;
+       LKTRTrace("%.*s, b%d, parent i%lu\n",
+                 AuDLNPair(dentry), bdst, dir->i_ino);
+       DiMustReadLock(parent);
+       IiMustReadLock(dir);
+
+       err = 0;
+       if (au_h_iptr(dir, bdst))
+               goto out;
+
+       di_read_unlock(parent, AuLock_IR);
+       di_write_lock_parent(parent);
+       /* someone else might change our inode while we were sleeping */
+       if (!au_h_iptr(dir, bdst))
+               err = au_cpup_dirs(dentry, bdst);
+       di_downgrade_lock(parent, AuLock_IR);
+
+ out:
+       dput(parent);
+       AuTraceErr(err);
+       return err;
+}
diff -urN linux/fs/aufs/cpup.h linux-aufs/fs/aufs/cpup.h
--- linux/fs/aufs/cpup.h        1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/cpup.h   2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,86 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * copy-up/down functions
+ *
+ * $Id$
+ */
+
+#ifndef __AUFS_CPUP_H__
+#define __AUFS_CPUP_H__
+
+#ifdef __KERNEL__
+
+#include <linux/fs.h>
+#include <linux/aufs_type.h>
+
+void au_cpup_attr_timesizes(struct inode *inode);
+void au_cpup_attr_nlink(struct inode *inode, int force);
+void au_cpup_attr_changeable(struct inode *inode);
+void au_cpup_igen(struct inode *inode, struct inode *h_inode);
+void au_cpup_attr_all(struct inode *inode, int force);
+
+/* ---------------------------------------------------------------------- */
+
+/* cpup flags */
+#define AuCpup_DTIME   1               /* do dtime_store/revert */
+#define AuCpup_KEEPLINO        (1 << 1)        /* do not clear the lower xino,
+                                          for link(2) */
+#define au_ftest_cpup(flags, name)     ((flags) & AuCpup_##name)
+#define au_fset_cpup(flags, name)      { (flags) |= AuCpup_##name; }
+#define au_fclr_cpup(flags, name)      { (flags) &= ~AuCpup_##name; }
+
+int au_sio_cpup_single(struct dentry *dentry, aufs_bindex_t bdst,
+                      aufs_bindex_t bsrc, loff_t len, unsigned int flags,
+                      struct dentry *dst_parent);
+int au_sio_cpup_simple(struct dentry *dentry, aufs_bindex_t bdst, loff_t len,
+                      unsigned int flags);
+int au_sio_cpup_wh(struct dentry *dentry, aufs_bindex_t bdst, loff_t len,
+                  struct file *file);
+
+int au_cp_dirs(struct dentry *dentry, aufs_bindex_t bdst,
+              int (*cp)(struct dentry *dentry, aufs_bindex_t bdst,
+                        struct dentry *h_parent, void *arg),
+              void *arg);
+int au_cpup_dirs(struct dentry *dentry, aufs_bindex_t bdst);
+int au_test_and_cpup_dirs(struct dentry *dentry, aufs_bindex_t bdst);
+
+/* ---------------------------------------------------------------------- */
+
+/* keep timestamps when copyup */
+struct au_dtime {
+       struct dentry *dt_dentry, *dt_h_dentry;
+       struct au_hinode *dt_hinode, *dt_hdir;
+       struct timespec dt_atime, dt_mtime;
+};
+void au_dtime_store(struct au_dtime *dt, struct dentry *dentry,
+                   struct dentry *h_dentry, struct au_hinode *hinode,
+                   struct au_hinode *hdir);
+void au_dtime_revert(struct au_dtime *dt);
+
+/* ---------------------------------------------------------------------- */
+
+static inline void au_cpup_attr_flags(struct inode *inode,
+                                     struct inode *h_inode)
+{
+       inode->i_flags |= h_inode->i_flags & ~(S_DEAD | S_PRIVATE);
+}
+
+#endif /* __KERNEL__ */
+#endif /* __AUFS_CPUP_H__ */
diff -urN linux/fs/aufs/dcsub.c linux-aufs/fs/aufs/dcsub.c
--- linux/fs/aufs/dcsub.c       1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/dcsub.c  2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,251 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * sub-routines for dentry cache
+ *
+ * $Id$
+ */
+
+#include "aufs.h"
+
+static void au_dpage_free(struct au_dpage *dpage)
+{
+       int i;
+
+       AuTraceEnter();
+       AuDebugOn(!dpage);
+
+       for (i = 0; i < dpage->ndentry; i++)
+               dput(dpage->dentries[i]);
+       free_page((unsigned long)dpage->dentries);
+}
+
+int au_dpages_init(struct au_dcsub_pages *dpages, gfp_t gfp)
+{
+       int err;
+       void *p;
+
+       AuTraceEnter();
+
+       err = -ENOMEM;
+       dpages->dpages = kmalloc(sizeof(*dpages->dpages), gfp);
+       if (unlikely(!dpages->dpages))
+               goto out;
+       p = (void *)__get_free_page(gfp);
+       if (unlikely(!p))
+               goto out_dpages;
+       dpages->dpages[0].ndentry = 0;
+       dpages->dpages[0].dentries = p;
+       dpages->ndpage = 1;
+       return 0; /* success */
+
+ out_dpages:
+       kfree(dpages->dpages);
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+void au_dpages_free(struct au_dcsub_pages *dpages)
+{
+       int i;
+
+       AuTraceEnter();
+
+       for (i = 0; i < dpages->ndpage; i++)
+               au_dpage_free(dpages->dpages + i);
+       kfree(dpages->dpages);
+}
+
+static int au_dpages_append(struct au_dcsub_pages *dpages,
+                           struct dentry *dentry, gfp_t gfp)
+{
+       int err, sz;
+       struct au_dpage *dpage;
+       void *p;
+
+       /* AuTraceEnter(); */
+
+       dpage = dpages->dpages + dpages->ndpage - 1;
+       AuDebugOn(!dpage);
+       sz = PAGE_SIZE / sizeof(dentry);
+       if (unlikely(dpage->ndentry >= sz)) {
+               LKTRLabel(new dpage);
+               err = -ENOMEM;
+               sz = dpages->ndpage * sizeof(*dpages->dpages);
+               p = au_kzrealloc(dpages->dpages, sz,
+                                sz + sizeof(*dpages->dpages), gfp);
+               if (unlikely(!p))
+                       goto out;
+               dpages->dpages = p;
+               dpage = dpages->dpages + dpages->ndpage;
+               p = (void *)__get_free_page(gfp);
+               if (unlikely(!p))
+                       goto out;
+               dpage->ndentry = 0;
+               dpage->dentries = p;
+               dpages->ndpage++;
+       }
+
+       dpage->dentries[dpage->ndentry++] = dget(dentry);
+       return 0; /* success */
+
+ out:
+       /* AuTraceErr(err); */
+       return err;
+}
+
+int au_dcsub_pages(struct au_dcsub_pages *dpages, struct dentry *root,
+                  au_dpages_test test, void *arg)
+{
+       int err;
+       struct dentry *this_parent = root;
+       struct list_head *next;
+       struct super_block *sb = root->d_sb;
+
+       AuTraceEnter();
+
+       err = 0;
+       spin_lock(&dcache_lock);
+ repeat:
+       next = this_parent->d_subdirs.next;
+ resume:
+       if (this_parent->d_sb == sb
+           && !IS_ROOT(this_parent)
+           && atomic_read(&this_parent->d_count)
+           && this_parent->d_inode
+           && (!test || test(this_parent, arg))) {
+               err = au_dpages_append(dpages, this_parent, GFP_ATOMIC);
+               if (unlikely(err))
+                       goto out;
+       }
+
+       while (next != &this_parent->d_subdirs) {
+               struct list_head *tmp = next;
+               struct dentry *dentry = list_entry(tmp, struct dentry,
+                                                  d_u.d_child);
+               next = tmp->next;
+               if (/*d_unhashed(dentry) || */!dentry->d_inode)
+                       continue;
+               if (!list_empty(&dentry->d_subdirs)) {
+                       this_parent = dentry;
+                       goto repeat;
+               }
+               if (dentry->d_sb == sb
+                   && atomic_read(&dentry->d_count)
+                   && (!test || test(dentry, arg))) {
+                       err = au_dpages_append(dpages, dentry, GFP_ATOMIC);
+                       if (unlikely(err))
+                               goto out;
+               }
+       }
+
+       if (this_parent != root) {
+               next = this_parent->d_u.d_child.next;
+               this_parent = this_parent->d_parent; /* dcache_lock is locked */
+               goto resume;
+       }
+ out:
+       spin_unlock(&dcache_lock);
+#if 0 /* debug */
+       if (!err) {
+               int i, j;
+               j = 0;
+               for (i = 0; i < dpages->ndpage; i++) {
+                       if ((dpages->dpages + i)->ndentry)
+                               AuDbg("%d: %d\n",
+                                     i, (dpages->dpages + i)->ndentry);
+                       j += (dpages->dpages + i)->ndentry;
+               }
+               if (j)
+                       AuDbg("ndpage %d, %d\n", dpages->ndpage, j);
+       }
+#endif
+       AuTraceErr(err);
+       return err;
+}
+
+int au_dcsub_pages_rev(struct au_dcsub_pages *dpages, struct dentry *dentry,
+                      int do_include, au_dpages_test test, void *arg)
+{
+       int err;
+
+       AuTraceEnter();
+
+       err = 0;
+       spin_lock(&dcache_lock);
+       if (do_include && (!test || test(dentry, arg))) {
+               err = au_dpages_append(dpages, dentry, GFP_ATOMIC);
+               if (unlikely(err))
+                       goto out;
+       }
+       while (!IS_ROOT(dentry)) {
+               dentry = dentry->d_parent; /* dcache_lock is locked */
+               if (!test || test(dentry, arg)) {
+                       err = au_dpages_append(dpages, dentry, GFP_ATOMIC);
+                       if (unlikely(err))
+                               break;
+               }
+       }
+
+ out:
+       spin_unlock(&dcache_lock);
+
+       AuTraceErr(err);
+       return err;
+}
+
+struct dentry *au_test_subdir(struct dentry *d1, struct dentry *d2)
+{
+       struct dentry *trap, **dentries;
+       int err, i, j;
+       struct au_dcsub_pages dpages;
+       struct au_dpage *dpage;
+
+       LKTRTrace("%.*s, %.*s\n", AuDLNPair(d1), AuDLNPair(d2));
+
+       trap = ERR_PTR(-ENOMEM);
+       err = au_dpages_init(&dpages, GFP_NOFS);
+       if (unlikely(err))
+               goto out;
+       err = au_dcsub_pages_rev(&dpages, d1, /*do_include*/1, NULL, NULL);
+       if (unlikely(err))
+               goto out_dpages;
+
+       trap = d1;
+       for (i = 0; !err && i < dpages.ndpage; i++) {
+               dpage = dpages.dpages + i;
+               dentries = dpage->dentries;
+               for (j = 0; !err && j < dpage->ndentry; j++) {
+                       struct dentry *d;
+                       d = dentries[j];
+                       err = (d == d2);
+                       if (!err)
+                               trap = d;
+               }
+       }
+       if (!err)
+               trap = NULL;
+
+ out_dpages:
+       au_dpages_free(&dpages);
+ out:
+       AuTraceErrPtr(trap);
+       return trap;
+}
diff -urN linux/fs/aufs/dcsub.h linux-aufs/fs/aufs/dcsub.h
--- linux/fs/aufs/dcsub.h       1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/dcsub.h  2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,54 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * sub-routines for dentry cache
+ *
+ * $Id$
+ */
+
+#ifndef __AUFS_DCSUB_H__
+#define __AUFS_DCSUB_H__
+
+#ifdef __KERNEL__
+
+#include <linux/dcache.h>
+
+struct au_dpage {
+       int ndentry;
+       struct dentry **dentries;
+};
+
+struct au_dcsub_pages {
+       int ndpage;
+       struct au_dpage *dpages;
+};
+
+/* ---------------------------------------------------------------------- */
+
+int au_dpages_init(struct au_dcsub_pages *dpages, gfp_t gfp);
+void au_dpages_free(struct au_dcsub_pages *dpages);
+typedef int (*au_dpages_test)(struct dentry *dentry, void *arg);
+int au_dcsub_pages(struct au_dcsub_pages *dpages, struct dentry *root,
+                  au_dpages_test test, void *arg);
+int au_dcsub_pages_rev(struct au_dcsub_pages *dpages, struct dentry *dentry,
+                      int do_include, au_dpages_test test, void *arg);
+struct dentry *au_test_subdir(struct dentry *d1, struct dentry *d2);
+
+#endif /* __KERNEL__ */
+#endif /* __AUFS_DCSUB_H__ */
diff -urN linux/fs/aufs/debug.c linux-aufs/fs/aufs/debug.c
--- linux/fs/aufs/debug.c       1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/debug.c  2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,522 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * debug print functions
+ *
+ * $Id$
+ */
+
+#include "aufs.h"
+
+atomic_t au_cond = ATOMIC_INIT(0);
+
+char *au_plevel = KERN_DEBUG;
+#define dpri(fmt, arg...) do { \
+       if (LktrCond) \
+               printk("%s" fmt, au_plevel, ##arg); \
+} while (0)
+
+/* ---------------------------------------------------------------------- */
+
+void au_dpri_whlist(struct au_nhash *whlist)
+{
+       int i;
+       struct hlist_head *head;
+       struct au_vdir_wh *tpos;
+       struct hlist_node *pos;
+
+       for (i = 0; i < AuSize_NHASH; i++) {
+               head = whlist->heads + i;
+               hlist_for_each_entry(tpos, pos, head, wh_hash)
+                       dpri("b%d, %.*s, %d\n",
+                            tpos->wh_bindex,
+                            tpos->wh_str.len, tpos->wh_str.name,
+                            tpos->wh_str.len);
+       }
+}
+
+void au_dpri_vdir(struct au_vdir *vdir)
+{
+       int i;
+       union au_vdir_deblk_p p;
+       unsigned char *o;
+
+       if (!vdir || IS_ERR(vdir)) {
+               dpri("err %ld\n", PTR_ERR(vdir));
+               return;
+       }
+
+       dpri("nblk %d, deblk %p, last{%d, %p}, ver %lu\n",
+            vdir->vd_nblk, vdir->vd_deblk,
+            vdir->vd_last.i, vdir->vd_last.p.p, vdir->vd_version);
+       for (i = 0; i < vdir->vd_nblk; i++) {
+               p.deblk = vdir->vd_deblk[i];
+               o = p.p;
+               dpri("[%d]: %p\n", i, o);
+       }
+}
+
+static int do_pri_inode(aufs_bindex_t bindex, struct inode *inode,
+                       struct dentry *wh)
+{
+       char *n = NULL;
+       int l = 0, ntfy = 0;
+
+       if (!inode || IS_ERR(inode)) {
+               dpri("i%d: err %ld\n", bindex, PTR_ERR(inode));
+               return -1;
+       }
+
+       /* the type of i_blocks depends upon CONFIG_LSF */
+       BUILD_BUG_ON(sizeof(inode->i_blocks) != sizeof(unsigned long)
+                    && sizeof(inode->i_blocks) != sizeof(u64));
+       if (wh) {
+               n = (void *)wh->d_name.name;
+               l = wh->d_name.len;
+       }
+
+       ntfy = au_test_inotify(inode);
+       dpri("i%d: i%lu, %s, cnt %d, nl %u, 0%o, ntfy %d, sz %llu, blk %llu,"
+            " ct %lld, np %lu, st 0x%lx, f 0x%x, g %x%s%.*s\n",
+            bindex,
+            inode->i_ino, inode->i_sb ? au_sbtype(inode->i_sb) : "??",
+            atomic_read(&inode->i_count), inode->i_nlink, inode->i_mode,
+            ntfy,
+            i_size_read(inode), (unsigned long long)inode->i_blocks,
+            (long long)timespec_to_ns(&inode->i_ctime) & 0x0ffff,
+            inode->i_mapping ? inode->i_mapping->nrpages : 0,
+            inode->i_state, inode->i_flags, inode->i_generation,
+            l ? ", wh " : "", l, n);
+       return 0;
+}
+
+void au_dpri_inode(struct inode *inode)
+{
+       struct au_iinfo *iinfo;
+       aufs_bindex_t bindex;
+       int err;
+
+       err = do_pri_inode(-1, inode, NULL);
+       if (err || !au_test_aufs(inode->i_sb))
+               return;
+
+       iinfo = au_ii(inode);
+       if (!iinfo)
+               return;
+       dpri("i-1: bstart %d, bend %d, gen %d\n",
+            iinfo->ii_bstart, iinfo->ii_bend, au_iigen(inode));
+       if (iinfo->ii_bstart < 0)
+               return;
+       for (bindex = iinfo->ii_bstart; bindex <= iinfo->ii_bend; bindex++)
+               do_pri_inode(bindex, iinfo->ii_hinode[0 + bindex].hi_inode,
+                            iinfo->ii_hinode[0 + bindex].hi_whdentry);
+}
+
+static int do_pri_dentry(aufs_bindex_t bindex, struct dentry *dentry,
+                        struct list_head *intent)
+{
+       struct dentry *wh = NULL;
+
+       if (!dentry || IS_ERR(dentry)) {
+               dpri("d%d: err %ld\n", bindex, PTR_ERR(dentry));
+               return -1;
+       }
+       /* do not call dget_parent() here */
+       dpri("d%d: %.*s?/%.*s, %s, cnt %d, flags 0x%x, intent %d\n",
+            bindex,
+            AuDLNPair(dentry->d_parent), AuDLNPair(dentry),
+            dentry->d_sb ? au_sbtype(dentry->d_sb) : "??",
+            atomic_read(&dentry->d_count), dentry->d_flags, !!intent);
+       if (bindex >= 0 && dentry->d_inode && au_test_aufs(dentry->d_sb)) {
+               struct au_iinfo *iinfo = au_ii(dentry->d_inode);
+               if (iinfo)
+                       wh = iinfo->ii_hinode[0 + bindex].hi_whdentry;
+       }
+       do_pri_inode(bindex, dentry->d_inode, wh);
+       return 0;
+}
+
+static struct list_head *au_dbg_h_intent(struct au_dinfo *dinfo,
+                                        aufs_bindex_t bindex)
+{
+#ifdef CONFIG_AUFS_BR_NFS
+       return dinfo->di_hdentry[0 + bindex].hd_intent_list;
+#else
+       return NULL;
+#endif
+}
+
+void au_dpri_dentry(struct dentry *dentry)
+{
+       struct au_dinfo *dinfo;
+       aufs_bindex_t bindex;
+       int err;
+
+       err = do_pri_dentry(-1, dentry, NULL);
+       if (err || !au_test_aufs(dentry->d_sb))
+               return;
+
+       dinfo = au_di(dentry);
+       if (!dinfo)
+               return;
+       dpri("d-1: bstart %d, bend %d, bwh %d, bdiropq %d, gen %d\n",
+            dinfo->di_bstart, dinfo->di_bend,
+            dinfo->di_bwh, dinfo->di_bdiropq, au_digen(dentry));
+       if (dinfo->di_bstart < 0)
+               return;
+       for (bindex = dinfo->di_bstart; bindex <= dinfo->di_bend; bindex++)
+               do_pri_dentry(bindex, dinfo->di_hdentry[0 + bindex].hd_dentry,
+                             au_dbg_h_intent(dinfo, bindex));
+}
+
+static int do_pri_file(aufs_bindex_t bindex, struct file *file)
+{
+       char a[32];
+
+       if (!file || IS_ERR(file)) {
+               dpri("f%d: err %ld\n", bindex, PTR_ERR(file));
+               return -1;
+       }
+       a[0] = 0;
+       if (bindex < 0
+           && file->f_dentry
+           && au_test_aufs(file->f_dentry->d_sb)
+           && au_fi(file))
+               snprintf(a, sizeof(a), ", mmapped %d", au_test_mmapped(file));
+       dpri("f%d: mode 0x%x, flags 0%o, cnt %ld, pos %llu%s\n",
+            bindex, file->f_mode, file->f_flags, (long)file_count(file),
+            file->f_pos, a);
+       if (file->f_dentry)
+               do_pri_dentry(bindex, file->f_dentry, NULL);
+       return 0;
+}
+
+void au_dpri_file(struct file *file)
+{
+       struct au_finfo *finfo;
+       aufs_bindex_t bindex;
+       int err;
+
+       err = do_pri_file(-1, file);
+       if (err || !file->f_dentry || !au_test_aufs(file->f_dentry->d_sb))
+               return;
+
+       finfo = au_fi(file);
+       if (!finfo)
+               return;
+       if (finfo->fi_bstart < 0)
+               return;
+       for (bindex = finfo->fi_bstart; bindex <= finfo->fi_bend; bindex++) {
+               struct au_hfile *hf;
+               hf = finfo->fi_hfile + bindex;
+               do_pri_file(bindex, hf ? hf->hf_file : NULL);
+       }
+}
+
+static int do_pri_br(aufs_bindex_t bindex, struct au_branch *br)
+{
+       struct vfsmount *mnt;
+       struct super_block *sb;
+
+       if (!br || IS_ERR(br)
+           || !(mnt = br->br_mnt) || IS_ERR(mnt)
+           || !(sb = mnt->mnt_sb) || IS_ERR(sb)) {
+               dpri("s%d: err %ld\n", bindex, PTR_ERR(br));
+               return -1;
+       }
+
+       dpri("s%d: {perm 0x%x, cnt %d, wbr %p}, "
+            "%s, dev 0x%02x%02x, flags 0x%lx, cnt(BIAS) %d, active %d, "
+            "xino %d\n",
+            bindex, br->br_perm, au_br_count(br), br->br_wbr,
+            au_sbtype(sb), MAJOR(sb->s_dev), MINOR(sb->s_dev),
+            sb->s_flags, sb->s_count - S_BIAS,
+            atomic_read(&sb->s_active), !!br->br_xino.xi_file);
+       return 0;
+}
+
+void au_dpri_sb(struct super_block *sb)
+{
+       struct au_sbinfo *sbinfo;
+       aufs_bindex_t bindex;
+       int err;
+       /* to reuduce stack size */
+       struct {
+               struct vfsmount mnt;
+               struct au_branch fake;
+       } *a;
+
+       /* this function can be called from magic sysrq */
+       a = kzalloc(sizeof(*a), GFP_ATOMIC);
+       if (unlikely(!a)) {
+               dpri("no memory\n");
+               return;
+       }
+
+       a->mnt.mnt_sb = sb;
+       a->fake.br_perm = 0;
+       a->fake.br_mnt = &a->mnt;
+       a->fake.br_xino.xi_file = NULL;
+       atomic_set(&a->fake.br_count, 0);
+       smp_mb(); /* atomic_set */
+       err = do_pri_br(-1, &a->fake);
+       kfree(a);
+       dpri("dev 0x%x\n", sb->s_dev);
+       if (err || !au_test_aufs(sb))
+               return;
+
+       sbinfo = au_sbi(sb);
+       if (!sbinfo)
+               return;
+       dpri("nw %d, gen %u, kobj %d\n",
+            atomic_read(&sbinfo->si_nowait.nw_len), sbinfo->si_generation,
+            atomic_read(&sbinfo->si_kobj.kref.refcount));
+       for (bindex = 0; bindex <= sbinfo->si_bend; bindex++)
+               do_pri_br(bindex, sbinfo->si_branch[0 + bindex]);
+}
+
+/* ---------------------------------------------------------------------- */
+
+void au_dbg_sleep(int sec)
+{
+       static DECLARE_WAIT_QUEUE_HEAD(wq);
+       wait_event_timeout(wq, 0, sec * HZ);
+}
+
+void au_dbg_sleep_jiffy(int jiffy)
+{
+       static DECLARE_WAIT_QUEUE_HEAD(wq);
+       wait_event_timeout(wq, 0, jiffy);
+}
+
+void au_dbg_iattr(struct iattr *ia)
+{
+#define AuBit(name)    if (ia->ia_valid & ATTR_ ## name) \
+                               dpri(#name "\n")
+       AuBit(MODE);
+       AuBit(UID);
+       AuBit(GID);
+       AuBit(SIZE);
+       AuBit(ATIME);
+       AuBit(MTIME);
+       AuBit(CTIME);
+       AuBit(ATIME_SET);
+       AuBit(MTIME_SET);
+       AuBit(FORCE);
+       AuBit(ATTR_FLAG);
+       AuBit(KILL_SUID);
+       AuBit(KILL_SGID);
+       AuBit(FILE);
+       AuBit(KILL_PRIV);
+       AuBit(OPEN);
+       AuBit(TIMES_SET);
+#undef AuBit
+       dpri("ia_file %p\n", ia->ia_file);
+}
+
+/* ---------------------------------------------------------------------- */
+
+void au_debug_sbinfo_init(struct au_sbinfo *sbinfo)
+{
+#ifdef ForceInotify
+       au_opt_set_udba(sbinfo->si_mntflags, UDBA_INOTIFY);
+#endif
+#ifdef ForceDlgt
+       au_opt_set(sbinfo->si_mntflags, DLGT);
+#endif
+#ifdef ForceNoPlink
+       au_opt_clr(sbinfo->si_mntflags, PLINK);
+#endif
+#ifdef ForceNoXino
+       au_opt_clr(sbinfo->si_mntflags, XINO);
+#endif
+#ifdef ForceNoRefrof
+       au_opt_clr(sbinfo->si_mntflags, REFROF);
+#endif
+#ifdef ForceShwh
+       au_opt_set(sbinfo->si_mntflags, SHWH);
+#endif
+
+#ifdef CONFIG_AUFS_DEBUG_LOCK
+       {
+               int i;
+               for (i = 0; i < AuDbgLock_Last; i++)
+                       au_spl_init(sbinfo->si_dbg_lock + i);
+       }
+#endif
+}
+
+int __init au_debug_init(void)
+{
+       aufs_bindex_t bindex;
+       struct au_vdir_destr destr;
+
+       bindex = -1;
+       AuDebugOn(bindex >= 0);
+
+       destr.len = -1;
+       AuDebugOn(destr.len < NAME_MAX);
+
+#ifdef CONFIG_4KSTACKS
+       AuWarn("CONFIG_4KSTACKS is defined.\n");
+#endif
+
+#ifdef ForceBrs
+       sysaufs_brs = 1;
+#endif
+
+#if 0 /* verbose debug */
+       {
+               union {
+                       struct au_branch *br;
+                       struct au_dinfo *di;
+                       struct au_finfo *fi;
+                       struct au_iinfo *ii;
+                       struct au_hinode *hi;
+                       struct au_sbinfo *si;
+                       struct au_vdir_destr *destr;
+                       struct au_vdir_de *de;
+                       struct au_vdir_wh *wh;
+                       struct au_vdir *vd;
+               } u;
+
+               pr_info("br{"
+                       "xino %d, "
+                       "id %d, perm %d, mnt %d, count %d, "
+                       "wbr %d, "
+                       "xup %d, xrun %d, "
+                       "gen %d, "
+                       "sa %d} %d\n",
+                       offsetof(typeof(*u.br), br_xino),
+                       offsetof(typeof(*u.br), br_id),
+                       offsetof(typeof(*u.br), br_perm),
+                       offsetof(typeof(*u.br), br_mnt),
+                       offsetof(typeof(*u.br), br_count),
+                       offsetof(typeof(*u.br), wbr),
+                       offsetof(typeof(*u.br), br_xino_upper),
+                       offsetof(typeof(*u.br), br_xino_running),
+                       offsetof(typeof(*u.br), br_generation),
+                       offsetof(typeof(*u.br), br_sabr),
+                       sizeof(*u.br));
+               pr_info("di{gen %d, rwsem %d, bstart %d, bend %d, bwh %d, "
+                       "bdiropq %d, hdentry %d} %d\n",
+                       offsetof(typeof(*u.di), di_generation),
+                       offsetof(typeof(*u.di), di_rwsem),
+                       offsetof(typeof(*u.di), di_bstart),
+                       offsetof(typeof(*u.di), di_bend),
+                       offsetof(typeof(*u.di), di_bwh),
+                       offsetof(typeof(*u.di), di_bdiropq),
+                       offsetof(typeof(*u.di), di_hdentry),
+                       sizeof(*u.di));
+               pr_info("fi{gen %d, rwsem %d, hfile %d, bstart %d, bend %d, "
+                       "h_vm_ops %d, vdir_cach %d} %d\n",
+                       offsetof(typeof(*u.fi), fi_generation),
+                       offsetof(typeof(*u.fi), fi_rwsem),
+                       offsetof(typeof(*u.fi), fi_hfile),
+                       offsetof(typeof(*u.fi), fi_bstart),
+                       offsetof(typeof(*u.fi), fi_bend),
+                       offsetof(typeof(*u.fi), fi_h_vm_ops),
+                       offsetof(typeof(*u.fi), fi_vdir_cache),
+                       sizeof(*u.fi));
+               pr_info("ii{gen %d, hsb %d, "
+                       "rwsem %d, bstart %d, bend %d, hinode %d, vdir %d} "
+                       "%d\n",
+                       offsetof(typeof(*u.ii), ii_generation),
+                       offsetof(typeof(*u.ii), ii_hsb1),
+                       offsetof(typeof(*u.ii), ii_rwsem),
+                       offsetof(typeof(*u.ii), ii_bstart),
+                       offsetof(typeof(*u.ii), ii_bend),
+                       offsetof(typeof(*u.ii), ii_hinode),
+                       offsetof(typeof(*u.ii), ii_vdir),
+                       sizeof(*u.ii));
+               pr_info("hi{inode %d, id %d, notify %d, wh %d} %d\n",
+                       offsetof(typeof(*u.hi), hi_inode),
+                       offsetof(typeof(*u.hi), hi_id),
+                       offsetof(typeof(*u.hi), hi_notify),
+                       offsetof(typeof(*u.hi), hi_whdentry),
+                       sizeof(*u.hi));
+               pr_info("si{nwt %d, rwsem %d, gen %d, stat %d, "
+                       "bend %d, last id %d, br %d, "
+                       "cpup %d, creat %d, ops %d, ops %d, "
+                       "rr %d, mfs %d, "
+                       "mntflags %d, "
+                       "xread %d, xwrite %d, xib %d, xmtx %d, buf %d, "
+                       "xlast %d, xnext %d, "
+                       "rdcache %d, "
+                       "dirwh %d, "
+                       "pl %d, "
+                       "mnt %d, "
+                       "sys %d, "
+                       /* "lvma_l %d, lvma %d" */
+                       "} %d\n",
+                       offsetof(typeof(*u.si), si_nowait),
+                       offsetof(typeof(*u.si), si_rwsem),
+                       offsetof(typeof(*u.si), si_generation),
+                       offsetof(typeof(*u.si), au_si_status),
+                       offsetof(typeof(*u.si), si_bend),
+                       offsetof(typeof(*u.si), si_last_br_id),
+                       offsetof(typeof(*u.si), si_branch),
+                       offsetof(typeof(*u.si), si_wbr_copyup),
+                       offsetof(typeof(*u.si), si_wbr_create),
+                       offsetof(typeof(*u.si), si_wbr_copyup_ops),
+                       offsetof(typeof(*u.si), si_wbr_create_ops),
+                       offsetof(typeof(*u.si), si_wbr_rr_next),
+                       offsetof(typeof(*u.si), si_wbr_mfs),
+                       offsetof(typeof(*u.si), si_mntflags),
+                       offsetof(typeof(*u.si), si_xread),
+                       offsetof(typeof(*u.si), si_xwrite),
+                       offsetof(typeof(*u.si), si_xib),
+                       offsetof(typeof(*u.si), si_xib_mtx),
+                       offsetof(typeof(*u.si), si_xib_buf),
+                       offsetof(typeof(*u.si), si_xib_last_pindex),
+                       offsetof(typeof(*u.si), si_xib_next_bit),
+                       offsetof(typeof(*u.si), si_rdcache),
+                       offsetof(typeof(*u.si), si_dirwh),
+                       offsetof(typeof(*u.si), si_plink),
+                       offsetof(typeof(*u.si), si_mnt),
+                       offsetof(typeof(*u.si), si_sa),
+                       /*offsetof(typeof(*u.si), si_lvma_lock),
+                       offsetof(typeof(*u.si), si_lvma),*/
+                       sizeof(*u.si));
+               pr_info("destr{len %d, name %d} %d\n",
+                       offsetof(typeof(*u.destr), len),
+                       offsetof(typeof(*u.destr), name),
+                       sizeof(*u.destr));
+               pr_info("de{ino %d, type %d, str %d} %d\n",
+                       offsetof(typeof(*u.de), de_ino),
+                       offsetof(typeof(*u.de), de_type),
+                       offsetof(typeof(*u.de), de_str),
+                       sizeof(*u.de));
+               pr_info("wh{hash %d, bindex %d, str %d} %d\n",
+                       offsetof(typeof(*u.wh), wh_hash),
+                       offsetof(typeof(*u.wh), wh_bindex),
+                       offsetof(typeof(*u.wh), wh_str),
+                       sizeof(*u.wh));
+               pr_info("vd{deblk %d, nblk %d, last %d, ver %d, jiffy %d} %d\n",
+                       offsetof(typeof(*u.vd), vd_deblk),
+                       offsetof(typeof(*u.vd), vd_nblk),
+                       offsetof(typeof(*u.vd), vd_last),
+                       offsetof(typeof(*u.vd), vd_version),
+                       offsetof(typeof(*u.vd), vd_jiffy),
+                       sizeof(*u.vd));
+       }
+#endif
+
+       return 0;
+}
diff -urN linux/fs/aufs/debug.h linux-aufs/fs/aufs/debug.h
--- linux/fs/aufs/debug.h       1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/debug.h  2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,333 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * debug print functions
+ *
+ * $Id$
+ */
+
+#ifndef __AUFS_DEBUG_H__
+#define __AUFS_DEBUG_H__
+
+#ifdef __KERNEL__
+
+#include <linux/fs.h>
+#include <linux/kd.h>
+#include <linux/vt_kern.h>
+#include <linux/sysrq.h>
+
+/* to debug easier, do not make it an inlined function */
+#define MtxMustLock(mtx)       AuDebugOn(!mutex_is_locked(mtx))
+
+#ifdef CONFIG_AUFS_DEBUG
+/* sparse warns about pointer */
+#define AuDebugOn(a)           BUG_ON(!!(a))
+extern atomic_t au_cond;
+#define au_debug_on()          atomic_inc_return(&au_cond)
+#define au_debug_off()         atomic_dec_return(&au_cond)
+static inline int au_debug_test(void)
+{
+       return atomic_read(&au_cond);
+}
+#else
+#define AuDebugOn(a)           do {} while (0)
+#define au_debug_on()          do {} while (0)
+#define au_debug_off()         do {} while (0)
+static inline int au_debug_test(void)
+{
+       return 0;
+}
+#endif /* CONFIG_AUFS_DEBUG */
+
+/* ---------------------------------------------------------------------- */
+
+/* debug print */
+#if defined(CONFIG_LKTR) || defined(CONFIG_LKTR_MODULE)
+#include <linux/lktr.h>
+#ifdef CONFIG_AUFS_DEBUG
+#undef LktrCond
+#define LktrCond       unlikely(au_debug_test() || (lktr_cond && lktr_cond()))
+#endif
+#else
+#define LktrCond                       au_debug_test()
+#define LKTRDumpVma(pre, vma, suf)     do {} while (0)
+#define LKTRDumpStack()                        do {} while (0)
+#define LKTRTrace(fmt, args...) do { \
+       if (LktrCond) \
+               AuDbg(fmt, ##args); \
+} while (0)
+#define LKTRLabel(label)               LKTRTrace("%s\n", #label)
+#endif /* CONFIG_LKTR */
+
+#define AuTraceErr(e) do { \
+       if (unlikely((e) < 0)) \
+               LKTRTrace("err %d\n", (int)(e)); \
+} while (0)
+
+#define AuTraceErrPtr(p) do { \
+       if (IS_ERR(p)) \
+               LKTRTrace("err %ld\n", PTR_ERR(p)); \
+} while (0)
+
+#define AuTraceEnter() LKTRLabel(enter)
+
+/* dirty macros for debug print, use with "%.*s" and caution */
+#define AuLNPair(qstr)         (qstr)->len, (qstr)->name
+#define AuDLNPair(d)           AuLNPair(&(d)->d_name)
+
+/* ---------------------------------------------------------------------- */
+
+#define AuDpri(lvl, fmt, arg...) \
+       printk(lvl AUFS_NAME " %s:%d:%s[%d]: " fmt, \
+              __func__, __LINE__, current->comm, current->pid, ##arg)
+#define AuDbg(fmt, arg...)     AuDpri(KERN_DEBUG, fmt, ##arg)
+#define AuInfo(fmt, arg...)    AuDpri(KERN_INFO, fmt, ##arg)
+#define AuWarn(fmt, arg...)    AuDpri(KERN_WARNING, fmt, ##arg)
+#define AuErr(fmt, arg...)     AuDpri(KERN_ERR, fmt, ##arg)
+#define AuIOErr(fmt, arg...)   AuErr("I/O Error, " fmt, ##arg)
+#define AuIOErrWhck(fmt, arg...) AuErr("I/O Error, try whck. " fmt, ##arg)
+#define AuWarn1(fmt, arg...) do { \
+       static unsigned char _c; \
+       if (!_c++) \
+               AuWarn(fmt, ##arg); \
+} while (0)
+
+#define AuErr1(fmt, arg...) do { \
+       static unsigned char _c; \
+       if (!_c++) \
+               AuErr(fmt, ##arg); \
+} while (0)
+
+#define AuIOErr1(fmt, arg...) do { \
+       static unsigned char _c; \
+       if (!_c++) \
+               AuIOErr(fmt, ##arg); \
+} while (0)
+
+#define AuUnsupportMsg "This operation is not supported." \
+                       " Please report this application to aufs-users ML."
+#define AuUnsupport(fmt, args...) do { \
+       AuErr(AuUnsupportMsg "\n" fmt, ##args); \
+       dump_stack(); \
+} while (0)
+
+/* ---------------------------------------------------------------------- */
+
+struct au_sbinfo;
+#ifdef CONFIG_AUFS_DEBUG
+extern char *au_plevel;
+struct au_nhash;
+void au_dpri_whlist(struct au_nhash *whlist);
+struct au_vdir;
+void au_dpri_vdir(struct au_vdir *vdir);
+void au_dpri_inode(struct inode *inode);
+void au_dpri_dentry(struct dentry *dentry);
+void au_dpri_file(struct file *filp);
+void au_dpri_sb(struct super_block *sb);
+void au_dbg_sleep(int sec);
+void au_dbg_sleep_jiffy(int jiffy);
+
+#ifndef ATTR_TIMES_SET
+#define ATTR_TIMES_SET 0
+#endif
+void au_dbg_iattr(struct iattr *ia);
+int __init au_debug_init(void);
+void au_debug_sbinfo_init(struct au_sbinfo *sbinfo);
+#define AuDbgWhlist(w) do { \
+       LKTRTrace(#w "\n"); \
+       au_dpri_whlist(w); \
+} while (0)
+
+#define AuDbgVdir(v) do { \
+       LKTRTrace(#v "\n"); \
+       au_dpri_vdir(v); \
+} while (0)
+
+#define AuDbgInode(i) do { \
+       LKTRTrace(#i "\n"); \
+       au_dpri_inode(i); \
+} while (0)
+
+#define AuDbgDentry(d) do { \
+       LKTRTrace(#d "\n"); \
+       au_dpri_dentry(d); \
+} while (0)
+
+#define AuDbgFile(f) do { \
+       LKTRTrace(#f "\n"); \
+       au_dpri_file(f); \
+} while (0)
+
+#define AuDbgSb(sb) do { \
+       LKTRTrace(#sb "\n"); \
+       au_dpri_sb(sb); \
+} while (0)
+
+#define AuDbgSleep(sec) do { \
+       AuDbg("sleep %d sec\n", sec); \
+       au_dbg_sleep(sec); \
+} while (0)
+
+#define AuDbgSleepJiffy(jiffy) do { \
+       AuDbg("sleep %d jiffies\n", jiffy); \
+       au_dbg_sleep_jiffy(jiffy); \
+} while (0)
+
+#define AuDbgIAttr(ia) do { \
+       AuDbg("ia_valid 0x%x\n", (ia)->ia_valid); \
+       au_dbg_iattr(ia); \
+} while (0)
+#else
+static inline int au_debug_init(void)
+{
+       return 0;
+}
+static inline void au_debug_sbinfo_init(struct au_sbinfo *sbinfo)
+{
+       /* empty */
+}
+#define AuDbgWhlist(w)         do {} while (0)
+#define AuDbgVdir(v)           do {} while (0)
+#define AuDbgInode(i)          do {} while (0)
+#define AuDbgDentry(d)         do {} while (0)
+#define AuDbgFile(f)           do {} while (0)
+#define AuDbgSb(sb)            do {} while (0)
+#define AuDbgSleep(sec)                do {} while (0)
+#define AuDbgSleepJiffy(jiffy) do {} while (0)
+#define AuDbgIAttr(ia)         do {} while (0)
+#endif /* CONFIG_AUFS_DEBUG */
+
+#ifdef DbgUdbaRace
+#define AuDbgSleep_UdbaRace()  AuDbgSleep(DbgUdbaRace)
+#else
+#define AuDbgSleep_UdbaRace()  do {} while (0)
+#endif
+
+/* ---------------------------------------------------------------------- */
+
+#ifdef CONFIG_AUFS_MAGIC_SYSRQ
+int __init au_sysrq_init(void);
+void au_sysrq_fin(void);
+
+#ifdef CONFIG_HW_CONSOLE
+#define au_dbg_blocked() do { \
+       WARN_ON(1); \
+       handle_sysrq('w', vc_cons[fg_console].d->vc_tty); \
+} while (0)
+#else
+#define au_dbg_blocked()       do {} while (0)
+#endif
+
+#else
+static inline int au_sysrq_init(void)
+{
+       return 0;
+}
+#define au_sysrq_fin()         do {} while (0)
+#define au_dbg_blocked()       do {} while (0)
+#endif /* CONFIG_AUFS_MAGIC_SYSRQ */
+
+enum {
+       AuDbgLock_SI_LOCKING,
+       AuDbgLock_SI_LOCKED,
+       AuDbgLock_DI_LOCKING,
+       AuDbgLock_DI_LOCKED,
+       AuDbgLock_II_LOCKING,
+       AuDbgLock_II_LOCKED,
+       AuDbgLock_Last
+};
+#ifdef CONFIG_AUFS_DEBUG_LOCK
+void au_dbg_locking_si_reg(struct super_block *sb, int flags);
+void au_dbg_locking_si_unreg(struct super_block *sb, int flags);
+void au_dbg_locked_si_reg(struct super_block *sb, int flags);
+void au_dbg_locked_si_unreg(struct super_block *sb, int flags);
+void au_dbg_locking_di_reg(struct dentry *d, int flags, unsigned int lsc);
+void au_dbg_locking_di_unreg(struct dentry *d, int flags);
+void au_dbg_locked_di_reg(struct dentry *d, int flags, unsigned int lsc);
+void au_dbg_locked_di_unreg(struct dentry *d, int flags);
+void au_dbg_locking_ii_reg(struct inode *i, int flags, unsigned int lsc);
+void au_dbg_locking_ii_unreg(struct inode *i, int flags);
+void au_dbg_locked_ii_reg(struct inode *i, int flags, unsigned int lsc);
+void au_dbg_locked_ii_unreg(struct inode *i, int flags);
+#else
+static inline
+void au_dbg_locking_si_reg(struct super_block *sb, int flags)
+{
+       /* empty */
+}
+static inline
+void au_dbg_locking_si_unreg(struct super_block *sb, int flags)
+{
+       /* empty */
+}
+static inline
+void au_dbg_locked_si_reg(struct super_block *sb, int flags)
+{
+       /* empty */
+}
+static inline
+void au_dbg_locked_si_unreg(struct super_block *sb, int flags)
+{
+       /* empty */
+}
+
+static inline
+void au_dbg_locking_di_reg(struct dentry *d, int flags, unsigned int lsc)
+{
+       /* empty */
+}
+static inline
+void au_dbg_locking_di_unreg(struct dentry *d, int flags)
+{
+       /* empty */
+}
+static inline
+void au_dbg_locked_di_reg(struct dentry *d, int flags, unsigned int lsc)
+{
+       /* empty */
+}
+static inline
+void au_dbg_locked_di_unreg(struct dentry *d, int flags)
+{
+       /* empty */
+}
+static inline
+void au_dbg_locking_ii_reg(struct inode *i, int flags, unsigned int lsc)
+{
+       /* empty */
+}
+static inline
+void au_dbg_locking_ii_unreg(struct inode *i, int flags)
+{
+       /* empty */
+}
+static inline
+void au_dbg_locked_ii_reg(struct inode *i, int flags, unsigned int lsc)
+{
+       /* empty */
+}
+static inline
+void au_dbg_locked_ii_unreg(struct inode *i, int flags)
+{
+       /* empty */
+}
+#endif /* CONFIG_AUFS_DEBUG_LOCK */
+
+#endif /* __KERNEL__ */
+#endif /* __AUFS_DEBUG_H__ */
diff -urN linux/fs/aufs/dentry.c linux-aufs/fs/aufs/dentry.c
--- linux/fs/aufs/dentry.c      1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/dentry.c 2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,972 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * lookup and dentry operations
+ *
+ * $Id$
+ */
+
+#include "aufs.h"
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * au_lkup_one() is a generic abstract entry function which calls
+ * lookup_one_len() or __lookup_hash() finally. it is some condisions that makes
+ * lookup complicated, which are nfs branch, open-intent and dlgt mode.
+ */
+
+#if defined(CONFIG_AUFS_BR_NFS) || defined(CONFIG_AUFS_DLGT)
+/* cf. lookup_one_len() in linux/fs/namei.c */
+struct dentry *au_lkup_one(const char *name, struct dentry *parent, int len,
+                          struct au_ndx *ndx)
+{
+       struct dentry *dentry;
+
+       LKTRTrace("%.*s/%.*s, ndx{%d, 0x%x}\n",
+                 AuDLNPair(parent), len, name, !!ndx->nfsmnt, ndx->flags);
+
+       ndx->nd_file = NULL;
+       if (!ndx->nfsmnt)
+               dentry = au_lkup_one_dlgt(name, parent, len, ndx->flags);
+       else
+               dentry = au_lkup_hash(name, parent, len, ndx);
+
+       AuTraceErrPtr(dentry);
+       return dentry;
+}
+#endif /* CONFIG_AUFS_BR_NFS || CONFIG_AUFS_DLGT */
+
+struct au_lkup_one_args {
+       struct dentry **errp;
+       const char *name;
+       struct dentry *parent;
+       int len;
+       struct au_ndx *ndx;
+};
+
+static void au_call_lkup_one(void *args)
+{
+       struct au_lkup_one_args *a = args;
+       *a->errp = au_lkup_one(a->name, a->parent, a->len, a->ndx);
+}
+
+#define AuLkup_ALLOW_NEG       1
+#define AuLkup_DLGT            (1 << 1)
+#define AuLkup_DIRPERM1                (1 << 2)
+#define au_ftest_lkup(flags, name)     ((flags) & AuLkup_##name)
+#define au_fset_lkup(flags, name)      { (flags) |= AuLkup_##name; }
+#define au_fclr_lkup(flags, name)      { (flags) &= ~AuLkup_##name; }
+#ifndef CONFIG_AUFS_DLGT
+#undef AuLkup_DLGT
+#define AuLkup_DLGT    0
+#undef AuLkup_DIRPERM1
+#define AuLkup_DIRPERM1        0
+#endif
+
+struct au_do_lookup_args {
+       unsigned int            flags;
+       mode_t                  type;
+       struct nameidata        *nd;
+};
+
+/*
+ * returns positive/negative dentry, NULL or an error.
+ * NULL means whiteout-ed or not-found.
+ */
+static /* noinline_for_stack */
+struct dentry *au_do_lookup(struct dentry *h_parent, struct dentry *dentry,
+                           aufs_bindex_t bindex, struct qstr *wh_name,
+                           struct au_do_lookup_args *args)
+{
+       struct dentry *h_dentry;
+       int err, wh_found, opq;
+       unsigned char wh_able;
+       struct inode *h_dir, *h_inode, *inode;
+       struct qstr *name;
+       struct super_block *sb;
+       unsigned int nd_flags;
+       struct au_ndx ndx = {
+               .flags  = 0,
+               .nd     = args->nd
+       };
+       const int allow_neg = au_ftest_lkup(args->flags, ALLOW_NEG);
+
+       LKTRTrace("%.*s/%.*s, b%d, {flags 0x%x, type 0%o, nd %d}\n",
+                 AuDLNPair(h_parent), AuDLNPair(dentry), bindex,
+                 args->flags, args->type, !!args->nd);
+       if (args->nd)
+               LKTRTrace("nd{0x%x}\n", args->nd->flags);
+       AuDebugOn(IS_ROOT(dentry));
+       h_dir = h_parent->d_inode;
+
+       nd_flags = 0;
+       wh_found = 0;
+       sb = dentry->d_sb;
+       ndx.nfsmnt = au_nfsmnt(sb, bindex);
+       if (au_ftest_lkup(args->flags, DLGT))
+               au_fset_ndx(ndx.flags, DLGT);
+       if (au_ftest_lkup(args->flags, DIRPERM1))
+               au_fset_ndx(ndx.flags, DIRPERM1);
+       LKTRTrace("nfsmnt %p\n", ndx.nfsmnt);
+       ndx.br = au_sbr(sb, bindex);
+       wh_able = !!au_br_whable(ndx.br->br_perm);
+       name = &dentry->d_name;
+       if (wh_able)
+               wh_found = au_test_robr_wh(name, h_parent, wh_name,
+                                          /*try_sio*/0, &ndx);
+       h_dentry = ERR_PTR(wh_found);
+       if (!wh_found)
+               goto real_lookup;
+       if (unlikely(wh_found < 0))
+               goto out;
+
+       /* We found a whiteout */
+       /* au_set_dbend(dentry, bindex); */
+       au_set_dbwh(dentry, bindex);
+       if (!allow_neg)
+               return NULL; /* success */
+       if (ndx.nd
+           && au_test_nfs(h_parent->d_sb)
+           && (ndx.nd->flags & LOOKUP_CREATE)) {
+               nd_flags = ndx.nd->flags;
+               ndx.nd->flags &= ~(LOOKUP_OPEN | LOOKUP_CREATE);
+       }
+
+ real_lookup:
+       /* do not superio. */
+       h_dentry = au_lkup_one(name->name, h_parent, name->len, &ndx);
+       if (IS_ERR(h_dentry))
+               goto out;
+       AuDebugOn(d_unhashed(h_dentry));
+       h_inode = h_dentry->d_inode;
+       if (!h_inode) {
+               if (!allow_neg)
+                       goto out_neg;
+       } else if (wh_found
+                  || (args->type && args->type != (h_inode->i_mode & S_IFMT)))
+               goto out_neg;
+
+       if (au_dbend(dentry) <= bindex)
+               au_set_dbend(dentry, bindex);
+       if (au_dbstart(dentry) < 0 || bindex < au_dbstart(dentry))
+               au_set_dbstart(dentry, bindex);
+       au_set_h_dptr(dentry, bindex, h_dentry);
+
+       err = au_br_nfs_h_intent(ndx.nd_file, dentry, bindex, args->nd);
+       if (unlikely(err)) {
+               h_dentry = ERR_PTR(err);
+               goto out;
+       }
+
+       inode = dentry->d_inode;
+       if (!h_inode || !S_ISDIR(h_inode->i_mode) || !wh_able
+           || (inode && !S_ISDIR(inode->i_mode)))
+               goto out; /* success */
+
+       mutex_lock_nested(&h_inode->i_mutex, AuLsc_I_CHILD);
+       opq = au_diropq_test(h_dentry, &ndx);
+       mutex_unlock(&h_inode->i_mutex);
+       if (opq > 0)
+               au_set_dbdiropq(dentry, bindex);
+       else if (unlikely(opq < 0)) {
+               au_set_h_dptr(dentry, bindex, NULL);
+               h_dentry = ERR_PTR(opq);
+       }
+       goto out;
+
+ out_neg:
+       dput(h_dentry);
+       h_dentry = NULL;
+ out:
+       if (nd_flags)
+               ndx.nd->flags |= (nd_flags & (LOOKUP_OPEN | LOOKUP_CREATE));
+       AuTraceErrPtr(h_dentry);
+       return h_dentry;
+}
+
+/*
+ * returns the number of hidden positive dentries,
+ * otherwise an error.
+ * can be called at unlinking with @type is zero.
+ */
+int au_lkup_dentry(struct dentry *dentry, aufs_bindex_t bstart, mode_t type,
+                  struct nameidata *nd)
+{
+       int npositive, err;
+       unsigned int mnt_flags;
+       aufs_bindex_t bindex, btail, bdiropq;
+       unsigned char isdir;
+       struct qstr whname;
+       struct au_do_lookup_args args = {
+               .type   = type,
+               .nd     = nd
+       };
+       const struct qstr *name = &dentry->d_name;
+       struct dentry *parent;
+       struct super_block *sb;
+       struct inode *inode;
+
+       LKTRTrace("%.*s, b%d, type 0%o\n", AuLNPair(name), bstart, type);
+       AuDebugOn(bstart < 0 || IS_ROOT(dentry));
+
+       /* dir may not be locked */
+       parent = dget_parent(dentry);
+
+       err = au_test_robr_shwh(dentry->d_sb, name);
+       if (unlikely(err))
+               goto out;
+
+       err = au_wh_name_alloc(name->name, name->len, &whname);
+       if (unlikely(err))
+               goto out;
+
+       sb = dentry->d_sb;
+       mnt_flags = au_mntflags(sb);
+       inode = dentry->d_inode;
+       isdir = !!(inode && S_ISDIR(inode->i_mode));
+       args.flags = 0;
+       if (au_test_dlgt(mnt_flags))
+               au_fset_lkup(args.flags, DLGT);
+       if (au_test_dirperm1(mnt_flags))
+               au_fset_lkup(args.flags, DIRPERM1);
+       if (!type)
+               au_fset_lkup(args.flags, ALLOW_NEG);
+       npositive = 0;
+       btail = au_dbtaildir(parent);
+       for (bindex = bstart; bindex <= btail; bindex++) {
+               struct dentry *h_parent, *h_dentry;
+               struct inode *h_inode, *h_dir;
+
+               h_dentry = au_h_dptr(dentry, bindex);
+               if (h_dentry) {
+                       if (h_dentry->d_inode)
+                               npositive++;
+                       if (type != S_IFDIR)
+                               break;
+                       continue;
+               }
+               h_parent = au_h_dptr(parent, bindex);
+               if (!h_parent)
+                       continue;
+               h_dir = h_parent->d_inode;
+               if (!h_dir || !S_ISDIR(h_dir->i_mode))
+                       continue;
+
+               mutex_lock_nested(&h_dir->i_mutex, AuLsc_I_PARENT);
+               h_dentry = au_do_lookup(h_parent, dentry, bindex, &whname,
+                                       &args);
+               mutex_unlock(&h_dir->i_mutex);
+               err = PTR_ERR(h_dentry);
+               if (IS_ERR(h_dentry))
+                       goto out_wh;
+               au_fclr_lkup(args.flags, ALLOW_NEG);
+
+               if (au_dbwh(dentry) >= 0)
+                       break;
+               if (!h_dentry)
+                       continue;
+               h_inode = h_dentry->d_inode;
+               if (!h_inode)
+                       continue;
+               npositive++;
+               if (!args.type)
+                       args.type = h_inode->i_mode & S_IFMT;
+               if (args.type != S_IFDIR)
+                       break;
+               else if (isdir) {
+                       /* the type of lowers may be different */
+                       bdiropq = au_dbdiropq(dentry);
+                       if (bdiropq >= 0 && bdiropq <= bindex)
+                               break;
+               }
+       }
+
+       if (npositive) {
+               LKTRLabel(positive);
+               au_update_dbstart(dentry);
+       }
+       err = npositive;
+       if (!au_opt_test(mnt_flags, UDBA_NONE) && au_dbstart(dentry) < 0)
+               /* both of real entry and whiteout found */
+               err = -EIO;
+
+ out_wh:
+       au_wh_name_free(&whname);
+ out:
+       dput(parent);
+       AuTraceErr(err);
+       return err;
+}
+
+struct dentry *au_sio_lkup_one(const char *name, struct dentry *parent, int len,
+                              struct au_ndx *ndx)
+{
+       struct dentry *dentry;
+       int wkq_err;
+
+       LKTRTrace("%.*s/%.*s\n", AuDLNPair(parent), len, name);
+
+       if (!au_test_h_perm_sio(parent->d_inode, MAY_EXEC,
+                               au_ftest_ndx(ndx->flags, DLGT)))
+               dentry = au_lkup_one(name, parent, len, ndx);
+       else {
+               /* todo: ugly? */
+               unsigned int flags = ndx->flags;
+               struct au_lkup_one_args args = {
+                       .errp   = &dentry,
+                       .name   = name,
+                       .parent = parent,
+                       .len    = len,
+                       .ndx    = ndx
+               };
+
+               au_fclr_ndx(ndx->flags, DLGT);
+               au_fclr_ndx(ndx->flags, DIRPERM1);
+               wkq_err = au_wkq_wait(au_call_lkup_one, &args, /*dlgt*/0);
+               if (unlikely(wkq_err))
+                       dentry = ERR_PTR(wkq_err);
+               ndx->flags = flags;
+       }
+
+       AuTraceErrPtr(dentry);
+       return dentry;
+}
+
+/*
+ * lookup @dentry on @bindex which should be negative.
+ */
+int au_lkup_neg(struct dentry *dentry, aufs_bindex_t bindex)
+{
+       int err;
+       struct dentry *parent, *h_parent, *h_dentry;
+       struct inode *h_dir;
+       struct au_ndx ndx = {
+               .flags  = 0,
+               .nd     = NULL,
+               /* .br  = NULL */
+       };
+       struct super_block *sb;
+       unsigned int mnt_flags;
+
+       LKTRTrace("%.*s, b%d\n", AuDLNPair(dentry), bindex);
+       /* dir may not be locked */
+       parent = dget_parent(dentry);
+       AuDebugOn(!parent || !parent->d_inode
+                 || !S_ISDIR(parent->d_inode->i_mode));
+       h_parent = au_h_dptr(parent, bindex);
+       AuDebugOn(!h_parent);
+       h_dir = h_parent->d_inode;
+       AuDebugOn(!h_dir || !S_ISDIR(h_dir->i_mode));
+
+       sb = dentry->d_sb;
+       mnt_flags = au_mntflags(sb);
+       ndx.nfsmnt = au_nfsmnt(sb, bindex);
+       if (au_test_dlgt(mnt_flags))
+               au_fset_ndx(ndx.flags, DLGT);
+       if (au_test_dirperm1(mnt_flags))
+               au_fset_ndx(ndx.flags, DIRPERM1);
+       h_dentry = au_sio_lkup_one(dentry->d_name.name, h_parent,
+                                  dentry->d_name.len, &ndx);
+       err = PTR_ERR(h_dentry);
+       if (IS_ERR(h_dentry))
+               goto out;
+       if (unlikely(h_dentry->d_inode)) {
+               err = -EIO;
+               AuIOErr("b%d %.*s should be negative.\n",
+                       bindex, AuDLNPair(h_dentry));
+               dput(h_dentry);
+               goto out;
+       }
+
+       if (bindex < au_dbstart(dentry))
+               au_set_dbstart(dentry, bindex);
+       if (au_dbend(dentry) < bindex)
+               au_set_dbend(dentry, bindex);
+       au_set_h_dptr(dentry, bindex, h_dentry);
+       err = 0;
+
+ out:
+       dput(parent);
+       AuTraceErr(err);
+       return err;
+}
+
+/*
+ * returns the number of found hidden positive dentries,
+ * otherwise an error.
+ */
+int au_refresh_hdentry(struct dentry *dentry, mode_t type)
+{
+       int npositive, new_sz;
+       struct au_dinfo *dinfo;
+       struct super_block *sb;
+       struct dentry *parent;
+       aufs_bindex_t bindex, parent_bend, parent_bstart, bwh, bdiropq, bend;
+       struct au_hdentry *p;
+       au_gen_t sgen;
+
+       LKTRTrace("%.*s, type 0%o\n", AuDLNPair(dentry), type);
+       DiMustWriteLock(dentry);
+       sb = dentry->d_sb;
+       AuDebugOn(IS_ROOT(dentry));
+       sgen = au_sigen(sb);
+       parent = dget_parent(dentry);
+       AuDebugOn(au_digen(parent) != sgen
+                 || au_iigen(parent->d_inode) != sgen);
+
+       npositive = -ENOMEM;
+       new_sz = sizeof(*dinfo->di_hdentry) * (au_sbend(sb) + 1);
+       dinfo = au_di(dentry);
+       p = au_kzrealloc(dinfo->di_hdentry, sizeof(*p) * (dinfo->di_bend + 1),
+                        new_sz, GFP_NOFS);
+       if (unlikely(!p))
+               goto out;
+       dinfo->di_hdentry = p;
+
+       bend = dinfo->di_bend;
+       bwh = dinfo->di_bwh;
+       bdiropq = dinfo->di_bdiropq;
+       p += dinfo->di_bstart;
+       for (bindex = dinfo->di_bstart; bindex <= bend; bindex++, p++) {
+               struct dentry *hd, *hdp;
+               struct au_hdentry tmp, *q;
+               aufs_bindex_t new_bindex;
+
+               hd = p->hd_dentry;
+               if (!hd)
+                       continue;
+               hdp = dget_parent(hd);
+               if (hdp == au_h_dptr(parent, bindex)) {
+                       dput(hdp);
+                       continue;
+               }
+
+               new_bindex = au_find_dbindex(parent, hdp);
+               dput(hdp);
+               AuDebugOn(new_bindex == bindex);
+               if (dinfo->di_bwh == bindex)
+                       bwh = new_bindex;
+               if (dinfo->di_bdiropq == bindex)
+                       bdiropq = new_bindex;
+               /* todo: test more? */
+               if (new_bindex < 0) {
+                       au_hdput(p, /*do_free*/0);
+                       p->hd_dentry = NULL;
+                       continue;
+               }
+               /* swap two hidden dentries, and loop again */
+               q = dinfo->di_hdentry + new_bindex;
+               tmp = *q;
+               *q = *p;
+               *p = tmp;
+               if (tmp.hd_dentry) {
+                       bindex--;
+                       p--;
+               }
+       }
+
+       /* todo: test more? */
+       dinfo->di_bwh = -1;
+       if (bwh >= 0 && bwh <= au_sbend(sb) && au_sbr_whable(sb, bwh))
+               dinfo->di_bwh = bwh;
+       dinfo->di_bdiropq = -1;
+       if (bdiropq >= 0
+           && bdiropq <= au_sbend(sb)
+           && au_sbr_whable(sb, bdiropq))
+               dinfo->di_bdiropq = bdiropq;
+       parent_bend = au_dbend(parent);
+       p = dinfo->di_hdentry;
+       for (bindex = 0; bindex <= parent_bend; bindex++, p++)
+               if (p->hd_dentry) {
+                       dinfo->di_bstart = bindex;
+                       break;
+               }
+       p = dinfo->di_hdentry + parent_bend;
+       for (bindex = parent_bend; bindex >= 0; bindex--, p--)
+               if (p->hd_dentry) {
+                       dinfo->di_bend = bindex;
+                       break;
+               }
+
+       npositive = 0;
+       parent_bstart = au_dbstart(parent);
+       if (type != S_IFDIR && dinfo->di_bstart == parent_bstart)
+               goto out_dgen; /* success */
+
+       npositive = au_lkup_dentry(dentry, parent_bstart, type, /*nd*/NULL);
+       if (npositive < 0)
+               goto out;
+       if (dinfo->di_bwh >= 0 && dinfo->di_bwh <= dinfo->di_bstart)
+               d_drop(dentry);
+
+ out_dgen:
+       au_update_digen(dentry);
+ out:
+       dput(parent);
+       AuTraceErr(npositive);
+       return npositive;
+}
+
+static int au_lock_nd(struct dentry *dentry, struct nameidata *nd)
+{
+       int locked = 0;
+       if (nd && dentry != nd->path.dentry) {
+               di_read_lock_parent(nd->path.dentry, 0);
+               locked = 1;
+       }
+       return locked;
+}
+
+static void au_unlock_nd(int locked, struct nameidata *nd)
+{
+       if (locked)
+               di_read_unlock(nd->path.dentry, 0);
+}
+
+/* #define TestingFuse */
+static noinline_for_stack
+int au_do_h_d_reval(struct dentry *dentry, aufs_bindex_t bindex,
+                   struct nameidata *nd, struct dentry *h_dentry)
+{
+       int err, valid, e;
+       int (*reval)(struct dentry *, struct nameidata *);
+       struct super_block *sb;
+       struct nameidata fake_nd, *p;
+
+       LKTRTrace("%.*s, b%d, nd %d\n", AuDLNPair(dentry), bindex, !!nd);
+
+       err = 0;
+       reval = NULL;
+       if (h_dentry->d_op)
+               reval = h_dentry->d_op->d_revalidate;
+       if (!reval)
+               goto out;
+
+       sb = dentry->d_sb;
+       if (nd) {
+               memcpy(&fake_nd, nd, sizeof(*nd));
+               err = au_fake_intent(&fake_nd, au_sbr(sb, bindex));
+               if (unlikely(err)) {
+                       err = -EINVAL;
+                       goto out;
+               }
+       }
+       p = au_fake_dm(&fake_nd, nd, sb, bindex);
+       AuDebugOn(IS_ERR(p));
+       AuDebugOn(nd && p != &fake_nd);
+       LKTRTrace("b%d\n", bindex);
+
+       /* it may return tri-state */
+       valid = reval(h_dentry, p);
+       if (unlikely(valid < 0))
+               err = valid;
+       else if (!valid)
+               err = -EINVAL;
+       else
+               AuDebugOn(err);
+
+       if (p) {
+               AuDebugOn(!nd);
+               e = au_hin_after_reval(p, dentry, bindex, nd->intent.open.file);
+#ifndef TestingFuse
+               au_update_fuse_h_inode(p->path.mnt, h_dentry); /*ignore*/
+#endif
+               if (unlikely(e && !err))
+                       err = e;
+       }
+#ifndef TestingFuse
+       else
+               au_update_fuse_h_inode(NULL, h_dentry); /*ignore*/
+#endif
+       au_fake_dm_release(p);
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+static noinline_for_stack
+int h_d_revalidate(struct dentry *dentry, struct inode *inode,
+                  struct nameidata *nd, int do_udba)
+{
+       int err;
+       aufs_bindex_t bindex, btail, bstart, ibs, ibe;
+       unsigned char plus, locked, unhashed, is_root, h_plus;
+       struct super_block *sb;
+       struct inode *first, *h_inode, *h_cached_inode;
+       umode_t mode, h_mode;
+       struct dentry *h_dentry;
+       struct qstr *name;
+
+       LKTRTrace("%.*s, nd %d\n", AuDLNPair(dentry), !!nd);
+       AuDebugOn(inode && au_digen(dentry) != au_iigen(inode));
+
+       err = 0;
+       sb = dentry->d_sb;
+       plus = 0;
+       mode = 0;
+       first = NULL;
+       ibs = -1;
+       ibe = -1;
+       unhashed = !!d_unhashed(dentry);
+       is_root = !!IS_ROOT(dentry);
+       name = &dentry->d_name;
+
+       /*
+        * Theoretically, REVAL test should be unnecessary in case of INOTIFY.
+        * But inotify doesn't fire some necessary events,
+        *      IN_ATTRIB for atime/nlink/pageio
+        *      IN_DELETE for NFS dentry
+        * Let's do REVAL test too.
+        */
+       if (do_udba && inode) {
+               mode = (inode->i_mode & S_IFMT);
+               plus = (inode->i_nlink > 0);
+               first = au_h_iptr(inode, au_ibstart(inode));
+               ibs = au_ibstart(inode);
+               ibe = au_ibend(inode);
+       }
+
+       bstart = au_dbstart(dentry);
+       btail = bstart;
+       if (inode && S_ISDIR(inode->i_mode))
+               btail = au_dbtaildir(dentry);
+       locked = !!au_lock_nd(dentry, nd);
+       for (bindex = bstart; bindex <= btail; bindex++) {
+               h_dentry = au_h_dptr(dentry, bindex);
+               if (!h_dentry)
+                       continue;
+
+               LKTRTrace("b%d, %.*s\n", bindex, AuDLNPair(h_dentry));
+#ifdef TestingFuse
+               /* force re-lookup for fuse, in order to update attributes */
+               if (au_test_fuse(h_dentry->d_sb))
+                       goto err;
+#endif
+
+               if (unlikely(do_udba
+                            && !is_root
+                            && (unhashed != !!d_unhashed(h_dentry)
+                                || name->len != h_dentry->d_name.len
+                                || memcmp(name->name, h_dentry->d_name.name,
+                                          name->len)
+                                    ))) {
+                       LKTRTrace("unhash 0x%x 0x%x, %.*s %.*s\n",
+                                 unhashed, d_unhashed(h_dentry),
+                                 AuDLNPair(dentry), AuDLNPair(h_dentry));
+                       goto err;
+               }
+
+               err = au_do_h_d_reval(dentry, bindex, nd, h_dentry);
+               if (unlikely(err))
+                       /* do not goto err, to keep the errno */
+                       break;
+
+               /* todo: plink too? */
+               if (!do_udba)
+                       continue;
+
+               /* UDBA tests */
+               h_inode = h_dentry->d_inode;
+               if (unlikely(!!inode != !!h_inode))
+                       goto err;
+
+               h_plus = plus;
+               h_mode = mode;
+               h_cached_inode = h_inode;
+               if (h_inode) {
+                       h_mode = (h_inode->i_mode & S_IFMT);
+                       h_plus = (h_inode->i_nlink > 0);
+               }
+               if (inode && ibs <= bindex && bindex <= ibe)
+                       h_cached_inode = au_h_iptr(inode, bindex);
+
+               LKTRTrace("{%d, 0%o, %p}, h{%d, 0%o, %p}\n",
+                         plus, mode, h_cached_inode,
+                         h_plus, h_mode, h_inode);
+               if (unlikely(plus != h_plus
+                            || mode != h_mode
+                            || h_cached_inode != h_inode))
+                       goto err;
+               continue;
+
+       err:
+               err = -EINVAL;
+               break;
+       }
+       au_unlock_nd(locked, nd);
+
+       /*
+        * judging by timestamps is meaningless since some filesystem uses
+        * CURRENT_TIME_SEC instead of CURRENT_TIME.
+        */
+       /*
+        * NFS may stop IN_DELETE because of DCACHE_NFSFS_RENAMED.
+        */
+
+       AuTraceErr(err);
+       return err;
+}
+
+static int simple_reval_dpath(struct dentry *dentry, au_gen_t sgen)
+{
+       int err;
+       mode_t type;
+       struct dentry *parent;
+       struct inode *inode;
+
+       LKTRTrace("%.*s, sgen %d\n", AuDLNPair(dentry), sgen);
+       SiMustAnyLock(dentry->d_sb);
+       DiMustWriteLock(dentry);
+       inode = dentry->d_inode;
+       AuDebugOn(!inode);
+
+       if (au_digen(dentry) == sgen && au_iigen(inode) == sgen)
+               return 0;
+
+       parent = dget_parent(dentry);
+       di_read_lock_parent(parent, AuLock_IR);
+       AuDebugOn(au_digen(parent) != sgen
+                 || au_iigen(parent->d_inode) != sgen);
+#ifdef CONFIG_AUFS_DEBUG
+       {
+               int i, j;
+               struct au_dcsub_pages dpages;
+               struct au_dpage *dpage;
+               struct dentry **dentries;
+
+               err = au_dpages_init(&dpages, GFP_NOFS);
+               AuDebugOn(err);
+               err = au_dcsub_pages_rev(&dpages, parent, /*do_include*/1, NULL,
+                                        NULL);
+               AuDebugOn(err);
+               for (i = dpages.ndpage - 1; !err && i >= 0; i--) {
+                       dpage = dpages.dpages + i;
+                       dentries = dpage->dentries;
+                       for (j = dpage->ndentry - 1; !err && j >= 0; j--)
+                               AuDebugOn(au_digen(dentries[j]) != sgen);
+               }
+               au_dpages_free(&dpages);
+       }
+#endif
+       type = (inode->i_mode & S_IFMT);
+       /* returns a number of positive dentries */
+       err = au_refresh_hdentry(dentry, type);
+       if (err >= 0)
+               err = au_refresh_hinode(inode, dentry);
+       di_read_unlock(parent, AuLock_IR);
+       dput(parent);
+       AuTraceErr(err);
+       return err;
+}
+
+int au_reval_dpath(struct dentry *dentry, au_gen_t sgen)
+{
+       int err;
+       struct dentry *d, *parent;
+       struct inode *inode;
+
+       LKTRTrace("%.*s, sgen %d\n", AuDLNPair(dentry), sgen);
+       AuDebugOn(!dentry->d_inode);
+       DiMustWriteLock(dentry);
+
+       if (!au_ftest_si(au_sbi(dentry->d_sb), FAILED_REFRESH_DIRS))
+               return simple_reval_dpath(dentry, sgen);
+
+       /* slow loop, keep it simple and stupid */
+       /* cf: au_cpup_dirs() */
+       err = 0;
+       parent = NULL;
+       while (au_digen(dentry) != sgen || au_iigen(dentry->d_inode) != sgen) {
+               d = dentry;
+               while (1) {
+                       dput(parent);
+                       parent = dget_parent(d);
+                       if (au_digen(parent) == sgen
+                           && au_iigen(parent->d_inode) == sgen)
+                               break;
+                       d = parent;
+               }
+
+               inode = d->d_inode;
+               if (d != dentry)
+                       di_write_lock_child(d);
+
+               /* someone might update our dentry while we were sleeping */
+               if (au_digen(d) != sgen || au_iigen(d->d_inode) != sgen) {
+                       di_read_lock_parent(parent, AuLock_IR);
+                       /* returns a number of positive dentries */
+                       err = au_refresh_hdentry(d, inode->i_mode & S_IFMT);
+                       if (err >= 0)
+                               err = au_refresh_hinode(inode, d);
+                       di_read_unlock(parent, AuLock_IR);
+               }
+
+               if (d != dentry)
+                       di_write_unlock(d);
+               dput(parent);
+               if (unlikely(err))
+                       break;
+       }
+
+       AuTraceErr(err);
+       return err;
+}
+
+/*
+ * THIS IS A BOOLEAN FUNCTION: returns 1 if valid, 0 otherwise.
+ * nfsd passes NULL as nameidata.
+ */
+static int aufs_d_revalidate(struct dentry *dentry, struct nameidata *nd)
+{
+       int valid, err;
+       au_gen_t sgen;
+       unsigned char do_udba;
+       struct nameidata tmp_nd, *ndp;
+       struct super_block *sb;
+       struct inode *inode;
+
+       LKTRTrace("dentry %.*s\n", AuDLNPair(dentry));
+       if (nd && nd->path.dentry)
+               LKTRTrace("nd{%.*s, 0x%x}\n",
+                         AuDLNPair(nd->path.dentry), nd->flags);
+       /*
+        * dir case: AuDebugOn(dentry->d_parent != nd->dentry);
+        * remove failure case:AuDebugOn(!IS_ROOT(dentry)
+        *                               && d_unhashed(dentry));
+       */
+       AuDebugOn(!dentry->d_fsdata);
+
+       err = -EINVAL;
+       sb = dentry->d_sb;
+       aufs_read_lock(dentry, AuLock_FLUSH | AuLock_DW);
+       inode = dentry->d_inode;
+       sgen = au_sigen(sb);
+       if (au_digen(dentry) != sgen) {
+               AuDebugOn(IS_ROOT(dentry));
+#ifdef ForceInotify
+               AuDbg("UDBA or digen, %.*s\n", AuDLNPair(dentry));
+#endif
+               if (inode)
+                       err = au_reval_dpath(dentry, sgen);
+               if (unlikely(err))
+                       goto out_dgrade;
+               AuDebugOn(au_digen(dentry) != sgen);
+       }
+       if (inode && au_iigen(inode) != sgen) {
+               AuDebugOn(IS_ROOT(dentry));
+#ifdef ForceInotify
+               AuDbg("UDBA or survived, %.*s\n", AuDLNPair(dentry));
+#endif
+               err = au_refresh_hinode(inode, dentry);
+               if (unlikely(err))
+                       goto out_dgrade;
+               AuDebugOn(au_iigen(inode) != sgen);
+       }
+       di_downgrade_lock(dentry, AuLock_IR);
+
+#if 0 /* todo: support it? */
+       /* parent dir i_nlink is not updated in the case of setattr */
+       if (S_ISDIR(inode->i_mode)) {
+               mutex_lock(&inode->i_mutex);
+               ii_write_lock(inode);
+               au_cpup_attr_nlink(inode);
+               ii_write_unlock(inode);
+               mutex_unlock(&inode->i_mutex);
+       }
+#endif
+
+       AuDebugOn(au_digen(dentry) != sgen);
+       AuDebugOn(inode && au_iigen(inode) != sgen);
+       err = -EINVAL;
+       do_udba = !au_opt_test(au_mntflags(sb), UDBA_NONE);
+       if (do_udba && inode) {
+               aufs_bindex_t bstart = au_ibstart(inode);
+               if (bstart >= 0
+                   && au_test_higen(inode, au_h_iptr(inode, bstart)))
+                       goto out;
+       }
+       ndp = au_dup_nd(au_sbi(sb), &tmp_nd, nd);
+#if 0
+       if (nd) {
+               path = nd->path;
+               nd->path.dentry = au_h_dptr(nd->path.dentry, bindex);
+       if (fake_nd->path.dentry) {
+               fake_nd->path.mnt = au_sbr_mnt(sb, bindex);
+               AuDebugOn(!fake_nd->path.mnt);
+               path_get(&fake_nd->path);
+               nd->path.
+                       }
+       }
+#endif
+       err = h_d_revalidate(dentry, inode, ndp, do_udba);
+       if (unlikely(!err && do_udba && au_dbstart(dentry) < 0))
+               /* both of real entry and whiteout found */
+               err = -EIO;
+       goto out;
+
+ out_dgrade:
+       di_downgrade_lock(dentry, AuLock_IR);
+ out:
+       au_store_fmode_exec(nd, inode);
+       aufs_read_unlock(dentry, AuLock_IR);
+       AuTraceErr(err);
+       valid = !err;
+       if (!valid)
+               LKTRTrace("%.*s invalid\n", AuDLNPair(dentry));
+       return valid;
+}
+
+static void aufs_d_release(struct dentry *dentry)
+{
+       struct au_dinfo *dinfo;
+       aufs_bindex_t bend, bindex;
+
+       LKTRTrace("%.*s\n", AuDLNPair(dentry));
+       AuDebugOn(!d_unhashed(dentry));
+
+       dinfo = dentry->d_fsdata;
+       if (!dinfo)
+               return;
+
+       /* dentry may not be revalidated */
+       bindex = dinfo->di_bstart;
+       if (bindex >= 0) {
+               struct au_hdentry *p;
+               bend = dinfo->di_bend;
+               AuDebugOn(bend < bindex);
+               p = dinfo->di_hdentry + bindex;
+               while (bindex++ <= bend) {
+                       if (p->hd_dentry)
+                               au_hdput(p, /*do_free*/1);
+                       p++;
+               }
+       }
+       kfree(dinfo->di_hdentry);
+       au_rwsem_destroy(&dinfo->di_rwsem);
+       au_cache_free_dinfo(dinfo);
+       au_hin_di_reinit(dentry);
+}
+
+struct dentry_operations aufs_dop = {
+       .d_revalidate   = aufs_d_revalidate,
+       .d_release      = aufs_d_release,
+       /* never use d_delete, especially in case of nfs server */
+};
diff -urN linux/fs/aufs/dentry.h linux-aufs/fs/aufs/dentry.h
--- linux/fs/aufs/dentry.h      1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/dentry.h 2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,396 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * lookup and dentry operations
+ *
+ * $Id$
+ */
+
+#ifndef __AUFS_DENTRY_H__
+#define __AUFS_DENTRY_H__
+
+#ifdef __KERNEL__
+
+#include <linux/fs.h>
+#include <linux/namei.h>
+#include <linux/aufs_type.h>
+#include "misc.h"
+#include "super.h"
+#include "vfsub.h"
+
+/* nameidata open_intent */
+enum {
+       AuIntent_AUFS,
+       AuIntent_BRANCH,
+       AuIntent_Last
+};
+
+struct au_hdintent {
+       struct list_head        hdi_list;
+       struct file             *hdi_file[AuIntent_Last];
+};
+
+struct au_hdentry {
+       struct dentry           *hd_dentry;
+
+#ifdef CONFIG_AUFS_BR_NFS
+       spinlock_t              hd_lock; /* intest_list */
+       struct list_head        *hd_intent_list;
+#endif
+};
+
+struct au_dinfo {
+       atomic_t                di_generation;
+
+       struct au_rwsem         di_rwsem;
+       aufs_bindex_t           di_bstart, di_bend, di_bwh, di_bdiropq;
+       struct au_hdentry       *di_hdentry;
+};
+
+/* nameidata extension flags */
+#define AuNdx_DLGT     1
+#define AuNdx_DIRPERM1 (1 << 1)
+#define au_ftest_ndx(flags, name)      ((flags) & AuNdx_##name)
+#define au_fset_ndx(flags, name)       { (flags) |= AuNdx_##name; }
+#define au_fclr_ndx(flags, name)       { (flags) &= ~AuNdx_##name; }
+#ifndef CONFIG_AUFS_DLGT
+#undef AuNdx_DLGT
+#define AuNdx_DLGT     0
+#undef AuNdx_DIRPERM1
+#define AuNdx_DIRPERM1 0
+#endif
+
+struct au_ndx {
+       struct vfsmount *nfsmnt;
+       unsigned int flags;
+       struct nameidata *nd;
+       struct au_branch *br;
+       struct file *nd_file;
+};
+
+/* ---------------------------------------------------------------------- */
+
+static inline void au_do_h_dentry_init(struct au_hdentry *hdentry)
+{
+       hdentry->hd_dentry = NULL;
+}
+
+#ifdef CONFIG_AUFS_BR_NFS
+static inline void au_h_dentry_init(struct au_hdentry *hdentry)
+{
+       au_do_h_dentry_init(hdentry);
+       spin_lock_init(&hdentry->hd_lock);
+}
+
+static inline void au_h_dentry_init_all(struct au_hdentry *hdentry, int n)
+{
+       while (n--)
+               spin_lock_init(&hdentry[n].hd_lock);
+}
+
+/* br_nfs.c */
+struct file *au_h_intent(struct dentry *dentry, aufs_bindex_t bindex,
+                        struct file *file);
+int au_br_nfs_h_intent(struct file *nd_file, struct dentry *dentry,
+                      aufs_bindex_t bindex, struct nameidata *nd);
+void au_hintent_put(struct au_hdentry *hd, int do_free);
+int au_fake_intent(struct nameidata *nd, struct au_branch *br);
+int au_hin_after_reval(struct nameidata *nd, struct dentry *dentry,
+                      aufs_bindex_t bindex, struct file *file);
+struct dentry *au_lkup_hash(const char *name, struct dentry *parent, int len,
+                           struct au_ndx *ndx);
+#else
+
+static inline void au_h_dentry_init(struct au_hdentry *hdentry)
+{
+       au_do_h_dentry_init(hdentry);
+}
+
+static inline void au_h_dentry_init_all(struct au_hdentry *hdentry, int n)
+{
+       /* nothing */
+}
+
+static inline
+struct file *au_h_intent(struct dentry *dentry, aufs_bindex_t bindex,
+                        struct file *file)
+{
+       /* return ERR_PTR(-ENOSYS); */
+       return NULL;
+}
+
+static inline
+int au_br_nfs_h_intent(struct file *nd_file, struct dentry *dentry,
+                      aufs_bindex_t bindex, struct nameidata *nd)
+{
+       return 0;
+}
+
+static inline void au_hintent_put(struct au_hdentry *hd, int do_free)
+{
+       /* empty */
+}
+
+static inline int au_fake_intent(struct nameidata *nd, struct au_branch *br)
+{
+       return 0;
+}
+
+static inline
+int au_hin_after_reval(struct nameidata *nd, struct dentry *dentry,
+                      aufs_bindex_t bindex, struct file *file)
+{
+       return 0;
+}
+
+#ifdef CONFIG_AUFS_DLGT
+static inline
+struct dentry *au_lkup_hash(const char *name, struct dentry *parent, int len,
+                           struct au_ndx *ndx)
+{
+       /* return ERR_PTR(-ENOSYS); */
+       return vfsub_lookup_one_len(name, parent, len);
+}
+#endif
+#endif /* CONFIG_AUFS_BR_NFS */
+
+#ifdef CONFIG_AUFS_DLGT
+/* dlgt.c */
+struct dentry *au_lkup_one_dlgt(const char *name, struct dentry *parent,
+                               int len, unsigned int flags);
+#elif defined(CONFIG_AUFS_BR_NFS)
+/* regardelss kernel version */
+static inline
+struct dentry *au_lkup_one_dlgt(const char *name, struct dentry *parent,
+                               int len, unsigned int flags)
+{
+       return vfsub_lookup_one_len(name, parent, len);
+}
+#endif
+
+/* dentry.c */
+extern struct dentry_operations aufs_dop;
+#if defined(CONFIG_AUFS_BR_NFS) || defined(CONFIG_AUFS_DLGT)
+struct dentry *au_lkup_one(const char *name, struct dentry *parent, int len,
+                          struct au_ndx *ndx);
+#else
+static inline
+struct dentry *au_lkup_one(const char *name, struct dentry *parent, int len,
+                          struct au_ndx *ndx)
+{
+       /* todo? ndx->nd_file = NULL; */
+       return vfsub_lookup_one_len(name, parent, len);
+}
+#endif
+struct dentry *au_sio_lkup_one(const char *name, struct dentry *parent, int len,
+                              struct au_ndx *ndx);
+int au_lkup_dentry(struct dentry *dentry, aufs_bindex_t bstart, mode_t type,
+                  struct nameidata *nd);
+int au_lkup_neg(struct dentry *dentry, aufs_bindex_t bindex);
+int au_refresh_hdentry(struct dentry *dentry, mode_t type);
+int au_reval_dpath(struct dentry *dentry, au_gen_t sgen);
+
+/* dinfo.c */
+int au_alloc_dinfo(struct dentry *dentry);
+struct au_dinfo *au_di(struct dentry *dentry);
+
+void di_read_lock(struct dentry *d, int flags, unsigned int lsc);
+void di_read_unlock(struct dentry *d, int flags);
+void di_downgrade_lock(struct dentry *d, int flags);
+void di_write_lock(struct dentry *d, unsigned int lsc);
+void di_write_unlock(struct dentry *d);
+void di_write_lock2_child(struct dentry *d1, struct dentry *d2, int isdir);
+void di_write_lock2_parent(struct dentry *d1, struct dentry *d2, int isdir);
+void di_write_unlock2(struct dentry *d1, struct dentry *d2);
+
+struct dentry *au_h_dptr(struct dentry *dentry, aufs_bindex_t bindex);
+
+aufs_bindex_t au_dbtail(struct dentry *dentry);
+aufs_bindex_t au_dbtaildir(struct dentry *dentry);
+#if 0 /* reserved for future use */
+aufs_bindex_t au_dbtail_generic(struct dentry *dentry);
+#endif
+
+void au_set_dbdiropq(struct dentry *dentry, aufs_bindex_t bindex);
+void au_set_h_dptr(struct dentry *dentry, aufs_bindex_t bindex,
+                  struct dentry *h_dentry);
+
+void au_update_dbrange(struct dentry *dentry, int do_put_zero);
+void au_update_dbstart(struct dentry *dentry);
+void au_update_dbend(struct dentry *dentry);
+int au_find_dbindex(struct dentry *dentry, struct dentry *h_dentry);
+
+/* ---------------------------------------------------------------------- */
+
+/* todo: memory barrier? */
+static inline au_gen_t au_digen(struct dentry *d)
+{
+       return atomic_read(&au_di(d)->di_generation);
+}
+
+#ifdef CONFIG_AUFS_HINOTIFY
+static inline au_gen_t au_digen_dec(struct dentry *d)
+{
+       return atomic_dec_return(&au_di(d)->di_generation);
+}
+
+static inline void au_hin_di_reinit(struct dentry *d)
+{
+       d->d_fsdata = NULL;
+}
+#else
+static inline void au_hin_di_reinit(struct dentry *d)
+{
+       /* empty */
+}
+#endif /* CONFIG_AUFS_HINOTIFY */
+
+/* ---------------------------------------------------------------------- */
+
+/* lock subclass for dinfo */
+enum {
+       AuLsc_DI_CHILD,         /* child first */
+       AuLsc_DI_CHILD2,        /* rename(2), link(2), and cpup at hinotify */
+       AuLsc_DI_CHILD3,        /* copyup dirs */
+       AuLsc_DI_PARENT,
+       AuLsc_DI_PARENT2,
+       AuLsc_DI_PARENT3,
+       AuLsc_DI_PARENT4
+};
+
+/*
+ * di_read_lock_child, di_write_lock_child,
+ * di_read_lock_child2, di_write_lock_child2,
+ * di_read_lock_child3, di_write_lock_child3,
+ * di_read_lock_parent, di_write_lock_parent,
+ * di_read_lock_parent2, di_write_lock_parent2,
+ * di_read_lock_parent3, di_write_lock_parent3,
+ * di_read_lock_parent4, di_write_lock_parent4,
+ */
+#define AuReadLockFunc(name, lsc) \
+static inline void di_read_lock_##name(struct dentry *d, int flags) \
+{ di_read_lock(d, flags, AuLsc_DI_##lsc); }
+
+#define AuWriteLockFunc(name, lsc) \
+static inline void di_write_lock_##name(struct dentry *d) \
+{ di_write_lock(d, AuLsc_DI_##lsc); }
+
+#define AuRWLockFuncs(name, lsc) \
+       AuReadLockFunc(name, lsc) \
+       AuWriteLockFunc(name, lsc)
+
+AuRWLockFuncs(child, CHILD);
+AuRWLockFuncs(child2, CHILD2);
+AuRWLockFuncs(child3, CHILD3);
+AuRWLockFuncs(parent, PARENT);
+AuRWLockFuncs(parent2, PARENT2);
+AuRWLockFuncs(parent3, PARENT3);
+AuRWLockFuncs(parent4, PARENT4);
+
+#undef AuReadLockFunc
+#undef AuWriteLockFunc
+#undef AuRWLockFuncs
+
+/* to debug easier, do not make them inlined functions */
+#define DiMustReadLock(d) do { \
+       SiMustAnyLock((d)->d_sb); \
+       AuRwMustReadLock(&au_di(d)->di_rwsem); \
+} while (0)
+
+#define DiMustWriteLock(d) do { \
+       SiMustAnyLock((d)->d_sb); \
+       AuRwMustWriteLock(&au_di(d)->di_rwsem); \
+} while (0)
+
+#define DiMustAnyLock(d) do { \
+       SiMustAnyLock((d)->d_sb); \
+       AuRwMustAnyLock(&au_di(d)->di_rwsem); \
+} while (0)
+
+#define DiMustNoWaiters(d)     AuRwMustNoWaiters(&au_di(d)->di_rwsem)
+
+/* ---------------------------------------------------------------------- */
+
+static inline aufs_bindex_t au_dbstart(struct dentry *dentry)
+{
+       DiMustAnyLock(dentry);
+       return au_di(dentry)->di_bstart;
+}
+
+static inline aufs_bindex_t au_dbend(struct dentry *dentry)
+{
+       DiMustAnyLock(dentry);
+       return au_di(dentry)->di_bend;
+}
+
+static inline aufs_bindex_t au_dbwh(struct dentry *dentry)
+{
+       DiMustAnyLock(dentry);
+       return au_di(dentry)->di_bwh;
+}
+
+static inline aufs_bindex_t au_dbdiropq(struct dentry *dentry)
+{
+       DiMustAnyLock(dentry);
+       AuDebugOn(dentry->d_inode
+                 && dentry->d_inode->i_mode
+                 && !S_ISDIR(dentry->d_inode->i_mode));
+       return au_di(dentry)->di_bdiropq;
+}
+
+/* todo: hard/soft set? */
+static inline void au_set_dbstart(struct dentry *dentry, aufs_bindex_t bindex)
+{
+       DiMustWriteLock(dentry);
+       AuDebugOn(au_sbend(dentry->d_sb) < bindex);
+       /* */
+       au_di(dentry)->di_bstart = bindex;
+}
+
+static inline void au_set_dbend(struct dentry *dentry, aufs_bindex_t bindex)
+{
+       DiMustWriteLock(dentry);
+       AuDebugOn(au_sbend(dentry->d_sb) < bindex
+                 || bindex < au_dbstart(dentry));
+       au_di(dentry)->di_bend = bindex;
+}
+
+static inline void au_set_dbwh(struct dentry *dentry, aufs_bindex_t bindex)
+{
+       DiMustWriteLock(dentry);
+       AuDebugOn(au_sbend(dentry->d_sb) < bindex);
+       /* dbwh can be outside of bstart - bend range */
+       au_di(dentry)->di_bwh = bindex;
+}
+
+static inline void au_hdput(struct au_hdentry *hd, int do_free)
+{
+       au_hintent_put(hd, do_free);
+       dput(hd->hd_dentry);
+}
+
+static inline void au_update_digen(struct dentry *dentry)
+{
+       AuDebugOn(!dentry->d_sb);
+       atomic_set(&au_di(dentry)->di_generation, au_sigen(dentry->d_sb));
+       /* smp_mb(); */ /* atomic_set */
+}
+
+#endif /* __KERNEL__ */
+#endif /* __AUFS_DENTRY_H__ */
diff -urN linux/fs/aufs/dinfo.c linux-aufs/fs/aufs/dinfo.c
--- linux/fs/aufs/dinfo.c       1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/dinfo.c  2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,436 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * dentry private data
+ *
+ * $Id$
+ */
+
+#include "aufs.h"
+
+int au_alloc_dinfo(struct dentry *dentry)
+{
+       struct au_dinfo *dinfo;
+       struct super_block *sb;
+       int nbr;
+
+       LKTRTrace("%.*s\n", AuDLNPair(dentry));
+       AuDebugOn(dentry->d_fsdata);
+
+       dinfo = au_cache_alloc_dinfo();
+       if (dinfo) {
+               sb = dentry->d_sb;
+               nbr = au_sbend(sb) + 1;
+               if (nbr <= 0)
+                       nbr = 1;
+               dinfo->di_hdentry = kcalloc(nbr, sizeof(*dinfo->di_hdentry),
+                                           GFP_NOFS);
+               if (dinfo->di_hdentry) {
+                       au_h_dentry_init_all(dinfo->di_hdentry, nbr);
+                       atomic_set(&dinfo->di_generation, au_sigen(sb));
+                       /* smp_mb(); */ /* atomic_set */
+                       au_rw_init_wlock_nested(&dinfo->di_rwsem,
+                                               AuLsc_DI_CHILD);
+                       au_dbg_locked_di_reg(dentry, AuLock_DW, AuLsc_DI_CHILD);
+                       dinfo->di_bstart = -1;
+                       dinfo->di_bend = -1;
+                       dinfo->di_bwh = -1;
+                       dinfo->di_bdiropq = -1;
+
+                       dentry->d_fsdata = dinfo;
+                       dentry->d_op = &aufs_dop;
+                       return 0; /* success */
+               }
+               au_cache_free_dinfo(dinfo);
+       }
+       AuTraceErr(-ENOMEM);
+       return -ENOMEM;
+}
+
+struct au_dinfo *au_di(struct dentry *dentry)
+{
+       struct au_dinfo *dinfo = dentry->d_fsdata;
+       AuDebugOn(!dinfo
+                || !dinfo->di_hdentry
+                /* || au_sbi(dentry->d_sb)->si_bend < dinfo->di_bend */
+                || dinfo->di_bend < dinfo->di_bstart
+                /* dbwh can be outside of this range */
+                || (0 <= dinfo->di_bdiropq
+                    && (dinfo->di_bdiropq < dinfo->di_bstart
+                        /* || dinfo->di_bend < dinfo->di_bdiropq */))
+               );
+       return dinfo;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static void do_ii_write_lock(struct inode *inode, unsigned int lsc)
+{
+       switch (lsc) {
+       case AuLsc_DI_CHILD:
+               ii_write_lock_child(inode);
+               break;
+       case AuLsc_DI_CHILD2:
+               ii_write_lock_child2(inode);
+               break;
+       case AuLsc_DI_CHILD3:
+               ii_write_lock_child3(inode);
+               break;
+       case AuLsc_DI_PARENT:
+               ii_write_lock_parent(inode);
+               break;
+       case AuLsc_DI_PARENT2:
+               ii_write_lock_parent2(inode);
+               break;
+       case AuLsc_DI_PARENT3:
+               ii_write_lock_parent3(inode);
+               break;
+       case AuLsc_DI_PARENT4:
+               ii_write_lock_parent4(inode);
+               break;
+       default:
+               BUG();
+       }
+}
+
+static void do_ii_read_lock(struct inode *inode, unsigned int lsc)
+{
+       switch (lsc) {
+       case AuLsc_DI_CHILD:
+               ii_read_lock_child(inode);
+               break;
+       case AuLsc_DI_CHILD2:
+               ii_read_lock_child2(inode);
+               break;
+       case AuLsc_DI_CHILD3:
+               ii_read_lock_child3(inode);
+               break;
+       case AuLsc_DI_PARENT:
+               ii_read_lock_parent(inode);
+               break;
+       case AuLsc_DI_PARENT2:
+               ii_read_lock_parent2(inode);
+               break;
+       case AuLsc_DI_PARENT3:
+               ii_read_lock_parent3(inode);
+               break;
+       case AuLsc_DI_PARENT4:
+               ii_read_lock_parent4(inode);
+               break;
+       default:
+               BUG();
+       }
+}
+
+void di_read_lock(struct dentry *d, int flags, unsigned int lsc)
+{
+       LKTRTrace("%.*s, %u\n", AuDLNPair(d), lsc);
+       SiMustAnyLock(d->d_sb);
+
+       /* todo: always nested? */
+       au_dbg_locking_di_reg(d, flags, lsc);
+       au_rw_read_lock_nested(&au_di(d)->di_rwsem, lsc);
+       au_dbg_locking_di_unreg(d, flags);
+       au_dbg_locked_di_reg(d, flags, lsc);
+       if (d->d_inode) {
+               if (au_ftest_lock(flags, IW))
+                       do_ii_write_lock(d->d_inode, lsc);
+               else if (au_ftest_lock(flags, IR))
+                       do_ii_read_lock(d->d_inode, lsc);
+       }
+}
+
+void di_read_unlock(struct dentry *d, int flags)
+{
+       LKTRTrace("%.*s\n", AuDLNPair(d));
+       SiMustAnyLock(d->d_sb);
+
+       if (d->d_inode) {
+               if (au_ftest_lock(flags, IW))
+                       ii_write_unlock(d->d_inode);
+               else if (au_ftest_lock(flags, IR))
+                       ii_read_unlock(d->d_inode);
+       }
+       au_rw_read_unlock(&au_di(d)->di_rwsem);
+       au_dbg_locked_di_unreg(d, flags);
+}
+
+void di_downgrade_lock(struct dentry *d, int flags)
+{
+       SiMustAnyLock(d->d_sb);
+
+       au_rw_dgrade_lock(&au_di(d)->di_rwsem);
+       if (d->d_inode && au_ftest_lock(flags, IR))
+               ii_downgrade_lock(d->d_inode);
+}
+
+void di_write_lock(struct dentry *d, unsigned int lsc)
+{
+       LKTRTrace("%.*s, %u\n", AuDLNPair(d), lsc);
+       SiMustAnyLock(d->d_sb);
+
+       /* todo: always nested? */
+       au_dbg_locking_di_reg(d, AuLock_IW, lsc);
+       au_rw_write_lock_nested(&au_di(d)->di_rwsem, lsc);
+       au_dbg_locking_di_unreg(d, AuLock_IW);
+       au_dbg_locked_di_reg(d, AuLock_IW, lsc);
+       if (d->d_inode)
+               do_ii_write_lock(d->d_inode, lsc);
+}
+
+void di_write_unlock(struct dentry *d)
+{
+       LKTRTrace("%.*s\n", AuDLNPair(d));
+       SiMustAnyLock(d->d_sb);
+
+       if (d->d_inode)
+               ii_write_unlock(d->d_inode);
+       au_rw_write_unlock(&au_di(d)->di_rwsem);
+       au_dbg_locked_di_unreg(d, AuLock_IW);
+}
+
+void di_write_lock2_child(struct dentry *d1, struct dentry *d2, int isdir)
+{
+       AuTraceEnter();
+       AuDebugOn(d1 == d2
+                 || d1->d_inode == d2->d_inode
+                 || d1->d_sb != d2->d_sb);
+
+       if (isdir && au_test_subdir(d1, d2)) {
+               di_write_lock_child(d1);
+               di_write_lock_child2(d2);
+       } else {
+               /* there should be no races */
+               di_write_lock_child(d2);
+               di_write_lock_child2(d1);
+       }
+}
+
+void di_write_lock2_parent(struct dentry *d1, struct dentry *d2, int isdir)
+{
+       AuTraceEnter();
+       AuDebugOn(d1 == d2
+                 || d1->d_inode == d2->d_inode
+                 || d1->d_sb != d2->d_sb);
+
+       if (isdir && au_test_subdir(d1, d2)) {
+               di_write_lock_parent(d1);
+               di_write_lock_parent2(d2);
+       } else {
+               /* there should be no races */
+               di_write_lock_parent(d2);
+               di_write_lock_parent2(d1);
+       }
+}
+
+void di_write_unlock2(struct dentry *d1, struct dentry *d2)
+{
+       di_write_unlock(d1);
+       if (d1->d_inode == d2->d_inode) {
+               au_rw_write_unlock(&au_di(d2)->di_rwsem);
+               au_dbg_locked_di_unreg(d2, AuLock_IW);
+       } else
+               di_write_unlock(d2);
+}
+
+/* ---------------------------------------------------------------------- */
+
+struct dentry *au_h_dptr(struct dentry *dentry, aufs_bindex_t bindex)
+{
+       struct dentry *d;
+
+       DiMustAnyLock(dentry);
+       if (au_dbstart(dentry) < 0 || bindex < au_dbstart(dentry))
+               return NULL;
+       AuDebugOn(bindex < 0
+                 /* || bindex > au_sbend(dentry->d_sb) */);
+       d = au_di(dentry)->di_hdentry[0 + bindex].hd_dentry;
+       AuDebugOn(d && (atomic_read(&d->d_count) <= 0));
+       return d;
+}
+
+aufs_bindex_t au_dbtail(struct dentry *dentry)
+{
+       aufs_bindex_t bend, bwh;
+
+       bend = au_dbend(dentry);
+       if (0 <= bend) {
+               bwh = au_dbwh(dentry);
+               if (!bwh)
+                       return bwh;
+               if (0 < bwh && bwh < bend)
+                       return bwh - 1;
+       }
+       return bend;
+}
+
+aufs_bindex_t au_dbtaildir(struct dentry *dentry)
+{
+       aufs_bindex_t bend, bopq;
+
+       AuDebugOn(dentry->d_inode
+                 && dentry->d_inode->i_mode
+                 && !S_ISDIR(dentry->d_inode->i_mode));
+
+       bend = au_dbtail(dentry);
+       if (0 <= bend) {
+               bopq = au_dbdiropq(dentry);
+               AuDebugOn(bend < bopq);
+               if (0 <= bopq && bopq < bend)
+                       bend = bopq;
+       }
+       return bend;
+}
+
+#if 0 /* reserved for future use */
+aufs_bindex_t au_dbtail_generic(struct dentry *dentry)
+{
+       struct inode *inode;
+
+       inode = dentry->d_inode;
+       if (inode && S_ISDIR(inode->i_mode))
+               return au_dbtaildir(dentry);
+       else
+               return au_dbtail(dentry);
+}
+#endif
+
+/* ---------------------------------------------------------------------- */
+
+void au_set_dbdiropq(struct dentry *dentry, aufs_bindex_t bindex)
+{
+       DiMustWriteLock(dentry);
+       AuDebugOn(au_sbend(dentry->d_sb) < bindex);
+       AuDebugOn((bindex >= 0
+                  && (bindex < au_dbstart(dentry)
+                      || au_dbend(dentry) < bindex))
+                 || (dentry->d_inode
+                     && dentry->d_inode->i_mode
+                     && !S_ISDIR(dentry->d_inode->i_mode)));
+       au_di(dentry)->di_bdiropq = bindex;
+}
+
+void au_set_h_dptr(struct dentry *dentry, aufs_bindex_t bindex,
+                  struct dentry *h_dentry)
+{
+       struct au_hdentry *hd = au_di(dentry)->di_hdentry + bindex;
+       DiMustWriteLock(dentry);
+       AuDebugOn(bindex < au_di(dentry)->di_bstart
+                 || bindex > au_di(dentry)->di_bend
+                 || (h_dentry && atomic_read(&h_dentry->d_count) <= 0)
+                 || (h_dentry && hd->hd_dentry)
+               );
+       if (hd->hd_dentry)
+               au_hdput(hd, /*do_free*/0);
+       hd->hd_dentry = h_dentry;
+}
+
+/* ---------------------------------------------------------------------- */
+
+void au_update_dbrange(struct dentry *dentry, int do_put_zero)
+{
+       struct au_dinfo *dinfo;
+       aufs_bindex_t bindex;
+       struct dentry *h_d;
+
+       LKTRTrace("%.*s, %d\n", AuDLNPair(dentry), do_put_zero);
+       DiMustWriteLock(dentry);
+
+       dinfo = au_di(dentry);
+       if (!dinfo || dinfo->di_bstart < 0)
+               return;
+
+       if (do_put_zero) {
+               for (bindex = dinfo->di_bstart; bindex <= dinfo->di_bend;
+                    bindex++) {
+                       h_d = dinfo->di_hdentry[0 + bindex].hd_dentry;
+                       if (h_d && !h_d->d_inode)
+                               au_set_h_dptr(dentry, bindex, NULL);
+               }
+       }
+
+       dinfo->di_bstart = -1;
+       while (++dinfo->di_bstart <= dinfo->di_bend)
+               if (dinfo->di_hdentry[0 + dinfo->di_bstart].hd_dentry)
+                       break;
+       if (dinfo->di_bstart > dinfo->di_bend) {
+               dinfo->di_bstart = -1;
+               dinfo->di_bend = -1;
+               return;
+       }
+
+       dinfo->di_bend++;
+       while (0 <= --dinfo->di_bend)
+               if (dinfo->di_hdentry[0 + dinfo->di_bend].hd_dentry)
+                       break;
+       AuDebugOn(dinfo->di_bstart > dinfo->di_bend || dinfo->di_bend < 0);
+}
+
+void au_update_dbstart(struct dentry *dentry)
+{
+       aufs_bindex_t bindex,
+               bstart = au_dbstart(dentry),
+               bend = au_dbend(dentry);
+       struct dentry *h_dentry;
+
+       LKTRTrace("%.*s\n", AuDLNPair(dentry));
+       DiMustWriteLock(dentry);
+
+       for (bindex = bstart; bindex <= bend; bindex++) {
+               h_dentry = au_h_dptr(dentry, bindex);
+               if (!h_dentry)
+                       continue;
+               if (h_dentry->d_inode) {
+                       au_set_dbstart(dentry, bindex);
+                       return;
+               }
+               au_set_h_dptr(dentry, bindex, NULL);
+       }
+}
+
+void au_update_dbend(struct dentry *dentry)
+{
+       aufs_bindex_t bindex,
+               bstart = au_dbstart(dentry),
+               bend = au_dbend(dentry);
+       struct dentry *h_dentry;
+
+       DiMustWriteLock(dentry);
+       for (bindex = bend; bindex <= bstart; bindex--) {
+               h_dentry = au_h_dptr(dentry, bindex);
+               if (!h_dentry)
+                       continue;
+               if (h_dentry->d_inode) {
+                       au_set_dbend(dentry, bindex);
+                       return;
+               }
+               au_set_h_dptr(dentry, bindex, NULL);
+       }
+}
+
+int au_find_dbindex(struct dentry *dentry, struct dentry *h_dentry)
+{
+       aufs_bindex_t bindex, bend;
+
+       bend = au_dbend(dentry);
+       for (bindex = au_dbstart(dentry); bindex <= bend; bindex++)
+               if (au_h_dptr(dentry, bindex) == h_dentry)
+                       return bindex;
+       return -1;
+}
diff -urN linux/fs/aufs/dir.c linux-aufs/fs/aufs/dir.c
--- linux/fs/aufs/dir.c 1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/dir.c    2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,559 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * directory operations
+ *
+ * $Id$
+ */
+
+#include <linux/fs_stack.h>
+#include "aufs.h"
+
+static int reopen_dir(struct file *file)
+{
+       int err;
+       struct dentry *dentry, *h_dentry;
+       aufs_bindex_t bindex, btail, bstart;
+       struct file *h_file;
+
+       dentry = file->f_dentry;
+       LKTRTrace("%.*s\n", AuDLNPair(dentry));
+       AuDebugOn(!S_ISDIR(dentry->d_inode->i_mode));
+
+       /* open all hidden dirs */
+       bstart = au_dbstart(dentry);
+#if 1 /* todo: necessary? */
+       for (bindex = au_fbstart(file); bindex < bstart; bindex++)
+               au_set_h_fptr(file, bindex, NULL);
+#endif
+       au_set_fbstart(file, bstart);
+       btail = au_dbtaildir(dentry);
+#if 1 /* todo: necessary? */
+       for (bindex = au_fbend(file); btail < bindex; bindex--)
+               au_set_h_fptr(file, bindex, NULL);
+#endif
+       au_set_fbend(file, btail);
+       for (bindex = bstart; bindex <= btail; bindex++) {
+               h_dentry = au_h_dptr(dentry, bindex);
+               if (!h_dentry)
+                       continue;
+               h_file = au_h_fptr(file, bindex);
+               if (h_file) {
+                       AuDebugOn(h_file->f_dentry != h_dentry);
+                       continue;
+               }
+
+               h_file = au_h_open(dentry, bindex, file->f_flags, file);
+               err = PTR_ERR(h_file);
+               if (IS_ERR(h_file))
+                       goto out; /* close all? */
+               /* cpup_file_flags(h_file, file); */
+               au_set_h_fptr(file, bindex, h_file);
+       }
+       au_update_figen(file);
+       /* todo: necessary? */
+       /* file->f_ra = h_file->f_ra; */
+       err = 0;
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+static int do_open_dir(struct file *file, int flags)
+{
+       int err;
+       aufs_bindex_t bindex, btail;
+       struct dentry *dentry, *h_dentry;
+       struct file *h_file;
+
+       dentry = file->f_dentry;
+       LKTRTrace("%.*s, 0x%x\n", AuDLNPair(dentry), flags);
+       AuDebugOn(!dentry->d_inode || !S_ISDIR(dentry->d_inode->i_mode));
+
+       err = 0;
+       au_set_fvdir_cache(file, NULL);
+       file->f_version = dentry->d_inode->i_version;
+       bindex = au_dbstart(dentry);
+       au_set_fbstart(file, bindex);
+       btail = au_dbtaildir(dentry);
+       au_set_fbend(file, btail);
+       for (; !err && bindex <= btail; bindex++) {
+               h_dentry = au_h_dptr(dentry, bindex);
+               if (!h_dentry)
+                       continue;
+
+               h_file = au_h_open(dentry, bindex, flags, file);
+               if (IS_ERR(h_file)) {
+                       err = PTR_ERR(h_file);
+                       break;
+               }
+               au_set_h_fptr(file, bindex, h_file);
+       }
+       au_update_figen(file);
+       /* todo: necessary? */
+       /* file->f_ra = h_file->f_ra; */
+       if (!err)
+               return 0; /* success */
+
+       /* close all */
+       for (bindex = au_fbstart(file); bindex <= btail; bindex++)
+               au_set_h_fptr(file, bindex, NULL);
+       au_set_fbstart(file, -1);
+       au_set_fbend(file, -1);
+       return err;
+}
+
+static int aufs_open_dir(struct inode *inode, struct file *file)
+{
+       LKTRTrace("i%lu, %.*s\n", inode->i_ino, AuDLNPair(file->f_dentry));
+
+       return au_do_open(inode, file, do_open_dir);
+}
+
+static int aufs_release_dir(struct inode *inode, struct file *file)
+{
+       struct au_vdir *vdir_cache;
+       struct super_block *sb;
+
+       LKTRTrace("i%lu, %.*s\n", inode->i_ino, AuDLNPair(file->f_dentry));
+
+       sb = file->f_dentry->d_sb;
+       si_noflush_read_lock(sb);
+       fi_write_lock(file);
+       vdir_cache = au_fvdir_cache(file);
+       if (vdir_cache)
+               au_vdir_free(vdir_cache);
+       fi_write_unlock(file);
+       au_finfo_fin(file);
+       si_read_unlock(sb);
+       return 0;
+}
+
+static int fsync_dir(struct dentry *dentry, int datasync)
+{
+       int err;
+       struct inode *inode;
+       struct super_block *sb;
+       aufs_bindex_t bend, bindex;
+
+       LKTRTrace("%.*s, %d\n", AuDLNPair(dentry), datasync);
+       DiMustAnyLock(dentry);
+       sb = dentry->d_sb;
+       SiMustAnyLock(sb);
+       inode = dentry->d_inode;
+       IMustLock(inode);
+       IiMustAnyLock(inode);
+
+       err = 0;
+       bend = au_dbend(dentry);
+       for (bindex = au_dbstart(dentry); !err && bindex <= bend; bindex++) {
+               struct dentry *h_dentry;
+               struct inode *h_inode;
+               struct file_operations *fop;
+
+               if (au_test_ro(sb, bindex, inode))
+                       continue;
+               h_dentry = au_h_dptr(dentry, bindex);
+               if (!h_dentry)
+                       continue;
+               h_inode = h_dentry->d_inode;
+               if (!h_inode)
+                       continue;
+
+               /* no mnt_want_write() */
+               /* cf. fs/nsfd/vfs.c and fs/nfsd/nfs4recover.c */
+               /* todo: inotiry fired? */
+               mutex_lock(&h_inode->i_mutex);
+               fop = (void *)h_inode->i_fop;
+               err = filemap_fdatawrite(h_inode->i_mapping);
+               if (!err && fop && fop->fsync)
+                       err = fop->fsync(NULL, h_dentry, datasync);
+               if (!err)
+                       err = filemap_fdatawrite(h_inode->i_mapping);
+               if (!err)
+                       au_update_fuse_h_inode(NULL, h_dentry); /*ignore*/
+               mutex_unlock(&h_inode->i_mutex);
+       }
+
+       AuTraceErr(err);
+       return err;
+}
+
+/*
+ * @file may be NULL
+ */
+static int aufs_fsync_dir(struct file *file, struct dentry *dentry,
+                         int datasync)
+{
+       int err;
+       struct inode *inode;
+       struct file *h_file;
+       struct super_block *sb;
+       aufs_bindex_t bend, bindex;
+
+       LKTRTrace("%.*s, %d\n", AuDLNPair(dentry), datasync);
+       inode = dentry->d_inode;
+       IMustLock(inode);
+
+       err = 0;
+       sb = dentry->d_sb;
+       si_noflush_read_lock(sb);
+       if (file) {
+               err = au_reval_and_lock_fdi(file, reopen_dir, /*wlock*/1,
+                                       /*locked*/1);
+               if (unlikely(err))
+                       goto out;
+       } else
+               di_write_lock_child(dentry);
+
+       if (file) {
+               bend = au_fbend(file);
+               for (bindex = au_fbstart(file); !err && bindex <= bend;
+                    bindex++) {
+                       h_file = au_h_fptr(file, bindex);
+                       if (!h_file || au_test_ro(sb, bindex, inode))
+                               continue;
+
+                       err = -EINVAL;
+                       if (h_file->f_op && h_file->f_op->fsync) {
+                               /* todo: try do_fsync() in fs/sync.c? */
+                               mutex_lock(&h_file->f_mapping->host->i_mutex);
+                               err = h_file->f_op->fsync
+                                       (h_file, h_file->f_dentry, datasync);
+                               if (!err)
+                                       au_update_fuse_h_inode
+                                               (h_file->f_vfsmnt,
+                                                h_file->f_dentry);
+                               /*ignore*/
+                               mutex_unlock(&h_file->f_mapping->host->i_mutex);
+                       }
+               }
+       } else
+               err = fsync_dir(dentry, datasync);
+       au_cpup_attr_timesizes(inode);
+       di_write_unlock(dentry);
+       if (file)
+               fi_write_unlock(file);
+
+ out:
+       si_read_unlock(sb);
+       AuTraceErr(err);
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static int aufs_readdir(struct file *file, void *dirent, filldir_t filldir)
+{
+       int err;
+       struct dentry *dentry;
+       struct inode *inode;
+       struct super_block *sb;
+
+       dentry = file->f_dentry;
+       LKTRTrace("%.*s, pos %lld\n", AuDLNPair(dentry), file->f_pos);
+       inode = dentry->d_inode;
+       IMustLock(inode);
+
+       sb = dentry->d_sb;
+       si_read_lock(sb, AuLock_FLUSH);
+       err = au_reval_and_lock_fdi(file, reopen_dir, /*wlock*/1, /*locked*/1);
+       if (unlikely(err))
+               goto out;
+       err = au_vdir_init(file);
+       di_downgrade_lock(dentry, AuLock_IR);
+       if (unlikely(err))
+               goto out_unlock;
+
+       if (!au_test_nfsd(current)) {
+               err = au_vdir_fill_de(file, dirent, filldir);
+       } else {
+               /*
+                * nfsd filldir may call lookup_one_len(), vfs_getattr(),
+                * encode_fh() and others.
+                */
+               struct inode *h_inode = au_h_iptr(inode, au_ibstart(inode));
+
+               di_read_unlock(dentry, AuLock_IR);
+               si_read_unlock(sb);
+               lockdep_off();
+               err = au_vdir_fill_de(file, dirent, filldir);
+               lockdep_on();
+               fsstack_copy_attr_atime(inode, h_inode);
+               fi_write_unlock(file);
+
+               AuTraceErr(err);
+               return err;
+       }
+
+       fsstack_copy_attr_atime(inode, au_h_iptr(inode, au_ibstart(inode)));
+
+ out_unlock:
+       di_read_unlock(dentry, AuLock_IR);
+       fi_write_unlock(file);
+ out:
+       si_read_unlock(sb);
+       AuTraceErr(err);
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+#define AuTestEmpty_WHONLY     1
+#define AuTestEmpty_DLGT       (1 << 1)
+#define AuTestEmpty_DIRPERM1   (1 << 2)
+#define AuTestEmpty_CALLED     (1 << 3)
+#define AuTestEmpty_SHWH       (1 << 4)
+#define au_ftest_testempty(flags, name)        ((flags) & AuTestEmpty_##name)
+#define au_fset_testempty(flags, name) { (flags) |= AuTestEmpty_##name; }
+#define au_fclr_testempty(flags, name) { (flags) &= ~AuTestEmpty_##name; }
+#ifndef CONFIG_AUFS_DLGT
+#undef AuTestEmpty_DLGT
+#define AuTestEmpty_DLGT       0
+#undef AuTestEmpty_DIRPERM1
+#define AuTestEmpty_DIRPERM1   0
+#endif
+#ifndef CONFIG_AUFS_SHWH
+#undef AuTestEmpty_SHWH
+#define AuTestEmpty_SHWH       0
+#endif
+
+struct test_empty_arg {
+       struct au_nhash *whlist;
+       unsigned int flags;
+       int err;
+       aufs_bindex_t bindex;
+};
+
+static int test_empty_cb(void *__arg, const char *__name, int namelen,
+                        loff_t offset, u64 ino, unsigned int d_type)
+{
+       struct test_empty_arg *arg = __arg;
+       char *name = (void *)__name;
+
+       LKTRTrace("%.*s\n", namelen, name);
+
+       arg->err = 0;
+       au_fset_testempty(arg->flags, CALLED);
+       /* smp_mb(); */
+       if (name[0] == '.'
+           && (namelen == 1 || (name[1] == '.' && namelen == 2)))
+               return 0; /* success */
+
+       if (namelen <= AUFS_WH_PFX_LEN
+           || memcmp(name, AUFS_WH_PFX, AUFS_WH_PFX_LEN)) {
+               if (au_ftest_testempty(arg->flags, WHONLY)
+                   && !au_nhash_test_known_wh(arg->whlist, name, namelen))
+                       arg->err = -ENOTEMPTY;
+               goto out;
+       }
+
+       name += AUFS_WH_PFX_LEN;
+       namelen -= AUFS_WH_PFX_LEN;
+       if (!au_nhash_test_known_wh(arg->whlist, name, namelen))
+               arg->err = au_nhash_append_wh
+                       (arg->whlist, name, namelen, ino, d_type, arg->bindex,
+                        au_ftest_testempty(arg->flags, SHWH));
+
+ out:
+       /* smp_mb(); */
+       AuTraceErr(arg->err);
+       return arg->err;
+}
+
+static int do_test_empty(struct dentry *dentry, struct test_empty_arg *arg)
+{
+       int err, dlgt;
+       struct file *h_file;
+
+       LKTRTrace("%.*s, {%p, 0x%x, %d}\n",
+                 AuDLNPair(dentry), arg->whlist, arg->flags, arg->bindex);
+
+       h_file = au_h_open(dentry, arg->bindex,
+                          O_RDONLY | O_NONBLOCK | O_DIRECTORY | O_LARGEFILE,
+                          /*file*/NULL);
+       err = PTR_ERR(h_file);
+       if (IS_ERR(h_file))
+               goto out;
+       err = 0;
+       if (au_opt_test(au_mntflags(dentry->d_sb), UDBA_INOTIFY)
+           && !h_file->f_dentry->d_inode->i_nlink)
+               goto out_put;
+
+       dlgt = au_ftest_testempty(arg->flags, DLGT);
+       do {
+               arg->err = 0;
+               au_fclr_testempty(arg->flags, CALLED);
+               /* smp_mb(); */
+               err = vfsub_readdir(h_file, test_empty_cb, arg, dlgt);
+               if (err >= 0)
+                       err = arg->err;
+       } while (!err && au_ftest_testempty(arg->flags, CALLED));
+
+ out_put:
+       fput(h_file);
+       au_sbr_put(dentry->d_sb, arg->bindex);
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+struct do_test_empty_args {
+       int *errp;
+       struct dentry *dentry;
+       struct test_empty_arg *arg;
+};
+
+static void call_do_test_empty(void *args)
+{
+       struct do_test_empty_args *a = args;
+       *a->errp = do_test_empty(a->dentry, a->arg);
+}
+
+static int sio_test_empty(struct dentry *dentry, struct test_empty_arg *arg)
+{
+       int err, wkq_err;
+       struct dentry *h_dentry;
+       struct inode *h_inode;
+
+       LKTRTrace("%.*s\n", AuDLNPair(dentry));
+       h_dentry = au_h_dptr(dentry, arg->bindex);
+       AuDebugOn(!h_dentry);
+       h_inode = h_dentry->d_inode;
+       AuDebugOn(!h_inode);
+
+       mutex_lock_nested(&h_inode->i_mutex, AuLsc_I_CHILD);
+       err = au_test_h_perm_sio(h_inode, MAY_EXEC | MAY_READ,
+                                au_test_dlgt(au_mntflags(dentry->d_sb)));
+       mutex_unlock(&h_inode->i_mutex);
+       if (!err)
+               err = do_test_empty(dentry, arg);
+       else {
+               struct do_test_empty_args args = {
+                       .errp   = &err,
+                       .dentry = dentry,
+                       .arg    = arg
+               };
+               unsigned int flags = arg->flags;
+
+               au_fclr_testempty(arg->flags, DLGT);
+               au_fclr_testempty(arg->flags, DIRPERM1);
+               wkq_err = au_wkq_wait(call_do_test_empty, &args, /*dlgt*/0);
+               if (unlikely(wkq_err))
+                       err = wkq_err;
+               arg->flags = flags;
+       }
+
+       AuTraceErr(err);
+       return err;
+}
+
+int au_test_empty_lower(struct dentry *dentry)
+{
+       int err;
+       struct inode *inode;
+       struct test_empty_arg arg;
+       struct au_nhash *whlist;
+       aufs_bindex_t bindex, bstart, btail;
+       unsigned int mnt_flags;
+
+       LKTRTrace("%.*s\n", AuDLNPair(dentry));
+       inode = dentry->d_inode;
+       AuDebugOn(!inode || !S_ISDIR(inode->i_mode));
+
+       whlist = au_nhash_new(GFP_NOFS);
+       err = PTR_ERR(whlist);
+       if (IS_ERR(whlist))
+               goto out;
+
+       bstart = au_dbstart(dentry);
+       mnt_flags = au_mntflags(dentry->d_sb);
+       arg.whlist = whlist;
+       arg.flags = 0;
+       if (au_test_dlgt(mnt_flags))
+               au_fset_testempty(arg.flags, DLGT);
+       if (au_opt_test(mnt_flags, SHWH))
+               au_fset_testempty(arg.flags, SHWH);
+       arg.bindex = bstart;
+       err = do_test_empty(dentry, &arg);
+       if (unlikely(err))
+               goto out_whlist;
+
+       au_fset_testempty(arg.flags, WHONLY);
+       if (au_test_dirperm1(mnt_flags))
+               au_fset_testempty(arg.flags, DIRPERM1);
+       btail = au_dbtaildir(dentry);
+       for (bindex = bstart + 1; !err && bindex <= btail; bindex++) {
+               struct dentry *h_dentry;
+               h_dentry = au_h_dptr(dentry, bindex);
+               if (h_dentry && h_dentry->d_inode) {
+                       arg.bindex = bindex;
+                       err = do_test_empty(dentry, &arg);
+               }
+       }
+
+ out_whlist:
+       au_nhash_del(whlist);
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+int au_test_empty(struct dentry *dentry, struct au_nhash *whlist)
+{
+       int err;
+       struct inode *inode;
+       struct test_empty_arg arg;
+       aufs_bindex_t bindex, btail;
+
+       LKTRTrace("%.*s\n", AuDLNPair(dentry));
+       inode = dentry->d_inode;
+       AuDebugOn(!inode || !S_ISDIR(inode->i_mode));
+
+       err = 0;
+       arg.whlist = whlist;
+       arg.flags = AuTestEmpty_WHONLY;
+       if (au_opt_test(au_mntflags(dentry->d_sb), SHWH))
+               au_fset_testempty(arg.flags, SHWH);
+       btail = au_dbtaildir(dentry);
+       for (bindex = au_dbstart(dentry); !err && bindex <= btail; bindex++) {
+               struct dentry *h_dentry;
+               h_dentry = au_h_dptr(dentry, bindex);
+               if (h_dentry && h_dentry->d_inode) {
+                       arg.bindex = bindex;
+                       err = sio_test_empty(dentry, &arg);
+               }
+       }
+
+       AuTraceErr(err);
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+struct file_operations aufs_dir_fop = {
+       .read           = generic_read_dir,
+       .readdir        = aufs_readdir,
+       /* .unlocked_ioctl      = aufs_ioctl_dir, */
+       .open           = aufs_open_dir,
+       .release        = aufs_release_dir,
+       .flush          = aufs_flush,
+       .fsync          = aufs_fsync_dir,
+};
diff -urN linux/fs/aufs/dir.h linux-aufs/fs/aufs/dir.h
--- linux/fs/aufs/dir.h 1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/dir.h    2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,147 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * directory operations
+ *
+ * $Id$
+ */
+
+#ifndef __AUFS_DIR_H__
+#define __AUFS_DIR_H__
+
+#ifdef __KERNEL__
+
+#include <linux/fs.h>
+#include <linux/aufs_type.h>
+
+/* ---------------------------------------------------------------------- */
+
+/* need to be faster and smaller */
+
+/* todo: changeable? */
+#define AuSize_DEBLK   512
+#define AuSize_NHASH   32
+#if AuSize_DEBLK < NAME_MAX || PAGE_SIZE < AuSize_DEBLK
+#error invalid size AuSize_DEBLK
+#endif
+
+typedef char au_vdir_deblk_t[AuSize_DEBLK];
+
+struct au_nhash {
+       struct hlist_head heads[AuSize_NHASH];
+};
+
+struct au_vdir_destr {
+       unsigned char   len;
+       char            name[0];
+} __packed;
+
+struct au_vdir_dehstr {
+       struct hlist_node       hash;
+       struct au_vdir_destr    *str;
+};
+
+struct au_vdir_de {
+       ino_t                   de_ino;
+       unsigned char           de_type;
+       /* caution: packed */
+       struct au_vdir_destr    de_str;
+} __packed;
+
+struct au_vdir_wh {
+       struct hlist_node       wh_hash;
+       aufs_bindex_t           wh_bindex;
+#ifdef CONFIG_AUFS_SHWH
+       ino_t                   wh_ino;
+       unsigned char           wh_type;
+       /* caution: packed */
+#endif
+       struct au_vdir_destr    wh_str;
+} __packed;
+
+union au_vdir_deblk_p {
+       unsigned char           *p;
+       au_vdir_deblk_t         *deblk;
+       struct au_vdir_de       *de;
+};
+
+struct au_vdir {
+       au_vdir_deblk_t **vd_deblk;
+       int             vd_nblk;
+       struct {
+               int                     i;
+               union au_vdir_deblk_p   p;
+       } vd_last;
+
+       unsigned long   vd_version;
+       unsigned long   vd_jiffy;
+};
+
+/* ---------------------------------------------------------------------- */
+
+/* dir.c */
+extern struct file_operations aufs_dir_fop;
+int au_test_empty_lower(struct dentry *dentry);
+int au_test_empty(struct dentry *dentry, struct au_nhash *whlist);
+
+/* vdir.c */
+struct au_nhash *au_nhash_new(gfp_t gfp);
+void au_nhash_del(struct au_nhash *nhash);
+void au_nhash_init(struct au_nhash *nhash);
+void au_nhash_move(struct au_nhash *dst, struct au_nhash *src);
+void au_nhash_fin(struct au_nhash *nhash);
+int au_nhash_test_longer_wh(struct au_nhash *whlist, aufs_bindex_t btgt,
+                           int limit);
+int au_nhash_test_known_wh(struct au_nhash *whlist, char *name, int namelen);
+int au_nhash_append_wh(struct au_nhash *whlist, char *name, int namelen,
+                      ino_t ino, unsigned int d_type, aufs_bindex_t bindex,
+                      unsigned char shwh);
+void au_vdir_free(struct au_vdir *vdir);
+int au_vdir_init(struct file *file);
+int au_vdir_fill_de(struct file *file, void *dirent, filldir_t filldir);
+
+/* ---------------------------------------------------------------------- */
+
+static inline
+void au_shwh_init_wh(struct au_vdir_wh *wh, ino_t ino, unsigned char d_type)
+{
+#ifdef CONFIG_AUFS_SHWH
+       wh->wh_ino = ino;
+       wh->wh_type = d_type;
+#endif
+}
+
+static inline void au_add_nlink(struct inode *dir, struct inode *h_dir)
+{
+       AuDebugOn(!S_ISDIR(dir->i_mode) || !S_ISDIR(h_dir->i_mode));
+       dir->i_nlink += h_dir->i_nlink - 2;
+       if (h_dir->i_nlink < 2)
+               dir->i_nlink += 2;
+}
+
+static inline void au_sub_nlink(struct inode *dir, struct inode *h_dir)
+{
+       AuDebugOn(!S_ISDIR(dir->i_mode) || !S_ISDIR(h_dir->i_mode));
+       dir->i_nlink -= h_dir->i_nlink - 2;
+       if (h_dir->i_nlink < 2)
+               dir->i_nlink -= 2;
+}
+
+#endif /* __KERNEL__ */
+#endif /* __AUFS_DIR_H__ */
diff -urN linux/fs/aufs/dlgt.c linux-aufs/fs/aufs/dlgt.c
--- linux/fs/aufs/dlgt.c        1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/dlgt.c   2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,113 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * lookup functions in 'delegate' mode
+ *
+ * $Id$
+ */
+
+#include "aufs.h"
+
+/* ---------------------------------------------------------------------- */
+
+struct au_lookup_one_len_args {
+       struct dentry **errp;
+       const char *name;
+       struct dentry *parent;
+       int len;
+};
+
+static void au_call_lookup_one_len(void *args)
+{
+       struct au_lookup_one_len_args *a = args;
+       *a->errp = vfsub_lookup_one_len(a->name, a->parent, a->len);
+}
+
+struct dentry *au_lkup_one_dlgt(const char *name, struct dentry *parent,
+                               int len, unsigned int flags)
+{
+       struct dentry *dentry;
+       int dirperm1;
+
+       LKTRTrace("%.*s/%.*s, 0x%x\n", AuDLNPair(parent), len, name, flags);
+
+       dirperm1 = au_ftest_ndx(flags, DIRPERM1);
+       if (!dirperm1 && !au_ftest_ndx(flags, DLGT))
+               dentry = vfsub_lookup_one_len(name, parent, len);
+       else {
+               int wkq_err;
+               struct au_lookup_one_len_args args = {
+                       .errp   = &dentry,
+                       .name   = name,
+                       .parent = parent,
+                       .len    = len
+               };
+               wkq_err = au_wkq_wait(au_call_lookup_one_len, &args,
+                                     /*dlgt*/!dirperm1);
+               if (unlikely(wkq_err))
+                       dentry = ERR_PTR(wkq_err);
+       }
+
+       AuTraceErrPtr(dentry);
+       return dentry;
+}
+
+/* ---------------------------------------------------------------------- */
+
+struct security_inode_permission_args {
+       int *errp;
+       struct inode *h_inode;
+       int mask;
+       struct nameidata *fake_nd;
+};
+
+static void call_security_inode_permission(void *args)
+{
+       struct security_inode_permission_args *a = args;
+       LKTRTrace("fsuid %d\n", current_fsuid());
+       *a->errp = vfsub_security_inode_permission(a->h_inode, a->mask,
+                                                  a->fake_nd);
+}
+
+int au_security_inode_permission(struct inode *h_inode, int mask,
+                                struct nameidata *fake_nd, int dlgt)
+{
+       int err;
+
+       AuTraceEnter();
+
+       if (!dlgt)
+               err = vfsub_security_inode_permission(h_inode, mask, fake_nd);
+       else {
+               int wkq_err;
+               struct security_inode_permission_args args = {
+                       .errp           = &err,
+                       .h_inode        = h_inode,
+                       .mask           = mask,
+                       .fake_nd        = fake_nd
+               };
+               wkq_err = au_wkq_wait(call_security_inode_permission, &args,
+                                     /*dlgt*/1);
+               if (unlikely(wkq_err))
+                       err = wkq_err;
+       }
+
+       AuTraceErr(err);
+       return err;
+}
diff -urN linux/fs/aufs/export.c linux-aufs/fs/aufs/export.c
--- linux/fs/aufs/export.c      1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/export.c 2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,826 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * export via nfs
+ *
+ * $Id$
+ */
+
+#include <linux/exportfs.h>
+#include <linux/mnt_namespace.h>
+#include <linux/random.h>
+#include "aufs.h"
+
+union conv {
+#ifdef CONFIG_AUFS_INO_T_64
+       __u32 a[2];
+#else
+       __u32 a[1];
+#endif
+       ino_t ino;
+};
+
+static ino_t decode_ino(__u32 *a)
+{
+       union conv u;
+
+       BUILD_BUG_ON(sizeof(u.ino) != sizeof(u.a));
+       u.a[0] = a[0];
+#ifdef CONFIG_AUFS_INO_T_64
+       u.a[1] = a[1];
+#endif
+       return u.ino;
+}
+
+static void encode_ino(__u32 *a, ino_t ino)
+{
+       union conv u;
+
+       u.ino = ino;
+       a[0] = u.a[0];
+#ifdef CONFIG_AUFS_INO_T_64
+       a[1] = u.a[1];
+#endif
+}
+
+/* NFS file handle */
+enum {
+       Fh_br_id,
+       Fh_sigen,
+#ifdef CONFIG_AUFS_INO_T_64
+       /* support 64bit inode number */
+       Fh_ino1,
+       Fh_ino2,
+       Fh_dir_ino1,
+       Fh_dir_ino2,
+#else
+       Fh_ino1,
+       Fh_dir_ino1,
+#endif
+       Fh_igen,
+       Fh_h_type,
+       Fh_tail,
+
+       Fh_ino = Fh_ino1,
+       Fh_dir_ino = Fh_dir_ino1
+};
+
+static int au_test_anon(struct dentry *dentry)
+{
+       return !!(dentry->d_flags & DCACHE_DISCONNECTED);
+}
+
+/* ---------------------------------------------------------------------- */
+/* inode generation external table */
+
+int au_xigen_inc(struct inode *inode)
+{
+       int err;
+       loff_t pos;
+       ssize_t sz;
+       __u32 igen;
+       struct super_block *sb;
+       struct au_sbinfo *sbinfo;
+
+       LKTRTrace("i%lu\n", (unsigned long)inode->i_ino);
+
+       err = 0;
+       sb = inode->i_sb;
+       if (unlikely(!au_opt_test_xino(au_mntflags(sb))))
+               goto out;
+
+       pos = inode->i_ino;
+       pos *= sizeof(igen);
+       igen = inode->i_generation + 1;
+       sbinfo = au_sbi(sb);
+       sz = xino_fwrite(sbinfo->si_xwrite, sbinfo->si_xigen, &igen,
+                        sizeof(igen), &pos);
+       if (sz == sizeof(igen))
+               goto out; /* success */
+
+       err = sz;
+       if (unlikely(sz >= 0)) {
+               err = -EIO;
+               AuIOErr("xigen error (%zd)\n", sz);
+       }
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+int au_xigen_new(struct inode *inode)
+{
+       int err;
+       loff_t pos;
+       ssize_t sz;
+       struct super_block *sb;
+       struct au_sbinfo *sbinfo;
+       struct file *file;
+
+       LKTRTrace("i%lu\n", inode->i_ino);
+
+       err = 0;
+       /* todo: dirty, at mount time */
+       if (inode->i_ino == AUFS_ROOT_INO)
+               goto out;
+       sb = inode->i_sb;
+       if (unlikely(!au_opt_test_xino(au_mntflags(sb))))
+               goto out;
+
+       err = -EFBIG;
+       pos = inode->i_ino;
+       if (unlikely(Au_LOFF_MAX / sizeof(inode->i_generation) - 1 < pos)) {
+               AuIOErr1("too large i%lld\n", pos);
+               goto out;
+       }
+       pos *= sizeof(inode->i_generation);
+
+       err = 0;
+       sbinfo = au_sbi(sb);
+       file = sbinfo->si_xigen;
+       BUG_ON(!file);
+
+       if (i_size_read(file->f_dentry->d_inode)
+           < pos + sizeof(inode->i_generation)) {
+               inode->i_generation = atomic_inc_return(&sbinfo->si_xigen_next);
+               sz = xino_fwrite(sbinfo->si_xwrite, file, &inode->i_generation,
+                                sizeof(inode->i_generation), &pos);
+       } else
+               sz = xino_fread(sbinfo->si_xread, file, &inode->i_generation,
+                               sizeof(inode->i_generation), &pos);
+       if (sz == sizeof(inode->i_generation))
+               goto out; /* success */
+
+       err = sz;
+       if (unlikely(sz >= 0)) {
+               err = -EIO;
+               AuIOErr("xigen error (%zd)\n", sz);
+       }
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+int au_xigen_set(struct super_block *sb, struct file *base)
+{
+       int err;
+       struct au_sbinfo *sbinfo;
+       struct file *file;
+
+       LKTRTrace("%.*s\n", AuDLNPair(base->f_dentry));
+       SiMustWriteLock(sb);
+
+       sbinfo = au_sbi(sb);
+       file = au_xino_create2(sb, base, sbinfo->si_xigen);
+       err = PTR_ERR(file);
+       if (IS_ERR(file))
+               goto out;
+       err = 0;
+       if (sbinfo->si_xigen)
+               fput(sbinfo->si_xigen);
+       sbinfo->si_xigen = file;
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+void au_xigen_clr(struct super_block *sb)
+{
+       struct au_sbinfo *sbinfo;
+
+       sbinfo = au_sbi(sb);
+       if (sbinfo->si_xigen) {
+               fput(sbinfo->si_xigen);
+               sbinfo->si_xigen = NULL;
+       }
+}
+
+/* ---------------------------------------------------------------------- */
+
+static struct dentry *decode_by_ino(struct super_block *sb, ino_t ino,
+                                   ino_t dir_ino)
+{
+       struct dentry *dentry, *d;
+       struct inode *inode;
+       au_gen_t sigen;
+
+       LKTRTrace("i%lu, diri%lu\n",
+                 (unsigned long)ino, (unsigned long)dir_ino);
+
+       dentry = NULL;
+       inode = ilookup(sb, ino);
+       if (!inode)
+               goto out;
+
+       dentry = ERR_PTR(-ESTALE);
+       sigen = au_sigen(sb);
+       if (unlikely(is_bad_inode(inode)
+                    || IS_DEADDIR(inode)
+                    || sigen != au_iigen(inode)))
+               goto out_iput;
+
+       dentry = NULL;
+       if (!dir_ino || S_ISDIR(inode->i_mode))
+               dentry = d_find_alias(inode);
+       else {
+               spin_lock(&dcache_lock);
+               list_for_each_entry(d, &inode->i_dentry, d_alias)
+                       if (!au_test_anon(d)
+                           && d->d_parent->d_inode->i_ino == dir_ino) {
+                               dentry = dget_locked(d);
+                               break;
+                       }
+               spin_unlock(&dcache_lock);
+       }
+       if (unlikely(dentry && sigen != au_digen(dentry))) {
+               dput(dentry);
+               dentry = ERR_PTR(-ESTALE);
+       }
+
+ out_iput:
+       iput(inode);
+ out:
+       AuTraceErrPtr(dentry);
+       return dentry;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* todo: dirty? */
+/*
+ * when you mntput() for the return value of this function,
+ * you have to store it to your local var.
+ * ie. never mntput si_mntcache directly.
+ */
+static struct vfsmount *au_do_mnt_get(struct super_block *sb)
+{
+       struct mnt_namespace *ns;
+       struct vfsmount *pos, *mnt;
+
+       AuTraceEnter();
+
+       /* vfsmount_lock is not exported */
+       /* no get/put ?? */
+       AuDebugOn(!current->nsproxy);
+       ns = current->nsproxy->mnt_ns;
+       AuDebugOn(!ns);
+       mnt = NULL;
+       /* the order (reverse) will not be a problem */
+       list_for_each_entry(pos, &ns->list, mnt_list)
+               if (pos->mnt_sb == sb) {
+                       mnt = pos;
+                       break;
+               }
+       AuDebugOn(!mnt);
+
+       return mntget(mnt);
+}
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 26)
+static struct vfsmount *au_mnt_get(struct super_block *sb)
+{
+       struct au_sbinfo *sbinfo;
+       struct vfsmount *mnt;
+
+       sbinfo = au_sbi(sb);
+       spin_lock(&sbinfo->si_mntcache_lock);
+       if (sbinfo->si_mntcache)
+               mnt = mntget(sbinfo->si_mntcache);
+       else {
+               sbinfo->si_mntcache = au_do_mnt_get(sb);
+               mnt = sbinfo->si_mntcache;
+       }
+       spin_unlock(&sbinfo->si_mntcache_lock);
+       return mnt;
+}
+#else
+static struct vfsmount *au_mnt_get(struct super_block *sb)
+{
+       return au_do_mnt_get(sb);
+}
+#endif
+
+struct au_nfsd_si_lock {
+       const au_gen_t sigen;
+       const aufs_bindex_t br_id;
+       unsigned char force_lock;
+};
+
+static aufs_bindex_t si_nfsd_read_lock(struct super_block *sb,
+                                      struct au_nfsd_si_lock *nsi_lock)
+{
+       aufs_bindex_t bindex;
+
+       si_read_lock(sb, AuLock_FLUSH);
+
+       /* branch id may be wrapped around */
+       bindex = au_br_index(sb, nsi_lock->br_id);
+       LKTRTrace("b%d\n", bindex);
+       if (bindex >= 0 && nsi_lock->sigen + AUFS_BRANCH_MAX > au_sigen(sb))
+               goto out; /* success */
+
+       if (!nsi_lock->force_lock)
+               si_read_unlock(sb);
+       bindex = -1;
+
+ out:
+       return bindex;
+}
+
+struct find_name_by_ino {
+       int called, found;
+       ino_t ino;
+       char *name;
+       int namelen;
+};
+
+static int
+find_name_by_ino(void *arg, const char *name, int namelen, loff_t offset,
+                u64 ino, unsigned int d_type)
+{
+       struct find_name_by_ino *a = arg;
+
+       a->called++;
+       if (a->ino != ino)
+               return 0;
+
+       memcpy(a->name, name, namelen);
+       a->namelen = namelen;
+       a->found = 1;
+       return 1;
+}
+
+static struct dentry *au_lkup_by_ino(struct path *path, ino_t ino,
+                                    struct au_nfsd_si_lock *nsi_lock)
+{
+       struct dentry *dentry, *parent;
+       struct file *file;
+       struct inode *dir;
+       struct find_name_by_ino arg;
+       int err;
+
+       parent = path->dentry;
+       LKTRTrace("%.*s, i%lu\n", AuDLNPair(parent), (unsigned long)ino);
+
+       if (nsi_lock)
+               si_read_unlock(parent->d_sb);
+       path_get(path);
+       file = dentry_open(parent, path->mnt, au_dir_roflags, file->f_cred);
+       dentry = (void *)file;
+       if (IS_ERR(file))
+               goto out;
+
+       dentry = ERR_PTR(-ENOMEM);
+       arg.name = __getname();
+       if (unlikely(!arg.name))
+               goto out_file;
+       arg.ino = ino;
+       arg.found = 0;
+       do {
+               arg.called = 0;
+               /* smp_mb(); */
+               err = vfsub_readdir(file, find_name_by_ino, &arg, /*dlgt*/0);
+       } while (!err && !arg.found && arg.called);
+       dentry = ERR_PTR(err);
+       if (unlikely(err))
+               goto out_name;
+       dentry = ERR_PTR(-ENOENT);
+       if (!arg.found)
+               goto out_name;
+
+       /* do not call au_lkup_one(), nor dlgt */
+       dir = parent->d_inode;
+       mutex_lock(&dir->i_mutex);
+       dentry = vfsub_lookup_one_len(arg.name, parent, arg.namelen);
+       mutex_unlock(&dir->i_mutex);
+       AuTraceErrPtr(dentry);
+       if (IS_ERR(dentry))
+               goto out_name;
+       AuDebugOn(au_test_anon(dentry));
+       if (unlikely(!dentry->d_inode)) {
+               dput(dentry);
+               dentry = ERR_PTR(-ENOENT);
+       }
+
+ out_name:
+       __putname(arg.name);
+ out_file:
+       fput(file);
+ out:
+       if (unlikely(nsi_lock
+                    && si_nfsd_read_lock(parent->d_sb, nsi_lock) < 0))
+               if (!IS_ERR(dentry)) {
+                       dput(dentry);
+                       dentry = ERR_PTR(-ESTALE);
+               }
+       AuTraceErrPtr(dentry);
+       return dentry;
+}
+
+static /* noinline_for_stack */
+struct dentry *decode_by_dir_ino(struct super_block *sb, ino_t ino,
+                                ino_t dir_ino, struct au_nfsd_si_lock *nsi_lock)
+{
+       struct dentry *dentry, *parent;
+       struct path path;
+
+       LKTRTrace("i%lu, diri%lu\n",
+                 (unsigned long)ino, (unsigned long)dir_ino);
+
+       parent = sb->s_root;
+       if (dir_ino != AUFS_ROOT_INO) {
+               parent = decode_by_ino(sb, dir_ino, 0);
+               dentry = parent;
+               if (!parent)
+                       goto out;
+               if (IS_ERR(parent))
+                       goto out;
+               AuDebugOn(au_test_anon(parent));
+       } else
+               dget(parent);
+
+       path.dentry = parent;
+       path.mnt = au_mnt_get(sb);
+       dentry = au_lkup_by_ino(&path, ino, nsi_lock);
+       path_put(&path);
+
+ out:
+       AuTraceErrPtr(dentry);
+       return dentry;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static int h_acceptable(void *expv, struct dentry *dentry)
+{
+       return 1;
+}
+
+static char *au_build_path(struct dentry *h_parent, struct path *h_rootpath,
+                          char *buf, int len, struct super_block *sb)
+{
+       char *p;
+       int n;
+       struct path path;
+
+       AuTraceEnter();
+
+       p = d_path(h_rootpath, buf, len);
+       if (IS_ERR(p))
+               goto out;
+       n = strlen(p);
+
+       path.mnt = h_rootpath->mnt;
+       path.dentry = h_parent;
+       p = d_path(&path, buf, len);
+       if (IS_ERR(p))
+               goto out;
+       LKTRTrace("%s\n", p);
+       if (n != 1)
+               p += n;
+       LKTRTrace("%p, %s, %ld\n",
+                 p, p, (long)(p - buf));
+
+       path.mnt = au_mnt_get(sb);
+       path.dentry = sb->s_root;
+       p = d_path(&path, buf, len - strlen(p));
+       mntput(path.mnt);
+       if (IS_ERR(p))
+               goto out;
+       if (n != 1)
+               p[strlen(p)] = '/';
+       LKTRTrace("%s\n", p);
+
+ out:
+       AuTraceErrPtr(p);
+       return p;
+}
+
+static noinline_for_stack
+struct dentry *decode_by_path(struct super_block *sb, aufs_bindex_t bindex,
+                             ino_t ino, __u32 *fh, int fh_len,
+                             struct au_nfsd_si_lock *nsi_lock)
+{
+       struct dentry *dentry, *h_parent, *root;
+       struct super_block *h_sb;
+       char *pathname, *p;
+       struct vfsmount *h_mnt;
+       struct au_branch *br;
+       int err;
+       struct nameidata nd;
+
+       LKTRTrace("b%d\n", bindex);
+       SiMustAnyLock(sb);
+
+       br = au_sbr(sb, bindex);
+       /* au_br_get(br); */
+       h_mnt = br->br_mnt;
+       h_sb = h_mnt->mnt_sb;
+       LKTRTrace("%s, h_decode_fh\n", au_sbtype(h_sb));
+       /* in linux-2.6.24, it takes struct fid * as file handle */
+       /* todo: call lower fh_to_dentry()? fh_to_parent()? */
+       h_parent = exportfs_decode_fh(h_mnt, (void *)(fh + Fh_tail),
+                                     fh_len - Fh_tail, fh[Fh_h_type],
+                                     h_acceptable, /*context*/NULL);
+       dentry = h_parent;
+       if (unlikely(!h_parent || IS_ERR(h_parent))) {
+               AuWarn1("%s decode_fh failed, %ld\n",
+                       au_sbtype(h_sb), PTR_ERR(h_parent));
+               goto out;
+       }
+       dentry = NULL;
+       if (unlikely(au_test_anon(h_parent))) {
+               AuWarn1("%s decode_fh returned a disconnected dentry\n",
+                       au_sbtype(h_sb));
+               goto out_h_parent;
+       }
+
+       dentry = ERR_PTR(-ENOMEM);
+       pathname = (void *)__get_free_page(GFP_NOFS);
+       if (unlikely(!pathname))
+               goto out_h_parent;
+
+       root = sb->s_root;
+       nd.path.mnt = h_mnt;
+       di_read_lock_parent(root, !AuLock_IR);
+       nd.path.dentry = au_h_dptr(root, bindex);
+       di_read_unlock(root, !AuLock_IR);
+       p = au_build_path(h_parent, &nd.path, pathname, PAGE_SIZE, sb);
+       dentry = (void *)p;
+       if (IS_ERR(p))
+               goto out_pathname;
+
+       LKTRTrace("%s\n", p);
+       si_read_unlock(sb);
+       err = vfsub_path_lookup(p, LOOKUP_FOLLOW | LOOKUP_DIRECTORY, &nd);
+       dentry = ERR_PTR(err);
+       if (unlikely(err))
+               goto out_relock;
+
+       dentry = ERR_PTR(-ENOENT);
+       AuDebugOn(au_test_anon(nd.path.dentry));
+       if (unlikely(!nd.path.dentry->d_inode))
+               goto out_nd;
+
+       if (ino != nd.path.dentry->d_inode->i_ino)
+               dentry = au_lkup_by_ino(&nd.path, ino, /*nsi_lock*/NULL);
+       else
+               dentry = dget(nd.path.dentry);
+
+ out_nd:
+       path_put(&nd.path);
+ out_relock:
+       if (unlikely(si_nfsd_read_lock(sb, nsi_lock) < 0))
+               if (!IS_ERR(dentry)) {
+                       dput(dentry);
+                       dentry = ERR_PTR(-ESTALE);
+               }
+ out_pathname:
+       free_page((unsigned long)pathname);
+ out_h_parent:
+       dput(h_parent);
+ out:
+       /* au_br_put(br); */
+       AuTraceErrPtr(dentry);
+       return dentry;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static struct dentry *
+aufs_fh_to_dentry(struct super_block *sb, struct fid *fid, int fh_len,
+                 int fh_type)
+{
+       struct dentry *dentry;
+       __u32 *fh = fid->raw;
+       ino_t ino, dir_ino;
+       aufs_bindex_t bindex;
+       struct au_nfsd_si_lock nsi_lock = {
+               .sigen          = fh[Fh_sigen],
+               .br_id          = fh[Fh_br_id],
+               .force_lock     = 0
+       };
+
+       LKTRTrace("%d, fh{br_id %u, sigen %u, i%u, diri%u, g%u}\n",
+                 fh_type, fh[Fh_br_id], fh[Fh_sigen], fh[Fh_ino],
+                 fh[Fh_dir_ino], fh[Fh_igen]);
+       AuDebugOn(fh_len < Fh_tail);
+
+       dentry = ERR_PTR(-ESTALE);
+       /* branch id may be wrapped around */
+       bindex = si_nfsd_read_lock(sb, &nsi_lock);
+       if (unlikely(bindex < 0))
+               goto out;
+       nsi_lock.force_lock = 1;
+
+       /* is this inode still cached? */
+       ino = decode_ino(fh + Fh_ino);
+       AuDebugOn(ino == AUFS_ROOT_INO);
+       dir_ino = decode_ino(fh + Fh_dir_ino);
+       dentry = decode_by_ino(sb, ino, dir_ino);
+       if (IS_ERR(dentry))
+               goto out_unlock;
+       if (dentry)
+               goto accept;
+
+       /* is the parent dir cached? */
+       dentry = decode_by_dir_ino(sb, ino, dir_ino, &nsi_lock);
+       if (IS_ERR(dentry))
+               goto out_unlock;
+       if (dentry)
+               goto accept;
+
+       /* lookup path */
+       dentry = decode_by_path(sb, bindex, ino, fh, fh_len, &nsi_lock);
+       if (IS_ERR(dentry))
+               goto out_unlock;
+       if (unlikely(!dentry))
+               /* todo?: make it ESTALE */
+               goto out_unlock;
+
+ accept:
+       LKTRLabel(accept);
+       if (dentry->d_inode->i_generation == fh[Fh_igen])
+               goto out_unlock; /* success */
+
+       LKTRLabel(stale);
+       dput(dentry);
+       dentry = ERR_PTR(-ESTALE);
+ out_unlock:
+       LKTRLabel(out_unlock);
+       si_read_unlock(sb);
+ out:
+       LKTRLabel(out);
+       if (0 && IS_ERR(dentry))
+               dentry = ERR_PTR(-ESTALE);
+       AuTraceErrPtr(dentry);
+       return dentry;
+}
+
+#if 0 /* reserved for future use */
+/* support subtreecheck option */
+static struct dentry *aufs_fh_to_parent(struct super_block *sb, struct fid *fid,
+                                       int fh_len, int fh_type)
+{
+       struct dentry *parent;
+       __u32 *fh = fid->raw;
+       ino_t dir_ino;
+
+       dir_ino = decode_ino(fh + Fh_dir_ino);
+       parent = decode_by_ino(sb, dir_ino, 0);
+       if (IS_ERR(parent))
+               goto out;
+       if (!parent)
+               parent = decode_by_path(sb, au_br_index(sb, fh[Fh_br_id]),
+                                       dir_ino, fh, fh_len);
+
+ out:
+       AuTraceErrPtr(parent);
+       return parent;
+}
+#endif
+
+/* ---------------------------------------------------------------------- */
+
+static int aufs_encode_fh(struct dentry *dentry, __u32 *fh, int *max_len,
+                         int connectable)
+{
+       int err;
+       aufs_bindex_t bindex, bend;
+       struct super_block *sb, *h_sb;
+       struct inode *inode;
+       struct dentry *parent, *h_parent;
+       struct au_branch *br;
+
+       LKTRTrace("%.*s, max %d, conn %d\n",
+                 AuDLNPair(dentry), *max_len, connectable);
+       AuDebugOn(au_test_anon(dentry));
+
+       parent = NULL;
+       err = -ENOSPC;
+       if (unlikely(*max_len <= Fh_tail)) {
+               AuWarn1("NFSv2 client (max_len %d)?\n", *max_len);
+               goto out;
+       }
+
+       err = FILEID_ROOT;
+       if (IS_ROOT(dentry)) {
+               AuDebugOn(dentry->d_inode->i_ino != AUFS_ROOT_INO);
+               goto out;
+       }
+
+       err = -EIO;
+       h_parent = NULL;
+       sb = dentry->d_sb;
+       aufs_read_lock(dentry, AuLock_FLUSH | AuLock_IR);
+       parent = dget_parent(dentry);
+       di_read_lock_parent(parent, !AuLock_IR);
+       inode = dentry->d_inode;
+       AuDebugOn(!inode);
+#ifdef CONFIG_AUFS_DEBUG
+       {
+               unsigned int mnt_flags = au_mntflags(sb);
+
+               if (unlikely(!au_opt_test_xino(mnt_flags)))
+                       AuWarn1("NFS-exporting requires xino\n");
+               if (unlikely(0 && !au_opt_test(mnt_flags, UDBA_INOTIFY)))
+                       AuWarn1("udba=inotify is recommended "
+                               "for NFS-exporting\n");
+       }
+#endif
+
+       bend = au_dbtaildir(parent);
+       for (bindex = au_dbstart(parent); bindex <= bend; bindex++) {
+               h_parent = au_h_dptr(parent, bindex);
+               if (h_parent) {
+                       dget(h_parent);
+                       break;
+               }
+       }
+       if (unlikely(!h_parent))
+               goto out_unlock;
+       LKTRTrace("b%d\n", bindex);
+
+       err = -EPERM;
+       br = au_sbr(sb, bindex);
+       h_sb = br->br_mnt->mnt_sb;
+       if (unlikely(!h_sb->s_export_op)) {
+               AuErr1("%s branch is not exportable\n", au_sbtype(h_sb));
+               goto out_dput;
+       }
+
+       fh[Fh_br_id] = br->br_id;
+       fh[Fh_sigen] = au_sigen(sb);
+       encode_ino(fh + Fh_ino, inode->i_ino);
+       encode_ino(fh + Fh_dir_ino, parent->d_inode->i_ino);
+       fh[Fh_igen] = inode->i_generation;
+
+       *max_len -= Fh_tail;
+       /* in linux-2.6.24, it takes struct fid * as file handle */
+       fh[Fh_h_type] = exportfs_encode_fh(h_parent, (void *)(fh + Fh_tail),
+                                          max_len,
+                                          /*connectable or subtreecheck*/0);
+       err = fh[Fh_h_type];
+       *max_len += Fh_tail;
+       /* todo: macros? */
+       if (err != 255)
+               err = 99;
+       else
+               AuWarn1("%s encode_fh failed\n", au_sbtype(h_sb));
+
+ out_dput:
+       dput(h_parent);
+ out_unlock:
+       di_read_unlock(parent, !AuLock_IR);
+       dput(parent);
+       aufs_read_unlock(dentry, AuLock_IR);
+ out:
+       AuTraceErr(err);
+       if (unlikely(err < 0))
+               err = 255;
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static struct export_operations aufs_export_op = {
+       .fh_to_dentry   = aufs_fh_to_dentry,
+       //.fh_to_parent = aufs_fh_to_parent,
+       .encode_fh      = aufs_encode_fh
+};
+
+void au_export_init(struct super_block *sb)
+{
+       struct au_sbinfo *sbinfo;
+       __u32 u;
+
+       AuTraceEnter();
+       SiMustWriteLock(sb);
+
+       sb->s_export_op = &aufs_export_op;
+       sbinfo = au_sbi(sb);
+       sbinfo->si_xigen = NULL;
+       get_random_bytes(&u, sizeof(u));
+       BUILD_BUG_ON(sizeof(u) != sizeof(int));
+       atomic_set(&sbinfo->si_xigen_next, u);
+       memset(&sbinfo->si_xinodir, 0, sizeof(struct path));
+}
diff -urN linux/fs/aufs/file.c linux-aufs/fs/aufs/file.c
--- linux/fs/aufs/file.c        1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/file.c   2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,777 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * handling file/dir, and address_space operation
+ *
+ * $Id$
+ */
+
+#include <linux/pagemap.h>
+#include "aufs.h"
+
+/*
+ * a dirty trick for handling FMODE_EXEC and deny_write_access().
+ * because FMODE_EXEC flag is not passed to f_op->open(),
+ * set it to file->private_data temporary.
+ */
+#if !defined(CONFIG_AUFS_MODULE) || defined(CONFIG_AUFS_DENY_WRITE_ACCESS_PATCH)
+int au_store_fmode_exec(struct nameidata *nd, struct inode *inode)
+{
+       int err;
+       union {
+               void *p;
+               unsigned long ul;
+       } u;
+
+       err = 0;
+       if (nd
+           && (nd->flags & LOOKUP_OPEN)
+           && nd->intent.open.file
+           && (nd->intent.open.flags & FMODE_EXEC)
+           && inode
+           && S_ISREG(inode->i_mode)) {
+               u.ul = nd->intent.open.flags;
+               nd->intent.open.file->private_data = u.p;
+               /* smp_mb(); */
+               err = 1;
+       }
+
+       return err;
+}
+#endif
+
+/* drop flags for writing */
+unsigned int au_file_roflags(unsigned int flags)
+{
+       flags &= ~(O_WRONLY | O_RDWR | O_APPEND | O_CREAT | O_TRUNC);
+       flags |= O_RDONLY | O_NOATIME;
+       return flags;
+}
+
+/* common functions to regular file and dir */
+struct file *au_h_open(struct dentry *dentry, aufs_bindex_t bindex, int flags,
+                      struct file *file)
+{
+       struct file *h_file;
+       struct dentry *h_dentry;
+       struct inode *h_inode;
+       struct super_block *sb;
+       struct au_branch *br;
+       int err;
+
+       LKTRTrace("%.*s, b%d, flags 0%o, f %d\n",
+                 AuDLNPair(dentry), bindex, flags, !!file);
+       h_dentry = au_h_dptr(dentry, bindex);
+       AuDebugOn(!h_dentry);
+       h_inode = h_dentry->d_inode;
+
+       /* a race condition can happen between open and unlink/rmdir */
+       h_file = ERR_PTR(-ENOENT);
+       if (unlikely((!d_unhashed(dentry) && d_unhashed(h_dentry))
+                    || !h_inode))
+               goto out;
+
+       sb = dentry->d_sb;
+       br = au_sbr(sb, bindex);
+       au_br_get(br);
+       /* drop flags for writing */
+       if (au_test_ro(sb, bindex, dentry->d_inode))
+               flags = au_file_roflags(flags);
+       flags &= ~O_CREAT;
+
+       h_file = NULL;
+       if (file && au_test_nfs(h_dentry->d_sb))
+               h_file = au_h_intent(dentry, bindex, file);
+       if (!h_file)
+               h_file = dentry_open(dget(h_dentry), mntget(br->br_mnt), flags, file->f_cred);
+
+       /*
+        * a dirty trick for handling FMODE_EXEC and deny_write_access().
+        */
+       if (file && (file->f_mode & FMODE_EXEC)) {
+               h_file->f_mode |= FMODE_EXEC;
+               smp_mb(); /* flush f_mode */
+               err = au_deny_write_access(h_file);
+               if (unlikely(err)) {
+                       fput(h_file);
+                       h_file = ERR_PTR(err);
+               }
+       }
+       if (IS_ERR(h_file))
+               au_br_put(br);
+
+out:
+       AuTraceErrPtr(h_file);
+       return h_file;
+}
+
+static int do_coo(struct dentry *dentry, aufs_bindex_t bstart)
+{
+       int err;
+       aufs_bindex_t bcpup;
+       unsigned char pin_flags;
+       struct au_pin pin;
+       struct dentry *parent;
+       struct mutex *h_mtx;
+       struct super_block *sb;
+
+       LKTRTrace("%.*s\n", AuDLNPair(dentry));
+       AuDebugOn(IS_ROOT(dentry));
+       DiMustWriteLock(dentry);
+
+       parent = dget_parent(dentry);
+       di_write_lock_parent(parent);
+       sb = dentry->d_sb;
+       err = AuWbrCopyup(au_sbi(sb), dentry);
+       bcpup = err;
+       if (err < 0) {
+               err = 0; /* stop copyup, it is not an error */
+               goto out_dgrade;
+       }
+       err = 0;
+
+       if (!au_h_dptr(parent, bcpup)) {
+               err = au_cpup_dirs(dentry, bcpup);
+               if (unlikely(err))
+                       goto out_dgrade;
+       }
+
+       di_downgrade_lock(parent, AuLock_IR);
+       pin_flags = AuPin_DI_LOCKED | AuPin_MNT_WRITE;
+       if (au_opt_test(au_mntflags(sb), UDBA_INOTIFY))
+               au_fset_pin(pin_flags, DO_GPARENT);
+       err = au_pin(&pin, dentry, bcpup, pin_flags);
+       if (unlikely(err))
+               goto out;
+       h_mtx = &au_h_dptr(dentry, bstart)->d_inode->i_mutex;
+       mutex_lock_nested(h_mtx, AuLsc_I_CHILD);
+       AuDebugOn(au_h_dptr(dentry, bcpup));
+       err = au_sio_cpup_simple(dentry, bcpup, -1, AuCpup_DTIME);
+       AuTraceErr(err);
+       mutex_unlock(h_mtx);
+       au_unpin(&pin);
+       goto out;
+
+ out_dgrade:
+       di_downgrade_lock(parent, AuLock_IR);
+ out:
+       di_read_unlock(parent, AuLock_IR);
+       dput(parent);
+       AuTraceErr(err);
+       return err;
+}
+
+int au_do_open(struct inode *inode, struct file *file,
+              int (*open)(struct file *file, int flags))
+{
+       int err;
+       struct dentry *dentry;
+       struct super_block *sb;
+       aufs_bindex_t bstart;
+       unsigned char coo;
+
+       dentry = file->f_dentry;
+       LKTRTrace("i%lu, %.*s\n", inode->i_ino, AuDLNPair(dentry));
+
+       sb = dentry->d_sb;
+       si_read_lock(sb, AuLock_FLUSH);
+       coo = 0;
+       if (!(sb->s_flags & MS_RDONLY))
+               switch (au_mntflags(sb) & AuOptMask_COO) {
+               case AuOpt_COO_LEAF:
+                       coo = !S_ISDIR(inode->i_mode);
+                       break;
+               case AuOpt_COO_ALL:
+                       coo = 1;
+                       break;
+               }
+       err = au_finfo_init(file);
+       if (unlikely(err))
+               goto out;
+
+       if (!coo)
+               di_read_lock_child(dentry, AuLock_IR);
+       else {
+               di_write_lock_child(dentry);
+               bstart = au_dbstart(dentry);
+               if (au_test_ro(sb, bstart, dentry->d_inode)) {
+                       err = do_coo(dentry, bstart);
+                       if (err) {
+                               di_write_unlock(dentry);
+                               goto out_finfo;
+                       }
+               }
+               di_downgrade_lock(dentry, AuLock_IR);
+       }
+
+       err = open(file, file->f_flags);
+       di_read_unlock(dentry, AuLock_IR);
+
+ out_finfo:
+       fi_write_unlock(file);
+       if (unlikely(err))
+               au_finfo_fin(file);
+ out:
+       si_read_unlock(sb);
+       AuTraceErr(err);
+       return err;
+}
+
+int au_reopen_nondir(struct file *file)
+{
+       int err;
+       aufs_bindex_t bstart, bindex, bend;
+       struct dentry *dentry;
+       struct file *h_file, *h_file_tmp;
+
+       dentry = file->f_dentry;
+       LKTRTrace("%.*s\n", AuDLNPair(dentry));
+       bstart = au_dbstart(dentry);
+       //bstart = au_ibstart(inode);
+       AuDebugOn(S_ISDIR(dentry->d_inode->i_mode)
+                 || !au_h_dptr(dentry, bstart)->d_inode);
+
+       h_file_tmp = NULL;
+       if (au_fbstart(file) == bstart) {
+               h_file = au_h_fptr(file, bstart);
+               if (file->f_mode == h_file->f_mode)
+                       return 0; /* success */
+               h_file_tmp = h_file;
+               get_file(h_file_tmp);
+               au_set_h_fptr(file, bstart, NULL);
+       }
+       AuDebugOn(au_fbstart(file) < bstart
+                 || au_fi(file)->fi_hfile[0 + bstart].hf_file);
+
+       h_file = au_h_open(dentry, bstart, file->f_flags & ~O_TRUNC, file);
+       err = PTR_ERR(h_file);
+       if (IS_ERR(h_file))
+               goto out; /* todo: close all? */
+       err = 0;
+       /* cpup_file_flags(h_file, file); */
+       au_set_fbstart(file, bstart);
+       au_set_h_fptr(file, bstart, h_file);
+       au_update_figen(file);
+       /* todo: necessary? */
+       /* file->f_ra = h_file->f_ra; */
+
+       /* close lower files */
+       bend = au_fbend(file);
+       for (bindex = bstart + 1; bindex <= bend; bindex++)
+               au_set_h_fptr(file, bindex, NULL);
+       au_set_fbend(file, bstart);
+
+ out:
+       if (h_file_tmp)
+               fput(h_file_tmp);
+       AuTraceErr(err);
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static int au_ready_to_write_wh(struct file *file, loff_t len,
+                               aufs_bindex_t bcpup)
+{
+       int err;
+       aufs_bindex_t old_bstart;
+       struct inode *inode;
+       struct dentry *dentry, *hi_wh, *old_h_dentry;
+       struct au_dinfo *dinfo;
+       struct super_block *sb;
+
+       AuTraceEnter();
+
+       dentry = file->f_dentry;
+       inode = dentry->d_inode;
+       hi_wh = au_hi_wh(inode, bcpup);
+       if (!hi_wh)
+               err = au_sio_cpup_wh(dentry, bcpup, len, file);
+       else {
+               /* already copied-up after unlink */
+               dinfo = au_di(dentry);
+               old_bstart = dinfo->di_bstart;
+               dinfo->di_bstart = bcpup;
+               old_h_dentry = dinfo->di_hdentry[0 + bcpup].hd_dentry;
+               dinfo->di_hdentry[0 + bcpup].hd_dentry = hi_wh;
+               err = au_reopen_nondir(file);
+               dinfo->di_hdentry[0 + bcpup].hd_dentry = old_h_dentry;
+               dinfo->di_bstart = old_bstart;
+       }
+
+       sb = dentry->d_sb;
+       if (!err && inode->i_nlink > 1 && au_opt_test(au_mntflags(sb), PLINK))
+               au_plink_append(sb, inode, au_h_dptr(dentry, bcpup), bcpup);
+
+       AuTraceErr(err);
+       return err;
+}
+
+/*
+ * prepare the @file for writing.
+ */
+int au_ready_to_write(struct file *file, loff_t len, struct au_pin *pin)
+{
+       int err;
+       unsigned char pin_flags;
+       aufs_bindex_t bstart, bcpup;
+       struct dentry *dentry, *parent, *h_dentry;
+       struct inode *h_inode, *inode;
+       struct super_block *sb;
+
+       dentry = file->f_dentry;
+       LKTRTrace("%.*s, len %lld\n", AuDLNPair(dentry), len);
+       FiMustWriteLock(file);
+
+       sb = dentry->d_sb;
+       bstart = au_fbstart(file);
+       AuDebugOn(au_fbr(file, bstart) != au_sbr(sb, bstart));
+
+       inode = dentry->d_inode;
+       AuDebugOn(S_ISDIR(inode->i_mode));
+       LKTRTrace("rdonly %d, bstart %d\n",
+                 au_test_ro(sb, bstart, inode), bstart);
+
+       err = au_test_ro(sb, bstart, inode);
+       if (!err && (au_h_fptr(file, bstart)->f_mode & FMODE_WRITE)) {
+               err = au_pin(pin, dentry, bstart, /*flags*/0);
+               goto out;
+       }
+
+       /* need to cpup */
+       parent = dget_parent(dentry);
+       di_write_lock_parent(parent);
+       err = AuWbrCopyup(au_sbi(sb), dentry);
+       bcpup = err;
+       if (unlikely(err < 0))
+               goto out_dgrade;
+       err = 0;
+
+       if (!au_h_dptr(parent, bcpup)) {
+               err = au_cpup_dirs(dentry, bcpup);
+               if (unlikely(err))
+                       goto out_dgrade;
+       }
+
+       pin_flags = AuPin_DI_LOCKED | AuPin_MNT_WRITE;
+       if (au_opt_test(au_mntflags(sb), UDBA_INOTIFY))
+               au_fset_pin(pin_flags, DO_GPARENT);
+       err = au_pin(pin, dentry, bcpup, pin_flags);
+       if (unlikely(err))
+               goto out_dgrade;
+
+       AuDebugOn(au_fbstart(file) != bstart);
+       h_dentry = au_h_fptr(file, bstart)->f_dentry;
+       h_inode = h_dentry->d_inode;
+       mutex_lock_nested(&h_inode->i_mutex, AuLsc_I_CHILD);
+       if (d_unhashed(dentry) /* || d_unhashed(h_dentry) */
+           /* || !h_inode->i_nlink */) {
+               err = au_ready_to_write_wh(file, len, bcpup);
+               di_downgrade_lock(parent, AuLock_IR);
+       } else {
+               di_downgrade_lock(parent, AuLock_IR);
+               if (!au_h_dptr(dentry, bcpup))
+                       err = au_sio_cpup_simple(dentry, bcpup, len,
+                                                AuCpup_DTIME);
+               AuTraceErr(err);
+               if (!err)
+                       err = au_reopen_nondir(file);
+               AuTraceErr(err);
+       }
+       mutex_unlock(&h_inode->i_mutex);
+
+       if (!err) {
+               au_unpin_gp(pin);
+               au_pin_set_parent_lflag(pin, /*lflag*/0);
+               goto out_dput; /* success */
+       }
+       au_unpin(pin);
+       goto out_unlock;
+
+ out_dgrade:
+       di_downgrade_lock(parent, AuLock_IR);
+ out_unlock:
+       di_read_unlock(parent, AuLock_IR);
+ out_dput:
+       dput(parent);
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static int au_file_refresh_by_inode(struct file *file, int *need_reopen)
+{
+       int err;
+       unsigned int mnt_flags;
+       unsigned char pin_flags;
+       aufs_bindex_t bstart, new_bstart, old_bstart;
+       struct au_pin pin;
+       struct au_finfo *finfo;
+       struct dentry *dentry, *parent, *old_h_dentry, *hi_wh;
+       struct inode *inode, *dir;
+       struct super_block *sb;
+       struct au_dinfo *dinfo;
+
+       dentry = file->f_dentry;
+       LKTRTrace("%.*s\n", AuDLNPair(dentry));
+       FiMustWriteLock(file);
+
+       err = 0;
+       finfo = au_fi(file);
+       inode = dentry->d_inode;
+       sb = dentry->d_sb;
+       mnt_flags = au_mntflags(sb);
+       pin_flags = AuPin_DI_LOCKED | AuPin_MNT_WRITE;
+       if (au_opt_test(mnt_flags, UDBA_INOTIFY))
+               au_fset_pin(pin_flags, DO_GPARENT);
+ again:
+       bstart = au_ibstart(inode);
+       if (bstart == finfo->fi_bstart)
+               goto out;
+
+       new_bstart = bstart;
+       parent = dget_parent(dentry);
+       dir = parent->d_inode;
+       if (au_test_ro(sb, bstart, inode)) {
+               di_read_lock_parent(parent, !AuLock_IR);
+               err = AuWbrCopyup(au_sbi(sb), dentry);
+               new_bstart = err;
+               di_read_unlock(parent, !AuLock_IR);
+               if (unlikely(err < 0))
+                       goto out_dput;
+               err = 0;
+       }
+       /* someone else might change our inode while we were sleeping */
+       /* todo: test more? */
+       if (bstart != au_ibstart(inode)) {
+               err = 0;
+               dput(parent);
+               goto again;
+       }
+       di_read_lock_parent(parent, AuLock_IR);
+       bstart = new_bstart;
+
+       hi_wh = au_hi_wh(inode, bstart);
+       if (au_opt_test(mnt_flags, PLINK)
+           && au_plink_test(sb, inode)
+           && !d_unhashed(dentry)) {
+               err = au_test_and_cpup_dirs(dentry, bstart);
+               if (unlikely(err))
+                       goto out_unlock;
+
+               /* always superio. */
+#if 1
+               err = au_pin(&pin, dentry, bstart, pin_flags);
+               if (!err)
+                       err = au_sio_cpup_simple(dentry, bstart, -1,
+                                                AuCpup_DTIME);
+               au_unpin(&pin);
+#else /* reserved for future use */
+               if (!au_test_wkq(current)) {
+                       int wkq_err;
+                       struct cpup_pseudo_link_args args = {
+                               .errp           = &err,
+                               .dentry         = dentry,
+                               .bdst           = bstart,
+                               .do_lock        = 1
+                       };
+                       wkq_err = au_wkq_wait(call_cpup_pseudo_link, &args);
+                       if (unlikely(wkq_err))
+                               err = wkq_err;
+               } else
+                       err = cpup_pseudo_link(dentry, bstart, /*do_lock*/1);
+#endif
+       } else if (hi_wh) {
+               /* already copied-up after unlink */
+               dinfo = au_di(dentry);
+               old_bstart = dinfo->di_bstart;
+               dinfo->di_bstart = bstart;
+               old_h_dentry = dinfo->di_hdentry[0 + bstart].hd_dentry;
+               dinfo->di_hdentry[0 + bstart].hd_dentry = hi_wh;
+               err = au_reopen_nondir(file);
+               dinfo->di_hdentry[0 + bstart].hd_dentry = old_h_dentry;
+               dinfo->di_bstart = old_bstart;
+               *need_reopen = 0;
+       }
+
+ out_unlock:
+       di_read_unlock(parent, AuLock_IR);
+ out_dput:
+       dput(parent);
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+/*
+ * after branch manipulating, refresh the file.
+ */
+static int refresh_file(struct file *file, int (*reopen)(struct file *file))
+{
+       int err, new_sz, need_reopen;
+       struct dentry *dentry;
+       aufs_bindex_t bend, bindex, brid;
+       struct au_hfile *p;
+       struct au_finfo *finfo;
+       struct super_block *sb;
+       struct inode *inode;
+
+       dentry = file->f_dentry;
+       LKTRTrace("%.*s\n", AuDLNPair(dentry));
+       FiMustWriteLock(file);
+       DiMustAnyLock(dentry);
+       inode = dentry->d_inode;
+       IiMustAnyLock(inode);
+
+       err = -ENOMEM;
+       sb = dentry->d_sb;
+       finfo = au_fi(file);
+       new_sz = sizeof(*finfo->fi_hfile) * (au_sbend(sb) + 1);
+       p = au_kzrealloc(finfo->fi_hfile, sizeof(*p) * (finfo->fi_bend + 1),
+                        new_sz, GFP_NOFS);
+       if (unlikely(!p))
+               goto out;
+       finfo->fi_hfile = p;
+
+       p += finfo->fi_bstart;
+       brid = p->hf_br->br_id;
+       bend = finfo->fi_bend;
+       for (bindex = finfo->fi_bstart; bindex <= bend; bindex++, p++) {
+               struct au_hfile tmp, *q;
+               aufs_bindex_t new_bindex;
+
+               if (!p->hf_file)
+                       continue;
+               new_bindex = au_find_bindex(sb, p->hf_br);
+               if (new_bindex == bindex)
+                       continue;
+               /* todo: test more? */
+               if (new_bindex < 0) {
+                       au_set_h_fptr(file, bindex, NULL);
+                       continue;
+               }
+
+               /* swap two hidden inode, and loop again */
+               q = finfo->fi_hfile + new_bindex;
+               tmp = *q;
+               *q = *p;
+               *p = tmp;
+               if (tmp.hf_file) {
+                       bindex--;
+                       p--;
+               }
+       }
+       {
+               aufs_bindex_t s = finfo->fi_bstart, e = finfo->fi_bend;
+               finfo->fi_bstart = 0;
+               finfo->fi_bend = au_sbend(sb);
+               finfo->fi_bstart = s;
+               finfo->fi_bend = e;
+       }
+
+       p = finfo->fi_hfile;
+       if (!au_test_mmapped(file) && !d_unhashed(dentry)) {
+               bend = au_sbend(sb);
+               for (finfo->fi_bstart = 0; finfo->fi_bstart <= bend;
+                    finfo->fi_bstart++, p++)
+                       if (p->hf_file) {
+                               if (p->hf_file->f_dentry
+                                   && p->hf_file->f_dentry->d_inode)
+                                       break;
+                               else
+                                       au_hfput(p);
+                       }
+       } else {
+               bend = au_br_index(sb, brid);
+               for (finfo->fi_bstart = 0; finfo->fi_bstart < bend;
+                    finfo->fi_bstart++, p++)
+                       if (p->hf_file)
+                               au_hfput(p);
+               bend = au_sbend(sb);
+       }
+
+       p = finfo->fi_hfile + bend;
+       for (finfo->fi_bend = bend; finfo->fi_bend >= finfo->fi_bstart;
+            finfo->fi_bend--, p--)
+               if (p->hf_file) {
+                       if (p->hf_file->f_dentry
+                           && p->hf_file->f_dentry->d_inode)
+                               break;
+                       else
+                               au_hfput(p);
+               }
+       AuDebugOn(finfo->fi_bend < finfo->fi_bstart);
+
+       err = 0;
+       need_reopen = 1;
+       if (!au_test_mmapped(file))
+               err = au_file_refresh_by_inode(file, &need_reopen);
+       if (!err && need_reopen && !d_unhashed(dentry))
+               err = reopen(file);
+       if (!err) {
+               au_update_figen(file);
+               return 0; /* success */
+       }
+
+       /* error, close all hidden files */
+       bend = au_fbend(file);
+       for (bindex = au_fbstart(file); bindex <= bend; bindex++)
+               au_set_h_fptr(file, bindex, NULL);
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+/* common function to regular file and dir */
+int au_reval_and_lock_fdi(struct file *file, int (*reopen)(struct file *file),
+                         int wlock, int locked)
+{
+       int err;
+       struct dentry *dentry;
+       struct super_block *sb;
+       aufs_bindex_t bstart;
+       unsigned char pseudo_link;
+       au_gen_t sgen, fgen;
+
+       dentry = file->f_dentry;
+       LKTRTrace("%.*s, w %d, l %d\n", AuDLNPair(dentry), wlock, locked);
+       sb = dentry->d_sb;
+       SiMustAnyLock(sb);
+
+       err = 0;
+       sgen = au_sigen(sb);
+       fi_write_lock(file);
+       fgen = au_figen(file);
+       di_write_lock_child(dentry);
+       bstart = au_dbstart(dentry);
+       pseudo_link = (bstart != au_ibstart(dentry->d_inode));
+       if (sgen == fgen && !pseudo_link && au_fbstart(file) == bstart) {
+               if (!wlock) {
+                       di_downgrade_lock(dentry, AuLock_IR);
+                       fi_downgrade_lock(file);
+               }
+               goto out; /* success */
+       }
+
+       LKTRTrace("sgen %d, fgen %d\n", sgen, fgen);
+       if (sgen != au_digen(dentry)
+           || sgen != au_iigen(dentry->d_inode)) {
+               /*
+                * d_path() and path_lookup() is a simple and good approach
+                * to revalidate. but si_rwsem in DEBUG_RWSEM will cause a
+                * deadlock. removed the code.
+                */
+               err = au_reval_dpath(dentry, sgen);
+               if (unlikely(err < 0))
+                       goto out;
+               AuDebugOn(au_digen(dentry) != sgen
+                         || au_iigen(dentry->d_inode) != sgen);
+       }
+
+       err = refresh_file(file, reopen
+                          /* , au_opt_test(au_mnt_flags(sb), REFROF) */);
+       if (!err) {
+               if (!wlock) {
+                       di_downgrade_lock(dentry, AuLock_IR);
+                       fi_downgrade_lock(file);
+               }
+       } else {
+               di_write_unlock(dentry);
+               fi_write_unlock(file);
+       }
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* cf. aufs_nopage() */
+/* for madvise(2) */
+static int aufs_readpage(struct file *file, struct page *page)
+{
+       AuTraceEnter();
+       unlock_page(page);
+       return 0;
+}
+
+/* they will never be called. */
+#ifdef CONFIG_AUFS_DEBUG
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 28)
+static int aufs_prepare_write(struct file *file, struct page *page,
+                             unsigned from, unsigned to)
+{ AuUnsupport(); return 0; }
+static int aufs_commit_write(struct file *file, struct page *page,
+                            unsigned from, unsigned to)
+{ AuUnsupport(); return 0; }
+#endif
+static int aufs_write_begin(struct file *file, struct address_space *mapping,
+                           loff_t pos, unsigned len, unsigned flags,
+                           struct page **pagep, void **fsdata)
+{ AuUnsupport(); return 0; }
+static int aufs_write_end(struct file *file, struct address_space *mapping,
+                         loff_t pos, unsigned len, unsigned copied,
+                         struct page *page, void *fsdata)
+{ AuUnsupport(); return 0; }
+static int aufs_writepage(struct page *page, struct writeback_control *wbc)
+{ AuUnsupport(); return 0; }
+static void aufs_sync_page(struct page *page)
+{ AuUnsupport(); }
+
+static int aufs_set_page_dirty(struct page *page)
+{ AuUnsupport(); return 0; }
+static void aufs_invalidatepage(struct page *page, unsigned long offset)
+{ AuUnsupport(); }
+static int aufs_releasepage(struct page *page, gfp_t gfp)
+{ AuUnsupport(); return 0; }
+static ssize_t aufs_direct_IO(int rw, struct kiocb *iocb,
+                             const struct iovec *iov, loff_t offset,
+                             unsigned long nr_segs)
+{ AuUnsupport(); return 0; }
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 26)
+static struct page *aufs_get_xip_page(struct address_space *mapping,
+                                     sector_t offset, int create)
+{ AuUnsupport(); return NULL; }
+#endif
+#endif /* CONFIG_AUFS_DEBUG */
+
+struct address_space_operations aufs_aop = {
+       .readpage       = aufs_readpage,
+#ifdef CONFIG_AUFS_DEBUG
+       .writepage      = aufs_writepage,
+       .sync_page      = aufs_sync_page,
+       .set_page_dirty = aufs_set_page_dirty,
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 28)
+       .prepare_write  = aufs_prepare_write,
+       .commit_write   = aufs_commit_write,
+#endif
+       .write_begin    = aufs_write_begin,
+       .write_end      = aufs_write_end,
+       .invalidatepage = aufs_invalidatepage,
+       .releasepage    = aufs_releasepage,
+       .direct_IO      = aufs_direct_IO,
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 26)
+       .get_xip_page   = aufs_get_xip_page,
+#endif
+#endif /* CONFIG_AUFS_DEBUG */
+};
diff -urN linux/fs/aufs/file.h linux-aufs/fs/aufs/file.h
--- linux/fs/aufs/file.h        1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/file.h   2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,257 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * file operations
+ *
+ * $Id$
+ */
+
+#ifndef __AUFS_FILE_H__
+#define __AUFS_FILE_H__
+
+#ifdef __KERNEL__
+
+#include <linux/file.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/aufs_type.h>
+#include "dentry.h"
+#include "misc.h"
+#include "super.h"
+
+/* ---------------------------------------------------------------------- */
+
+struct au_branch;
+struct au_hfile {
+       struct file             *hf_file;
+       struct au_branch        *hf_br;
+};
+
+struct au_vdir;
+struct au_finfo {
+       atomic_t                fi_generation;
+
+       struct au_rwsem         fi_rwsem;
+       struct au_hfile         *fi_hfile;
+       aufs_bindex_t           fi_bstart, fi_bend;
+
+       union {
+               struct vm_operations_struct     *fi_h_vm_ops;
+               struct au_vdir                  *fi_vdir_cache;
+       };
+};
+
+/* ---------------------------------------------------------------------- */
+
+/* file.c */
+extern struct address_space_operations aufs_aop;
+unsigned int au_file_roflags(unsigned int flags);
+struct file *au_h_open(struct dentry *dentry, aufs_bindex_t bindex, int flags,
+                      struct file *file);
+int au_do_open(struct inode *inode, struct file *file,
+              int (*open)(struct file *file, int flags));
+int au_reopen_nondir(struct file *file);
+struct au_pin;
+int au_ready_to_write(struct file *file, loff_t len, struct au_pin *pin);
+int au_reval_and_lock_fdi(struct file *file, int (*reopen)(struct file *file),
+                         int wlock, int locked);
+
+/* f_op.c */
+extern struct file_operations aufs_file_fop;
+int aufs_flush(struct file *file, fl_owner_t id);
+
+/* finfo.c */
+struct au_finfo *au_fi(struct file *file);
+struct au_branch *au_fbr(struct file *file, aufs_bindex_t bindex);
+struct file *au_h_fptr(struct file *file, aufs_bindex_t bindex);
+
+void au_hfput(struct au_hfile *hf);
+void au_set_h_fptr(struct file *file, aufs_bindex_t bindex,
+                  struct file *h_file);
+
+void au_finfo_fin(struct file *file);
+int au_finfo_init(struct file *file);
+
+#ifdef CONFIG_AUFS_ROBR
+/* robr.c */
+struct file *au_robr_safe_file(struct vm_area_struct *vma);
+void au_robr_reset_file(struct vm_area_struct *vma, struct file *file);
+#else
+static inline struct file *au_robr_safe_file(struct vm_area_struct *vma)
+{
+       struct file *file;
+
+       file = vma->vm_file;
+       if (file->private_data && au_test_aufs(file->f_dentry->d_sb))
+               return file;
+       return NULL;
+}
+
+static inline
+void au_robr_reset_file(struct vm_area_struct *vma, struct file *file)
+{
+       vma->vm_file = file;
+       /* smp_mb(); */ /* flush vm_file */
+}
+#endif /* CONFIG_AUFS_ROBR */
+
+#if 0 /* reserved for future use */
+/* ioctl.c */
+long aufs_ioctl(struct file *file, unsigned int cmd, unsigned long arg);
+long aufs_ioctl_dir(struct file *file, unsigned int cmd, unsigned long arg);
+#endif
+
+/* ---------------------------------------------------------------------- */
+
+/* todo: memory barrier? */
+static inline au_gen_t au_figen(struct file *f)
+{
+       return atomic_read(&au_fi(f)->fi_generation);
+}
+
+static inline int au_test_mmapped(struct file *f)
+{
+       return !!(au_fi(f)->fi_h_vm_ops);
+}
+
+static inline int au_test_aufs_file(struct file *f)
+{
+       return !(f->f_dentry->d_inode->i_mode
+                & (S_IFCHR | S_IFBLK | S_IFIFO | S_IFSOCK));
+}
+
+/* ---------------------------------------------------------------------- */
+
+#if !defined(CONFIG_AUFS_MODULE) || defined(CONFIG_AUFS_DENY_WRITE_ACCESS_PATCH)
+int au_store_fmode_exec(struct nameidata *nd, struct inode *inode);
+
+static inline int au_deny_write_access(struct file *h_file)
+{
+       LKTRTrace("%.*s\n", AuDLNPair(h_file->f_dentry));
+       return deny_write_access(h_file);
+}
+
+static inline void au_allow_write_access(struct file *h_file)
+{
+       allow_write_access(h_file);
+}
+
+#else
+
+static inline int au_store_fmode_exec(struct nameidata *nd, struct inode *inode)
+{
+       /* nothing */
+       return 0;
+}
+
+static inline int au_deny_write_access(struct file *h_file)
+{
+       /* nothing */
+       return 0;
+}
+
+static inline void au_allow_write_access(struct file *h_file)
+{
+       /* nothing */
+}
+#endif /* CONFIG_AUFS_DENY_WRITE_ACCESS_PATCH */
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * fi_read_lock, fi_write_lock,
+ * fi_read_unlock, fi_write_unlock, fi_downgrade_lock
+ */
+AuSimpleRwsemFuncs(fi, struct file *f, au_fi(f)->fi_rwsem);
+
+/* to debug easier, do not make them inlined functions */
+#define FiMustReadLock(f) do { \
+       SiMustAnyLock((f)->f_dentry->d_sb); \
+       AuRwMustReadLock(&au_fi(f)->fi_rwsem); \
+} while (0)
+
+#define FiMustWriteLock(f) do { \
+       SiMustAnyLock((f)->f_dentry->d_sb); \
+       AuRwMustWriteLock(&au_fi(f)->fi_rwsem); \
+} while (0)
+
+#define FiMustAnyLock(f) do { \
+       SiMustAnyLock((f)->f_dentry->d_sb); \
+       AuRwMustAnyLock(&au_fi(f)->fi_rwsem); \
+} while (0)
+
+#define FiMustNoWaiters(f)     AuRwMustNoWaiters(&au_fi(f)->fi_rwsem)
+
+/* ---------------------------------------------------------------------- */
+
+/* todo: hard/soft set? */
+static inline aufs_bindex_t au_fbstart(struct file *file)
+{
+       FiMustAnyLock(file);
+       return au_fi(file)->fi_bstart;
+}
+
+static inline aufs_bindex_t au_fbend(struct file *file)
+{
+       FiMustAnyLock(file);
+       return au_fi(file)->fi_bend;
+}
+
+static inline struct au_vdir *au_fvdir_cache(struct file *file)
+{
+#ifdef CONFIG_AUFS_EXPORT
+       AuRwMustAnyLock(&au_fi(file)->fi_rwsem);
+#else
+       FiMustAnyLock(file);
+#endif
+       return au_fi(file)->fi_vdir_cache;
+}
+
+static inline void au_set_fbstart(struct file *file, aufs_bindex_t bindex)
+{
+       FiMustWriteLock(file);
+       AuDebugOn(au_sbend(file->f_dentry->d_sb) < bindex);
+       au_fi(file)->fi_bstart = bindex;
+}
+
+static inline void au_set_fbend(struct file *file, aufs_bindex_t bindex)
+{
+       FiMustWriteLock(file);
+       AuDebugOn(au_sbend(file->f_dentry->d_sb) < bindex
+                 || bindex < au_fbstart(file));
+       au_fi(file)->fi_bend = bindex;
+}
+
+static inline void au_set_fvdir_cache(struct file *file,
+                                     struct au_vdir *vdir_cache)
+{
+       FiMustWriteLock(file);
+       AuDebugOn(!S_ISDIR(file->f_dentry->d_inode->i_mode)
+                 || (au_fi(file)->fi_vdir_cache && vdir_cache));
+       au_fi(file)->fi_vdir_cache = vdir_cache;
+}
+
+static inline void au_update_figen(struct file *file)
+{
+       atomic_set(&au_fi(file)->fi_generation, au_digen(file->f_dentry));
+       /* smp_mb(); */ /* atomic_set */
+}
+
+#endif /* __KERNEL__ */
+#endif /* __AUFS_FILE_H__ */
diff -urN linux/fs/aufs/finfo.c linux-aufs/fs/aufs/finfo.c
--- linux/fs/aufs/finfo.c       1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/finfo.c  2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,186 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * file private data
+ *
+ * $Id$
+ */
+
+#include "aufs.h"
+
+struct au_finfo *au_fi(struct file *file)
+{
+       struct au_finfo *finfo = file->private_data;
+       AuDebugOn(!finfo
+                 || !finfo->fi_hfile
+                 || (0 < finfo->fi_bend
+                     && (/* au_sbi(file->f_dentry->d_sb)->si_bend
+                            < finfo->fi_bend
+                            || */ finfo->fi_bend < finfo->fi_bstart)));
+       return finfo;
+}
+
+struct au_branch *au_fbr(struct file *file, aufs_bindex_t bindex)
+{
+       struct au_finfo *finfo = au_fi(file);
+       struct au_hfile *hf;
+
+       FiMustAnyLock(file);
+       AuDebugOn(!finfo
+                 || finfo->fi_bstart < 0
+                 || bindex < finfo->fi_bstart
+                 || finfo->fi_bend < bindex);
+       hf = finfo->fi_hfile + bindex;
+       AuDebugOn(hf->hf_br && au_br_count(hf->hf_br) <= 0);
+       return hf->hf_br;
+}
+
+struct file *au_h_fptr(struct file *file, aufs_bindex_t bindex)
+{
+       struct au_finfo *finfo = au_fi(file);
+       struct au_hfile *hf;
+
+       FiMustAnyLock(file);
+       AuDebugOn(!finfo
+                 || finfo->fi_bstart < 0
+                 || bindex < finfo->fi_bstart
+                 || finfo->fi_bend < bindex);
+       hf = finfo->fi_hfile + bindex;
+       AuDebugOn(hf->hf_file
+                 && file_count(hf->hf_file) <= 0
+                 && au_br_count(hf->hf_br) <= 0);
+       return hf->hf_file;
+}
+
+void au_hfput(struct au_hfile *hf)
+{
+       if (hf->hf_file->f_mode & FMODE_EXEC)
+               au_allow_write_access(hf->hf_file);
+       fput(hf->hf_file);
+       hf->hf_file = NULL;
+       AuDebugOn(!hf->hf_br);
+       au_br_put(hf->hf_br);
+       hf->hf_br = NULL;
+}
+
+void au_set_h_fptr(struct file *file, aufs_bindex_t bindex, struct file *val)
+{
+       struct au_finfo *finfo = au_fi(file);
+       struct au_hfile *hf;
+
+       FiMustWriteLock(file);
+       AuDebugOn(!finfo
+                 || finfo->fi_bstart < 0
+                 || bindex < finfo->fi_bstart
+                 || finfo->fi_bend < bindex);
+       AuDebugOn(val && file_count(val) <= 0);
+       hf = finfo->fi_hfile + bindex;
+       AuDebugOn(val && hf->hf_file);
+       if (hf->hf_file)
+               au_hfput(hf);
+       if (val) {
+               hf->hf_file = val;
+               hf->hf_br = au_sbr(file->f_dentry->d_sb, bindex);
+       }
+}
+
+void au_finfo_fin(struct file *file)
+{
+       struct au_finfo *finfo;
+       struct dentry *dentry;
+       aufs_bindex_t bindex, bend;
+
+       dentry = file->f_dentry;
+       LKTRTrace("%.*s\n", AuDLNPair(dentry));
+       SiMustAnyLock(dentry->d_sb);
+
+       fi_write_lock(file);
+       bend = au_fbend(file);
+       bindex = au_fbstart(file);
+       if (bindex >= 0)
+               for (; bindex <= bend; bindex++)
+                       au_set_h_fptr(file, bindex, NULL);
+
+       finfo = au_fi(file);
+#ifdef CONFIG_AUFS_DEBUG
+       if (finfo->fi_bstart >= 0) {
+               bend = au_fbend(file);
+               for (bindex = finfo->fi_bstart; bindex <= bend; bindex++) {
+                       struct au_hfile *hf;
+                       hf = finfo->fi_hfile + bindex;
+                       AuDebugOn(hf->hf_file || hf->hf_br);
+               }
+       }
+#endif
+
+       kfree(finfo->fi_hfile);
+       fi_write_unlock(file);
+       au_rwsem_destroy(&finfo->fi_rwsem);
+       au_cache_free_finfo(finfo);
+}
+
+int au_finfo_init(struct file *file)
+{
+       struct au_finfo *finfo;
+       struct dentry *dentry;
+       union {
+               void *p;
+               unsigned long ul;
+       } u;
+
+       dentry = file->f_dentry;
+       LKTRTrace("%.*s\n", AuDLNPair(dentry));
+       AuDebugOn(!dentry->d_inode);
+
+       finfo = au_cache_alloc_finfo();
+       if (finfo) {
+               finfo->fi_hfile = kcalloc(au_sbend(dentry->d_sb) + 1,
+                                         sizeof(*finfo->fi_hfile), GFP_NOFS);
+               if (finfo->fi_hfile) {
+                       au_rw_init_wlock(&finfo->fi_rwsem);
+                       //au_dbg_lock_fi_reg(file);
+                       finfo->fi_bstart = -1;
+                       finfo->fi_bend = -1;
+                       atomic_set(&finfo->fi_generation, au_digen(dentry));
+                       /* smp_mb(); */ /* atomic_set */
+
+                       /*
+                        * a dirty trick for handling FMODE_EXEC and
+                        * deny_write_access().
+                        * because FMODE_EXEC flag is not passed to
+                        * f_op->open(),
+                        * aufs set it to file->private_data temporary in lookup
+                        * or dentry revalidation operations.
+                        * restore the flag to f_mode here.
+                        */
+                       u.p = file->private_data;
+                       if (u.ul & FMODE_EXEC) {
+                               file->f_mode |= FMODE_EXEC;
+                               smp_mb(); /* flush f_mode */
+                       }
+
+                       file->private_data = finfo;
+                       return 0; /* success */
+               }
+               au_cache_free_finfo(finfo);
+       }
+
+       AuTraceErr(-ENOMEM);
+       return -ENOMEM;
+}
diff -urN linux/fs/aufs/f_op.c linux-aufs/fs/aufs/f_op.c
--- linux/fs/aufs/f_op.c        1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/f_op.c   2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,673 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * file and vm operations
+ *
+ * $Id$
+ */
+
+#include <linux/fs_stack.h>
+#include <linux/poll.h>
+#include "aufs.h"
+
+/* common function to regular file and dir */
+int aufs_flush(struct file *file, fl_owner_t id)
+{
+       int err;
+       struct dentry *dentry;
+       aufs_bindex_t bindex, bend;
+       struct file *h_file;
+
+       dentry = file->f_dentry;
+       LKTRTrace("%.*s\n", AuDLNPair(dentry));
+
+       si_noflush_read_lock(dentry->d_sb);
+       fi_read_lock(file);
+       di_read_lock_child(dentry, AuLock_IW);
+
+       err = 0;
+       bend = au_fbend(file);
+       for (bindex = au_fbstart(file); !err && bindex <= bend; bindex++) {
+               h_file = au_h_fptr(file, bindex);
+               if (h_file && h_file->f_op && h_file->f_op->flush) {
+                       err = h_file->f_op->flush(h_file, id);
+                       if (!err)
+                               au_update_fuse_h_inode
+                                       (h_file->f_vfsmnt, h_file->f_dentry);
+                       /*ignore*/
+               }
+       }
+       au_cpup_attr_timesizes(dentry->d_inode);
+
+       di_read_unlock(dentry, AuLock_IW);
+       fi_read_unlock(file);
+       si_read_unlock(dentry->d_sb);
+       AuTraceErr(err);
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static int do_open_nondir(struct file *file, int flags)
+{
+       int err;
+       aufs_bindex_t bindex;
+       struct super_block *sb;
+       struct file *h_file;
+       struct dentry *dentry;
+       struct inode *inode;
+       struct au_finfo *finfo;
+
+       dentry = file->f_dentry;
+       LKTRTrace("%.*s, flags 0%o\n", AuDLNPair(dentry), flags);
+       FiMustWriteLock(file);
+       inode = dentry->d_inode;
+       AuDebugOn(!inode || S_ISDIR(inode->i_mode));
+
+       err = 0;
+       finfo = au_fi(file);
+       finfo->fi_h_vm_ops = NULL;
+       sb = dentry->d_sb;
+       bindex = au_dbstart(dentry);
+       AuDebugOn(!au_h_dptr(dentry, bindex)->d_inode);
+       /* O_TRUNC is processed already */
+       BUG_ON(au_test_ro(sb, bindex, inode) && (flags & O_TRUNC));
+
+       h_file = au_h_open(dentry, bindex, flags, file);
+       if (IS_ERR(h_file))
+               err = PTR_ERR(h_file);
+       else {
+               au_set_fbstart(file, bindex);
+               au_set_fbend(file, bindex);
+               au_set_h_fptr(file, bindex, h_file);
+               au_update_figen(file);
+               /* todo: necessary? */
+               /* file->f_ra = h_file->f_ra; */
+               err = 0;
+       }
+       AuTraceErr(err);
+       return err;
+}
+
+static int aufs_open_nondir(struct inode *inode, struct file *file)
+{
+       LKTRTrace("i%lu, %.*s\n", inode->i_ino, AuDLNPair(file->f_dentry));
+
+       return au_do_open(inode, file, do_open_nondir);
+}
+
+static int aufs_release_nondir(struct inode *inode, struct file *file)
+{
+       struct super_block *sb = file->f_dentry->d_sb;
+
+       LKTRTrace("i%lu, %.*s\n", inode->i_ino, AuDLNPair(file->f_dentry));
+
+       si_noflush_read_lock(sb);
+       au_finfo_fin(file);
+       si_read_unlock(sb);
+       return 0;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static ssize_t aufs_read(struct file *file, char __user *buf, size_t count,
+                        loff_t *ppos)
+{
+       ssize_t err;
+       struct dentry *dentry;
+       struct file *h_file;
+       struct super_block *sb;
+       struct inode *h_inode;
+
+       dentry = file->f_dentry;
+       LKTRTrace("%.*s, cnt %zu, pos %lld\n", AuDLNPair(dentry), count, *ppos);
+
+       sb = dentry->d_sb;
+       si_read_lock(sb, AuLock_FLUSH);
+       err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/0,
+                                   /*locked*/0);
+       if (unlikely(err))
+               goto out;
+
+       /* support LSM and notify */
+       h_file = au_h_fptr(file, au_fbstart(file));
+       h_inode = h_file->f_dentry->d_inode;
+       err = vfsub_read_u(h_file, buf, count, ppos,
+                          au_test_dlgt(au_mntflags(sb)));
+       /* todo: necessary? */
+       /* file->f_ra = h_file->f_ra; */
+       fsstack_copy_attr_atime(dentry->d_inode, h_file->f_dentry->d_inode);
+
+       di_read_unlock(dentry, AuLock_IR);
+       fi_read_unlock(file);
+ out:
+       si_read_unlock(sb);
+       AuTraceErr(err);
+       return err;
+}
+
+static ssize_t aufs_write(struct file *file, const char __user *ubuf,
+                         size_t count, loff_t *ppos)
+{
+       ssize_t err;
+       struct dentry *dentry;
+       struct inode *inode;
+       struct super_block *sb;
+       unsigned int mnt_flags;
+       struct file *h_file;
+       char __user *buf = (char __user *)ubuf;
+       struct au_hin_ignore ign;
+       struct vfsub_args vargs;
+       aufs_bindex_t bstart;
+       int hinotify;
+       struct au_pin pin;
+
+       dentry = file->f_dentry;
+       LKTRTrace("%.*s, cnt %zu, pos %lld\n", AuDLNPair(dentry), count, *ppos);
+
+       inode = dentry->d_inode;
+       mutex_lock(&inode->i_mutex);
+       sb = dentry->d_sb;
+       si_read_lock(sb, AuLock_FLUSH);
+       mnt_flags = au_mntflags(sb);
+       hinotify = !!au_opt_test(mnt_flags, UDBA_INOTIFY);
+       vfsub_args_init(&vargs, &ign, au_test_dlgt(mnt_flags), 0);
+
+       err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/1,
+                                   /*locked*/1);
+       if (unlikely(err))
+               goto out;
+       err = au_ready_to_write(file, -1, &pin);
+       di_downgrade_lock(dentry, AuLock_IR);
+       if (unlikely(err))
+               goto out_unlock;
+
+       bstart = au_fbstart(file);
+       h_file = au_h_fptr(file, bstart);
+       if (!hinotify) {
+               au_unpin(&pin);
+               err = vfsub_write_u(h_file, buf, count, ppos, &vargs);
+       } else {
+               vfsub_ign_hinode(&vargs, IN_MODIFY, au_pinned_hdir(&pin));
+               err = vfsub_write_u(h_file, buf, count, ppos, &vargs);
+               au_unpin(&pin);
+       }
+       au_cpup_attr_timesizes(inode);
+
+ out_unlock:
+       di_read_unlock(dentry, AuLock_IR);
+       fi_write_unlock(file);
+ out:
+       si_read_unlock(sb);
+       mutex_unlock(&inode->i_mutex);
+       AuTraceErr(err);
+       return err;
+}
+
+#ifdef CONFIG_AUFS_SPLICE_PATCH
+static int au_test_loopback(void)
+{
+       const char c = current->comm[4];
+       /* true if a kernel thread named 'loop[0-9].*' accesses a file */
+       const int loopback = (current->mm == NULL
+                             && '0' <= c && c <= '9'
+                             && strncmp(current->comm, "loop", 4) == 0);
+       return loopback;
+}
+
+static ssize_t aufs_splice_read(struct file *file, loff_t *ppos,
+                               struct pipe_inode_info *pipe, size_t len,
+                               unsigned int flags)
+{
+       ssize_t err;
+       struct file *h_file;
+       struct dentry *dentry;
+       struct super_block *sb;
+
+       dentry = file->f_dentry;
+       LKTRTrace("%.*s, pos %lld, len %zu\n", AuDLNPair(dentry), *ppos, len);
+
+       sb = dentry->d_sb;
+       si_read_lock(sb, AuLock_FLUSH);
+       err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/0,
+                                   /*locked*/0);
+       if (unlikely(err))
+               goto out;
+
+       err = -EINVAL;
+       /* support LSM and notify */
+       h_file = au_h_fptr(file, au_fbstart(file));
+       if (au_test_loopback()) {
+               file->f_mapping = h_file->f_mapping;
+               smp_mb(); /* unnecessary? */
+       }
+       err = vfsub_splice_to(h_file, ppos, pipe, len, flags,
+                             au_test_dlgt(au_mntflags(sb)));
+       /* todo: necessasry? */
+       /* file->f_ra = h_file->f_ra; */
+       fsstack_copy_attr_atime(dentry->d_inode, h_file->f_dentry->d_inode);
+       di_read_unlock(dentry, AuLock_IR);
+       fi_read_unlock(file);
+
+ out:
+       si_read_unlock(sb);
+       AuTraceErr(err);
+       return err;
+}
+
+static ssize_t
+aufs_splice_write(struct pipe_inode_info *pipe, struct file *file, loff_t *ppos,
+                 size_t len, unsigned int flags)
+{
+       ssize_t err;
+       struct dentry *dentry;
+       struct inode *inode, *h_inode;
+       struct super_block *sb;
+       struct file *h_file;
+       /* struct au_hin_ignore ign; */
+       struct vfsub_args vargs;
+       unsigned int mnt_flags;
+       struct au_pin pin;
+
+       dentry = file->f_dentry;
+       LKTRTrace("%.*s, len %zu, pos %lld\n", AuDLNPair(dentry), len, *ppos);
+
+       inode = dentry->d_inode;
+       mutex_lock(&inode->i_mutex);
+       sb = dentry->d_sb;
+       si_read_lock(sb, AuLock_FLUSH);
+       mnt_flags = au_mntflags(sb);
+       vfsub_args_init(&vargs, /*&ign*/NULL, au_test_dlgt(mnt_flags), 0);
+
+       err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/1,
+                                   /*locked*/1);
+       if (unlikely(err))
+               goto out;
+       err = au_ready_to_write(file, -1, &pin);
+       di_downgrade_lock(dentry, AuLock_IR);
+       if (unlikely(err))
+               goto out_unlock;
+
+       /* support LSM and notify */
+       /* current vfs_splice_from() doesn't fire up the inotify event */
+       h_file = au_h_fptr(file, au_fbstart(file));
+       h_inode = h_file->f_dentry->d_inode;
+       if (1 || !au_opt_test(mnt_flags, UDBA_INOTIFY)) {
+               au_unpin(&pin);
+               err = vfsub_splice_from(pipe, h_file, ppos, len, flags, &vargs);
+       }
+#if 0 /* reserved for future use */
+       else {
+               struct dentry *parent = dget_parent(dentry);
+               vfsub_ign_hinode(&vargs, IN_MODIFY, au_pinned_hdir(&pin));
+               err = vfsub_splice_from(pipe, h_file, ppos, len, flags, &vargs);
+               au_unpin(&pin);
+       }
+#endif
+       au_cpup_attr_timesizes(inode);
+
+ out_unlock:
+       di_read_unlock(dentry, AuLock_IR);
+       fi_write_unlock(file);
+ out:
+       si_read_unlock(sb);
+       mutex_unlock(&inode->i_mutex);
+       AuTraceErr(err);
+       return err;
+}
+#endif /* CONFIG_AUFS_SPLICE_PATCH */
+
+/* ---------------------------------------------------------------------- */
+
+static int aufs_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+       int err;
+       struct dentry *dentry;
+       struct file *file, *h_file;
+       struct inode *inode;
+       static DECLARE_WAIT_QUEUE_HEAD(wq);
+       struct au_finfo *finfo;
+
+       AuTraceEnter();
+       AuDebugOn(!vma || !vma->vm_file);
+       /* todo: non-robr mode, user vm_file as it is? */
+       wait_event(wq, (file = au_robr_safe_file(vma)));
+       AuDebugOn(!au_test_aufs(file->f_dentry->d_sb));
+       dentry = file->f_dentry;
+       LKTRTrace("%.*s\n", AuDLNPair(dentry));
+       inode = dentry->d_inode;
+       AuDebugOn(!S_ISREG(inode->i_mode));
+
+       /* do not revalidate, no si lock */
+       finfo = au_fi(file);
+       h_file = finfo->fi_hfile[0 + finfo->fi_bstart].hf_file;
+       AuDebugOn(!h_file || !au_test_mmapped(file));
+       fi_write_lock(file);
+       vma->vm_file = h_file;
+       err = finfo->fi_h_vm_ops->fault(vma, vmf);
+       /* todo: necessary? */
+       /* file->f_ra = h_file->f_ra; */
+       au_robr_reset_file(vma, file);
+       fi_write_unlock(file);
+#if 0 /* def CONFIG_SMP */
+       /* wake_up_nr(&wq, online_cpu - 1); */
+       wake_up_all(&wq);
+#else
+       wake_up(&wq);
+#endif
+
+       if (!(err & VM_FAULT_ERROR)) {
+#if 0 /* debug */
+               struct page *page;
+               page = vmf->page;
+               AuDbg("%p, %d\n", page, page_mapcount(page));
+
+               page->mapping = file->f_mapping;
+               get_page(page);
+               file->f_mapping = h_file->f_mapping;
+               touch_atime(NULL, dentry);
+               inode->i_atime = h_file->f_dentry->d_inode->i_atime;
+#endif
+       }
+       AuTraceErr(err);
+       return err;
+}
+
+static struct vm_operations_struct aufs_vm_ops = {
+       .fault          = aufs_fault,
+#if 0 /* reserved for future use */
+       .open           = aufs_vmaopen,
+       .close          = aufs_vmaclose,
+       unsigned long (*nopfn)(struct vm_area_struct *area,
+                              unsigned long address);
+       page_mkwrite(struct vm_area_struct *vma, struct page *page)
+#endif
+};
+
+/* ---------------------------------------------------------------------- */
+
+static struct vm_operations_struct *au_vm_ops(struct file *h_file,
+                                             struct vm_area_struct *vma)
+{
+       struct vm_operations_struct *vm_ops;
+       int err;
+
+       AuTraceEnter();
+
+       au_br_nfs_lockdep_off(h_file->f_vfsmnt->mnt_sb);
+       err = h_file->f_op->mmap(h_file, vma);
+       au_br_nfs_lockdep_on(h_file->f_vfsmnt->mnt_sb);
+       vm_ops = ERR_PTR(err);
+       if (unlikely(err))
+               goto out;
+       vm_ops = vma->vm_ops;
+       err = do_munmap(current->mm, vma->vm_start,
+                       vma->vm_end - vma->vm_start);
+       if (unlikely(err)) {
+               AuIOErr("failed internal unmapping %.*s, %d\n",
+                       AuDLNPair(h_file->f_dentry), err);
+               vm_ops = ERR_PTR(-EIO);
+       }
+
+ out:
+       AuTraceErrPtr(vm_ops);
+       return vm_ops;
+}
+
+static int aufs_mmap(struct file *file, struct vm_area_struct *vma)
+{
+       int err;
+       unsigned char wlock, mmapped;
+       struct dentry *dentry;
+       struct super_block *sb;
+       struct file *h_file;
+       struct vm_operations_struct *vm_ops;
+
+       dentry = file->f_dentry;
+       LKTRTrace("%.*s, %lx, len %lu\n",
+                 AuDLNPair(dentry), vma->vm_start,
+                 vma->vm_end - vma->vm_start);
+       AuDebugOn(!S_ISREG(dentry->d_inode->i_mode));
+       AuDebugOn(down_write_trylock(&vma->vm_mm->mmap_sem));
+
+       mmapped = au_test_mmapped(file); /* can be harmless race condition */
+       wlock = !!(file->f_mode & FMODE_WRITE);
+       sb = dentry->d_sb;
+       si_read_lock(sb, AuLock_FLUSH);
+       err = au_reval_and_lock_fdi(file, au_reopen_nondir, wlock | !mmapped,
+                               /*locked*/0);
+       if (unlikely(err))
+               goto out;
+
+       if (wlock) {
+               struct au_pin pin;
+
+               err = au_ready_to_write(file, -1, &pin);
+               di_downgrade_lock(dentry, AuLock_IR);
+               if (unlikely(err))
+                       goto out_unlock;
+               au_unpin(&pin);
+       } else if (!mmapped)
+               di_downgrade_lock(dentry, AuLock_IR);
+
+       h_file = au_h_fptr(file, au_fbstart(file));
+       if (au_test_fuse(h_file->f_dentry->d_sb)) {
+               /*
+                * by this assignment, f_mapping will differs from aufs inode
+                * i_mapping.
+                * if someone else mixes the use of f_dentry->d_inode and
+                * f_mapping->host, then a problem may arise.
+                */
+               file->f_mapping = h_file->f_mapping;
+       }
+
+       if (0 && h_file->f_op->mmap == generic_file_mmap) {
+               err = generic_file_mmap(file, vma); /* instead of h_file */
+               if (unlikely(err))
+                       goto out_unlock;
+               au_fi(file)->fi_h_vm_ops = vma->vm_ops;
+       } else {
+               vm_ops = NULL;
+               if (!mmapped) {
+                       vm_ops = au_vm_ops(h_file, vma);
+                       err = PTR_ERR(vm_ops);
+                       if (IS_ERR(vm_ops))
+                               goto out_unlock;
+               }
+
+               err = generic_file_mmap(file, vma);
+               if (unlikely(err))
+                       goto out_unlock;
+               vma->vm_ops = &aufs_vm_ops;
+               /* test again */
+               if (!au_test_mmapped(file)) {
+                       FiMustWriteLock(file);
+                       au_fi(file)->fi_h_vm_ops = vm_ops;
+               }
+       }
+
+       file_accessed(h_file);
+       au_update_fuse_h_inode(h_file->f_vfsmnt, h_file->f_dentry); /*ignore*/
+       fsstack_copy_attr_atime(dentry->d_inode, h_file->f_dentry->d_inode);
+
+ out_unlock:
+       di_read_unlock(dentry, AuLock_IR);
+       if (!wlock && mmapped)
+               fi_read_unlock(file);
+       else
+               fi_write_unlock(file);
+ out:
+       si_read_unlock(sb);
+       AuTraceErr(err);
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static unsigned int aufs_poll(struct file *file, poll_table *wait)
+{
+       unsigned int mask;
+       struct file *h_file;
+       int err;
+       struct dentry *dentry;
+       struct super_block *sb;
+
+       dentry = file->f_dentry;
+       LKTRTrace("%.*s, wait %p\n", AuDLNPair(dentry), wait);
+       AuDebugOn(S_ISDIR(dentry->d_inode->i_mode));
+
+       /* We should pretend an error happened. */
+       mask = POLLERR /* | POLLIN | POLLOUT */;
+       sb = dentry->d_sb;
+       si_read_lock(sb, AuLock_FLUSH);
+       err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/0,
+                                   /*locked*/0);
+       if (unlikely(err))
+               goto out;
+
+       /* it is not an error of hidden_file has no operation */
+       mask = DEFAULT_POLLMASK;
+       h_file = au_h_fptr(file, au_fbstart(file));
+       if (h_file->f_op && h_file->f_op->poll)
+               mask = h_file->f_op->poll(h_file, wait);
+       di_read_unlock(dentry, AuLock_IR);
+       fi_read_unlock(file);
+
+ out:
+       si_read_unlock(sb);
+       AuTraceErr((int)mask);
+       return mask;
+}
+
+static int aufs_fsync_nondir(struct file *file, struct dentry *dentry,
+                            int datasync)
+{
+       int err;
+       struct inode *inode;
+       struct file *h_file;
+       struct super_block *sb;
+       struct au_pin pin;
+
+       LKTRTrace("%.*s, %d\n", AuDLNPair(dentry), datasync);
+       inode = dentry->d_inode;
+
+       IMustLock(file->f_mapping->host);
+       if (inode != file->f_mapping->host) {
+               mutex_unlock(&file->f_mapping->host->i_mutex);
+               mutex_lock(&inode->i_mutex);
+       }
+       IMustLock(inode);
+
+       sb = dentry->d_sb;
+       si_read_lock(sb, AuLock_FLUSH);
+       err = 0; /* -EBADF; */ /* posix? */
+       if (unlikely(!(file->f_mode & FMODE_WRITE)))
+               goto out;
+       err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/1,
+                                   /*locked*/1);
+       if (unlikely(err))
+               goto out;
+       err = au_ready_to_write(file, -1, &pin);
+       di_downgrade_lock(dentry, AuLock_IR);
+       if (unlikely(err))
+               goto out_unlock;
+       au_unpin(&pin);
+
+       err = -EINVAL;
+       h_file = au_h_fptr(file, au_fbstart(file));
+       if (h_file->f_op && h_file->f_op->fsync) {
+               struct mutex *h_mtx = &h_file->f_dentry->d_inode->i_mutex;
+
+               mutex_lock_nested(h_mtx, AuLsc_I_CHILD);
+               err = h_file->f_op->fsync(h_file, h_file->f_dentry, datasync);
+               if (!err)
+                       au_update_fuse_h_inode(h_file->f_vfsmnt,
+                                              h_file->f_dentry);
+               au_cpup_attr_timesizes(inode);
+               mutex_unlock(h_mtx);
+       }
+
+ out_unlock:
+       di_read_unlock(dentry, AuLock_IR);
+       fi_write_unlock(file);
+ out:
+       si_read_unlock(sb);
+       if (inode != file->f_mapping->host) {
+               mutex_unlock(&inode->i_mutex);
+               mutex_lock(&file->f_mapping->host->i_mutex);
+       }
+       AuTraceErr(err);
+       return err;
+}
+
+static int aufs_fasync(int fd, struct file *file, int flag)
+{
+       int err;
+       struct file *h_file;
+       struct dentry *dentry;
+       struct super_block *sb;
+
+       dentry = file->f_dentry;
+       LKTRTrace("%.*s, %d\n", AuDLNPair(dentry), flag);
+
+       sb = dentry->d_sb;
+       si_read_lock(sb, AuLock_FLUSH);
+       err = au_reval_and_lock_fdi(file, au_reopen_nondir, /*wlock*/0,
+                                   /*locked*/0);
+       if (unlikely(err))
+               goto out;
+
+       h_file = au_h_fptr(file, au_fbstart(file));
+       if (h_file->f_op && h_file->f_op->fasync)
+               err = h_file->f_op->fasync(fd, h_file, flag);
+       di_read_unlock(dentry, AuLock_IR);
+       fi_read_unlock(file);
+
+ out:
+       si_read_unlock(sb);
+       AuTraceErr(err);
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+struct file_operations aufs_file_fop = {
+       /*
+        * while generic_file_llseek/_unlocked() don't use BKL,
+        * don't use it since it operates file->f_mapping->host.
+        * in aufs, it may be a real file and may confuse users by UDBA.
+        */
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 27)
+       /* .llseek              = generic_file_llseek, */
+#endif
+       .read           = aufs_read,
+       .write          = aufs_write,
+       .poll           = aufs_poll,
+       /* .unlocked_ioctl      = aufs_ioctl, */
+       .mmap           = aufs_mmap,
+       .open           = aufs_open_nondir,
+       .flush          = aufs_flush,
+       .release        = aufs_release_nondir,
+       .fsync          = aufs_fsync_nondir,
+       .fasync         = aufs_fasync,
+#ifdef CONFIG_AUFS_SPLICE_PATCH
+       .splice_write   = aufs_splice_write,
+       .splice_read    = aufs_splice_read,
+#endif
+};
diff -urN linux/fs/aufs/getattr.c linux-aufs/fs/aufs/getattr.c
--- linux/fs/aufs/getattr.c     1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/getattr.c        2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,133 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * inode attributes on NFS/FUSE branch or HINOTIFY
+ *
+ * $Id$
+ */
+
+#include "aufs.h"
+
+static struct dentry *
+au_h_dget_any(struct dentry *dentry, aufs_bindex_t *bindex)
+{
+       struct dentry *h_dentry;
+       struct inode *inode, *h_inode;
+       struct super_block *sb;
+       aufs_bindex_t ib, db;
+
+       /* must be positive dentry */
+       inode = dentry->d_inode;
+       LKTRTrace("%.*s, i%lu\n", AuDLNPair(dentry), inode->i_ino);
+
+       sb = dentry->d_sb;
+       db = au_dbstart(dentry);
+       ib = au_ibstart(inode);
+       if (db == ib) {
+               *bindex = db;
+               h_dentry = dget(au_h_dptr(dentry, db));
+               if (h_dentry)
+                       goto out; /* success */
+       }
+
+       *bindex = ib;
+       h_inode = au_h_iptr(inode, ib);
+       h_dentry = d_find_alias(h_inode);
+       if (h_dentry)
+               goto out; /* success */
+
+#if 0
+       if (au_opt_test(au_mntflags(sb), PLINK)
+           && au_plink_test(sb, inode)) {
+               h_dentry = au_plink_lkup(sb, ib, inode);
+               if (IS_ERR(h_dentry))
+                       goto out;
+               AuDebugOn(!h_dentry->d_inode);
+               goto out; /* success */
+       }
+#endif
+
+       h_dentry = dget(au_hi_wh(inode, ib));
+
+ out:
+       AuTraceErrPtr(h_dentry);
+       return h_dentry;
+}
+
+int aufs_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *st)
+{
+       int err;
+       unsigned int mnt_flags;
+       aufs_bindex_t bindex;
+       unsigned char did_lock;
+       struct inode *inode;
+       struct dentry *h_dentry;
+       struct super_block *sb, *h_sb;
+
+       LKTRTrace("%.*s\n", AuDLNPair(dentry));
+
+       err = 0;
+       sb = dentry->d_sb;
+       si_read_lock(sb, AuLock_FLUSH);
+       mnt_flags = au_mntflags(sb);
+       if (dentry != sb->s_root) {
+               di_read_lock_parent(dentry, AuLock_IR);
+               inode = dentry->d_inode;
+               did_lock = 1;
+
+               /* todo: test bit inotify option too? */
+               bindex = au_ibstart(inode);
+               h_sb = au_sbr_sb(sb, bindex);
+               /* todo: fix this condition */
+               if ((au_opt_test(mnt_flags, PLINK) && au_plink_test(sb, inode))
+                   /* au_iigen(inode) == au_sigen(sb) */
+                   || (!au_test_fuse(h_sb) && !au_test_nfs(h_sb)))
+                       goto fill;
+
+               h_dentry = au_h_dget_any(dentry, &bindex);
+               err = PTR_ERR(h_dentry);
+               if (IS_ERR(h_dentry))
+                       goto out;
+       } else {
+               /* lock free root dinfo */
+               did_lock = 0;
+               bindex = 0;
+               inode = dentry->d_inode;
+               h_dentry = dget(au_di(dentry)->di_hdentry->hd_dentry);
+       }
+
+       err = -EIO;
+       if (h_dentry && h_dentry->d_inode)
+               err = vfsub_getattr(au_sbr_mnt(sb, bindex), h_dentry, st,
+                                   au_test_dlgt(mnt_flags));
+       dput(h_dentry);
+       if (!err) {
+               /* todo: I don't like this approach */
+               au_cpup_attr_all(inode, /*force*/0);
+       fill:
+               generic_fillattr(inode, st);
+       }
+
+ out:
+       if (did_lock)
+               di_read_unlock(dentry, AuLock_IR);
+       si_read_unlock(sb);
+       AuTraceErr(err);
+       return err;
+}
diff -urN linux/fs/aufs/hinode.h linux-aufs/fs/aufs/hinode.h
--- linux/fs/aufs/hinode.h      1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/hinode.h 2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,175 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * lower (branch filesystem) inode and setting inotify
+ *
+ * $Id$
+ */
+
+#ifndef __AUFS_HINODE_H__
+#define __AUFS_HINODE_H__
+
+#ifdef __KERNEL__
+
+#include <linux/fs.h>
+#include <linux/inotify.h>
+#include <linux/aufs_type.h>
+#include "super.h"
+#include "vfsub.h"
+
+/* ---------------------------------------------------------------------- */
+
+struct au_hinotify {
+#ifdef CONFIG_AUFS_HINOTIFY
+       struct au_splhead       hin_ignore;
+       struct inotify_watch    hin_watch;
+       struct inode            *hin_aufs_inode;        /* no get/put */
+#endif
+};
+
+struct au_hinode {
+       struct inode            *hi_inode;
+       aufs_bindex_t           hi_id;
+#ifdef CONFIG_AUFS_HINOTIFY
+       struct au_hinotify      *hi_notify;
+#endif
+
+       /* reference to the copied-up whiteout with get/put */
+       struct dentry           *hi_whdentry;
+};
+
+struct au_hin_ignore {
+#ifdef CONFIG_AUFS_HINOTIFY
+       struct list_head        ign_list;
+
+       pid_t                   ign_pid;
+       __u32                   ign_events, ign_handled;
+       struct au_hinode        *ign_hinode;
+#endif
+};
+
+/* ---------------------------------------------------------------------- */
+
+#ifdef CONFIG_AUFS_HINOTIFY
+/* inotify events */
+static const __u32 AuInMask = (IN_MOVE | IN_DELETE | IN_CREATE
+                              /* | IN_ACCESS */
+                              | IN_MODIFY | IN_ATTRIB
+                              /* | IN_DELETE_SELF | IN_MOVE_SELF */
+       );
+
+static inline
+void au_hin_init(struct au_hinode *hinode, struct au_hinotify *val)
+{
+       hinode->hi_notify = val;
+}
+
+/* hinotify.c */
+int au_hin_alloc(struct au_hinode *hinode, struct inode *inode,
+                struct inode *h_inode);
+void au_hin_free(struct au_hinode *hinode);
+void au_hin_ctl(struct au_hinode *hinode, const __u32 mask);
+void au_reset_hinotify(struct inode *inode, unsigned int flags);
+
+int au_hin_verify_gen(struct dentry *dentry);
+
+int __init au_inotify_init(void);
+void au_inotify_fin(void);
+
+static inline void au_hin_suspend(struct au_hinode *hinode)
+{
+       au_hin_ctl(hinode, 0);
+}
+
+static inline void au_hin_resume(struct au_hinode *hinode)
+{
+       au_hin_ctl(hinode, AuInMask);
+}
+
+#else
+
+static inline
+void au_hin_init(struct au_hinode *hinode, struct au_hinotify *val)
+{
+       /* empty */
+}
+
+static inline
+int au_hin_alloc(struct au_hinode *hinode, struct inode *inode,
+                struct inode *h_inode)
+{
+       return -EOPNOTSUPP;
+}
+
+static inline void au_hin_free(struct au_hinode *hinode)
+{
+       /* nothing */
+}
+
+static inline void au_reset_hinotify(struct inode *inode, unsigned int flags)
+{
+       /* nothing */
+}
+
+static inline int au_hin_verify_gen(struct dentry *dentry)
+{
+       return 0;
+}
+
+static inline int au_inotify_init(void)
+{
+       return 0;
+}
+
+#define au_inotify_fin()       do {} while (0)
+
+static inline void au_hin_suspend(struct au_hinode *hinode)
+{
+       /* empty */
+}
+
+static inline void au_hin_resume(struct au_hinode *hinode)
+{
+       /* empty */
+}
+#endif /* CONFIG_AUFS_HINOTIFY */
+
+#if defined(CONFIG_AUFS_HINOTIFY) && defined(CONFIG_AUFS_DEBUG)
+static inline void au_hin_list_del(struct list_head *e)
+{
+       list_del_init(e);
+}
+
+void au_dbg_hin_list(struct vfsub_args *vargs);
+#else
+static inline void au_hin_list_del(struct list_head *e)
+{
+       list_del(e);
+}
+
+static inline void au_dbg_hin_list(struct vfsub_args *vargs)
+{
+       /* empty */
+}
+#endif /* CONFIG_AUFS_DEBUG */
+
+/* ---------------------------------------------------------------------- */
+
+#endif /* __KERNEL__ */
+#endif /* __AUFS_HINODE_H__ */
diff -urN linux/fs/aufs/hin_or_dlgt.c linux-aufs/fs/aufs/hin_or_dlgt.c
--- linux/fs/aufs/hin_or_dlgt.c 1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/hin_or_dlgt.c    2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,736 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * sub-routines for vfs in hinotify or dlgt mode
+ *
+ * $Id$
+ */
+
+#include <linux/uaccess.h>
+#include "aufs.h"
+
+#if !defined(CONFIG_AUFS_HINOTIFY) && !defined(CONFIG_AUFS_DLGT)
+#error mis-configuraion or Makefile
+#endif
+
+/* ---------------------------------------------------------------------- */
+
+struct permission_args {
+       int *errp;
+       struct inode *inode;
+       int mask;
+       struct nameidata *nd;
+};
+
+static void call_permission(void *args)
+{
+       struct permission_args *a = args;
+       *a->errp = do_vfsub_permission(a->inode, a->mask, a->nd);
+}
+
+int vfsub_permission(struct inode *inode, int mask, struct nameidata *nd,
+                    int dlgt)
+{
+       if (!dlgt)
+               return do_vfsub_permission(inode, mask, nd);
+       else {
+               int err, wkq_err;
+               struct permission_args args = {
+                       .errp   = &err,
+                       .inode  = inode,
+                       .mask   = mask,
+                       .nd     = nd
+               };
+               wkq_err = au_wkq_wait(call_permission, &args, /*dlgt*/1);
+               if (unlikely(wkq_err))
+                       err = wkq_err;
+               return err;
+       }
+}
+
+/* ---------------------------------------------------------------------- */
+
+struct create_args {
+       int *errp;
+       struct inode *dir;
+       struct dentry *dentry;
+       int mode;
+       struct nameidata *nd;
+       struct vfsub_args *vargs;
+};
+
+static void call_create(void *args)
+{
+       struct create_args *a = args;
+       vfsub_ignore(a->vargs);
+       *a->errp = do_vfsub_create(a->dir, a->dentry, a->mode, a->nd);
+       if (unlikely(*a->errp))
+               vfsub_unignore(a->vargs);
+       au_dbg_hin_list(a->vargs);
+}
+
+int vfsub_create(struct inode *dir, struct dentry *dentry, int mode,
+                struct nameidata *nd, struct vfsub_args *vargs)
+{
+       int err;
+       struct create_args args = {
+               .errp   = &err,
+               .dir    = dir,
+               .dentry = dentry,
+               .mode   = mode,
+               .nd     = nd,
+               .vargs  = vargs
+       };
+
+       if (!vfsub_ftest(vargs->flags, DLGT))
+               call_create(&args);
+       else {
+               int wkq_err;
+               wkq_err = au_wkq_wait(call_create, &args, /*dlgt*/1);
+               if (unlikely(wkq_err))
+                       err = wkq_err;
+       }
+       return err;
+}
+
+struct symlink_args {
+       int *errp;
+       struct inode *dir;
+       struct dentry *dentry;
+       const char *symname;
+       int mode;
+       struct vfsub_args *vargs;
+};
+
+static void call_symlink(void *args)
+{
+       struct symlink_args *a = args;
+       vfsub_ignore(a->vargs);
+       *a->errp = do_vfsub_symlink(a->dir, a->dentry, a->symname, a->mode);
+       if (unlikely(*a->errp))
+               vfsub_unignore(a->vargs);
+       au_dbg_hin_list(a->vargs);
+}
+
+int vfsub_symlink(struct inode *dir, struct dentry *dentry, const char *symname,
+                 int mode, struct vfsub_args *vargs)
+{
+       int err;
+       struct symlink_args args = {
+               .errp           = &err,
+               .dir            = dir,
+               .dentry         = dentry,
+               .symname        = symname,
+               .mode           = mode,
+               .vargs          = vargs
+       };
+
+       if (!vfsub_ftest(vargs->flags, DLGT))
+               call_symlink(&args);
+       else {
+               int wkq_err;
+               wkq_err = au_wkq_wait(call_symlink, &args, /*dlgt*/1);
+               if (unlikely(wkq_err))
+                       err = wkq_err;
+       }
+       return err;
+}
+
+struct mknod_args {
+       int *errp;
+       struct inode *dir;
+       struct dentry *dentry;
+       int mode;
+       dev_t dev;
+       struct vfsub_args *vargs;
+};
+
+static void call_mknod(void *args)
+{
+       struct mknod_args *a = args;
+       vfsub_ignore(a->vargs);
+       *a->errp = do_vfsub_mknod(a->dir, a->dentry, a->mode, a->dev);
+       if (unlikely(*a->errp))
+               vfsub_unignore(a->vargs);
+       au_dbg_hin_list(a->vargs);
+}
+
+int vfsub_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev,
+               struct vfsub_args *vargs)
+{
+       int err;
+       struct mknod_args args = {
+               .errp   = &err,
+               .dir    = dir,
+               .dentry = dentry,
+               .mode   = mode,
+               .dev    = dev,
+               .vargs  = vargs
+       };
+
+       if (!vfsub_ftest(vargs->flags, DLGT))
+               call_mknod(&args);
+       else {
+               int wkq_err;
+               wkq_err = au_wkq_wait(call_mknod, &args, /*dlgt*/1);
+               if (unlikely(wkq_err))
+                       err = wkq_err;
+       }
+       return err;
+}
+
+struct mkdir_args {
+       int *errp;
+       struct inode *dir;
+       struct dentry *dentry;
+       int mode;
+       struct vfsub_args *vargs;
+};
+
+static void call_mkdir(void *args)
+{
+       struct mkdir_args *a = args;
+       vfsub_ignore(a->vargs);
+       *a->errp = do_vfsub_mkdir(a->dir, a->dentry, a->mode);
+       if (unlikely(*a->errp))
+               vfsub_unignore(a->vargs);
+       au_dbg_hin_list(a->vargs);
+}
+
+int vfsub_mkdir(struct inode *dir, struct dentry *dentry, int mode,
+               struct vfsub_args *vargs)
+{
+       int err;
+       struct mkdir_args args = {
+               .errp   = &err,
+               .dir    = dir,
+               .dentry = dentry,
+               .mode   = mode,
+               .vargs  = vargs
+       };
+
+       if (!vfsub_ftest(vargs->flags, DLGT))
+               call_mkdir(&args);
+       else {
+               int wkq_err;
+               wkq_err = au_wkq_wait(call_mkdir, &args, /*dlgt*/1);
+               if (unlikely(wkq_err))
+                       err = wkq_err;
+       }
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+struct link_args {
+       int *errp;
+       struct inode *dir;
+       struct dentry *src_dentry, *dentry;
+       struct vfsub_args *vargs;
+};
+
+static void call_link(void *args)
+{
+       struct link_args *a = args;
+       vfsub_ignore(a->vargs);
+       *a->errp = do_vfsub_link(a->src_dentry, a->dir, a->dentry);
+       if (unlikely(*a->errp))
+               vfsub_unignore(a->vargs);
+       au_dbg_hin_list(a->vargs);
+}
+
+int vfsub_link(struct dentry *src_dentry, struct inode *dir,
+              struct dentry *dentry, struct vfsub_args *vargs)
+{
+       int err;
+       struct link_args args = {
+               .errp           = &err,
+               .src_dentry     = src_dentry,
+               .dir            = dir,
+               .dentry         = dentry,
+               .vargs          = vargs
+       };
+
+       if (!vfsub_ftest(vargs->flags, DLGT))
+               call_link(&args);
+       else {
+               int wkq_err;
+               wkq_err = au_wkq_wait(call_link, &args, /*dlgt*/1);
+               if (unlikely(wkq_err))
+                       err = wkq_err;
+       }
+       return err;
+}
+
+struct rename_args {
+       int *errp;
+       struct inode *src_dir, *dir;
+       struct dentry *src_dentry, *dentry;
+       struct vfsub_args *vargs;
+};
+
+static void call_rename(void *args)
+{
+       struct rename_args *a = args;
+       vfsub_ignore(a->vargs);
+       *a->errp = do_vfsub_rename(a->src_dir, a->src_dentry, a->dir,
+                                  a->dentry);
+       if (unlikely(*a->errp))
+               vfsub_unignore(a->vargs);
+       au_dbg_hin_list(a->vargs);
+}
+
+int vfsub_rename(struct inode *src_dir, struct dentry *src_dentry,
+                struct inode *dir, struct dentry *dentry,
+                struct vfsub_args *vargs)
+{
+       int err;
+       struct rename_args args = {
+               .errp           = &err,
+               .src_dir        = src_dir,
+               .src_dentry     = src_dentry,
+               .dir            = dir,
+               .dentry         = dentry,
+               .vargs          = vargs
+       };
+
+       if (!vfsub_ftest(vargs->flags, DLGT))
+               call_rename(&args);
+       else {
+               int wkq_err;
+               wkq_err = au_wkq_wait(call_rename, &args, /*dlgt*/1);
+               if (unlikely(wkq_err))
+                       err = wkq_err;
+       }
+       return err;
+}
+
+struct rmdir_args {
+       int *errp;
+       struct inode *dir;
+       struct dentry *dentry;
+       struct vfsub_args *vargs;
+};
+
+static void call_rmdir(void *args)
+{
+       struct rmdir_args *a = args;
+       vfsub_ignore(a->vargs);
+       *a->errp = do_vfsub_rmdir(a->dir, a->dentry);
+       if (unlikely(*a->errp))
+               vfsub_unignore(a->vargs);
+       au_dbg_hin_list(a->vargs);
+}
+
+int vfsub_rmdir(struct inode *dir, struct dentry *dentry,
+               struct vfsub_args *vargs)
+{
+       int err;
+       struct rmdir_args args = {
+               .errp   = &err,
+               .dir    = dir,
+               .dentry = dentry,
+               .vargs  = vargs
+       };
+
+       if (!vfsub_ftest(vargs->flags, DLGT))
+               call_rmdir(&args);
+       else {
+               int wkq_err;
+               wkq_err = au_wkq_wait(call_rmdir, &args, /*dlgt*/1);
+               if (unlikely(wkq_err))
+                       err = wkq_err;
+       }
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+struct read_args {
+       ssize_t *errp;
+       struct file *file;
+       union {
+               void *kbuf;
+               char __user *ubuf;
+       };
+       size_t count;
+       loff_t *ppos;
+};
+
+static void call_read_k(void *args)
+{
+       struct read_args *a = args;
+       LKTRTrace("%.*s, cnt %zu, pos %lld\n",
+                 AuDLNPair(a->file->f_dentry), a->count, *a->ppos);
+       *a->errp = do_vfsub_read_k(a->file, a->kbuf, a->count, a->ppos);
+}
+
+ssize_t vfsub_read_u(struct file *file, char __user *ubuf, size_t count,
+                    loff_t *ppos, int dlgt)
+{
+       if (!dlgt)
+               return do_vfsub_read_u(file, ubuf, count, ppos);
+       else {
+               int wkq_err;
+               ssize_t err, read;
+               struct read_args args = {
+                       .errp   = &err,
+                       .file   = file,
+                       .count  = count,
+                       .ppos   = ppos
+               };
+
+               if (!count)
+                       return 0;
+
+               /*
+                * workaround an application bug.
+                * generally, read(2) or write(2) may return the value shorter
+                * than requested. But many applications don't support it,
+                * for example bash.
+                */
+               err = -ENOMEM;
+               if (args.count > PAGE_SIZE)
+                       args.count = PAGE_SIZE;
+               args.kbuf = kmalloc(args.count, GFP_NOFS);
+               if (unlikely(!args.kbuf))
+                       goto out;
+
+               read = 0;
+               do {
+                       wkq_err = au_wkq_wait(call_read_k, &args, /*dlgt*/1);
+                       if (unlikely(wkq_err))
+                               err = wkq_err;
+                       if (unlikely(err > 0
+                                    && copy_to_user(ubuf, args.kbuf, err))) {
+                               err = -EFAULT;
+                               goto out_free;
+                       } else if (!err)
+                               break;
+                       else if (unlikely(err < 0))
+                               goto out_free;
+                       count -= err;
+                       /* do not read too much because of file i/o pointer */
+                       if (count < args.count)
+                               args.count = count;
+                       ubuf += err;
+                       read += err;
+               } while (count);
+               smp_mb(); /* flush ubuf */
+               err = read;
+
+       out_free:
+               kfree(args.kbuf);
+       out:
+               return err;
+       }
+}
+
+ssize_t vfsub_read_k(struct file *file, void *kbuf, size_t count, loff_t *ppos,
+                    int dlgt)
+{
+       if (!dlgt)
+               return do_vfsub_read_k(file, kbuf, count, ppos);
+       else {
+               ssize_t err;
+               int wkq_err;
+               struct read_args args = {
+                       .errp   = &err,
+                       .file   = file,
+                       .count  = count,
+                       .ppos   = ppos
+               };
+               args.kbuf = kbuf;
+               wkq_err = au_wkq_wait(call_read_k, &args, /*dlgt*/1);
+               if (unlikely(wkq_err))
+                       err = wkq_err;
+               return err;
+       }
+}
+
+struct write_args {
+       ssize_t *errp;
+       struct file *file;
+       union {
+               void *kbuf;
+               const char __user *ubuf;
+       };
+       size_t count;
+       loff_t *ppos;
+       struct vfsub_args *vargs;
+};
+
+static void call_write_k(void *args)
+{
+       struct write_args *a = args;
+       vfsub_ignore(a->vargs);
+       *a->errp = do_vfsub_write_k(a->file, a->kbuf, a->count, a->ppos);
+       if (unlikely(*a->errp <= 0))
+               vfsub_unignore(a->vargs);
+       au_dbg_hin_list(a->vargs);
+}
+
+ssize_t vfsub_write_u(struct file *file, const char __user *ubuf, size_t count,
+                     loff_t *ppos, struct vfsub_args *vargs)
+{
+       ssize_t err;
+
+       if (!vfsub_ftest(vargs->flags, DLGT)) {
+               vfsub_ignore(vargs);
+               err = do_vfsub_write_u(file, ubuf, count, ppos);
+               if (unlikely(err <= 0))
+                       vfsub_unignore(vargs);
+               au_dbg_hin_list(vargs);
+       } else {
+               ssize_t written;
+               int wkq_err;
+               struct write_args args = {
+                       .errp   = &err,
+                       .file   = file,
+                       .count  = count,
+                       .ppos   = ppos,
+                       .vargs  = vargs
+               };
+
+               if (!count)
+                       return 0;
+
+               /*
+                * workaround an application bug.
+                * generally, read(2) or write(2) may return the value shorter
+                * than requested. But many applications don't support it,
+                * for example bash.
+                */
+               err = -ENOMEM;
+               if (args.count > PAGE_SIZE)
+                       args.count = PAGE_SIZE;
+               args.kbuf = kmalloc(args.count, GFP_NOFS);
+               if (unlikely(!args.kbuf))
+                       goto out;
+
+               written = 0;
+               do {
+                       if (unlikely(copy_from_user(args.kbuf, ubuf,
+                                                   args.count))) {
+                               err = -EFAULT;
+                               goto out_free;
+                       }
+
+                       wkq_err = au_wkq_wait(call_write_k, &args, /*dlgt*/1);
+                       if (unlikely(wkq_err))
+                               err = wkq_err;
+                       if (err > 0) {
+                               count -= err;
+                               if (count < args.count)
+                                       args.count = count;
+                               ubuf += err;
+                               written += err;
+                       } else if (!err)
+                               break;
+                       else if (unlikely(err < 0))
+                               goto out_free;
+               } while (count);
+               err = written;
+
+       out_free:
+               kfree(args.kbuf);
+       }
+ out:
+       return err;
+}
+
+ssize_t vfsub_write_k(struct file *file, void *kbuf, size_t count, loff_t *ppos,
+                     struct vfsub_args *vargs)
+{
+       ssize_t err;
+       struct write_args args = {
+               .errp   = &err,
+               .file   = file,
+               .count  = count,
+               .ppos   = ppos,
+               .vargs  = vargs
+       };
+
+       args.kbuf = kbuf;
+       if (!vfsub_ftest(vargs->flags, DLGT))
+               call_write_k(&args);
+       else {
+               int wkq_err;
+               wkq_err = au_wkq_wait(call_write_k, &args, /*dlgt*/1);
+               if (unlikely(wkq_err))
+                       err = wkq_err;
+       }
+       return err;
+}
+
+struct readdir_args {
+       int *errp;
+       struct file *file;
+       filldir_t filldir;
+       void *arg;
+};
+
+static void call_readdir(void *args)
+{
+       struct readdir_args *a = args;
+       *a->errp = do_vfsub_readdir(a->file, a->filldir, a->arg);
+}
+
+int vfsub_readdir(struct file *file, filldir_t filldir, void *arg, int dlgt)
+{
+       if (!dlgt)
+               return do_vfsub_readdir(file, filldir, arg);
+       else {
+               int err, wkq_err;
+               struct readdir_args args = {
+                       .errp           = &err,
+                       .file           = file,
+                       .filldir        = filldir,
+                       .arg            = arg
+               };
+               wkq_err = au_wkq_wait(call_readdir, &args, /*dlgt*/1);
+               if (unlikely(wkq_err))
+                       err = wkq_err;
+               return err;
+       }
+}
+
+/* ---------------------------------------------------------------------- */
+
+struct splice_to_args {
+       long *errp;
+       struct file *in;
+       loff_t *ppos;
+       struct pipe_inode_info *pipe;
+       size_t len;
+       unsigned int flags;
+};
+
+static void call_splice_to(void *args)
+{
+       struct splice_to_args *a = args;
+       *a->errp = do_vfsub_splice_to(a->in, a->ppos, a->pipe, a->len,
+                                     a->flags);
+}
+
+long vfsub_splice_to(struct file *in, loff_t *ppos,
+                    struct pipe_inode_info *pipe, size_t len,
+                    unsigned int flags, int dlgt)
+{
+       if (!dlgt)
+               return do_vfsub_splice_to(in, ppos, pipe, len, flags);
+       else {
+               long err;
+               int wkq_err;
+               struct splice_to_args args = {
+                       .errp   = &err,
+                       .in     = in,
+                       .ppos   = ppos,
+                       .pipe   = pipe,
+                       .len    = len,
+                       .flags  = flags
+               };
+               wkq_err = au_wkq_wait(call_splice_to, &args, /*dlgt*/1);
+               if (unlikely(wkq_err))
+                       err = wkq_err;
+               return err;
+       }
+}
+
+struct splice_from_args {
+       long *errp;
+       struct pipe_inode_info *pipe;
+       struct file *out;
+       loff_t *ppos;
+       size_t len;
+       unsigned int flags;
+       struct vfsub_args *vargs;
+};
+
+static void call_splice_from(void *args)
+{
+       struct splice_from_args *a = args;
+       vfsub_ignore(a->vargs);
+       *a->errp = do_vfsub_splice_from(a->pipe, a->out, a->ppos, a->len,
+                                       a->flags);
+       if (unlikely(*a->errp < 0))
+               vfsub_unignore(a->vargs);
+       au_dbg_hin_list(a->vargs);
+}
+
+long vfsub_splice_from(struct pipe_inode_info *pipe, struct file *out,
+                      loff_t *ppos, size_t len, unsigned int flags,
+                      struct vfsub_args *vargs)
+{
+       long err;
+       struct splice_from_args args = {
+               .errp   = &err,
+               .pipe   = pipe,
+               .out    = out,
+               .ppos   = ppos,
+               .len    = len,
+               .flags  = flags,
+               .vargs  = vargs
+       };
+
+       if (!vfsub_ftest(vargs->flags, DLGT))
+               call_splice_from(&args);
+       else {
+               int wkq_err;
+               wkq_err = au_wkq_wait(call_splice_from, &args, /*dlgt*/1);
+               if (unlikely(wkq_err))
+                       err = wkq_err;
+       }
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+struct getattr_args {
+       int *errp;
+       struct vfsmount *mnt;
+       struct dentry *dentry;
+       struct kstat *st;
+};
+
+static void call_getattr(void *args)
+{
+       struct getattr_args *a = args;
+       *a->errp = do_vfsub_getattr(a->mnt, a->dentry, a->st);
+}
+
+int vfsub_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *st,
+                 int dlgt)
+{
+       if (!dlgt)
+               return do_vfsub_getattr(mnt, dentry, st);
+       else {
+               int err, wkq_err;
+               struct getattr_args args = {
+                       .errp   = &err,
+                       .mnt    = mnt,
+                       .dentry = dentry,
+                       .st     = st
+               };
+               wkq_err = au_wkq_wait(call_getattr, &args, /*dlgt*/1);
+               if (unlikely(wkq_err))
+                       err = wkq_err;
+               return err;
+       }
+}
diff -urN linux/fs/aufs/hinotify.c linux-aufs/fs/aufs/hinotify.c
--- linux/fs/aufs/hinotify.c    1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/hinotify.c       2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,1146 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * internal/hidden inotify handler
+ *
+ * $Id$
+ */
+
+#include "aufs.h"
+
+/*
+#ifdef DbgInotify
+#define AuDbgHin(args...)      AuDbg(##args)
+#else
+#define AuDbgHin(args...)      do {} while ()
+#endif
+*/
+
+static struct inotify_handle *in_handle;
+
+AuCacheFuncs(hinotify, AuCache_HINOTIFY);
+
+int au_hin_alloc(struct au_hinode *hinode, struct inode *inode,
+                struct inode *h_inode)
+{
+       int err;
+       struct au_hinotify *hin;
+       s32 wd;
+
+       LKTRTrace("i%lu, hi%lu\n", inode->i_ino, h_inode->i_ino);
+
+       err = -ENOMEM;
+       hin = au_cache_alloc_hinotify();
+       if (hin) {
+               AuDebugOn(hinode->hi_notify);
+               hinode->hi_notify = hin;
+               au_spl_init(&hin->hin_ignore);
+               hin->hin_aufs_inode = inode;
+
+               inotify_init_watch(&hin->hin_watch);
+               wd = inotify_add_watch(in_handle, &hin->hin_watch, h_inode,
+                                      AuInMask);
+               if (wd >= 0)
+                       return 0; /* success */
+
+               err = wd;
+               put_inotify_watch(&hin->hin_watch);
+               au_cache_free_hinotify(hin);
+               hinode->hi_notify = NULL;
+       }
+
+       AuTraceErr(err);
+       return err;
+}
+
+void au_hin_free(struct au_hinode *hinode)
+{
+       int err;
+       struct au_hinotify *hin;
+
+       AuTraceEnter();
+
+       hin = hinode->hi_notify;
+       if (hin) {
+               err = 0;
+               if (atomic_read(&hin->hin_watch.count))
+                       err = inotify_rm_watch(in_handle, &hin->hin_watch);
+               if (unlikely(err))
+                       /* it means the watch is already removed */
+                       LKTRTrace("failed inotify_rm_watch() %d\n", err);
+               au_cache_free_hinotify(hin);
+               hinode->hi_notify = NULL;
+       }
+}
+
+/* ---------------------------------------------------------------------- */
+
+void au_hin_ctl(struct au_hinode *hinode, const __u32 mask)
+{
+       struct inode *h_inode;
+       struct inotify_watch *watch;
+
+       h_inode = hinode->hi_inode;
+       LKTRTrace("hi%lu, sb %p, 0x%x\n", h_inode->i_ino, h_inode->i_sb, mask);
+       IMustLock(h_inode);
+       if (!hinode->hi_notify)
+               return;
+
+       watch = &hinode->hi_notify->hin_watch;
+#if 0 /* reserved for future use */
+       {
+               u32 wd;
+               wd = inotify_find_update_watch(in_handle, h_inode, mask);
+               AuTraceErr(wd);
+               /* ignore an err; */
+       }
+#else
+       /* struct inotify_handle is hidden */
+       mutex_lock(&h_inode->inotify_mutex);
+       /* mutex_lock(&watch->ih->mutex); */
+       watch->mask = mask;
+       /* mutex_unlock(&watch->ih->mutex); */
+       mutex_unlock(&h_inode->inotify_mutex);
+#endif
+       LKTRTrace("watch %p, mask %u\n", watch, watch->mask);
+}
+
+void au_reset_hinotify(struct inode *inode, unsigned int flags)
+{
+       aufs_bindex_t bindex, bend;
+       struct inode *hi;
+       struct dentry *iwhdentry;
+
+       LKTRTrace("i%lu, 0x%x\n", inode->i_ino, flags);
+
+       bend = au_ibend(inode);
+       for (bindex = au_ibstart(inode); bindex <= bend; bindex++) {
+               hi = au_h_iptr(inode, bindex);
+               if (hi) {
+                       /* mutex_lock_nested(&hi->i_mutex, AuLsc_I_CHILD); */
+                       iwhdentry = au_hi_wh(inode, bindex);
+                       if (iwhdentry)
+                               dget(iwhdentry);
+                       au_igrab(hi);
+                       au_set_h_iptr(inode, bindex, NULL, 0);
+                       au_set_h_iptr(inode, bindex, au_igrab(hi),
+                                     flags & ~AuHi_XINO);
+                       iput(hi);
+                       dput(iwhdentry);
+                       /* mutex_unlock(&hi->i_mutex); */
+               }
+       }
+}
+
+/* ---------------------------------------------------------------------- */
+
+void au_unpin_gp(struct au_pin *args)
+{
+       struct au_pin1 *gp;
+
+       gp = au_pin_gp(args);
+       AuDebugOn(!gp);
+       if (gp->dentry)
+               LKTRTrace("%.*s\n", AuDLNPair(gp->dentry));
+       else
+               AuTraceEnter();
+
+       au_do_unpin(gp, NULL);
+}
+
+int au_hin_verify_gen(struct dentry *dentry)
+{
+       struct super_block *sb = dentry->d_sb;
+       au_gen_t sigen;
+       struct inode *inode;
+
+       if (!au_opt_test(au_mntflags(sb), UDBA_INOTIFY))
+               return 0;
+
+       sigen = au_sigen(dentry->d_sb);
+       inode = dentry->d_inode;
+       return au_digen(dentry) != sigen
+               || (inode && au_iigen(inode) != sigen);
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* cf. fsnotify_change() */
+__u32 vfsub_events_notify_change(struct iattr *ia)
+{
+       __u32 events;
+       const unsigned int amtime = (ATTR_ATIME | ATTR_MTIME);
+
+       events = 0;
+       if ((ia->ia_valid & (ATTR_UID | ATTR_GID | ATTR_MODE))
+           || (ia->ia_valid & amtime) == amtime)
+               events |= IN_ATTRIB;
+       if ((ia->ia_valid & ATTR_SIZE)
+           || (ia->ia_valid & amtime) == ATTR_MTIME)
+               events |= IN_MODIFY;
+       return events;
+}
+
+void vfsub_ign_hinode(struct vfsub_args *vargs, __u32 events,
+                     struct au_hinode *hinode)
+{
+       struct au_hinotify *hin;
+       struct super_block *sb;
+       struct au_hin_ignore *ign;
+
+       if (!hinode)
+               return;
+
+       hin = hinode->hi_notify;
+       if (!hin || !hin->hin_watch.mask)
+               return;
+
+       sb = hin->hin_aufs_inode->i_sb;
+       AuDebugOn(!au_opt_test(au_mntflags(sb), UDBA_INOTIFY));
+
+       ign = vargs->ignore + vargs->nignore++;
+       ign->ign_events = events;
+       ign->ign_handled = 0;
+       ign->ign_hinode = hinode;
+
+       {
+               struct inode *h_inode;
+               h_inode = hinode->hi_inode;
+               if (!mutex_is_locked(&h_inode->i_mutex))
+                       au_dbg_blocked();
+               IMustLock(h_inode);
+       }
+}
+
+static void au_hin_ignore(struct au_hin_ignore *ign)
+{
+       struct au_hinode *hinode;
+       __u32 events;
+       struct au_hinotify *hin;
+       struct inode *h_inode;
+
+       hinode = ign->ign_hinode;
+       events = ign->ign_events;
+       LKTRTrace("0x%x\n", events);
+       AuDebugOn(!hinode || !events);
+
+       hin = hinode->hi_notify;
+       h_inode = hinode->hi_inode;
+       if (h_inode && hin) {
+               LKTRTrace("hi%lu\n", h_inode->i_ino);
+#ifdef DbgInotify
+               AuDbg("hi%lu, 0x%x\n", h_inode->i_ino, events);
+#endif
+
+               au_spl_add(&ign->ign_list, &hin->hin_ignore);
+               /* AuDbg("list_add %p, 0x%x\n", ign, events); */
+       }
+#if 1 /* todo: test dlgt */
+       else
+               /*
+                * it may happen by this scenario.
+                * - a file and its parent dir exist on two branches
+                * - a file on the upper branch is opened
+                * - the parent dir and the file are removed by udba
+                * - the parent is re-accessed, and new dentry/inode in
+                *   aufs is generated for it, based upon the one on the lower
+                *   branch
+                * - the opened file is re-accessed, re-validated, and it may be
+                *   re-connected to the new parent dentry
+                * it means the file in aufs cannot get the actual removed
+                * parent dir on the branch.
+                */
+               INIT_LIST_HEAD(&ign->ign_list);
+#endif
+}
+
+static void au_hin_unignore(struct au_hin_ignore *ign)
+{
+       struct au_hinode *hinode;
+       __u32 events;
+       struct au_hinotify *hin;
+       struct inode *h_inode;
+
+       hinode = ign->ign_hinode;
+       events = ign->ign_events;
+       LKTRTrace("0x%x\n", events);
+       /* AuDbg("0x%x\n", events); */
+       AuDebugOn(!hinode || !events);
+
+       hin = hinode->hi_notify;
+       h_inode = hinode->hi_inode;
+       if (!h_inode || !hin)
+               return;
+       LKTRTrace("hi%lu\n", h_inode->i_ino);
+#ifdef DbgInotify
+       AuDbg("hi%lu, 0x%x\n", h_inode->i_ino, events);
+#endif
+
+       spin_lock(&hin->hin_ignore.spin);
+       au_hin_list_del(&ign->ign_list);
+       spin_unlock(&hin->hin_ignore.spin);
+       /* AuDbg("list_del %p, 0x%x\n", ign, events); */
+}
+
+static int au_hin_test_ignore(u32 mask, struct au_hinotify *hin)
+{
+       int do_ignore;
+       u32 events;
+       struct au_hin_ignore *ign, *tmp;
+       struct list_head *head;
+
+       do_ignore = 0;
+       head = &hin->hin_ignore.head;
+       spin_lock(&hin->hin_ignore.spin);
+       list_for_each_entry_safe(ign, tmp, head, ign_list) {
+               /* AuDbg("ign %p\n", ign); */
+               if (ign->ign_pid == current->pid) {
+                       events = (mask & ign->ign_events);
+                       if (events) {
+                               do_ignore = 1;
+                               ign->ign_handled |= events;
+                               if (ign->ign_events == ign->ign_handled) {
+                                       list_del_init(&ign->ign_list);
+                                       /*
+                                       AuDbg("list_del %p, 0x%x\n",
+                                             ign, events);
+                                       */
+                               }
+                               break;
+                       }
+               }
+       }
+       spin_unlock(&hin->hin_ignore.spin);
+
+       return do_ignore;
+}
+
+void vfsub_ignore(struct vfsub_args *vargs)
+{
+       int n;
+       struct au_hin_ignore *ign;
+       struct super_block *sb;
+       struct au_hinode *hinode;
+       struct inode *h_inode;
+
+       n = vargs->nignore;
+       if (!n)
+               return;
+
+       ign = vargs->ignore;
+       hinode = ign->ign_hinode;
+       sb = hinode->hi_notify->hin_aufs_inode->i_sb;
+       h_inode = hinode->hi_inode;
+       if (au_opt_test(au_mntflags(sb), UDBA_INOTIFY)) {
+               if (!mutex_is_locked(&h_inode->i_mutex))
+                       au_dbg_blocked();
+               IMustLock(h_inode);
+       }
+       while (n-- > 0) {
+               ign->ign_pid = current->pid;
+               au_hin_ignore(ign++);
+       }
+}
+
+void vfsub_unignore(struct vfsub_args *vargs)
+{
+       int n;
+       struct au_hin_ignore *ign;
+
+       n = vargs->nignore;
+       if (!n)
+               return;
+
+       ign = vargs->ignore;
+       while (n-- > 0)
+               au_hin_unignore(ign++);
+}
+
+#ifdef CONFIG_AUFS_DEBUG
+void au_dbg_hin_list(struct vfsub_args *vargs)
+{
+       int n;
+       struct au_hin_ignore *ign;
+
+       n = vargs->nignore;
+       if (!n)
+               return;
+
+       ign = vargs->ignore;
+       while (n-- > 0) {
+               /* AuDebugOn(!list_empty(&ign++->ign_list)); */
+               if (list_empty(&ign++->ign_list))
+                       continue;
+               ign--;
+               AuDbg("%d: pid %d, 0x%x\n",
+                     n + 1, ign->ign_pid, ign->ign_events);
+               au_hin_unignore(ign);
+               ign++;
+               au_dbg_blocked();
+       }
+}
+#endif
+
+/* ---------------------------------------------------------------------- */
+
+static char *in_name(u32 mask)
+{
+#ifdef CONFIG_AUFS_DEBUG
+#define test_ret(flag) if (mask & flag) \
+                               return #flag;
+       test_ret(IN_ACCESS);
+       test_ret(IN_MODIFY);
+       test_ret(IN_ATTRIB);
+       test_ret(IN_CLOSE_WRITE);
+       test_ret(IN_CLOSE_NOWRITE);
+       test_ret(IN_OPEN);
+       test_ret(IN_MOVED_FROM);
+       test_ret(IN_MOVED_TO);
+       test_ret(IN_CREATE);
+       test_ret(IN_DELETE);
+       test_ret(IN_DELETE_SELF);
+       test_ret(IN_MOVE_SELF);
+       test_ret(IN_UNMOUNT);
+       test_ret(IN_Q_OVERFLOW);
+       test_ret(IN_IGNORED);
+       return "";
+#undef test_ret
+#else
+       return "??";
+#endif
+}
+
+/* ---------------------------------------------------------------------- */
+
+static struct dentry *lookup_wlock_by_name(char *name, unsigned int nlen,
+                                          struct inode *dir)
+{
+       struct dentry *dentry, *d, *parent;
+       struct qstr *dname;
+
+       LKTRTrace("%.*s, dir%lu\n", nlen, name, dir->i_ino);
+
+       parent = d_find_alias(dir);
+       if (!parent)
+               return NULL;
+
+       dentry = NULL;
+       spin_lock(&dcache_lock);
+       list_for_each_entry(d, &parent->d_subdirs, d_u.d_child) {
+               LKTRTrace("%.*s\n", AuDLNPair(d));
+               dname = &d->d_name;
+               if (dname->len != nlen || memcmp(dname->name, name, nlen))
+                       continue;
+               if (!atomic_read(&d->d_count) || !d->d_fsdata) {
+                       spin_lock(&d->d_lock);
+                       __d_drop(d);
+                       spin_unlock(&d->d_lock);
+                       continue;
+               }
+
+               dentry = dget(d);
+               break;
+       }
+       spin_unlock(&dcache_lock);
+       dput(parent);
+
+       if (dentry) {
+#if 0
+       lktr_set_pid(current->pid, LktrArrayPid);
+       AuDbgDentry(dentry);
+       lktr_clear_pid(current->pid, LktrArrayPid);
+#endif
+               di_write_lock_child(dentry);
+       }
+       return dentry;
+}
+
+static struct inode *lookup_wlock_by_ino(struct super_block *sb,
+                                        aufs_bindex_t bindex, ino_t h_ino)
+{
+       struct inode *inode;
+       struct au_xino_entry xinoe;
+       int err;
+
+       LKTRTrace("b%d, hi%lu\n", bindex, (unsigned long)h_ino);
+       AuDebugOn(!au_opt_test_xino(au_mntflags(sb)));
+
+       inode = NULL;
+       err = au_xino_read(sb, bindex, h_ino, &xinoe);
+       if (!err && xinoe.ino)
+               inode = ilookup(sb, xinoe.ino);
+       if (!inode)
+               goto out;
+       if (unlikely(inode->i_ino == AUFS_ROOT_INO)) {
+               AuWarn("wrong root branch\n");
+               iput(inode);
+               inode = NULL;
+               goto out;
+       }
+
+       ii_write_lock_child(inode);
+
+ out:
+       return inode;
+}
+
+static int hin_xino(struct inode *inode, struct inode *h_inode)
+{
+       int err;
+       aufs_bindex_t bindex, bend, bfound, bstart;
+       struct inode *h_i;
+
+       LKTRTrace("i%lu, hi%lu\n", inode->i_ino, h_inode->i_ino);
+
+       err = 0;
+       if (unlikely(inode->i_ino == AUFS_ROOT_INO)) {
+               AuWarn("branch root dir was changed\n");
+               goto out;
+       }
+
+       bfound = -1;
+       bend = au_ibend(inode);
+       bstart = au_ibstart(inode);
+#if 0 /* reserved for future use */
+       if (bindex == bend) {
+               /* keep this ino in rename case */
+               goto out;
+       }
+#endif
+       for (bindex = bstart; bindex <= bend; bindex++) {
+               if (au_h_iptr(inode, bindex) == h_inode) {
+                       bfound = bindex;
+                       break;
+               }
+       }
+       if (bfound < 0)
+               goto out;
+
+       for (bindex = bstart; bindex <= bend; bindex++) {
+               h_i = au_h_iptr(inode, bindex);
+               if (h_i)
+                       err = au_xino_write0(inode->i_sb, bindex, h_i->i_ino,
+                                            0);
+               /* ignore this error */
+               /* bad action? */
+       }
+
+       /* children inode number will be broken */
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+static int hin_gen_tree(struct dentry *dentry)
+{
+       int err, i, j, ndentry;
+       struct au_dcsub_pages dpages;
+       struct au_dpage *dpage;
+       struct dentry **dentries;
+
+       LKTRTrace("%.*s\n", AuDLNPair(dentry));
+
+       err = au_dpages_init(&dpages, GFP_NOFS);
+       if (unlikely(err))
+               goto out;
+       err = au_dcsub_pages(&dpages, dentry, NULL, NULL);
+       if (unlikely(err))
+               goto out_dpages;
+
+       for (i = 0; i < dpages.ndpage; i++) {
+               dpage = dpages.dpages + i;
+               dentries = dpage->dentries;
+               ndentry = dpage->ndentry;
+               for (j = 0; j < ndentry; j++) {
+                       struct dentry *d;
+                       d = dentries[j];
+                       LKTRTrace("%.*s\n", AuDLNPair(d));
+                       if (IS_ROOT(d))
+                               continue;
+
+                       d_drop(d);
+                       au_digen_dec(d);
+                       if (d->d_inode)
+                               /* todo: reset children xino?
+                                  cached children only? */
+                               au_iigen_dec(d->d_inode);
+               }
+       }
+
+ out_dpages:
+       au_dpages_free(&dpages);
+
+       /* discard children */
+       dentry_unhash(dentry);
+       dput(dentry);
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+/*
+ * return 0 if processed.
+ */
+static int hin_gen_by_inode(char *name, unsigned int nlen, struct inode *inode,
+                           const unsigned int isdir)
+{
+       int err;
+       struct dentry *d;
+       struct qstr *dname;
+
+       LKTRTrace("%.*s, i%lu\n", nlen, name, inode->i_ino);
+
+       err = 1;
+       if (unlikely(inode->i_ino == AUFS_ROOT_INO)) {
+               AuWarn("branch root dir was changed\n");
+               err = 0;
+               goto out;
+       }
+
+       if (!isdir) {
+               AuDebugOn(!name);
+               au_iigen_dec(inode);
+               spin_lock(&dcache_lock);
+               list_for_each_entry(d, &inode->i_dentry, d_alias) {
+                       dname = &d->d_name;
+                       if (dname->len != nlen
+                           && memcmp(dname->name, name, nlen))
+                               continue;
+                       err = 0;
+                       spin_lock(&d->d_lock);
+                       __d_drop(d);
+                       au_digen_dec(d);
+                       spin_unlock(&d->d_lock);
+                       break;
+               }
+               spin_unlock(&dcache_lock);
+       } else {
+               au_fset_si(au_sbi(inode->i_sb), FAILED_REFRESH_DIRS);
+               d = d_find_alias(inode);
+               if (!d) {
+                       au_iigen_dec(inode);
+                       goto out;
+               }
+
+               dname = &d->d_name;
+               if (dname->len == nlen && !memcmp(dname->name, name, nlen))
+                       err = hin_gen_tree(d);
+               dput(d);
+       }
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+static int hin_gen_by_name(struct dentry *dentry, const unsigned int isdir)
+{
+       int err;
+       struct inode *inode;
+
+       LKTRTrace("%.*s\n", AuDLNPair(dentry));
+
+       inode = dentry->d_inode;
+       if (IS_ROOT(dentry)
+           /* || (inode && inode->i_ino == AUFS_ROOT_INO) */
+               ) {
+               AuWarn("branch root dir was changed\n");
+               return 0;
+       }
+
+       err = 0;
+       if (!isdir) {
+               d_drop(dentry);
+               au_digen_dec(dentry);
+               if (inode)
+                       au_iigen_dec(inode);
+       } else {
+               au_fset_si(au_sbi(dentry->d_sb), FAILED_REFRESH_DIRS);
+               if (inode)
+                       err = hin_gen_tree(dentry);
+       }
+
+       AuTraceErr(err);
+       return err;
+}
+
+static void hin_attr(struct inode *inode, struct inode *h_inode)
+{
+       struct dentry *h_dentry;
+
+       LKTRTrace("i%lu, hi%lu\n", inode->i_ino, h_inode->i_ino);
+
+       if (au_h_iptr(inode, au_ibstart(inode)) != h_inode)
+               return;
+
+       h_dentry = d_find_alias(h_inode);
+       if (h_dentry) {
+               au_update_fuse_h_inode(NULL, h_dentry);
+               /* ignore an error*/
+               dput(h_dentry);
+       }
+
+       au_cpup_attr_all(inode, /*force*/1);
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* hinotify job flags */
+#define AuHinJob_XINO0 1
+#define AuHinJob_GEN   (1 << 1)
+#define AuHinJob_DIRENT        (1 << 2)
+#define AuHinJob_ATTR  (1 << 3)
+#define AuHinJob_ISDIR (1 << 4)
+#define AuHinJob_TRYXINO0 (1 << 5)
+#define AuHinJob_MNTPNT        (1 << 6)
+#define au_ftest_hinjob(flags, name)   ((flags) & AuHinJob_##name)
+#define au_fset_hinjob(flags, name)    { (flags) |= AuHinJob_##name; }
+#define au_fclr_hinjob(flags, name)    { (flags) &= ~AuHinJob_##name; }
+
+struct hin_job_args {
+       unsigned int flags;
+       struct inode *inode, *h_inode, *dir, *h_dir;
+       struct dentry *dentry;
+       char *h_name;
+       int h_nlen;
+};
+
+static int hin_job(struct hin_job_args *a)
+{
+       const unsigned int isdir = au_ftest_hinjob(a->flags, ISDIR);
+
+       /* reset xino */
+       if (au_ftest_hinjob(a->flags, XINO0) && a->inode)
+               hin_xino(a->inode, a->h_inode);
+       /* ignore this error */
+
+       if (au_ftest_hinjob(a->flags, TRYXINO0)
+           && a->inode
+           && a->h_inode) {
+               mutex_lock_nested(&a->h_inode->i_mutex, AuLsc_I_CHILD);
+               if (!a->h_inode->i_nlink)
+                       hin_xino(a->inode, a->h_inode);
+               /* ignore this error */
+               mutex_unlock(&a->h_inode->i_mutex);
+       }
+
+       /* make the generation obsolete */
+       if (au_ftest_hinjob(a->flags, GEN)) {
+               int err = -1;
+               if (a->inode)
+                       err = hin_gen_by_inode(a->h_name, a->h_nlen, a->inode,
+                                              isdir);
+               if (err && a->dentry)
+                       hin_gen_by_name(a->dentry, isdir);
+               /* ignore this error */
+       }
+
+       /* make dir entries obsolete */
+       if (au_ftest_hinjob(a->flags, DIRENT) && a->inode) {
+               struct au_vdir *vdir;
+               IiMustWriteLock(a->inode);
+               vdir = au_ivdir(a->inode);
+               if (vdir)
+                       vdir->vd_jiffy = 0;
+               /* IMustLock(a->inode); */
+               /* a->inode->i_version++; */
+       }
+
+       /* update the attr */
+       if (au_ftest_hinjob(a->flags, ATTR) && a->inode && a->h_inode) {
+               mutex_lock_nested(&a->h_inode->i_mutex, AuLsc_I_CHILD);
+               hin_attr(a->inode, a->h_inode);
+               mutex_unlock(&a->h_inode->i_mutex);
+       }
+
+       /* can do nothing but warn */
+       if (au_ftest_hinjob(a->flags, MNTPNT)
+           && a->dentry
+           && d_mountpoint(a->dentry))
+               AuWarn("mount-point %.*s is removed or renamed\n",
+                      AuDLNPair(a->dentry));
+
+       return 0;
+}
+
+/* ---------------------------------------------------------------------- */
+
+enum { CHILD, PARENT };
+struct postproc_args {
+       struct inode *h_dir, *dir, *h_child_inode;
+       u32 mask;
+       unsigned int flags[2];
+       unsigned int h_child_nlen;
+       char h_child_name[];
+};
+
+static void postproc(void *_args)
+{
+       struct postproc_args *a = _args;
+       struct super_block *sb;
+       aufs_bindex_t bindex, bend, bfound;
+       unsigned char xino, try_iput;
+       int err;
+       struct inode *inode;
+       ino_t h_ino;
+       struct hin_job_args args;
+       struct dentry *dentry;
+       struct au_sbinfo *sbinfo;
+
+       AuDebugOn(!_args);
+       AuDebugOn(!a->h_dir);
+       AuDebugOn(!a->dir);
+       AuDebugOn(!a->mask);
+       LKTRTrace("mask 0x%x %s, i%lu, hi%lu, hci%lu\n",
+                 a->mask, in_name(a->mask), a->dir->i_ino, a->h_dir->i_ino,
+                 a->h_child_inode ? a->h_child_inode->i_ino : 0);
+
+       inode = NULL;
+       dentry = NULL;
+       /*
+        * do not lock a->dir->i_mutex here
+        * because of d_revalidate() may cause a deadlock.
+        */
+#if 0
+       /*
+        * just wait for the dir becoming non-busy.
+        * for instance, prevent NFSD lookup from "nlink == 0" message.
+        * but it is not guranteed.
+        */
+       mutex_lock(&a->dir->i_mutex);
+       mutex_unlock(&a->dir->i_mutex);
+#endif
+
+       sb = a->dir->i_sb;
+       AuDebugOn(!sb);
+       sbinfo = au_sbi(sb);
+       AuDebugOn(!sbinfo);
+       /* big aufs lock */
+       si_noflush_write_lock(sb);
+
+       ii_read_lock_parent(a->dir);
+       bfound = -1;
+       bend = au_ibend(a->dir);
+       for (bindex = au_ibstart(a->dir); bindex <= bend; bindex++)
+               if (au_h_iptr(a->dir, bindex) == a->h_dir) {
+                       bfound = bindex;
+                       break;
+               }
+       ii_read_unlock(a->dir);
+       if (unlikely(bfound < 0))
+               goto out;
+
+       xino = !!au_opt_test_xino(au_mntflags(sb));
+       h_ino = 0;
+       if (a->h_child_inode)
+               h_ino = a->h_child_inode->i_ino;
+
+       if (a->h_child_nlen
+           && (au_ftest_hinjob(a->flags[CHILD], GEN)
+               || au_ftest_hinjob(a->flags[CHILD], MNTPNT)))
+               dentry = lookup_wlock_by_name(a->h_child_name, a->h_child_nlen,
+                                             a->dir);
+       try_iput = 0;
+       if (dentry)
+               inode = dentry->d_inode;
+       if (xino && !inode && h_ino
+           && (au_ftest_hinjob(a->flags[CHILD], XINO0)
+               || au_ftest_hinjob(a->flags[CHILD], TRYXINO0)
+               || au_ftest_hinjob(a->flags[CHILD], GEN)
+               || au_ftest_hinjob(a->flags[CHILD], ATTR))) {
+               inode = lookup_wlock_by_ino(sb, bfound, h_ino);
+               try_iput = 1;
+           }
+
+       args.flags = a->flags[CHILD];
+       args.dentry = dentry;
+       args.inode = inode;
+       args.h_inode = a->h_child_inode;
+       args.dir = a->dir;
+       args.h_dir = a->h_dir;
+       args.h_name = a->h_child_name;
+       args.h_nlen = a->h_child_nlen;
+       err = hin_job(&args);
+       if (dentry) {
+               if (dentry->d_fsdata)
+                       di_write_unlock(dentry);
+               dput(dentry);
+       }
+       if (inode && try_iput) {
+               ii_write_unlock(inode);
+               iput(inode);
+       }
+
+       ii_write_lock_parent(a->dir);
+       args.flags = a->flags[PARENT];
+       args.dentry = NULL;
+       args.inode = a->dir;
+       args.h_inode = a->h_dir;
+       args.dir = NULL;
+       args.h_dir = NULL;
+       args.h_name = NULL;
+       args.h_nlen = 0;
+       err = hin_job(&args);
+       ii_write_unlock(a->dir);
+
+ out:
+       au_nwt_done(&sbinfo->si_nowait);
+       si_write_unlock(sb);
+
+       iput(a->h_child_inode);
+       iput(a->h_dir);
+       iput(a->dir);
+       kfree(a);
+}
+
+static void aufs_inotify(struct inotify_watch *watch, u32 wd, u32 mask,
+                        u32 cookie, const char *h_child_name,
+                        struct inode *h_child_inode)
+{
+       struct au_hinotify *hinotify;
+       struct postproc_args *args;
+       int len, wkq_err;
+       unsigned char isdir, isroot, wh;
+       char *p;
+       struct inode *dir;
+       unsigned int flags[2];
+
+       LKTRTrace("i%lu, wd %d, mask 0x%x %s, cookie 0x%x, hcname %s, hi%lu\n",
+                 watch->inode->i_ino, wd, mask, in_name(mask), cookie,
+                 h_child_name ? h_child_name : "",
+                 h_child_inode ? h_child_inode->i_ino : 0);
+
+       /* if IN_UNMOUNT happens, there must be another bug */
+       if (mask & (IN_IGNORED | IN_UNMOUNT)) {
+               put_inotify_watch(watch);
+               return;
+       }
+
+#ifdef DbgInotify
+       if (!h_child_name || strcmp(h_child_name, AUFS_XINO_FNAME))
+               AuDbg("i%lu, wd %d, mask 0x%x %s, cookie 0x%x, hcname %s,"
+                     " hi%lu\n",
+                     watch->inode->i_ino, wd, mask, in_name(mask), cookie,
+                     h_child_name ? h_child_name : "",
+                     h_child_inode ? h_child_inode->i_ino : 0);
+#endif
+
+       hinotify = container_of(watch, struct au_hinotify, hin_watch);
+       AuDebugOn(!hinotify || !hinotify->hin_aufs_inode);
+       if (au_hin_test_ignore(mask, hinotify)) {
+#ifdef DbgInotify
+               AuDbg("ignored\n");
+#endif
+               return;
+       }
+#if 0 /* tmp debug */
+       if (h_child_name && !strcmp(h_child_name, AUFS_XINO_FNAME)) {
+       AuDbg("i%lu, wd %d, mask 0x%x %s, cookie 0x%x, hcname %s, hi%lu\n",
+                 watch->inode->i_ino, wd, mask, in_name(mask), cookie,
+                 h_child_name ? h_child_name : "",
+                 h_child_inode ? h_child_inode->i_ino : 0);
+       //au_dbg_blocked();
+       }
+#endif
+
+       dir = igrab(hinotify->hin_aufs_inode);
+       if (!dir)
+               return;
+       isroot = (dir->i_ino == AUFS_ROOT_INO);
+       len = 0;
+       wh = 0;
+       if (h_child_name) {
+               len = strlen(h_child_name);
+               if (!memcmp(h_child_name, AUFS_WH_PFX, AUFS_WH_PFX_LEN)) {
+                       h_child_name += AUFS_WH_PFX_LEN;
+                       len -= AUFS_WH_PFX_LEN;
+                       wh = 1;
+               }
+       }
+
+       isdir = 0;
+       if (h_child_inode)
+               isdir = !!S_ISDIR(h_child_inode->i_mode);
+       flags[PARENT] = AuHinJob_ISDIR;
+       flags[CHILD] = 0;
+       if (isdir)
+               flags[CHILD] = AuHinJob_ISDIR;
+       switch (mask & IN_ALL_EVENTS) {
+       case IN_MODIFY:
+               /*FALLTHROUGH*/
+       case IN_ATTRIB:
+               if (h_child_inode) {
+                       if (!wh)
+                               au_fset_hinjob(flags[CHILD], ATTR);
+               } else
+                       au_fset_hinjob(flags[PARENT], ATTR);
+               break;
+
+               /* IN_MOVED_FROM is the first event in rename(2) */
+       case IN_MOVED_FROM:
+       case IN_MOVED_TO:
+               AuDebugOn(!h_child_name || !h_child_inode);
+               au_fset_hinjob(flags[CHILD], GEN);
+               au_fset_hinjob(flags[CHILD], ATTR);
+               if (1 || isdir)
+                       au_fset_hinjob(flags[CHILD], XINO0);
+               au_fset_hinjob(flags[CHILD], MNTPNT);
+
+               au_fset_hinjob(flags[PARENT], ATTR);
+               au_fset_hinjob(flags[PARENT], DIRENT);
+               break;
+
+       case IN_CREATE:
+               AuDebugOn(!h_child_name || !h_child_inode);
+               au_fset_hinjob(flags[PARENT], ATTR);
+               au_fset_hinjob(flags[PARENT], DIRENT);
+               au_fset_hinjob(flags[CHILD], GEN);
+               /* hard link */
+               if (!isdir && h_child_inode->i_nlink > 1)
+                       au_fset_hinjob(flags[CHILD], ATTR);
+               break;
+
+       case IN_DELETE:
+               /*
+                * aufs never be able to get this child inode.
+                * revalidation should be in d_revalidate()
+                * by checking i_nlink, i_generation or d_unhashed().
+                */
+               AuDebugOn(!h_child_name);
+               au_fset_hinjob(flags[PARENT], ATTR);
+               au_fset_hinjob(flags[PARENT], DIRENT);
+               au_fset_hinjob(flags[CHILD], GEN);
+               au_fset_hinjob(flags[CHILD], TRYXINO0);
+               au_fset_hinjob(flags[CHILD], MNTPNT);
+               break;
+
+       case IN_DELETE_SELF:
+#if 0
+               if (!isroot)
+                       au_fset_hinjob(flags[PARENT], GEN);
+               /*FALLTHROUGH*/
+#endif
+
+       case IN_MOVE_SELF:
+#if 0
+               /*
+                * when an inotify is set to an aufs inode,
+                * such inode can be isolated and this event can be fired
+                * solely.
+                */
+               AuDebugOn(h_child_name || h_child_inode);
+               if (unlikely(isroot)) {
+                       AuWarn("root branch was moved\n");
+                       iput(dir);
+                       return;
+               }
+               au_fset_hinjob(flags[PARENT], XINO0);
+               au_fset_hinjob(flags[PARENT], GEN);
+               au_fset_hinjob(flags[PARENT], ATTR);
+               au_fset_hinjob(flags[PARENT], DIRENT);
+               /* au_fset_hinjob(flags[PARENT], MNTPNT); */
+               break;
+#endif
+
+       case IN_ACCESS:
+       default:
+               AuDebugOn(1);
+       }
+
+       if (wh)
+               h_child_inode = NULL;
+
+       /* iput() and kfree() will be called in postproc() */
+       /*
+        * inotify_mutex is already acquired and kmalloc/prune_icache may lock
+        * iprune_mutex. strange.
+        */
+       lockdep_off();
+       args = kmalloc(sizeof(*args) + len + 1, GFP_NOFS);
+       lockdep_on();
+       if (unlikely(!args)) {
+               AuErr1("no memory\n");
+               iput(dir);
+               return;
+       }
+       args->flags[PARENT] = flags[PARENT];
+       args->flags[CHILD] = flags[CHILD];
+       args->mask = mask;
+       args->dir = dir;
+       args->h_dir = igrab(watch->inode);
+       if (h_child_inode)
+               h_child_inode = igrab(h_child_inode); /* can be NULL */
+       args->h_child_inode = h_child_inode;
+       args->h_child_nlen = len;
+       if (len) {
+               p = (void *)args;
+               p += sizeof(*args);
+               memcpy(p, h_child_name, len + 1);
+       }
+
+       lockdep_off();
+       wkq_err = au_wkq_nowait(postproc, args, dir->i_sb, /*dlgt*/0);
+       lockdep_on();
+       if (unlikely(wkq_err))
+               AuErr("wkq %d\n", wkq_err);
+}
+
+static void aufs_inotify_destroy(struct inotify_watch *watch)
+{
+       return;
+}
+
+static struct inotify_operations aufs_inotify_ops = {
+       .handle_event   = aufs_inotify,
+       .destroy_watch  = aufs_inotify_destroy
+};
+
+/* ---------------------------------------------------------------------- */
+
+static void au_hin_destroy_cache(void)
+{
+       kmem_cache_destroy(au_cachep[AuCache_HINOTIFY]);
+       au_cachep[AuCache_HINOTIFY] = NULL;
+}
+
+int __init au_inotify_init(void)
+{
+       int err;
+
+       err = -ENOMEM;
+       au_cachep[AuCache_HINOTIFY] = AuCache(au_hinotify);
+       if (au_cachep[AuCache_HINOTIFY]) {
+               err = 0;
+               in_handle = inotify_init(&aufs_inotify_ops);
+               if (IS_ERR(in_handle)) {
+                       err = PTR_ERR(in_handle);
+                       au_hin_destroy_cache();
+               }
+       }
+       AuTraceErr(err);
+       return err;
+}
+
+void au_inotify_fin(void)
+{
+       inotify_destroy(in_handle);
+       if (au_cachep[AuCache_HINOTIFY])
+               au_hin_destroy_cache();
+}
diff -urN linux/fs/aufs/iinfo.c linux-aufs/fs/aufs/iinfo.c
--- linux/fs/aufs/iinfo.c       1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/iinfo.c  2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,284 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * inode private data
+ *
+ * $Id$
+ */
+
+#include "aufs.h"
+
+struct au_iinfo *au_ii(struct inode *inode)
+{
+       struct au_iinfo *iinfo;
+
+       iinfo = &(container_of(inode, struct aufs_icntnr, vfs_inode)->iinfo);
+       /* bad_inode case */
+       if (unlikely(!iinfo->ii_hinode))
+               return NULL;
+       AuDebugOn(!iinfo->ii_hinode
+                 /* || au_sbi(inode->i_sb)->si_bend < iinfo->ii_bend */
+                 || iinfo->ii_bend < iinfo->ii_bstart);
+       return iinfo;
+}
+
+struct inode *au_h_iptr(struct inode *inode, aufs_bindex_t bindex)
+{
+       struct inode *hidden_inode;
+
+       /* lock free root dinfo/inode */
+       if (inode->i_ino != AUFS_ROOT_INO) {
+               IiMustAnyLock(inode);
+               AuDebugOn(bindex < 0 || au_ibend(inode) < bindex);
+       } else {
+               SiMustAnyLock(inode->i_sb);
+               AuDebugOn(bindex < 0 || au_sbend(inode->i_sb) < bindex);
+       }
+       hidden_inode = au_ii(inode)->ii_hinode[0 + bindex].hi_inode;
+       AuDebugOn(hidden_inode && atomic_read(&hidden_inode->i_count) <= 0);
+       return hidden_inode;
+}
+
+aufs_bindex_t au_ii_br_id(struct inode *inode, aufs_bindex_t bindex)
+{
+       IiMustAnyLock(inode);
+       AuDebugOn(bindex < 0
+                 || au_ibend(inode) < bindex
+                 || !au_ii(inode)->ii_hinode[0 + bindex].hi_inode);
+       return au_ii(inode)->ii_hinode[0 + bindex].hi_id;
+}
+
+/* todo: hard/soft set? */
+void au_set_ibstart(struct inode *inode, aufs_bindex_t bindex)
+{
+       struct au_iinfo *iinfo = au_ii(inode);
+       struct inode *h_inode;
+
+       IiMustWriteLock(inode);
+       AuDebugOn(au_sbend(inode->i_sb) < bindex);
+       iinfo->ii_bstart = bindex;
+       h_inode = iinfo->ii_hinode[bindex + 0].hi_inode;
+       if (h_inode)
+               au_cpup_igen(inode, h_inode);
+}
+
+unsigned int au_hi_flags(struct inode *inode, int isdir)
+{
+       unsigned int flags;
+       const unsigned int mnt_flags = au_mntflags(inode->i_sb);
+
+       flags = 0;
+       if (au_opt_test_xino(mnt_flags))
+               au_fset_hi(flags, XINO);
+       if (isdir && au_opt_test(mnt_flags, UDBA_INOTIFY))
+               au_fset_hi(flags, NOTIFY);
+       return flags;
+}
+
+void au_set_h_iptr(struct inode *inode, aufs_bindex_t bindex,
+                  struct inode *h_inode, unsigned int flags)
+{
+       struct au_hinode *hinode;
+       struct inode *hi;
+       struct au_iinfo *iinfo = au_ii(inode);
+
+       LKTRTrace("i%lu, b%d, hi%lu, flags 0x%x\n",
+                 inode->i_ino, bindex, h_inode ? h_inode->i_ino : 0, flags);
+       IiMustWriteLock(inode);
+       hinode = iinfo->ii_hinode + bindex;
+       hi = hinode->hi_inode;
+       AuDebugOn(bindex < au_ibstart(inode) || au_ibend(inode) < bindex);
+       AuDebugOn(h_inode && atomic_read(&h_inode->i_count) <= 0);
+       AuDebugOn(h_inode && hi);
+
+       if (hi)
+               au_hiput(hinode);
+       hinode->hi_inode = h_inode;
+       if (h_inode) {
+               int err;
+               struct super_block *sb = inode->i_sb;
+
+               if (bindex == iinfo->ii_bstart)
+                       au_cpup_igen(inode, h_inode);
+               hinode->hi_id = au_sbr_id(sb, bindex);
+               if (au_ftest_hi(flags, XINO)) {
+                       struct au_xino_entry xinoe = {
+                               .ino    = inode->i_ino,
+                               /* .h_gen       = h_inode->i_generation */
+                       };
+                       err = au_xino_write(sb, bindex, h_inode->i_ino, &xinoe);
+                       if (unlikely(err))
+                               AuIOErr1("failed au_xino_write() %d\n", err);
+               }
+
+               if (au_ftest_hi(flags, NOTIFY)
+                   && au_br_hinotifyable(au_sbr_perm(sb, bindex))) {
+                       err = au_hin_alloc(hinode, inode, h_inode);
+                       if (unlikely(err))
+                               AuIOErr1("au_hin_alloc() %d\n", err);
+               }
+       }
+}
+
+void au_set_hi_wh(struct inode *inode, aufs_bindex_t bindex,
+                 struct dentry *h_wh)
+{
+       struct au_hinode *hinode;
+
+       IiMustWriteLock(inode);
+       hinode = au_ii(inode)->ii_hinode + bindex;
+       AuDebugOn(hinode->hi_whdentry);
+       hinode->hi_whdentry = h_wh;
+}
+
+void au_update_iigen(struct inode *inode)
+{
+       AuDebugOn(!inode->i_sb);
+       atomic_set(&au_ii(inode)->ii_generation, au_sigen(inode->i_sb));
+       /* smp_mb(); */ /* atomic_set */
+}
+
+/* it may be called at remount time, too */
+void au_update_brange(struct inode *inode, int do_put_zero)
+{
+       struct au_iinfo *iinfo;
+
+       LKTRTrace("i%lu, %d\n", inode->i_ino, do_put_zero);
+       IiMustWriteLock(inode);
+
+       iinfo = au_ii(inode);
+       if (!iinfo || iinfo->ii_bstart < 0)
+               return;
+
+       if (do_put_zero) {
+               aufs_bindex_t bindex;
+               for (bindex = iinfo->ii_bstart; bindex <= iinfo->ii_bend;
+                    bindex++) {
+                       struct inode *h_i;
+                       h_i = iinfo->ii_hinode[0 + bindex].hi_inode;
+                       if (h_i && !h_i->i_nlink)
+                               au_set_h_iptr(inode, bindex, NULL, 0);
+               }
+       }
+
+       iinfo->ii_bstart = -1;
+       while (++iinfo->ii_bstart <= iinfo->ii_bend)
+               if (iinfo->ii_hinode[0 + iinfo->ii_bstart].hi_inode)
+                       break;
+       if (iinfo->ii_bstart > iinfo->ii_bend) {
+               iinfo->ii_bstart = -1;
+               iinfo->ii_bend = -1;
+               return;
+       }
+
+       iinfo->ii_bend++;
+       while (0 <= --iinfo->ii_bend)
+               if (iinfo->ii_hinode[0 + iinfo->ii_bend].hi_inode)
+                       break;
+       AuDebugOn(iinfo->ii_bstart > iinfo->ii_bend || iinfo->ii_bend < 0);
+}
+
+/* ---------------------------------------------------------------------- */
+
+int au_iinfo_init(struct inode *inode)
+{
+       struct au_iinfo *iinfo;
+       struct super_block *sb;
+       int nbr, i;
+
+       sb = inode->i_sb;
+       AuDebugOn(!sb);
+       iinfo = &(container_of(inode, struct aufs_icntnr, vfs_inode)->iinfo);
+       AuDebugOn(iinfo->ii_hinode);
+       nbr = au_sbend(sb) + 1;
+       if (nbr <= 0)
+               nbr = 1;
+       iinfo->ii_hinode = kcalloc(nbr, sizeof(*iinfo->ii_hinode), GFP_NOFS);
+       if (iinfo->ii_hinode) {
+               for (i = 0; i < nbr; i++)
+                       iinfo->ii_hinode[i].hi_id = -1;
+               atomic_set(&iinfo->ii_generation, au_sigen(sb));
+               /* smp_mb(); */ /* atomic_set */
+               au_rw_init_nolock(&iinfo->ii_rwsem);
+               iinfo->ii_bstart = -1;
+               iinfo->ii_bend = -1;
+               iinfo->ii_vdir = NULL;
+               return 0;
+       }
+       return -ENOMEM;
+}
+
+static int au_iinfo_write0(struct super_block *sb, struct au_hinode *hinode,
+                          ino_t ino)
+{
+       int err, locked;
+       aufs_bindex_t bindex;
+
+       err = 0;
+       locked = si_noflush_read_trylock(sb); /* crucio! */
+       bindex = au_br_index(sb, hinode->hi_id);
+       if (bindex >= 0)
+               err = au_xino_write0(sb, bindex, hinode->hi_inode->i_ino, ino);
+       /* error action? */
+       if (locked)
+               si_read_unlock(sb);
+       return err;
+}
+
+void au_iinfo_fin(struct inode *inode)
+{
+       struct au_iinfo *iinfo;
+       aufs_bindex_t bend;
+       unsigned char unlinked;
+       struct au_hinode *hi;
+       struct super_block *sb;
+       ino_t ino;
+
+       iinfo = au_ii(inode);
+       /* bad_inode case */
+       if (!iinfo)
+               return;
+
+       if (iinfo->ii_vdir)
+               au_vdir_free(iinfo->ii_vdir);
+
+       if (iinfo->ii_bstart >= 0) {
+               sb = inode->i_sb;
+               unlinked = !inode->i_nlink;
+               ino = 0;
+               if (unlinked)
+                       ino = inode->i_ino;
+               hi = iinfo->ii_hinode + iinfo->ii_bstart;
+               bend = iinfo->ii_bend;
+               while (iinfo->ii_bstart++ <= bend) {
+                       if (hi->hi_inode) {
+                               if (unlinked || !hi->hi_inode->i_nlink) {
+                                       au_iinfo_write0(sb, hi, ino);
+                                       /* ignore this error */
+                                       ino = 0;
+                               }
+                               au_hiput(hi);
+                       }
+                       hi++;
+               }
+       }
+
+       kfree(iinfo->ii_hinode);
+       au_rwsem_destroy(&iinfo->ii_rwsem);
+}
diff -urN linux/fs/aufs/inode.c linux-aufs/fs/aufs/inode.c
--- linux/fs/aufs/inode.c       1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/inode.c  2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,421 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * inode functions
+ *
+ * $Id$
+ */
+
+#include "aufs.h"
+
+int au_refresh_hinode_self(struct inode *inode)
+{
+       int err, new_sz, update;
+       struct inode *first;
+       struct au_hinode *p, *q, tmp;
+       struct super_block *sb;
+       struct au_iinfo *iinfo;
+       aufs_bindex_t bindex, bend, new_bindex;
+
+       LKTRTrace("i%lu\n", inode->i_ino);
+       IiMustWriteLock(inode);
+
+       err = -ENOMEM;
+       update = 0;
+       sb = inode->i_sb;
+       bend = au_sbend(sb);
+       new_sz = sizeof(*iinfo->ii_hinode) * (bend + 1);
+       iinfo = au_ii(inode);
+       p = au_kzrealloc(iinfo->ii_hinode, sizeof(*p) * (iinfo->ii_bend + 1),
+                        new_sz, GFP_NOFS);
+       if (unlikely(!p))
+               goto out;
+
+       iinfo->ii_hinode = p;
+       p = iinfo->ii_hinode + iinfo->ii_bstart;
+       first = p->hi_inode;
+       err = 0;
+       for (bindex = iinfo->ii_bstart; bindex <= iinfo->ii_bend;
+            bindex++, p++) {
+               if (!p->hi_inode)
+                       continue;
+
+               new_bindex = au_br_index(sb, p->hi_id);
+               if (new_bindex == bindex)
+                       continue;
+               if (new_bindex < 0) {
+                       update++;
+                       au_hiput(p);
+                       p->hi_inode = NULL;
+                       continue;
+               }
+
+               if (new_bindex < iinfo->ii_bstart)
+                       iinfo->ii_bstart = new_bindex;
+               if (iinfo->ii_bend < new_bindex)
+                       iinfo->ii_bend = new_bindex;
+               /* swap two hidden inode, and loop again */
+               q = iinfo->ii_hinode + new_bindex;
+               tmp = *q;
+               *q = *p;
+               *p = tmp;
+               if (tmp.hi_inode) {
+                       bindex--;
+                       p--;
+               }
+       }
+       au_update_brange(inode, /*do_put_zero*/0);
+
+       if (unlikely(err))
+               goto out;
+
+       if (1 || first != au_h_iptr(inode, iinfo->ii_bstart))
+               au_cpup_attr_all(inode, /*force*/0);
+       if (update && S_ISDIR(inode->i_mode))
+               inode->i_version++;
+       au_update_iigen(inode);
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+int au_refresh_hinode(struct inode *inode, struct dentry *dentry)
+{
+       int err, update;
+       struct inode *first;
+       struct au_hinode *p;
+       struct super_block *sb;
+       struct au_iinfo *iinfo;
+       aufs_bindex_t bindex, bend;
+       unsigned char isdir;
+       unsigned int flags;
+
+       LKTRTrace("%.*s\n", AuDLNPair(dentry));
+       IiMustWriteLock(inode);
+
+       err = au_refresh_hinode_self(inode);
+       if (unlikely(err))
+               goto out;
+
+       sb = dentry->d_sb;
+       bend = au_sbend(sb);
+       iinfo = au_ii(inode);
+       update = 0;
+       p = iinfo->ii_hinode + iinfo->ii_bstart;
+       first = p->hi_inode;
+       isdir = S_ISDIR(inode->i_mode);
+       flags = au_hi_flags(inode, isdir);
+       bend = au_dbend(dentry);
+       for (bindex = au_dbstart(dentry); bindex <= bend; bindex++) {
+               struct inode *hi;
+               struct dentry *hd;
+
+               hd = au_h_dptr(dentry, bindex);
+               if (!hd || !hd->d_inode)
+                       continue;
+
+               if (iinfo->ii_bstart <= bindex && bindex <= iinfo->ii_bend) {
+                       hi = au_h_iptr(inode, bindex);
+                       if (hi) {
+                               if (hi == hd->d_inode)
+                                       continue;
+                               err = -ESTALE;
+                               break;
+                       }
+               }
+               if (bindex < iinfo->ii_bstart)
+                       iinfo->ii_bstart = bindex;
+               if (iinfo->ii_bend < bindex)
+                       iinfo->ii_bend = bindex;
+               au_set_h_iptr(inode, bindex, au_igrab(hd->d_inode), flags);
+               update++;
+       }
+       au_update_brange(inode, /*do_put_zero*/0);
+
+       if (unlikely(err))
+               goto out;
+
+       if (1 || first != au_h_iptr(inode, iinfo->ii_bstart))
+               au_cpup_attr_all(inode, /*force*/0);
+       if (update && isdir)
+               inode->i_version++;
+       au_update_iigen(inode);
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+static int set_inode(struct inode *inode, struct dentry *dentry)
+{
+       int err;
+       struct dentry *h_dentry;
+       struct inode *h_inode;
+       umode_t mode;
+       aufs_bindex_t bindex, bstart, btail;
+       unsigned char isdir;
+       struct au_iinfo *iinfo;
+       unsigned int flags;
+
+       LKTRTrace("i%lu, %.*s\n", inode->i_ino, AuDLNPair(dentry));
+       AuDebugOn(!(inode->i_state & I_NEW));
+       IiMustWriteLock(inode);
+       bstart = au_dbstart(dentry);
+       h_dentry = au_h_dptr(dentry, bstart);
+       AuDebugOn(!h_dentry);
+       h_inode = h_dentry->d_inode;
+       AuDebugOn(!h_inode);
+
+       err = 0;
+       isdir = 0;
+       mode = h_inode->i_mode;
+       switch (mode & S_IFMT) {
+       case S_IFREG:
+               btail = au_dbtail(dentry);
+               inode->i_op = &aufs_iop;
+               inode->i_fop = &aufs_file_fop;
+               inode->i_mapping->a_ops = &aufs_aop;
+               break;
+       case S_IFDIR:
+               isdir = 1;
+               btail = au_dbtaildir(dentry);
+               inode->i_op = &aufs_dir_iop;
+               inode->i_fop = &aufs_dir_fop;
+               break;
+       case S_IFLNK:
+               btail = au_dbtail(dentry);
+               inode->i_op = &aufs_symlink_iop;
+               /* inode->i_fop = &aufs_file_fop; */
+               break;
+       case S_IFBLK:
+       case S_IFCHR:
+       case S_IFIFO:
+       case S_IFSOCK:
+               btail = au_dbtail(dentry);
+               inode->i_op = &aufs_iop;
+               init_special_inode(inode, mode,
+                                  au_h_rdev(h_inode, /*h_mnt*/NULL, h_dentry));
+               break;
+       default:
+               AuIOErr("Unknown file type 0%o\n", mode);
+               err = -EIO;
+               goto out;
+       }
+
+       /* do not set inotify for whiteouted dirs (SHWH mode) */
+       flags = au_hi_flags(inode, isdir);
+       if (au_opt_test(au_mntflags(dentry->d_sb), SHWH)
+           && au_ftest_hi(flags, NOTIFY)
+           && dentry->d_name.len > AUFS_WH_PFX_LEN
+           && !memcmp(dentry->d_name.name, AUFS_WH_PFX, AUFS_WH_PFX_LEN))
+               au_fclr_hi(flags, NOTIFY);
+       iinfo = au_ii(inode);
+       iinfo->ii_bstart = bstart;
+       iinfo->ii_bend = btail;
+       for (bindex = bstart; bindex <= btail; bindex++) {
+               h_dentry = au_h_dptr(dentry, bindex);
+               if (!h_dentry)
+                       continue;
+               AuDebugOn(!h_dentry->d_inode);
+               au_set_h_iptr(inode, bindex, au_igrab(h_dentry->d_inode),
+                             flags);
+       }
+       au_cpup_attr_all(inode, /*force*/1);
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+/* successful returns with iinfo write_locked */
+/* todo: return with unlocked? */
+static int reval_inode(struct inode *inode, struct dentry *dentry, int *matched)
+{
+       int err;
+       struct inode *h_inode, *h_dinode;
+       aufs_bindex_t bindex, bend;
+
+       LKTRTrace("i%lu, %.*s\n", inode->i_ino, AuDLNPair(dentry));
+
+       *matched = 0;
+
+       /*
+        * before this function, if aufs got any iinfo lock, it must be only
+        * one, the parent dir.
+        * it can happen by UDBA and the obsoleted inode number.
+        */
+       err = -EIO;
+       if (unlikely(inode->i_ino == parent_ino(dentry)))
+               goto out;
+
+       h_dinode = au_h_dptr(dentry, au_dbstart(dentry))->d_inode;
+       /* mutex_lock_nested(&inode->i_mutex, AuLsc_I_CHILD); */
+       ii_write_lock_new_child(inode);
+       /* it happend */
+       if (unlikely(IS_DEADDIR(inode)))
+               goto out_unlock;
+
+       err = 0;
+       bend = au_ibend(inode);
+       for (bindex = au_ibstart(inode); bindex <= bend; bindex++) {
+               h_inode = au_h_iptr(inode, bindex);
+               if (h_inode && h_inode == h_dinode) {
+                       /* && (ibs != bstart
+                          || !au_test_higen(inode, h_inode))); */
+                       *matched = 1;
+                       err = 0;
+                       if (au_iigen(inode) != au_digen(dentry))
+                               err = au_refresh_hinode(inode, dentry);
+                       break;
+               }
+       }
+
+ out_unlock:
+       if (unlikely(err))
+               ii_write_unlock(inode);
+       /* mutex_unlock(&inode->i_mutex); */
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+/* successful returns with iinfo write_locked */
+/* todo: return with unlocked? */
+struct inode *au_new_inode(struct dentry *dentry, int must_new)
+{
+       struct inode *inode, *h_inode;
+       struct dentry *h_dentry;
+       struct super_block *sb;
+       ino_t h_ino;
+       int err, match;
+       aufs_bindex_t bstart;
+       struct au_xino_entry xinoe;
+
+       LKTRTrace("%.*s\n", AuDLNPair(dentry));
+       sb = dentry->d_sb;
+       bstart = au_dbstart(dentry);
+       h_dentry = au_h_dptr(dentry, bstart);
+       AuDebugOn(!h_dentry);
+       h_inode = h_dentry->d_inode;
+       AuDebugOn(!h_inode);
+
+       h_ino = h_inode->i_ino;
+       err = au_xino_read(sb, bstart, h_ino, &xinoe);
+       inode = ERR_PTR(err);
+       if (unlikely(err))
+               goto out;
+ new_ino:
+       if (!xinoe.ino) {
+               xinoe.ino = au_xino_new_ino(sb);
+               if (!xinoe.ino) {
+                       inode = ERR_PTR(-EIO);
+                       goto out;
+               }
+       }
+
+       LKTRTrace("i%lu\n", (unsigned long)xinoe.ino);
+       inode = au_iget_locked(sb, xinoe.ino);
+       err = PTR_ERR(inode);
+       if (IS_ERR(inode))
+               goto out;
+
+       LKTRTrace("%lx, new %d\n", inode->i_state, !!(inode->i_state & I_NEW));
+       if (inode->i_state & I_NEW) {
+               ii_write_lock_new_child(inode);
+               err = set_inode(inode, dentry);
+               unlock_new_inode(inode);
+               if (!err)
+                       goto out; /* success */
+               iget_failed(inode);
+               ii_write_unlock(inode);
+               goto out_iput;
+       } else if (!must_new) {
+               AuDebugOn(inode->i_state & I_LOCK);
+               err = reval_inode(inode, dentry, &match);
+               if (!err)
+                       goto out; /* success */
+               else if (match)
+                       goto out_iput;
+       }
+
+       if (unlikely(au_test_unique_ino(h_dentry, h_ino)))
+               AuWarn1("Un-notified UDBA or repeatedly renamed dir,"
+                       " b%d, %s, %.*s, hi%lu, i%lu.\n",
+                       bstart, au_sbtype(h_dentry->d_sb), AuDLNPair(dentry),
+                       (unsigned long)h_ino, (unsigned long)xinoe.ino);
+       xinoe.ino = 0;
+       err = au_xino_write0(sb, bstart, h_ino, 0);
+       if (!err) {
+               iput(inode);
+               goto new_ino;
+       }
+       /* force noxino? */
+
+ out_iput:
+       iput(inode);
+       inode = ERR_PTR(err);
+ out:
+       AuTraceErrPtr(inode);
+       return inode;
+}
+
+/* ---------------------------------------------------------------------- */
+
+int au_test_ro(struct super_block *sb, aufs_bindex_t bindex,
+              struct inode *inode)
+{
+       int err;
+
+       err = au_br_rdonly(au_sbr(sb, bindex));
+
+       /* pseudo-link after flushed may out of bounds */
+       if (!err
+           && inode
+           && au_ibstart(inode) <= bindex
+           && bindex <= au_ibend(inode)) {
+               /*
+                * permission check is unnecessary since vfsub routine
+                * will be called later
+                */
+               struct inode *hi = au_h_iptr(inode, bindex);
+               if (hi)
+                       err = IS_IMMUTABLE(hi) ? -EROFS : 0;
+       }
+
+       AuTraceErr(err);
+       return err;
+}
+
+int au_test_h_perm(struct inode *h_inode, int mask, int dlgt)
+{
+       if (!current_fsuid())
+               return 0;
+       /* todo: fake nameidata? */
+       return vfsub_permission(h_inode, mask, NULL, dlgt);
+}
+
+int au_test_h_perm_sio(struct inode *h_inode, int mask, int dlgt)
+{
+       if (au_test_nfs(h_inode->i_sb)
+           && (mask & MAY_WRITE)
+           && S_ISDIR(h_inode->i_mode))
+               mask |= MAY_READ; /* force permission check */
+       return au_test_h_perm(h_inode, mask, dlgt);
+}
diff -urN linux/fs/aufs/inode.h linux-aufs/fs/aufs/inode.h
--- linux/fs/aufs/inode.h       1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/inode.h  2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,595 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * inode operations
+ *
+ * $Id$
+ */
+
+#ifndef __AUFS_INODE_H__
+#define __AUFS_INODE_H__
+
+#ifdef __KERNEL__
+
+#include <linux/fs.h>
+#include <linux/namei.h>
+#include <linux/security.h>
+#include <linux/aufs_type.h>
+#include "hinode.h"
+#include "misc.h"
+#include "super.h"
+
+struct au_hinode;
+struct au_vdir;
+struct au_iinfo {
+       atomic_t                ii_generation;
+       struct super_block      *ii_hsb1;       /* no get/put */
+
+       struct au_rwsem         ii_rwsem;
+       aufs_bindex_t           ii_bstart, ii_bend;
+       __u32                   ii_higen;
+       struct au_hinode        *ii_hinode;
+       struct au_vdir          *ii_vdir;
+};
+
+struct aufs_icntnr {
+       struct au_iinfo iinfo;
+       struct inode vfs_inode;
+};
+
+/* au_pin flags */
+#define AuPin_DI_LOCKED                1
+#define AuPin_DO_GPARENT       (1 << 1)
+#define AuPin_MNT_WRITE                (1 << 2)
+#define AuPin_VFS_RENAME       (1 << 3)
+/* will be set automatically */
+#define AuPin_VERIFY           (1 << 4)
+#define au_ftest_pin(flags, name)      ((flags) & AuPin_##name)
+#define au_fset_pin(flags, name)       { (flags) |= AuPin_##name; }
+#define au_fclr_pin(flags, name)       { (flags) &= ~AuPin_##name; }
+
+struct au_pin1 {
+       /* input */
+       struct dentry *dentry;
+       unsigned char lsc_di, lsc_hi, flags;
+       aufs_bindex_t bindex;
+
+       /* output */
+       struct dentry *parent;
+       struct inode *h_dir;
+};
+
+enum {AuPin_PARENT, AuPin_GPARENT};
+struct au_pin {
+#ifdef CONFIG_AUFS_HINOTIFY
+       struct au_pin1 pin[2];
+#else
+       struct au_pin1 pin[1]; /* no grand parent */
+#endif
+};
+
+/* ---------------------------------------------------------------------- */
+
+/* inode.c */
+int au_refresh_hinode_self(struct inode *inode);
+int au_refresh_hinode(struct inode *inode, struct dentry *dentry);
+struct inode *au_new_inode(struct dentry *dentry, int must_new);
+int au_test_ro(struct super_block *sb, aufs_bindex_t bindex,
+              struct inode *inode);
+int au_test_h_perm(struct inode *h_inode, int mask, int dlgt);
+int au_test_h_perm_sio(struct inode *h_inode, int mask, int dlgt);
+
+/* i_op.c */
+extern struct inode_operations aufs_iop, aufs_symlink_iop, aufs_dir_iop;
+
+/* au_wr_dir flags */
+#define AuWrDir_ADD_ENTRY      1
+#define AuWrDir_ISDIR          (1 << 1)
+#define au_ftest_wrdir(flags, name)    ((flags) & AuWrDir_##name)
+#define au_fset_wrdir(flags, name)     { (flags) |= AuWrDir_##name; }
+#define au_fclr_wrdir(flags, name)     { (flags) &= ~AuWrDir_##name; }
+
+struct au_wr_dir_args {
+       aufs_bindex_t force_btgt;
+       unsigned char flags;
+};
+int au_wr_dir(struct dentry *dentry, struct dentry *src_dentry,
+             struct au_wr_dir_args *args);
+
+void au_pin_init(struct au_pin *args, struct dentry *dentry,
+                aufs_bindex_t bindex, int lsc_di, int lsc_hi,
+                unsigned char flags);
+int au_pin(struct au_pin *args, struct dentry *dentry, aufs_bindex_t bindex,
+          unsigned char flags) __must_check;
+int au_do_pin(struct au_pin1 *p, struct au_pin1 *gp) __must_check;
+void au_do_unpin(struct au_pin1 *p, struct au_pin1 *gp);
+
+/* i_op_add.c */
+struct au_ndx;
+int au_may_add(struct dentry *dentry, aufs_bindex_t bindex,
+              struct dentry *h_parent, int isdir, struct au_ndx *ndx);
+int aufs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev);
+int aufs_symlink(struct inode *dir, struct dentry *dentry, const char *symname);
+int aufs_create(struct inode *dir, struct dentry *dentry, int mode,
+               struct nameidata *nd);
+int aufs_link(struct dentry *src_dentry, struct inode *dir,
+             struct dentry *dentry);
+int aufs_mkdir(struct inode *dir, struct dentry *dentry, int mode);
+
+/* i_op_del.c */
+int au_wr_dir_need_wh(struct dentry *dentry, int isdir, aufs_bindex_t *bcpup);
+int au_may_del(struct dentry *dentry, aufs_bindex_t bindex,
+              struct dentry *h_parent, int isdir, struct au_ndx *ndx);
+int aufs_unlink(struct inode *dir, struct dentry *dentry);
+int aufs_rmdir(struct inode *dir, struct dentry *dentry);
+
+/* i_op_ren.c */
+int au_wbr(struct dentry *dentry, aufs_bindex_t btgt);
+int aufs_rename(struct inode *src_dir, struct dentry *src_dentry,
+               struct inode *dir, struct dentry *dentry);
+
+#ifdef CONFIG_AUFS_DLGT
+/* dlgt.c */
+int au_security_inode_permission(struct inode *h_inode, int mask,
+                                struct nameidata *fake_nd, int dlgt);
+#else
+static inline
+int au_security_inode_permission(struct inode *h_inode, int mask,
+                                struct nameidata *fake_nd, int dlgt)
+{
+       return vfsub_security_inode_permission(h_inode, mask, fake_nd);
+}
+#endif /* CONFIG_AUFS_DLGT */
+
+#ifdef CONFIG_AUFS_GETATTR
+/* getattr.c */
+int aufs_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *st);
+#endif
+
+#if 0 /* reserved for future use */
+/* xattr.c */
+int aufs_setxattr(struct dentry *dentry, const char *name, const void *value,
+                 size_t sz, int flags);
+ssize_t aufs_getxattr(struct dentry *dentry, const char *name, void *value,
+                     size_t sz);
+ssize_t aufs_listxattr(struct dentry *dentry, char *list, size_t sz);
+int aufs_removexattr(struct dentry *dentry, const char *name);
+#endif
+
+/* iinfo.c */
+struct au_iinfo *au_ii(struct inode *inode);
+struct inode *au_h_iptr(struct inode *inode, aufs_bindex_t bindex);
+aufs_bindex_t au_ii_br_id(struct inode *inode, aufs_bindex_t bindex);
+
+void au_set_ibstart(struct inode *inode, aufs_bindex_t bindex);
+void au_set_hi_wh(struct inode *inode, aufs_bindex_t bindex,
+                 struct dentry *h_wh);
+unsigned int au_hi_flags(struct inode *inode, int isdir);
+
+/* hinode flags */
+#define AuHi_XINO      1
+#define AuHi_NOTIFY    (1 << 1)
+#define au_ftest_hi(flags, name)       ((flags) & AuHi_##name)
+#define au_fset_hi(flags, name)                { (flags) |= AuHi_##name; }
+#define au_fclr_hi(flags, name)                { (flags) &= ~AuHi_##name; }
+#ifndef CONFIG_AUFS_HINOTIFY
+#undef AuHi_NOTIFY
+#define AuHi_NOTIFY    0
+#endif
+
+void au_set_h_iptr(struct inode *inode, aufs_bindex_t bindex,
+                  struct inode *h_inode, unsigned int flags);
+
+void au_update_iigen(struct inode *inode);
+void au_update_brange(struct inode *inode, int do_put_zero);
+
+int au_iinfo_init(struct inode *inode);
+void au_iinfo_fin(struct inode *inode);
+
+/* plink.c */
+#ifdef CONFIG_AUFS_DEBUG
+void au_plink_list(struct super_block *sb);
+#else
+static inline void au_plink_list(struct super_block *sb)
+{
+       /* nothing */
+}
+#endif
+int au_plink_test(struct super_block *sb, struct inode *inode);
+struct dentry *au_plink_lkup(struct super_block *sb, aufs_bindex_t bindex,
+                            struct inode *inode);
+void au_plink_append(struct super_block *sb, struct inode *inode,
+                    struct dentry *h_dentry, aufs_bindex_t bindex);
+void au_plink_put(struct super_block *sb);
+void au_plink_half_refresh(struct super_block *sb, aufs_bindex_t br_id);
+
+/* ---------------------------------------------------------------------- */
+
+/* lock subclass for iinfo */
+enum {
+       AuLsc_II_CHILD,         /* child first */
+       AuLsc_II_CHILD2,        /* rename(2), link(2), and cpup at hinotify */
+       AuLsc_II_CHILD3,        /* copyup dirs */
+       AuLsc_II_PARENT,        /* see AuLsc_I_PARENT in vfsub.h */
+       AuLsc_II_PARENT2,
+       AuLsc_II_PARENT3,
+       AuLsc_II_PARENT4,
+       AuLsc_II_NEW_CHILD,
+};
+
+/*
+ * ii_read_lock_child, ii_write_lock_child,
+ * ii_read_lock_child2, ii_write_lock_child2,
+ * ii_read_lock_child3, ii_write_lock_child3,
+ * ii_read_lock_parent, ii_write_lock_parent,
+ * ii_read_lock_parent2, ii_write_lock_parent2,
+ * ii_read_lock_parent3, ii_write_lock_parent3,
+ * ii_read_lock_parent4, ii_write_lock_parent4,
+ * ii_read_lock_new_child, ii_write_lock_new_child,
+ */
+#define AuReadLockFunc(name, lsc) \
+static inline void ii_read_lock_##name(struct inode *i) \
+{ \
+       au_dbg_locking_ii_reg(i, 0, AuLsc_II_##lsc); \
+       au_rw_read_lock_nested(&au_ii(i)->ii_rwsem, AuLsc_II_##lsc); \
+       au_dbg_locking_ii_unreg(i, 0); \
+       au_dbg_locked_ii_reg(i, 0, AuLsc_II_##lsc); \
+}
+
+#define AuWriteLockFunc(name, lsc) \
+static inline void ii_write_lock_##name(struct inode *i) \
+{ \
+       au_dbg_locking_ii_reg(i, 1, AuLsc_II_##lsc); \
+       au_rw_write_lock_nested(&au_ii(i)->ii_rwsem, AuLsc_II_##lsc); \
+       au_dbg_locking_ii_unreg(i, 1); \
+       au_dbg_locked_ii_reg(i, 1, AuLsc_II_##lsc); \
+}
+
+#define AuRWLockFuncs(name, lsc) \
+       AuReadLockFunc(name, lsc) \
+       AuWriteLockFunc(name, lsc)
+
+AuRWLockFuncs(child, CHILD);
+AuRWLockFuncs(child2, CHILD2);
+AuRWLockFuncs(child3, CHILD3);
+AuRWLockFuncs(parent, PARENT);
+AuRWLockFuncs(parent2, PARENT2);
+AuRWLockFuncs(parent3, PARENT3);
+AuRWLockFuncs(parent4, PARENT4);
+AuRWLockFuncs(new_child, NEW_CHILD);
+
+#undef AuReadLockFunc
+#undef AuWriteLockFunc
+#undef AuRWLockFuncs
+
+/*
+ * ii_read_unlock, ii_write_unlock, ii_downgrade_lock
+ */
+AuSimpleUnlockRwsemFuncs(ii_do, struct inode *i, au_ii(i)->ii_rwsem);
+static inline void ii_read_unlock(struct inode *i)
+{
+       ii_do_read_unlock(i);
+       au_dbg_locked_ii_unreg(i, 0);
+}
+
+static inline void ii_write_unlock(struct inode *i)
+{
+       ii_do_write_unlock(i);
+       au_dbg_locked_ii_unreg(i, 0);
+}
+
+static inline void ii_downgrade_lock(struct inode *i)
+{
+       ii_do_downgrade_lock(i);
+}
+
+/* to debug easier, do not make them inlined functions */
+#define IiMustReadLock(i) do { \
+       SiMustAnyLock((i)->i_sb); \
+       AuRwMustReadLock(&au_ii(i)->ii_rwsem); \
+} while (0)
+
+#define IiMustWriteLock(i) do { \
+       SiMustAnyLock((i)->i_sb); \
+       AuRwMustWriteLock(&au_ii(i)->ii_rwsem); \
+} while (0)
+
+#define IiMustAnyLock(i) do { \
+       SiMustAnyLock((i)->i_sb); \
+       AuRwMustAnyLock(&au_ii(i)->ii_rwsem); \
+} while (0)
+
+#define IiMustNoWaiters(i)     AuRwMustNoWaiters(&au_ii(i)->ii_rwsem)
+
+/* ---------------------------------------------------------------------- */
+
+static inline struct inode *au_igrab(struct inode *inode)
+{
+       if (inode) {
+               AuDebugOn(!atomic_read(&inode->i_count));
+               atomic_inc_return(&inode->i_count);
+       }
+       return inode;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static inline aufs_bindex_t au_ibstart(struct inode *inode)
+{
+       /* lock free root dinfo/inode */
+       if (inode->i_ino != AUFS_ROOT_INO)
+               IiMustAnyLock(inode);
+       else
+               SiMustAnyLock(inode->i_sb);
+       return au_ii(inode)->ii_bstart;
+}
+
+static inline aufs_bindex_t au_ibend(struct inode *inode)
+{
+       /* lock free root dinfo/inode */
+       if (inode->i_ino != AUFS_ROOT_INO)
+               IiMustAnyLock(inode);
+       else
+               SiMustAnyLock(inode->i_sb);
+       return au_ii(inode)->ii_bend;
+}
+
+static inline struct au_vdir *au_ivdir(struct inode *inode)
+{
+       IiMustAnyLock(inode);
+       AuDebugOn(!S_ISDIR(inode->i_mode));
+       return au_ii(inode)->ii_vdir;
+}
+
+static inline struct dentry *au_hi_wh(struct inode *inode, aufs_bindex_t bindex)
+{
+       struct au_hinode *hinode;
+       IiMustAnyLock(inode);
+       hinode = au_ii(inode)->ii_hinode + bindex;
+       return hinode->hi_whdentry;
+}
+
+static inline void au_set_ibend(struct inode *inode, aufs_bindex_t bindex)
+{
+       IiMustWriteLock(inode);
+       AuDebugOn(au_sbend(inode->i_sb) < bindex || bindex < au_ibstart(inode));
+       au_ii(inode)->ii_bend = bindex;
+}
+
+static inline void au_set_ivdir(struct inode *inode, struct au_vdir *vdir)
+{
+       IiMustWriteLock(inode);
+       AuDebugOn(!S_ISDIR(inode->i_mode) || (au_ii(inode)->ii_vdir && vdir));
+       au_ii(inode)->ii_vdir = vdir;
+}
+
+static inline void au_hiput(struct au_hinode *hinode)
+{
+       au_hin_free(hinode);
+       dput(hinode->hi_whdentry);
+       iput(hinode->hi_inode);
+}
+
+static inline struct au_hinode *au_hi(struct inode *inode, aufs_bindex_t bindex)
+{
+       /* todo: this lock check causes some unnecessary locks in callers. */
+       IiMustAnyLock(inode);
+       return au_ii(inode)->ii_hinode + bindex;
+}
+
+/* tiny test for inode number */
+/* tmpfs generation is too rough */
+static inline int au_test_higen(struct inode *inode, struct inode *h_inode)
+{
+       struct au_iinfo *iinfo;
+
+       IiMustAnyLock(inode);
+
+       iinfo = au_ii(inode);
+       return !(iinfo->ii_hsb1 == h_inode->i_sb
+                && iinfo->ii_higen == h_inode->i_generation);
+}
+
+static inline au_gen_t au_iigen(struct inode *inode)
+{
+       return atomic_read(&au_ii(inode)->ii_generation);
+}
+
+#ifdef CONFIG_AUFS_HINOTIFY
+static inline au_gen_t au_iigen_dec(struct inode *inode)
+{
+       /* AuDbg("i%lu\n", inode->i_ino); */
+       return atomic_dec_return(&au_ii(inode)->ii_generation);
+}
+#endif
+
+/* ---------------------------------------------------------------------- */
+
+#ifdef CONFIG_AUFS_HINOTIFY
+static inline struct au_pin1 *au_pin_gp(struct au_pin *args)
+{
+       return args->pin + AuPin_GPARENT;
+}
+
+/* hinotify.c */
+void au_unpin_gp(struct au_pin *args);
+
+#else
+
+static inline struct au_pin1 *au_pin_gp(struct au_pin *args)
+{
+       return NULL;
+}
+
+static inline void au_unpin_gp(struct au_pin *args)
+{
+       /* empty */
+}
+#endif /* HINOTIFY */
+
+static inline void au_unpin(struct au_pin *args)
+{
+       au_do_unpin(args->pin + AuPin_PARENT, au_pin_gp(args));
+}
+
+static inline
+struct au_hinode *au_do_pinned_hdir(struct au_pin1 *pin)
+{
+       if (pin && pin->parent)
+               return au_hi(pin->parent->d_inode, pin->bindex);
+       return NULL;
+}
+
+struct dentry *au_do_pinned_h_parent(struct au_pin1 *pin);
+
+static inline struct dentry *au_do_pinned_parent(struct au_pin1 *pin)
+{
+       if (pin)
+               return pin->parent;
+       return NULL;
+}
+
+static inline struct inode *au_do_pinned_h_dir(struct au_pin1 *pin)
+{
+       if (pin)
+               return pin->h_dir;
+       return NULL;
+}
+
+static inline
+void au_pin_do_set_dentry(struct au_pin1 *pin, struct dentry *dentry)
+{
+       if (pin)
+               pin->dentry = dentry;
+}
+
+static inline
+void au_pin_do_set_parent(struct au_pin1 *pin, struct dentry *parent)
+{
+       if (pin) {
+               dput(pin->parent);
+               pin->parent = dget(parent);
+       }
+}
+
+static inline void au_pin_do_set_h_dir(struct au_pin1 *pin, struct inode *h_dir)
+{
+       if (pin) {
+               iput(pin->h_dir);
+               pin->h_dir = au_igrab(h_dir);
+       }
+}
+
+static inline
+void au_pin_do_set_parent_lflag(struct au_pin1 *pin, unsigned char lflag)
+{
+       if (pin) {
+               /* dirty macros require brackets */
+               if (lflag) {
+                       au_fset_pin(pin->flags, DI_LOCKED);
+               } else {
+                       au_fclr_pin(pin->flags, DI_LOCKED);
+               }
+       }
+}
+
+static inline
+struct au_hinode *au_pinned_hdir(struct au_pin *args)
+{
+       return au_do_pinned_hdir(args->pin + AuPin_PARENT);
+}
+
+static inline
+struct au_hinode *au_pinned_hgdir(struct au_pin *args)
+{
+       return au_do_pinned_hdir(au_pin_gp(args));
+}
+
+static inline
+struct dentry *au_pinned_h_parent(struct au_pin *args)
+{
+       return au_do_pinned_h_parent(args->pin + AuPin_PARENT);
+}
+
+#if 0 /* reserved for future use */
+static inline
+struct dentry *au_pinned_h_gparent(struct au_pin *args)
+{
+       return au_do_pinned_h_parent(au_pin_gp(args));
+}
+#endif
+
+static inline
+struct dentry *au_pinned_parent(struct au_pin *args)
+{
+       return au_do_pinned_parent(args->pin + AuPin_PARENT);
+}
+
+static inline
+struct dentry *au_pinned_gparent(struct au_pin *args)
+{
+       return au_do_pinned_parent(au_pin_gp(args));
+}
+
+static inline
+struct inode *au_pinned_h_dir(struct au_pin *args)
+{
+       return au_do_pinned_h_dir(args->pin + AuPin_PARENT);
+}
+
+static inline
+struct inode *au_pinned_h_gdir(struct au_pin *args)
+{
+       return au_do_pinned_h_dir(au_pin_gp(args));
+}
+
+static inline void au_pin_set_parent(struct au_pin *args, struct dentry *d)
+{
+       au_pin_do_set_parent(args->pin + AuPin_PARENT, d);
+}
+
+static inline void au_pin_set_gparent(struct au_pin *args, struct dentry *d)
+{
+       au_pin_do_set_parent(au_pin_gp(args), d);
+}
+
+static inline void au_pin_set_h_dir(struct au_pin *args, struct inode *h_dir)
+{
+       au_pin_do_set_h_dir(args->pin + AuPin_PARENT, h_dir);
+}
+
+static inline void au_pin_set_h_gdir(struct au_pin *args, struct inode *h_dir)
+{
+       au_pin_do_set_h_dir(au_pin_gp(args), h_dir);
+}
+
+static inline
+void au_pin_set_parent_lflag(struct au_pin *args, unsigned char lflag)
+{
+       au_pin_do_set_parent_lflag(args->pin + AuPin_PARENT, lflag);
+}
+
+static inline
+void au_pin_set_gparent_lflag(struct au_pin *args, unsigned char lflag)
+{
+       au_pin_do_set_parent_lflag(au_pin_gp(args), lflag);
+}
+
+#endif /* __KERNEL__ */
+#endif /* __AUFS_INODE_H__ */
diff -urN linux/fs/aufs/i_op_add.c linux-aufs/fs/aufs/i_op_add.c
--- linux/fs/aufs/i_op_add.c    1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/i_op_add.c       2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,757 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * inode operations (add entry)
+ *
+ * $Id$
+ */
+
+#include "aufs.h"
+
+/*
+ * final procedure of adding a new entry, except link(2).
+ * remove whiteout, instantiate, copyup the parent dir's times and size
+ * and update version.
+ * if it failed, re-create the removed whiteout.
+ */
+static int epilog(struct inode *dir, aufs_bindex_t bindex,
+                 struct dentry *wh_dentry, struct dentry *dentry)
+{
+       int err, rerr;
+       aufs_bindex_t bwh;
+       struct inode *inode, *h_dir;
+       struct dentry *wh;
+       struct au_ndx ndx;
+       struct super_block *sb;
+
+       LKTRTrace("wh %p, %.*s\n", wh_dentry, AuDLNPair(dentry));
+
+       sb = dentry->d_sb;
+       bwh = -1;
+       if (wh_dentry) {
+               h_dir = wh_dentry->d_parent->d_inode; /* dir inode is locked */
+               IMustLock(h_dir);
+               AuDebugOn(au_h_iptr(dir, bindex) != h_dir);
+               bwh = au_dbwh(dentry);
+               err = au_wh_unlink_dentry(au_hi(dir, bindex), wh_dentry, dentry,
+                                         /*dlgt*/0);
+               if (unlikely(err))
+                       goto out;
+       }
+
+       inode = au_new_inode(dentry, /*must_new*/1);
+       if (!IS_ERR(inode)) {
+               d_instantiate(dentry, inode);
+               dir = dentry->d_parent->d_inode; /* dir inode is locked */
+               IMustLock(dir);
+               /* or always cpup dir mtime? */
+               if (au_ibstart(dir) == au_dbstart(dentry))
+                       au_cpup_attr_timesizes(dir);
+               dir->i_version++;
+               return 0; /* success */
+       }
+
+       err = PTR_ERR(inode);
+       if (!wh_dentry)
+               goto out;
+
+       /* revert */
+       ndx.flags = 0;
+       if (au_test_dlgt(au_mntflags(sb)))
+               au_fset_ndx(ndx.flags, DLGT);
+       ndx.nfsmnt = au_nfsmnt(sb, bwh);
+       ndx.nd = NULL;
+       /* ndx.br = NULL; */
+       /* dir inode is locked */
+       wh = au_wh_create(dentry, bwh, wh_dentry->d_parent, &ndx);
+       rerr = PTR_ERR(wh);
+       if (IS_ERR(wh)) {
+               AuIOErr("%.*s reverting whiteout failed(%d, %d)\n",
+                       AuDLNPair(dentry), err, rerr);
+               err = -EIO;
+       } else
+               dput(wh);
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+/*
+ * simple tests for the adding inode operations.
+ * following the checks in vfs, plus the parent-child relationship.
+ */
+int au_may_add(struct dentry *dentry, aufs_bindex_t bindex,
+              struct dentry *h_parent, int isdir, struct au_ndx *ndx)
+{
+       int err, exist;
+       struct dentry *h_dentry;
+       struct inode *h_inode;
+       umode_t h_mode;
+
+       LKTRTrace("%.*s/%.*s, b%d, dir %d\n",
+                 AuDLNPair(h_parent), AuDLNPair(dentry), bindex, isdir);
+
+       exist = !!dentry->d_inode;
+       h_dentry = au_h_dptr(dentry, bindex);
+       h_inode = h_dentry->d_inode;
+       if (!exist) {
+               err = -EEXIST;
+               if (unlikely(h_inode))
+                       goto out;
+       } else {
+               /* rename(2) case */
+               err = -EIO;
+               if (unlikely(!h_inode || !h_inode->i_nlink))
+                       goto out;
+
+               h_mode = h_inode->i_mode;
+               if (!isdir) {
+                       err = -EISDIR;
+                       if (unlikely(S_ISDIR(h_mode)))
+                               goto out;
+               } else if (unlikely(!S_ISDIR(h_mode))) {
+                       err = -ENOTDIR;
+                       goto out;
+               }
+       }
+
+       err = -EIO;
+       /* expected parent dir is locked */
+       if (unlikely(h_parent != h_dentry->d_parent))
+               goto out;
+       err = 0;
+
+       if (au_opt_test(au_mntflags(dentry->d_sb), UDBA_INOTIFY)) {
+               struct dentry *h_latest;
+               struct qstr *qstr = &dentry->d_name;
+
+               err = -EACCES;
+               if (unlikely(au_test_h_perm
+                            (h_parent->d_inode, MAY_EXEC | MAY_WRITE,
+                             au_ftest_ndx(ndx->flags, DLGT))))
+                       goto out;
+
+               h_latest = au_sio_lkup_one(qstr->name, h_parent, qstr->len,
+                                          ndx);
+               err = PTR_ERR(h_latest);
+               if (IS_ERR(h_latest))
+                       goto out;
+               err = -EIO;
+               dput(h_latest);
+               /* fuse d_revalidate always return 0 for negative dentries */
+               if (h_latest == h_dentry || au_test_fuse(h_dentry->d_sb))
+                       err = 0;
+       }
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+/*
+ * initial procedure of adding a new entry.
+ * prepare writable branch and the parent dir, lock it,
+ * lookup whiteout for the new entry.
+ */
+static struct dentry*
+lock_hdir_lkup_wh(struct dentry *dentry, struct au_dtime *dt,
+                 struct dentry *src_dentry, struct au_pin *pin,
+                 struct au_wr_dir_args *wr_dir_args)
+{
+       struct dentry *wh_dentry, *h_parent;
+       struct super_block *sb;
+       int err;
+       unsigned int mnt_flags;
+       unsigned char pin_flags;
+       aufs_bindex_t bstart, bcpup;
+       struct au_ndx ndx;
+
+       LKTRTrace("%.*s, src %p\n", AuDLNPair(dentry), src_dentry);
+
+       bstart = au_dbstart(dentry);
+       err = au_wr_dir(dentry, src_dentry, wr_dir_args);
+       bcpup = err;
+       wh_dentry = ERR_PTR(err);
+       if (unlikely(err < 0))
+               goto out;
+
+       sb = dentry->d_sb;
+       mnt_flags = au_mntflags(sb);
+       pin_flags = AuPin_DI_LOCKED | AuPin_MNT_WRITE;
+       if (dt && au_opt_test(mnt_flags, UDBA_INOTIFY))
+               au_fset_pin(pin_flags, DO_GPARENT);
+       err = au_pin(pin, dentry, bcpup, pin_flags);
+       wh_dentry = ERR_PTR(err);
+       if (unlikely(err))
+               goto out;
+
+       ndx.nfsmnt = au_nfsmnt(sb, bcpup);
+       ndx.flags = 0;
+       if (au_test_dlgt(mnt_flags))
+               au_fset_ndx(ndx.flags, DLGT);
+       ndx.nd = NULL;
+       /* ndx.br = NULL; */
+       /* ndx.nd_file = NULL; */
+
+       h_parent = au_pinned_h_parent(pin);
+       if (!au_opt_test(mnt_flags, UDBA_NONE) && au_dbstart(dentry) == bcpup) {
+               struct nameidata nd;
+
+               if (ndx.nfsmnt) {
+                       /* todo: dirty? */
+                       ndx.nd = &nd;
+                       ndx.br = au_sbr(sb, bcpup);
+                       memset(&nd, 0, sizeof(nd));
+                       nd.flags = LOOKUP_CREATE;
+                       nd.intent.open.flags = O_EXCL;
+               }
+               err = au_may_add(dentry, bcpup, h_parent,
+                                au_ftest_wrdir(wr_dir_args->flags, ISDIR),
+                                &ndx);
+               wh_dentry = ERR_PTR(err);
+               if (unlikely(err))
+                       goto out_unpin;
+               ndx.nd = NULL;
+               ndx.br = NULL;
+       }
+
+       if (dt)
+               au_dtime_store(dt, au_pinned_parent(pin), h_parent,
+                              au_pinned_hdir(pin), au_pinned_hgdir(pin));
+
+       wh_dentry = NULL;
+       if (/* bcpup != bstart || */ bcpup != au_dbwh(dentry))
+               goto out; /* success */
+
+       wh_dentry = au_wh_lkup(h_parent, &dentry->d_name, &ndx);
+
+ out_unpin:
+       if (IS_ERR(wh_dentry))
+               au_unpin(pin);
+ out:
+       AuTraceErrPtr(wh_dentry);
+       return wh_dentry;
+}
+
+/* ---------------------------------------------------------------------- */
+
+enum { Mknod, Symlink, Creat };
+struct simple_arg {
+       int type;
+       union {
+               struct {
+                       int mode;
+                       struct nameidata *nd;
+               } c;
+               struct {
+                       const char *symname;
+               } s;
+               struct {
+                       int mode;
+                       dev_t dev;
+               } m;
+       } u;
+};
+
+static int add_simple(struct inode *dir, struct dentry *dentry,
+                     struct simple_arg *arg)
+{
+       int err;
+       struct dentry *h_dentry, *wh_dentry, *parent;
+       struct inode *h_dir;
+       struct au_dtime dt;
+       struct vfsub_args vargs;
+       struct super_block *sb;
+       aufs_bindex_t bstart;
+       unsigned char created;
+       struct au_hin_ignore ign;
+       struct au_pin pin;
+       struct au_wr_dir_args wr_dir_args = {
+               .force_btgt     = -1,
+               .flags          = AuWrDir_ADD_ENTRY
+       };
+
+       LKTRTrace("type %d, %.*s\n", arg->type, AuDLNPair(dentry));
+       IMustLock(dir);
+
+       sb = dir->i_sb;
+       parent = dentry->d_parent; /* dir inode is locked */
+       aufs_read_lock(dentry, AuLock_DW);
+       vfsub_args_init(&vargs, &ign, !!au_test_dlgt(au_mntflags(sb)), 0);
+       di_write_lock_parent(parent);
+       wh_dentry = lock_hdir_lkup_wh(dentry, &dt, /*src_dentry*/NULL, &pin,
+                                     &wr_dir_args);
+       err = PTR_ERR(wh_dentry);
+       if (IS_ERR(wh_dentry))
+               goto out;
+
+       bstart = au_dbstart(dentry);
+       h_dentry = au_h_dptr(dentry, bstart);
+       h_dir = au_pinned_h_dir(&pin);
+       vfsub_ign_hinode(&vargs, IN_CREATE, au_pinned_hdir(&pin));
+
+       switch (arg->type) {
+       case Creat:
+               AuDebugOn(au_test_nfs(h_dir->i_sb) && !arg->u.c.nd);
+               err = au_h_create(h_dir, h_dentry, arg->u.c.mode, &vargs,
+                                 arg->u.c.nd, au_nfsmnt(sb, bstart));
+               break;
+       case Symlink:
+               err = vfsub_symlink(h_dir, h_dentry, arg->u.s.symname,
+                                   S_IALLUGO, &vargs);
+               break;
+       case Mknod:
+               err = vfsub_mknod(h_dir, h_dentry, arg->u.m.mode, arg->u.m.dev,
+                                 &vargs);
+               break;
+       default:
+               BUG();
+       }
+       created = !err;
+       if (!err)
+               err = epilog(dir, bstart, wh_dentry, dentry);
+
+       /* revert */
+       if (unlikely(created && err && h_dentry->d_inode)) {
+               int rerr;
+               vfsub_args_reinit(&vargs);
+               vfsub_ign_hinode(&vargs, IN_DELETE, au_pinned_hdir(&pin));
+               rerr = vfsub_unlink(h_dir, h_dentry, &vargs);
+               if (rerr) {
+                       AuIOErr("%.*s revert failure(%d, %d)\n",
+                               AuDLNPair(dentry), err, rerr);
+                       err = -EIO;
+               }
+               /* todo: inotify will be fired to the grand parent dir? */
+               au_dtime_revert(&dt);
+               d_drop(dentry);
+       }
+
+       au_unpin(&pin);
+       dput(wh_dentry);
+
+ out:
+       if (unlikely(err)) {
+               au_update_dbstart(dentry);
+               d_drop(dentry);
+       }
+       di_write_unlock(parent);
+       aufs_read_unlock(dentry, AuLock_DW);
+       AuTraceErr(err);
+       if (unlikely(err == -EBUSY && au_test_nfsd(current)))
+               err = -ESTALE;
+       return err;
+}
+
+int aufs_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev)
+{
+       struct simple_arg arg = {
+               .type = Mknod,
+               .u.m = {
+                       .mode   = mode,
+                       .dev    = dev
+               }
+       };
+       return add_simple(dir, dentry, &arg);
+}
+
+int aufs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
+{
+       struct simple_arg arg = {
+               .type = Symlink,
+               .u.s.symname = symname
+       };
+       return add_simple(dir, dentry, &arg);
+}
+
+int aufs_create(struct inode *dir, struct dentry *dentry, int mode,
+               struct nameidata *nd)
+{
+       struct simple_arg arg = {
+               .type = Creat,
+               .u.c = {
+                       .mode   = mode,
+                       .nd     = nd
+               }
+       };
+       return add_simple(dir, dentry, &arg);
+}
+
+/* ---------------------------------------------------------------------- */
+
+struct au_link_args {
+       unsigned int mnt_flags;
+       unsigned char pin_flags;
+       aufs_bindex_t bdst, bsrc;
+       struct vfsub_args vargs;
+       struct au_pin pin;
+       struct au_hin_ignore ign;
+       struct dentry *h_dentry;
+       struct dentry *src_parent, *parent;
+};
+
+static int au_cpup_before_link(struct dentry *src_dentry, struct inode *dir,
+                              struct dentry *dentry, struct au_link_args *a)
+{
+       int err;
+       const int hinotify = au_opt_test(a->mnt_flags, UDBA_INOTIFY);
+       struct mutex *h_mtx;
+
+       LKTRTrace("src %.*s, i%lu, dst %.*s\n",
+                 AuDLNPair(src_dentry), dir->i_ino, AuDLNPair(dentry));
+
+       di_read_lock_parent(a->src_parent, AuLock_IR);
+       err = au_test_and_cpup_dirs(src_dentry, a->bdst);
+       if (unlikely(err))
+               goto out;
+
+       AuDebugOn(au_dbstart(src_dentry) != a->bsrc);
+       h_mtx = &au_h_dptr(src_dentry, a->bsrc)->d_inode->i_mutex;
+       a->pin_flags = AuPin_DI_LOCKED | AuPin_MNT_WRITE;
+       if (hinotify)
+               au_fset_pin(a->pin_flags, DO_GPARENT);
+       err = au_pin(&a->pin, src_dentry, a->bdst, a->pin_flags);
+       if (unlikely(err))
+               goto out;
+       mutex_lock_nested(h_mtx, AuLsc_I_CHILD);
+       /* todo: no KEEPLINO because of noplink? */
+       err = au_sio_cpup_simple(src_dentry, a->bdst, -1,
+                                AuCpup_DTIME /* | AuCpup_KEEPLINO */);
+       mutex_unlock(h_mtx);
+       au_unpin(&a->pin);
+
+ out:
+       di_read_unlock(a->src_parent, AuLock_IR);
+       AuTraceErr(err);
+       return err;
+}
+
+static int au_cpup_or_link(struct dentry *src_dentry, struct au_link_args *a)
+{
+       int err;
+       struct inode *h_inode;
+       aufs_bindex_t bstart;
+       struct dentry *h_src_dentry;
+
+       AuTraceEnter();
+       AuDebugOn(au_dbstart(src_dentry) != a->bsrc);
+
+       bstart = au_ibstart(src_dentry->d_inode);
+       h_inode = NULL;
+       if (bstart <= a->bdst)
+               h_inode = au_h_iptr(src_dentry->d_inode, a->bdst);
+       if (!h_inode || !h_inode->i_nlink) {
+               /* copyup src_dentry as the name of dentry. */
+               au_set_dbstart(src_dentry, a->bdst);
+               au_set_h_dptr(src_dentry, a->bdst, dget(a->h_dentry));
+               h_inode = au_h_dptr(src_dentry, a->bsrc)->d_inode;
+               mutex_lock_nested(&h_inode->i_mutex, AuLsc_I_CHILD);
+               err = au_sio_cpup_single(src_dentry, a->bdst, a->bsrc, -1,
+                                        AuCpup_KEEPLINO, a->parent);
+               mutex_unlock(&h_inode->i_mutex);
+               au_set_h_dptr(src_dentry, a->bdst, NULL);
+               au_set_dbstart(src_dentry, a->bsrc);
+       } else {
+               /* the inode of src_dentry already exists on a.bdst branch */
+               h_src_dentry = d_find_alias(h_inode);
+               if (h_src_dentry) {
+                       /* vfsub_args_reinit(&a->vargs); */
+                       vfsub_ign_hinode(&a->vargs, IN_CREATE,
+                                        au_pinned_hdir(&a->pin));
+                       err = vfsub_link(h_src_dentry, au_pinned_h_dir(&a->pin),
+                                        a->h_dentry, &a->vargs);
+                       dput(h_src_dentry);
+               } else {
+                       AuIOErr("no dentry found for i%lu on b%d\n",
+                               h_inode->i_ino, a->bdst);
+                       err = -EIO;
+               }
+       }
+
+       if (!err)
+               au_plink_append(src_dentry->d_sb, src_dentry->d_inode,
+                               a->h_dentry, a->bdst);
+
+       AuTraceErr(err);
+       return err;
+}
+
+int aufs_link(struct dentry *src_dentry, struct inode *dir,
+             struct dentry *dentry)
+{
+       int err, rerr;
+       struct au_dtime dt;
+       struct super_block *sb;
+       struct au_link_args *a;
+       struct au_wr_dir_args wr_dir_args = {
+               /* .force_btgt  = -1, */
+               .flags          = AuWrDir_ADD_ENTRY
+       };
+       struct dentry *wh_dentry, *h_src_dentry;
+       struct inode *inode;
+
+       LKTRTrace("src %.*s, i%lu, dst %.*s\n",
+                 AuDLNPair(src_dentry), dir->i_ino, AuDLNPair(dentry));
+       IMustLock(dir);
+       inode = src_dentry->d_inode;
+       IMustLock(inode);
+       AuDebugOn(S_ISDIR(inode->i_mode));
+
+       err = -ENOMEM;
+       a = kzalloc(sizeof(*a), GFP_NOFS);
+       if (unlikely(!a))
+               goto out;
+
+       sb = dentry->d_sb;
+       a->parent = dentry->d_parent; /* dir inode is locked */
+       aufs_read_and_write_lock2(dentry, src_dentry, /*AuLock_FLUSH*/0);
+       a->src_parent = dget_parent(src_dentry);
+       wr_dir_args.force_btgt = au_dbstart(src_dentry);
+       a->mnt_flags = au_mntflags(sb);
+       vfsub_args_init(&a->vargs, &a->ign, au_test_dlgt(a->mnt_flags), 0);
+
+       di_write_lock_parent(a->parent);
+       wr_dir_args.force_btgt = au_wbr(dentry, wr_dir_args.force_btgt);
+       wh_dentry = lock_hdir_lkup_wh(dentry, &dt, src_dentry, &a->pin,
+                                     &wr_dir_args);
+       err = PTR_ERR(wh_dentry);
+       if (IS_ERR(wh_dentry))
+               goto out_unlock;
+       err = 0;
+
+       a->bdst = au_dbstart(dentry);
+       a->h_dentry = au_h_dptr(dentry, a->bdst);
+
+       /* todo: minor optimize,
+          their sb may be same while their bindex differs? */
+       a->bsrc = au_dbstart(src_dentry);
+       if (au_opt_test(a->mnt_flags, PLINK)) {
+               if (a->bdst < a->bsrc
+                   /* && h_src_dentry->d_sb != a->h_dentry->d_sb */)
+                       err = au_cpup_or_link(src_dentry, a);
+               else {
+                       h_src_dentry = au_h_dptr(src_dentry, a->bdst);
+                       AuDebugOn(!h_src_dentry);
+                       AuDebugOn(!h_src_dentry->d_inode);
+                       vfsub_ign_hinode(&a->vargs, IN_CREATE,
+                                        au_pinned_hdir(&a->pin));
+                       err = vfsub_link(h_src_dentry, au_pinned_h_dir(&a->pin),
+                                        a->h_dentry, &a->vargs);
+               }
+       } else {
+               /*
+                * copyup src_dentry to the branch we process,
+                * and then link(2) to it.
+                */
+               if (a->bdst < a->bsrc
+                   /* && h_src_dentry->d_sb != a->h_dentry->d_sb */) {
+                       au_unpin(&a->pin);
+                       di_write_unlock(a->parent);
+                       err = au_cpup_before_link(src_dentry, dir, dentry, a);
+                       if (!err) {
+                               a->pin_flags
+                                       = AuPin_DI_LOCKED | AuPin_MNT_WRITE;
+                               if (au_opt_test(a->mnt_flags, UDBA_INOTIFY))
+                                       au_fset_pin(a->pin_flags, DO_GPARENT);
+                               di_write_lock_parent(a->parent);
+                               err = au_pin(&a->pin, dentry, a->bdst,
+                                            a->pin_flags);
+                               if (unlikely(err))
+                                       goto out_wh;
+                       }
+               }
+               if (!err) {
+                       /* vfsub_args_reinit(&a->vargs); */
+                       vfsub_ign_hinode(&a->vargs, IN_CREATE,
+                                        au_pinned_hdir(&a->pin));
+                       h_src_dentry = au_h_dptr(src_dentry, a->bdst);
+                       err = vfsub_link(h_src_dentry, au_pinned_h_dir(&a->pin),
+                                        a->h_dentry, &a->vargs);
+               }
+       }
+       if (unlikely(err))
+               goto out_unpin;
+
+       if (wh_dentry) {
+               err = au_wh_unlink_dentry(au_pinned_hdir(&a->pin), wh_dentry,
+                                         dentry, /*dlgt*/0);
+               if (unlikely(err))
+                       goto out_revert;
+       }
+
+#if 0 /* cannot support it */
+       /* fuse has different memory inode for the same inode number */
+       if (au_test_fuse(a->h_dentry->d_sb)) {
+               LKTRLabel(here);
+               d_drop(a->h_dentry);
+               /*d_drop(h_src_dentry);
+                 d_drop(src_dentry);*/
+               inc_nlink(a->inode);
+               a->inode->i_ctime = dir->i_ctime;
+       }
+#endif
+
+       dir->i_version++;
+       if (au_ibstart(dir) == au_dbstart(dentry))
+               au_cpup_attr_timesizes(dir);
+       if (!d_unhashed(a->h_dentry)
+           /* || h_old_inode->i_nlink <= nlink */
+           /* || SB_NFS(h_src_dentry->d_sb) */) {
+               d_instantiate(dentry, au_igrab(inode));
+               inc_nlink(inode);
+               inode->i_ctime = dir->i_ctime;
+       } else
+               /* nfs case (< 2.6.15) */
+               d_drop(dentry);
+       goto out_unpin; /* success */
+
+ out_revert:
+       vfsub_args_reinit(&a->vargs);
+       vfsub_ign_hinode(&a->vargs, IN_DELETE, au_pinned_hdir(&a->pin));
+       rerr = vfsub_unlink(au_pinned_h_dir(&a->pin), a->h_dentry, &a->vargs);
+       if (!rerr)
+               goto out_dt;
+       AuIOErr("%.*s reverting failed(%d, %d)\n",
+               AuDLNPair(dentry), err, rerr);
+       err = -EIO;
+ out_dt:
+       d_drop(dentry);
+       au_dtime_revert(&dt);
+ out_unpin:
+       au_unpin(&a->pin);
+ out_wh:
+       dput(wh_dentry);
+ out_unlock:
+       if (unlikely(err)) {
+               au_update_dbstart(dentry);
+               d_drop(dentry);
+       }
+       di_write_unlock(a->parent);
+       dput(a->src_parent);
+       aufs_read_and_write_unlock2(dentry, src_dentry);
+       kfree(a);
+ out:
+       AuTraceErr(err);
+       if (unlikely(err == -EBUSY && au_test_nfsd(current)))
+               err = -ESTALE;
+       return err;
+}
+
+int aufs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
+{
+       int err, rerr;
+       struct dentry *h_dentry, *wh_dentry, *parent, *opq_dentry;
+       struct mutex *h_mtx;
+       struct au_dtime dt;
+       aufs_bindex_t bindex;
+       unsigned char diropq, dlgt;
+       unsigned int mnt_flags;
+       struct au_hin_ignore ign;
+       struct vfsub_args vargs;
+       struct au_pin pin;
+       struct au_wr_dir_args wr_dir_args = {
+               .force_btgt     = -1,
+               .flags          = AuWrDir_ADD_ENTRY | AuWrDir_ISDIR
+       };
+
+       LKTRTrace("i%lu, %.*s, mode 0%o\n",
+                 dir->i_ino, AuDLNPair(dentry), mode);
+       IMustLock(dir);
+
+       aufs_read_lock(dentry, AuLock_DW);
+       parent = dentry->d_parent; /* dir inode is locked */
+       mnt_flags = au_mntflags(dentry->d_sb);
+       dlgt = !!au_test_dlgt(mnt_flags);
+       vfsub_args_init(&vargs, &ign, dlgt, 0);
+
+       di_write_lock_parent(parent);
+       wh_dentry = lock_hdir_lkup_wh(dentry, &dt, /*src_dentry*/NULL, &pin,
+                                     &wr_dir_args);
+       err = PTR_ERR(wh_dentry);
+       if (IS_ERR(wh_dentry))
+               goto out;
+
+       bindex = au_dbstart(dentry);
+       h_dentry = au_h_dptr(dentry, bindex);
+       vfsub_ign_hinode(&vargs, IN_CREATE, au_pinned_hdir(&pin));
+       err = vfsub_mkdir(au_pinned_h_dir(&pin), h_dentry, mode, &vargs);
+       if (unlikely(err))
+               goto out_unlock;
+
+       /* make the dir opaque */
+       diropq = 0;
+       h_mtx = &h_dentry->d_inode->i_mutex;
+       if (wh_dentry || au_opt_test(mnt_flags, ALWAYS_DIROPQ)) {
+               mutex_lock_nested(h_mtx, AuLsc_I_CHILD);
+               opq_dentry = au_diropq_create(dentry, bindex, /*dlgt*/0);
+               mutex_unlock(h_mtx);
+               err = PTR_ERR(opq_dentry);
+               if (IS_ERR(opq_dentry))
+                       goto out_dir;
+               dput(opq_dentry);
+               diropq = 1;
+       }
+
+       err = epilog(dir, bindex, wh_dentry, dentry);
+       if (!err) {
+               inc_nlink(dir);
+               goto out_unlock; /* success */
+       }
+
+       /* revert */
+       if (diropq) {
+               LKTRLabel(revert opq);
+               mutex_lock_nested(h_mtx, AuLsc_I_CHILD);
+               rerr = au_diropq_remove(dentry, bindex, dlgt);
+               mutex_unlock(h_mtx);
+               if (rerr) {
+                       AuIOErr("%.*s reverting diropq failed(%d, %d)\n",
+                               AuDLNPair(dentry), err, rerr);
+                       err = -EIO;
+               }
+       }
+
+ out_dir:
+       LKTRLabel(revert dir);
+       vfsub_args_reinit(&vargs);
+       vfsub_ign_hinode(&vargs, IN_DELETE, au_pinned_hdir(&pin));
+       rerr = vfsub_rmdir(au_pinned_h_dir(&pin), h_dentry, &vargs);
+       if (rerr) {
+               AuIOErr("%.*s reverting dir failed(%d, %d)\n",
+                       AuDLNPair(dentry), err, rerr);
+               err = -EIO;
+       }
+       d_drop(dentry);
+       au_dtime_revert(&dt);
+ out_unlock:
+       au_unpin(&pin);
+       dput(wh_dentry);
+ out:
+       if (unlikely(err)) {
+               au_update_dbstart(dentry);
+               d_drop(dentry);
+       }
+       di_write_unlock(parent);
+       aufs_read_unlock(dentry, AuLock_DW);
+       AuTraceErr(err);
+       if (unlikely(err == -EBUSY && au_test_nfsd(current)))
+               err = -ESTALE;
+       return err;
+}
diff -urN linux/fs/aufs/i_op.c linux-aufs/fs/aufs/i_op.c
--- linux/fs/aufs/i_op.c        1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/i_op.c   2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,1049 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * inode operations (except add/del/rename)
+ *
+ * $Id$
+ */
+
+#include <linux/fs_stack.h>
+#include <linux/uaccess.h>
+#include "aufs.h"
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 27)
+static int h_permission(struct inode *h_inode, int mask,
+                       struct vfsmount *h_mnt, int brperm, int dlgt)
+{
+       int err, submask;
+       const int write_mask = (mask & (MAY_WRITE | MAY_APPEND));
+
+       LKTRTrace("ino %lu, mask 0x%x, brperm 0x%x\n",
+                 h_inode->i_ino, mask, brperm);
+
+       err = -EACCES;
+       if ((write_mask && IS_IMMUTABLE(h_inode))
+           || ((mask & MAY_EXEC) && S_ISREG(h_inode->i_mode)
+               && (h_mnt->mnt_flags & MNT_NOEXEC)))
+               goto out;
+
+       /*
+        * - skip hidden fs test in the case of write to ro branch.
+        * - nfs dir permission write check is optimized, but a policy for
+        *   link/rename requires a real check.
+        */
+       submask = mask & ~MAY_APPEND;
+       if ((write_mask && !au_br_writable(brperm))
+           || (au_test_nfs(h_inode->i_sb) && S_ISDIR(h_inode->i_mode)
+               && write_mask && !(mask & MAY_READ))
+           || !h_inode->i_op
+           || !h_inode->i_op->permission) {
+               /* LKTRLabel(generic_permission); */
+               err = generic_permission(h_inode, submask, NULL);
+       } else {
+               /* LKTRLabel(h_inode->permission); */
+               err = h_inode->i_op->permission(h_inode, submask);
+               AuTraceErr(err);
+       }
+
+#if 1 /* todo: export? */
+       if (!err)
+               err = au_security_inode_permission(h_inode, mask, NULL,
+                                                  dlgt);
+#endif
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+static int aufs_permission(struct inode *inode, int mask)
+{
+       int err;
+       aufs_bindex_t bindex, bend;
+       unsigned char dlgt;
+       const unsigned char isdir = S_ISDIR(inode->i_mode);
+       struct inode *h_inode;
+       struct super_block *sb;
+       unsigned int mnt_flags;
+       const int write_mask = (mask & (MAY_WRITE | MAY_APPEND));
+
+       LKTRTrace("ino %lu, mask 0x%x, isdir %d, write_mask %d\n",
+                 inode->i_ino, mask, isdir, write_mask);
+
+       sb = inode->i_sb;
+       si_read_lock(sb, AuLock_FLUSH);
+       ii_read_lock_child(inode);
+       mnt_flags = au_mntflags(sb);
+       dlgt = !!au_test_dlgt(mnt_flags);
+
+       if (!isdir || write_mask || au_test_dirperm1(mnt_flags)) {
+               h_inode = au_h_iptr(inode, au_ibstart(inode));
+               AuDebugOn(!h_inode
+                         || ((h_inode->i_mode & S_IFMT)
+                             != (inode->i_mode & S_IFMT)));
+               err = 0;
+               bindex = au_ibstart(inode);
+               LKTRTrace("b%d\n", bindex);
+               err = h_permission(h_inode, mask, au_sbr_mnt(sb, bindex),
+                                  au_sbr_perm(sb, bindex), dlgt);
+
+               if (write_mask && !err) {
+                       /* test whether the upper writable branch exists */
+                       err = -EROFS;
+                       for (; bindex >= 0; bindex--)
+                               if (!au_br_rdonly(au_sbr(sb, bindex))) {
+                                       err = 0;
+                                       break;
+                               }
+               }
+               goto out;
+       }
+
+       /* non-write to dir */
+       err = 0;
+       bend = au_ibend(inode);
+       for (bindex = au_ibstart(inode); !err && bindex <= bend; bindex++) {
+               h_inode = au_h_iptr(inode, bindex);
+               if (!h_inode)
+                       continue;
+               AuDebugOn(!S_ISDIR(h_inode->i_mode));
+
+               LKTRTrace("b%d\n", bindex);
+               err = h_permission(h_inode, mask, au_sbr_mnt(sb, bindex),
+                                  au_sbr_perm(sb, bindex), dlgt);
+       }
+
+ out:
+       ii_read_unlock(inode);
+       si_read_unlock(sb);
+       AuTraceErr(err);
+       if (unlikely(err == -EBUSY && au_test_nfsd(current)))
+               err = -ESTALE;
+       return err;
+}
+#else
+
+static int silly_lock(struct inode *inode, struct nameidata *nd)
+{
+       int locked = 0;
+       struct super_block *sb = inode->i_sb;
+
+       LKTRTrace("i%lu, nd %p\n", inode->i_ino, nd);
+
+       if (!nd || !nd->path.dentry) {
+               si_read_lock(sb, AuLock_FLUSH);
+               ii_read_lock_child(inode);
+       } else if (nd->path.dentry->d_inode != inode) {
+               locked = 1;
+               /* lock child first, then parent */
+               si_read_lock(sb, AuLock_FLUSH);
+               ii_read_lock_child(inode);
+               di_read_lock_parent(nd->path.dentry, 0);
+       } else {
+               locked = 2;
+               aufs_read_lock(nd->path.dentry, AuLock_FLUSH | AuLock_IR);
+       }
+       return locked;
+}
+
+static void silly_unlock(int locked, struct inode *inode, struct nameidata *nd)
+{
+       struct super_block *sb = inode->i_sb;
+
+       LKTRTrace("locked %d, i%lu, nd %p\n", locked, inode->i_ino, nd);
+
+       switch (locked) {
+       case 0:
+               ii_read_unlock(inode);
+               si_read_unlock(sb);
+               break;
+       case 1:
+               di_read_unlock(nd->path.dentry, 0);
+               ii_read_unlock(inode);
+               si_read_unlock(sb);
+               break;
+       case 2:
+               aufs_read_unlock(nd->path.dentry, AuLock_IR);
+               break;
+       default:
+               BUG();
+       }
+}
+
+static int h_permission(struct inode *h_inode, int mask,
+                       struct nameidata *fake_nd, int brperm, int dlgt)
+{
+       int err, submask;
+       const int write_mask = (mask & (MAY_WRITE | MAY_APPEND));
+
+       LKTRTrace("ino %lu, mask 0x%x, brperm 0x%x\n",
+                 h_inode->i_ino, mask, brperm);
+
+       err = -EACCES;
+       if ((write_mask && IS_IMMUTABLE(h_inode))
+           || ((mask & MAY_EXEC) && S_ISREG(h_inode->i_mode)
+               && fake_nd && fake_nd->path.mnt
+               && (fake_nd->path.mnt->mnt_flags & MNT_NOEXEC)))
+               goto out;
+
+       /*
+        * - skip hidden fs test in the case of write to ro branch.
+        * - nfs dir permission write check is optimized, but a policy for
+        *   link/rename requires a real check.
+        */
+       submask = mask & ~MAY_APPEND;
+       if ((write_mask && !au_br_writable(brperm))
+           || (au_test_nfs(h_inode->i_sb) && S_ISDIR(h_inode->i_mode)
+               && write_mask && !(mask & MAY_READ))
+           || !h_inode->i_op
+           || !h_inode->i_op->permission) {
+               /* LKTRLabel(generic_permission); */
+               err = generic_permission(h_inode, submask, NULL);
+       } else {
+               /* LKTRLabel(h_inode->permission); */
+               err = h_inode->i_op->permission(h_inode, submask, fake_nd);
+               AuTraceErr(err);
+       }
+
+#if 1 /* todo: export? */
+       if (!err)
+               err = au_security_inode_permission(h_inode, mask, fake_nd,
+                                                  dlgt);
+#endif
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+static int aufs_permission(struct inode *inode, int mask, struct nameidata *nd)
+{
+       int err;
+       aufs_bindex_t bindex, bend;
+       unsigned char locked, dlgt, do_nd;
+       const unsigned char isdir = S_ISDIR(inode->i_mode);
+       struct inode *h_inode;
+       struct super_block *sb;
+       unsigned int mnt_flags;
+       struct path path;
+       const int write_mask = (mask & (MAY_WRITE | MAY_APPEND));
+
+       LKTRTrace("ino %lu, mask 0x%x, isdir %d, write_mask %d, "
+                 "nd %d{%d, %d}\n",
+                 inode->i_ino, mask, isdir, write_mask,
+                 !!nd, nd ? !!nd->path.dentry : 0, nd ? !!nd->path.mnt : 0);
+
+       sb = inode->i_sb;
+       locked = silly_lock(inode, nd);
+       do_nd = (nd && locked >= 1);
+       mnt_flags = au_mntflags(sb);
+       dlgt = !!au_test_dlgt(mnt_flags);
+
+       if (!isdir || write_mask || au_test_dirperm1(mnt_flags)) {
+               h_inode = au_h_iptr(inode, au_ibstart(inode));
+               AuDebugOn(!h_inode
+                         || ((h_inode->i_mode & S_IFMT)
+                             != (inode->i_mode & S_IFMT)));
+               err = 0;
+               bindex = au_ibstart(inode);
+               LKTRTrace("b%d\n", bindex);
+               if (do_nd) {
+                       path = nd->path;
+                       nd->path.mnt = au_sbr_mnt(sb, bindex);
+                       nd->path.dentry = au_h_dptr(nd->path.dentry, bindex);
+                       path_get(&nd->path);
+                       err = h_permission(h_inode, mask, nd,
+                                          au_sbr_perm(sb, bindex), dlgt);
+                       path_put(&nd->path);
+                       nd->path = path;
+               } else {
+                       AuDebugOn(nd && nd->path.mnt);
+                       err = h_permission(h_inode, mask, nd,
+                                          au_sbr_perm(sb, bindex), dlgt);
+               }
+
+               if (write_mask && !err) {
+                       /* test whether the upper writable branch exists */
+                       err = -EROFS;
+                       for (; bindex >= 0; bindex--)
+                               if (!au_br_rdonly(au_sbr(sb, bindex))) {
+                                       err = 0;
+                                       break;
+                               }
+               }
+               goto out;
+       }
+
+       /* non-write to dir */
+       if (do_nd)
+               path = nd->path;
+       else {
+               path.mnt = NULL;
+               path.dentry = NULL;
+       }
+       err = 0;
+       bend = au_ibend(inode);
+       for (bindex = au_ibstart(inode); !err && bindex <= bend; bindex++) {
+               h_inode = au_h_iptr(inode, bindex);
+               if (!h_inode)
+                       continue;
+               AuDebugOn(!S_ISDIR(h_inode->i_mode));
+
+               LKTRTrace("b%d\n", bindex);
+               if (do_nd) {
+                       nd->path.mnt = au_sbr_mnt(sb, bindex);
+                       nd->path.dentry = au_h_dptr(path.dentry, bindex);
+                       path_get(&nd->path);
+                       err = h_permission(h_inode, mask, nd,
+                                          au_sbr_perm(sb, bindex), dlgt);
+                       path_put(&nd->path);
+               } else {
+                       AuDebugOn(nd && nd->path.mnt);
+                       err = h_permission(h_inode, mask, nd,
+                                          au_sbr_perm(sb, bindex), dlgt);
+               }
+       }
+       if (do_nd)
+               nd->path = path;
+
+ out:
+       silly_unlock(locked, inode, nd);
+       AuTraceErr(err);
+       if (unlikely(err == -EBUSY && au_test_nfsd(current)))
+               err = -ESTALE;
+       return err;
+}
+#endif /* KERNEL_VERSION(2, 6, 27) */
+
+/* ---------------------------------------------------------------------- */
+
+static struct dentry *aufs_lookup(struct inode *dir, struct dentry *dentry,
+                                 struct nameidata *nd)
+{
+       struct dentry *ret, *parent;
+       int err, npositive;
+       struct inode *inode, *h_inode;
+       struct nameidata tmp_nd, *ndp;
+       aufs_bindex_t bstart;
+       struct mutex *mtx;
+       struct super_block *sb;
+
+       LKTRTrace("dir %lu, %.*s, nd{0x%x}\n",
+                 dir->i_ino, AuDLNPair(dentry), nd ? nd->flags : 0);
+       AuDebugOn(IS_ROOT(dentry));
+       IMustLock(dir);
+
+       sb = dir->i_sb;
+       si_read_lock(sb, AuLock_FLUSH);
+       err = au_alloc_dinfo(dentry);
+       ret = ERR_PTR(err);
+       if (unlikely(err))
+               goto out;
+
+       /* nd can be NULL */
+       ndp = au_dup_nd(au_sbi(sb), &tmp_nd, nd);
+       parent = dentry->d_parent; /* dir inode is locked */
+       di_read_lock_parent(parent, AuLock_IR);
+       npositive = au_lkup_dentry(dentry, au_dbstart(parent), /*type*/0, ndp);
+       di_read_unlock(parent, AuLock_IR);
+       err = npositive;
+       ret = ERR_PTR(err);
+       if (unlikely(err < 0))
+               goto out_unlock;
+
+       inode = NULL;
+       if (npositive) {
+               bstart = au_dbstart(dentry);
+               h_inode = au_h_dptr(dentry, bstart)->d_inode;
+               AuDebugOn(!h_inode);
+               if (!S_ISDIR(h_inode->i_mode)) {
+                       /*
+                        * stop 'race'-ing between hardlinks under different
+                        * parents.
+                        */
+                       mtx = &au_sbr(sb, bstart)->br_xino.xi_nondir_mtx;
+                       mutex_lock(mtx);
+                       inode = au_new_inode(dentry, /*must_new*/0);
+                       mutex_unlock(mtx);
+               } else
+                       inode = au_new_inode(dentry, /*must_new*/0);
+               ret = (void *)inode;
+       }
+       if (!IS_ERR(inode)) {
+               ret = d_splice_alias(inode, dentry);
+               if (unlikely(IS_ERR(ret) && inode))
+                       ii_write_unlock(inode);
+               AuDebugOn(nd
+                         && (nd->flags & LOOKUP_OPEN)
+                         && nd->intent.open.file
+                         && nd->intent.open.file->f_dentry);
+               au_store_fmode_exec(nd, inode);
+       }
+
+ out_unlock:
+       di_write_unlock(dentry);
+ out:
+       si_read_unlock(sb);
+       AuTraceErrPtr(ret);
+       if (unlikely(err == -EBUSY && au_test_nfsd(current)))
+               err = -ESTALE;
+       return ret;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * decide the branch and the parent dir where we will create a new entry.
+ * returns new bindex or an error.
+ * copyup the parent dir if needed.
+ */
+int au_wr_dir(struct dentry *dentry, struct dentry *src_dentry,
+             struct au_wr_dir_args *args)
+{
+       int err;
+       aufs_bindex_t bcpup, bstart, src_bstart;
+       struct super_block *sb;
+       struct dentry *parent;
+       struct au_sbinfo *sbinfo;
+       const int add_entry = au_ftest_wrdir(args->flags, ADD_ENTRY);
+
+       LKTRTrace("%.*s, src %p, {%d, 0x%x}\n",
+                 AuDLNPair(dentry), src_dentry, args->force_btgt, args->flags);
+
+       sb = dentry->d_sb;
+       sbinfo = au_sbi(sb);
+       parent = dget_parent(dentry);
+       bstart = au_dbstart(dentry);
+       bcpup = bstart;
+       if (args->force_btgt < 0) {
+               if (src_dentry) {
+                       src_bstart = au_dbstart(src_dentry);
+                       if (src_bstart < bstart)
+                               bcpup = src_bstart;
+               } else if (add_entry) {
+                       err = AuWbrCreate(sbinfo, dentry,
+                                         au_ftest_wrdir(args->flags, ISDIR));
+                       bcpup = err;
+               }
+
+               if (bcpup < 0 || au_test_ro(sb, bcpup, dentry->d_inode)) {
+                       if (add_entry)
+                               err = AuWbrCopyup(sbinfo, dentry);
+                       else {
+                               if (!IS_ROOT(dentry)) {
+                                       di_read_lock_parent(parent, !AuLock_IR);
+                                       err = AuWbrCopyup(sbinfo, dentry);
+                                       di_read_unlock(parent, !AuLock_IR);
+                               } else
+                                       err = AuWbrCopyup(sbinfo, dentry);
+                       }
+                       bcpup = err;
+                       if (unlikely(err < 0))
+                               goto out;
+               }
+       } else {
+               bcpup = args->force_btgt;
+               AuDebugOn(au_test_ro(sb, bcpup, dentry->d_inode));
+       }
+       LKTRTrace("bstart %d, bcpup %d\n", bstart, bcpup);
+       if (bstart < bcpup)
+               au_update_dbrange(dentry, /*do_put_zero*/1);
+
+       err = bcpup;
+       if (bcpup == bstart)
+               goto out; /* success */
+
+       /* copyup the new parent into the branch we process */
+       if (add_entry) {
+               au_update_dbstart(dentry);
+               IMustLock(parent->d_inode);
+               DiMustWriteLock(parent);
+               IiMustWriteLock(parent->d_inode);
+       } else
+               di_write_lock_parent(parent);
+
+       err = 0;
+       if (!au_h_dptr(parent, bcpup)) {
+               if (bstart < bcpup)
+                       err = au_cpdown_dirs(dentry, bcpup);
+               else
+                       err = au_cpup_dirs(dentry, bcpup);
+       }
+       if (!err && add_entry) {
+               struct dentry *h_parent;
+               struct inode *h_dir;
+
+               h_parent = au_h_dptr(parent, bcpup);
+               AuDebugOn(!h_parent);
+               h_dir = h_parent->d_inode;
+               AuDebugOn(!h_dir);
+               mutex_lock_nested(&h_dir->i_mutex, AuLsc_I_PARENT);
+               err = au_lkup_neg(dentry, bcpup);
+               mutex_unlock(&h_dir->i_mutex);
+               if (bstart < bcpup && au_dbstart(dentry) < 0) {
+                       au_set_dbstart(dentry, 0);
+                       au_update_dbrange(dentry, /*do_put_zero*/0);
+               }
+       }
+
+       if (!add_entry)
+               di_write_unlock(parent);
+       if (!err)
+               err = bcpup; /* success */
+ out:
+       dput(parent);
+       LKTRTrace("err %d\n", err);
+       AuTraceErr(err);
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+struct dentry *au_do_pinned_h_parent(struct au_pin1 *pin)
+{
+       if (pin && pin->parent)
+               return au_h_dptr(pin->parent, pin->bindex);
+       return NULL;
+}
+
+void au_do_unpin(struct au_pin1 *p, struct au_pin1 *gp)
+{
+       if (p->dentry)
+               LKTRTrace("%.*s\n", AuDLNPair(p->dentry));
+       LKTRTrace("p{%d, %d, %d, %d, 0x%x}, gp %p\n",
+                 p->lsc_di, p->lsc_hi, !!p->parent, !!p->h_dir, p->flags, gp);
+
+       if (au_ftest_pin(p->flags, MNT_WRITE))
+               au_br_drop_write(au_sbr(p->dentry->d_sb, p->bindex));
+       if (au_ftest_pin(p->flags, VFS_RENAME))
+               vfsub_unlock_rename_mutex(au_sbr_sb(p->dentry->d_sb,
+                                                   p->bindex));
+       if (!p->h_dir)
+               return;
+
+       mutex_unlock(&p->h_dir->i_mutex);
+       if (gp)
+               au_do_unpin(gp, NULL);
+       if (!au_ftest_pin(p->flags, DI_LOCKED))
+               di_read_unlock(p->parent, AuLock_IR);
+       iput(p->h_dir);
+       dput(p->parent);
+       p->parent = NULL;
+       p->h_dir = NULL;
+}
+
+int au_do_pin(struct au_pin1 *p, struct au_pin1 *gp)
+{
+       int err;
+       struct dentry *h_dentry;
+
+       LKTRTrace("%.*s, %d, b%d, 0x%x\n",
+                 AuDLNPair(p->dentry), !!gp, p->bindex, p->flags);
+       AuDebugOn(au_ftest_pin(p->flags, DO_GPARENT) && !gp);
+       /* AuDebugOn(!do_gp && gp); */
+
+       err = 0;
+       if (IS_ROOT(p->dentry)) {
+               if (au_ftest_pin(p->flags, VFS_RENAME))
+                       vfsub_lock_rename_mutex(au_sbr_sb(p->dentry->d_sb,
+                                                         p->bindex));
+               if (au_ftest_pin(p->flags, MNT_WRITE)) {
+                       err = au_br_want_write(au_sbr(p->dentry->d_sb,
+                                                     p->bindex));
+                       if (unlikely(err))
+                               au_fclr_pin(p->flags, MNT_WRITE);
+               }
+               goto out;
+       }
+
+       h_dentry = NULL;
+       if (p->bindex <= au_dbend(p->dentry))
+               h_dentry = au_h_dptr(p->dentry, p->bindex);
+
+       p->parent = dget_parent(p->dentry);
+       if (!au_ftest_pin(p->flags, DI_LOCKED))
+               di_read_lock(p->parent, AuLock_IR, p->lsc_di);
+       else
+               DiMustAnyLock(p->parent);
+       AuDebugOn(!p->parent->d_inode);
+       p->h_dir = au_igrab(au_h_iptr(p->parent->d_inode, p->bindex));
+       /* udba case */
+       if (unlikely(au_ftest_pin(p->flags, VERIFY) && !p->h_dir)) {
+               err = -EIO;
+               if (!au_ftest_pin(p->flags, DI_LOCKED))
+                       di_read_unlock(p->parent, AuLock_IR);
+               dput(p->parent);
+               p->parent = NULL;
+               goto out;
+       }
+
+       if (au_ftest_pin(p->flags, DO_GPARENT)) {
+               gp->dentry = p->parent;
+               err = au_do_pin(gp, NULL);
+               if (unlikely(err))
+                       gp->dentry = NULL;
+       }
+       if (au_ftest_pin(p->flags, VFS_RENAME))
+               vfsub_lock_rename_mutex(p->h_dir->i_sb);
+       mutex_lock_nested(&p->h_dir->i_mutex, p->lsc_hi);
+       if (!err) {
+               /* todo: call d_revalidate() here? */
+#if 0
+               if (h_dentry && h_dentry->d_op && h_dentry->d_op->d_revalidate
+                   && !h_dentry->d_op->d_revalidate(h_dentry, NULL))
+                       err = -EIO;
+#endif
+               if (!h_dentry
+                   || !au_ftest_pin(p->flags, VERIFY)
+                   || !au_verify_parent(h_dentry, p->h_dir)) {
+                       if (au_ftest_pin(p->flags, MNT_WRITE)) {
+                               err = au_br_want_write(au_sbr(p->dentry->d_sb,
+                                                             p->bindex));
+                               if (unlikely(err))
+                                       au_fclr_pin(p->flags, MNT_WRITE);
+                       }
+                       if (!err)
+                               goto out; /* success */
+               } else
+                       err = -EIO;
+       }
+
+       AuDbgDentry(p->dentry);
+       AuDbgDentry(h_dentry);
+       AuDbgDentry(p->parent);
+       AuDbgInode(p->h_dir);
+       if (h_dentry)
+               AuDbgDentry(h_dentry->d_parent);
+
+       au_do_unpin(p, gp);
+       if (au_ftest_pin(p->flags, DO_GPARENT))
+               gp->dentry = NULL;
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+void au_pin_init(struct au_pin *args, struct dentry *dentry,
+                aufs_bindex_t bindex, int lsc_di, int lsc_hi,
+                unsigned char flags)
+{
+       struct au_pin1 *p;
+       unsigned char f;
+
+       AuTraceEnter();
+
+       memset(args, 0, sizeof(*args));
+       p = args->pin + AuPin_PARENT;
+       p->dentry = dentry;
+       p->lsc_di = lsc_di;
+       p->lsc_hi = lsc_hi;
+       p->flags = flags;
+       p->bindex = bindex;
+       if (!au_opt_test(au_mntflags(dentry->d_sb), UDBA_NONE))
+               au_fset_pin(p->flags, VERIFY);
+       if (!au_ftest_pin(flags, DO_GPARENT))
+               return;
+
+       f = p->flags;
+       p = au_pin_gp(args);
+       if (p) {
+               p->lsc_di = lsc_di + 1; /* child first */
+               p->lsc_hi = lsc_hi - 1; /* parent first */
+               p->bindex = bindex;
+               p->flags = f & ~(AuPin_MNT_WRITE
+                               | AuPin_DO_GPARENT
+                               | AuPin_DI_LOCKED);
+       }
+}
+
+int au_pin(struct au_pin *args, struct dentry *dentry, aufs_bindex_t bindex,
+          unsigned char flags)
+{
+       LKTRTrace("%.*s, b%d, 0x%x\n",
+                 AuDLNPair(dentry), bindex, flags);
+
+       au_pin_init(args, dentry, bindex, AuLsc_DI_PARENT, AuLsc_I_PARENT2,
+                   flags);
+       return au_do_pin(args->pin + AuPin_PARENT, au_pin_gp(args));
+}
+
+/* ---------------------------------------------------------------------- */
+
+struct au_icpup_args {
+       unsigned char isdir, hinotify, did_cpup; /* flags */
+       unsigned char pin_flags;
+       aufs_bindex_t btgt;
+       struct au_pin pin;
+       struct au_hin_ignore ign[2];
+       struct vfsub_args vargs;
+       struct dentry *h_dentry;
+       struct inode *h_inode;
+};
+
+/* todo: refine it */
+static int au_lock_and_icpup(struct dentry *dentry, loff_t sz,
+                            struct au_icpup_args *a)
+{
+       int err;
+       aufs_bindex_t bstart;
+       struct super_block *sb;
+       struct dentry *hi_wh, *parent;
+       struct inode *inode;
+       struct au_wr_dir_args wr_dir_args = {
+               .force_btgt     = -1,
+               .flags          = 0
+       };
+
+       LKTRTrace("%.*s, %lld\n", AuDLNPair(dentry), sz);
+
+       di_write_lock_child(dentry);
+       bstart = au_dbstart(dentry);
+       sb = dentry->d_sb;
+       inode = dentry->d_inode;
+       a->isdir = !!S_ISDIR(inode->i_mode);
+       if (a->isdir)
+               au_fset_wrdir(wr_dir_args.flags, ISDIR);
+       /* plink or hi_wh() */
+       if (bstart != au_ibstart(inode))
+               wr_dir_args.force_btgt = au_ibstart(inode);
+       err = au_wr_dir(dentry, /*src_dentry*/NULL, &wr_dir_args);
+       if (unlikely(err < 0))
+               goto out_dentry;
+       a->btgt = err;
+       a->did_cpup = (err != bstart);
+       err = 0;
+
+       /* crazy udba locks */
+       a->pin_flags = AuPin_MNT_WRITE;
+       a->hinotify = !!au_opt_test(au_mntflags(sb), UDBA_INOTIFY);
+       if (a->hinotify)
+               au_fset_pin(a->pin_flags, DO_GPARENT);
+       parent = NULL;
+       if (!IS_ROOT(dentry)) {
+               au_fset_pin(a->pin_flags, DI_LOCKED);
+               parent = dget_parent(dentry);
+               di_write_lock_parent(parent);
+       }
+       err = au_pin(&a->pin, dentry, a->btgt, a->pin_flags);
+       if (unlikely(err)) {
+               if (parent) {
+                       di_write_unlock(parent);
+                       dput(parent);
+               }
+               goto out_dentry;
+       }
+       a->h_dentry = au_h_dptr(dentry, bstart);
+       a->h_inode = a->h_dentry->d_inode;
+       AuDebugOn(!a->h_inode);
+       mutex_lock_nested(&a->h_inode->i_mutex, AuLsc_I_CHILD);
+       if (!a->did_cpup) {
+               au_unpin_gp(&a->pin);
+               if (parent) {
+                       au_pin_set_parent_lflag(&a->pin, /*lflag*/0);
+                       di_downgrade_lock(parent, AuLock_IR);
+                       dput(parent);
+               }
+               goto out; /* success */
+       }
+
+       hi_wh = NULL;
+       if (!d_unhashed(dentry)) {
+               if (parent) {
+                       au_pin_set_parent_lflag(&a->pin, /*lflag*/0);
+                       di_downgrade_lock(parent, AuLock_IR);
+                       dput(parent);
+               }
+               err = au_sio_cpup_simple(dentry, a->btgt, sz, AuCpup_DTIME);
+               if (!err)
+                       a->h_dentry = au_h_dptr(dentry, a->btgt);
+       } else {
+               hi_wh = au_hi_wh(inode, a->btgt);
+               if (!hi_wh) {
+                       err = au_sio_cpup_wh(dentry, a->btgt, sz,
+                                            /*file*/NULL);
+                       if (!err)
+                               hi_wh = au_hi_wh(inode, a->btgt);
+                       /* todo: revalidate hi_wh? */
+               }
+               if (parent) {
+                       au_pin_set_parent_lflag(&a->pin, /*lflag*/0);
+                       di_downgrade_lock(parent, AuLock_IR);
+                       dput(parent);
+               }
+               if (!hi_wh)
+                       a->h_dentry = au_h_dptr(dentry, a->btgt);
+               else
+                       a->h_dentry = hi_wh; /* do not dget here */
+       }
+
+       mutex_unlock(&a->h_inode->i_mutex);
+       a->h_inode = a->h_dentry->d_inode;
+       AuDebugOn(!a->h_inode);
+       if (!err) {
+               mutex_lock_nested(&a->h_inode->i_mutex, AuLsc_I_CHILD);
+               au_unpin_gp(&a->pin);
+               goto out; /* success */
+       }
+
+       au_unpin(&a->pin);
+
+ out_dentry:
+       di_write_unlock(dentry);
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+static int aufs_setattr(struct dentry *dentry, struct iattr *ia)
+{
+       int err;
+       struct inode *inode;
+       struct super_block *sb;
+       __u32 events;
+       struct file *file;
+       loff_t sz;
+       struct au_icpup_args *a;
+
+       LKTRTrace("%.*s\n", AuDLNPair(dentry));
+       inode = dentry->d_inode;
+       IMustLock(inode);
+
+       err = -ENOMEM;
+       a = kzalloc(sizeof(*a), GFP_NOFS);
+       if (unlikely(!a))
+               goto out;
+
+       file = NULL;
+       sb = dentry->d_sb;
+       si_read_lock(sb, AuLock_FLUSH);
+       vfsub_args_init(&a->vargs, a->ign, au_test_dlgt(au_mntflags(sb)), 0);
+
+       if (ia->ia_valid & ATTR_FILE) {
+               /* currently ftruncate(2) only */
+               file = ia->ia_file;
+               fi_write_lock(file);
+               ia->ia_file = au_h_fptr(file, au_fbstart(file));
+       }
+
+       sz = -1;
+       if ((ia->ia_valid & ATTR_SIZE)
+           && ia->ia_size < i_size_read(inode))
+               sz = ia->ia_size;
+       err = au_lock_and_icpup(dentry, sz, a);
+       if (unlikely(err < 0))
+               goto out_si;
+       if (a->did_cpup) {
+               ia->ia_file = NULL;
+               ia->ia_valid &= ~ATTR_FILE;
+       }
+
+       if ((ia->ia_valid & ATTR_SIZE)
+           && ia->ia_size < i_size_read(inode)) {
+               err = vmtruncate(inode, ia->ia_size);
+               if (unlikely(err))
+                       goto out_unlock;
+       }
+
+       if (ia->ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
+               ia->ia_valid &= ~ATTR_MODE;
+
+       events = 0;
+       if (a->hinotify) {
+               events = vfsub_events_notify_change(ia);
+               if (events) {
+                       if (a->isdir)
+                               vfsub_ign_hinode(&a->vargs, events,
+                                                au_hi(inode, a->btgt));
+                       vfsub_ign_hinode(&a->vargs, events,
+                                        au_pinned_hdir(&a->pin));
+               }
+       }
+       err = vfsub_notify_change(a->h_dentry, ia, &a->vargs);
+       if (!err)
+               au_cpup_attr_changeable(inode);
+
+ out_unlock:
+       mutex_unlock(&a->h_inode->i_mutex);
+       au_unpin(&a->pin);
+       di_write_unlock(dentry);
+ out_si:
+       if (file) {
+               fi_write_unlock(file);
+               ia->ia_file = file;
+               ia->ia_valid |= ATTR_FILE;
+       }
+       si_read_unlock(sb);
+       kfree(a);
+ out:
+       AuTraceErr(err);
+       if (unlikely(err == -EBUSY && au_test_nfsd(current)))
+               err = -ESTALE;
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static int h_readlink(struct dentry *dentry, int bindex, char __user *buf,
+                     int bufsiz)
+{
+       struct super_block *sb;
+       struct dentry *h_dentry;
+
+       LKTRTrace("%.*s, b%d, %d\n", AuDLNPair(dentry), bindex, bufsiz);
+
+       h_dentry = au_h_dptr(dentry, bindex);
+       if (unlikely(/* !h_dentry
+                       || !h_dentry->d_inode
+                       || */
+                   !h_dentry->d_inode->i_op
+                   || !h_dentry->d_inode->i_op->readlink))
+               return -EINVAL;
+
+       sb = dentry->d_sb;
+       if (!au_test_ro(sb, bindex, dentry->d_inode)) {
+               touch_atime(au_sbr_mnt(sb, bindex), h_dentry);
+               au_update_fuse_h_inode(NULL, h_dentry); /*ignore*/
+               fsstack_copy_attr_atime(dentry->d_inode, h_dentry->d_inode);
+       }
+       return h_dentry->d_inode->i_op->readlink(h_dentry, buf, bufsiz);
+}
+
+static int aufs_readlink(struct dentry *dentry, char __user *buf, int bufsiz)
+{
+       int err;
+
+       LKTRTrace("%.*s, %d\n", AuDLNPair(dentry), bufsiz);
+
+       aufs_read_lock(dentry, AuLock_IR);
+       err = h_readlink(dentry, au_dbstart(dentry), buf, bufsiz);
+       aufs_read_unlock(dentry, AuLock_IR);
+       AuTraceErr(err);
+       if (unlikely(err == -EBUSY && au_test_nfsd(current)))
+               err = -ESTALE;
+       return err;
+}
+
+static void *aufs_follow_link(struct dentry *dentry, struct nameidata *nd)
+{
+       int err;
+       char *buf;
+       mm_segment_t old_fs;
+
+       LKTRTrace("%.*s, nd %.*s\n",
+                 AuDLNPair(dentry), AuDLNPair(nd->path.dentry));
+
+       err = -ENOMEM;
+       buf = __getname();
+       if (unlikely(!buf))
+               goto out;
+
+       aufs_read_lock(dentry, AuLock_IR);
+       old_fs = get_fs();
+       set_fs(KERNEL_DS);
+       err = h_readlink(dentry, au_dbstart(dentry), (char __user *)buf,
+                        PATH_MAX);
+       set_fs(old_fs);
+       aufs_read_unlock(dentry, AuLock_IR);
+
+       if (err >= 0) {
+               buf[err] = 0;
+               /* will be freed by put_link */
+               nd_set_link(nd, buf);
+               return NULL; /* success */
+       }
+       __putname(buf);
+
+ out:
+       path_put(&nd->path);
+       AuTraceErr(err);
+       if (unlikely(err == -EBUSY && au_test_nfsd(current)))
+               err = -ESTALE;
+       return ERR_PTR(err);
+}
+
+static void aufs_put_link(struct dentry *dentry, struct nameidata *nd,
+                         void *cookie)
+{
+       LKTRTrace("%.*s\n", AuDLNPair(dentry));
+       __putname(nd_get_link(nd));
+}
+
+/* ---------------------------------------------------------------------- */
+
+static void aufs_truncate_range(struct inode *inode, loff_t start, loff_t end)
+{
+       AuUnsupport();
+}
+
+/* ---------------------------------------------------------------------- */
+
+struct inode_operations aufs_symlink_iop = {
+       .permission     = aufs_permission,
+       .setattr        = aufs_setattr,
+#ifdef CONFIG_AUFS_GETATTR
+       .getattr        = aufs_getattr,
+#endif
+
+       .readlink       = aufs_readlink,
+       .follow_link    = aufs_follow_link,
+       .put_link       = aufs_put_link
+};
+
+struct inode_operations aufs_dir_iop = {
+       .create         = aufs_create,
+       .lookup         = aufs_lookup,
+       .link           = aufs_link,
+       .unlink         = aufs_unlink,
+       .symlink        = aufs_symlink,
+       .mkdir          = aufs_mkdir,
+       .rmdir          = aufs_rmdir,
+       .mknod          = aufs_mknod,
+       .rename         = aufs_rename,
+
+       .permission     = aufs_permission,
+       .setattr        = aufs_setattr,
+#ifdef CONFIG_AUFS_GETATTR
+       .getattr        = aufs_getattr,
+#endif
+
+#if 0 /* reserved for future use */
+       .setxattr       = aufs_setxattr,
+       .getxattr       = aufs_getxattr,
+       .listxattr      = aufs_listxattr,
+       .removexattr    = aufs_removexattr
+#endif
+};
+
+struct inode_operations aufs_iop = {
+       .permission     = aufs_permission,
+       .setattr        = aufs_setattr,
+#ifdef CONFIG_AUFS_GETATTR
+       .getattr        = aufs_getattr,
+#endif
+
+#if 0 /* reserved for future use */
+       .setxattr       = aufs_setxattr,
+       .getxattr       = aufs_getxattr,
+       .listxattr      = aufs_listxattr,
+       .removexattr    = aufs_removexattr,
+#endif
+
+       .truncate_range = aufs_truncate_range
+};
diff -urN linux/fs/aufs/i_op_del.c linux-aufs/fs/aufs/i_op_del.c
--- linux/fs/aufs/i_op_del.c    1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/i_op_del.c       2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,566 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * inode operations (del entry)
+ *
+ * $Id$
+ */
+
+#include "aufs.h"
+
+/* returns,
+ * 0: wh is unnecessary
+ * plus: wh is necessary
+ * minus: error
+ */
+int au_wr_dir_need_wh(struct dentry *dentry, int isdir, aufs_bindex_t *bcpup)
+{
+       int need_wh, err;
+       aufs_bindex_t bstart;
+       struct dentry *h_dentry;
+       struct super_block *sb;
+
+       LKTRTrace("%.*s, isdir %d, *bcpup %d\n",
+                 AuDLNPair(dentry), isdir, *bcpup);
+       sb = dentry->d_sb;
+
+       bstart = au_dbstart(dentry);
+       LKTRTrace("bcpup %d, bstart %d\n", *bcpup, bstart);
+       h_dentry = au_h_dptr(dentry, bstart);
+       if (*bcpup < 0) {
+               *bcpup = bstart;
+               if (au_test_ro(sb, bstart, dentry->d_inode)) {
+                       err = AuWbrCopyup(au_sbi(sb), dentry);
+                       *bcpup = err;
+                       if (unlikely(err < 0))
+                               goto out;
+               }
+       } else
+               AuDebugOn(bstart < *bcpup
+                         || au_test_ro(sb, *bcpup, dentry->d_inode));
+       LKTRTrace("bcpup %d, bstart %d\n", *bcpup, bstart);
+
+       if (*bcpup != bstart) {
+               err = au_cpup_dirs(dentry, *bcpup);
+               if (unlikely(err))
+                       goto out;
+               need_wh = 1;
+       } else {
+               aufs_bindex_t old_bend, new_bend, bdiropq = -1;
+               old_bend = au_dbend(dentry);
+               if (isdir) {
+                       bdiropq = au_dbdiropq(dentry);
+                       au_set_dbdiropq(dentry, -1);
+               }
+               need_wh = au_lkup_dentry(dentry, bstart + 1, /*type*/0,
+                                        /*nd*/NULL);
+               err = need_wh;
+               if (isdir)
+                       au_set_dbdiropq(dentry, bdiropq);
+               if (unlikely(err < 0))
+                       goto out;
+               new_bend = au_dbend(dentry);
+               if (!need_wh && old_bend != new_bend) {
+                       au_set_h_dptr(dentry, new_bend, NULL);
+                       au_set_dbend(dentry, old_bend);
+#if 0 /* todo: remove this? */
+               } else if (!au_h_dptr(dentry, new_bend)->d_inode) {
+                       LKTRTrace("negative\n");
+                       au_set_h_dptr(dentry, new_bend, NULL);
+                       au_set_dbend(dentry, old_bend);
+                       need_wh = 0;
+#endif
+               }
+       }
+       LKTRTrace("need_wh %d\n", need_wh);
+       err = need_wh;
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+/*
+ * simple tests for the removal inode operations.
+ * following the checks in vfs, plus the parent-child relationship.
+ */
+int au_may_del(struct dentry *dentry, aufs_bindex_t bindex,
+              struct dentry *h_parent, int isdir, struct au_ndx *ndx)
+{
+       int err, exist;
+       struct super_block *sb;
+       struct dentry *h_dentry;
+       struct inode *h_inode;
+       umode_t h_mode;
+
+       LKTRTrace("%.*s/%.*s, b%d, dir %d\n",
+                 AuDLNPair(h_parent), AuDLNPair(dentry), bindex, isdir);
+
+       sb = dentry->d_sb;
+       exist = !!dentry->d_inode;
+       h_dentry = au_h_dptr(dentry, bindex);
+       h_inode = h_dentry->d_inode;
+       if (exist) {
+               err = -ENOENT;
+               if (unlikely(!h_inode || !h_inode->i_nlink))
+                       goto out;
+
+               h_mode = h_inode->i_mode;
+               if (!isdir) {
+                       err = -EISDIR;
+                       if (unlikely(S_ISDIR(h_mode)))
+                               goto out;
+               } else if (unlikely(!S_ISDIR(h_mode))) {
+                       err = -ENOTDIR;
+                       goto out;
+               }
+       } else {
+               /* rename(2) case */
+               err = -EIO;
+               if (unlikely(h_inode))
+                       goto out;
+       }
+
+       err = -ENOENT;
+       /* expected parent dir is locked */
+       if (unlikely(h_parent != h_dentry->d_parent))
+               goto out;
+       err = 0;
+
+       /*
+        * some filesystem may unlink a dir and corrupt its consistency.
+        * so let's try heavy test.
+        */
+       if (1 /*au_opt_test(au_mntflags(sb), UDBA_INOTIFY)*/) {
+               struct dentry *h_latest;
+               struct qstr *qstr = &dentry->d_name;
+
+               err = -EACCES;
+               if (unlikely(au_test_h_perm(h_parent->d_inode,
+                                           MAY_EXEC | MAY_WRITE,
+                                           au_ftest_ndx(ndx->flags, DLGT))))
+                       goto out;
+
+               h_latest = au_sio_lkup_one(qstr->name, h_parent, qstr->len,
+                                          ndx);
+               err = -EIO;
+               if (IS_ERR(h_latest))
+                       goto out;
+               dput(h_latest);
+               if (h_latest == h_dentry)
+                       err = 0;
+       }
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+static struct dentry *
+lock_hdir_create_wh(struct dentry *dentry, int isdir, aufs_bindex_t *rbcpup,
+                   struct au_dtime *dt, struct au_pin *pin)
+{
+       struct dentry *wh_dentry, *h_parent;
+       struct super_block *sb;
+       int err, need_wh;
+       unsigned int mnt_flags;
+       unsigned char pin_flags;
+       aufs_bindex_t bcpup;
+       struct au_ndx ndx;
+
+       LKTRTrace("%.*s, isdir %d\n", AuDLNPair(dentry), isdir);
+
+       need_wh = au_wr_dir_need_wh(dentry, isdir, rbcpup);
+       err = need_wh;
+       wh_dentry = ERR_PTR(err);
+       if (unlikely(err < 0))
+               goto out;
+
+       sb = dentry->d_sb;
+       mnt_flags = au_mntflags(sb);
+       bcpup = *rbcpup;
+       pin_flags = AuPin_DI_LOCKED | AuPin_MNT_WRITE;
+       if (au_opt_test(mnt_flags, UDBA_INOTIFY))
+               au_fset_pin(pin_flags, DO_GPARENT);
+       err = au_pin(pin, dentry, bcpup, pin_flags);
+       wh_dentry = ERR_PTR(err);
+       if (unlikely(err))
+               goto out;
+       h_parent = au_pinned_h_parent(pin);
+       if (!au_opt_test(mnt_flags, UDBA_NONE) && au_dbstart(dentry) == bcpup) {
+               ndx.nfsmnt = au_nfsmnt(sb, bcpup);
+               ndx.flags = 0;
+               if (au_test_dlgt(mnt_flags))
+                       au_fset_ndx(ndx.flags, DLGT);
+               ndx.nd = NULL;
+               /* ndx.br = au_sbr(sb, bcpup); */
+               /* ndx.nd_file = NULL; */
+               err = au_may_del(dentry, bcpup, h_parent, isdir, &ndx);
+               wh_dentry = ERR_PTR(err);
+               if (unlikely(err))
+                       goto out_unpin;
+       }
+
+       au_dtime_store(dt, au_pinned_parent(pin), h_parent, au_pinned_hdir(pin),
+                      au_pinned_hgdir(pin));
+       wh_dentry = NULL;
+       if (!need_wh)
+               goto out; /* success, no need to create whiteout */
+
+       ndx.nfsmnt = au_nfsmnt(sb, bcpup);
+       ndx.flags = 0;
+       if (au_test_dlgt(mnt_flags))
+               au_fset_ndx(ndx.flags, DLGT);
+       ndx.nd = NULL;
+       /* ndx.br = NULL; */
+       wh_dentry = au_wh_create(dentry, bcpup, h_parent, &ndx);
+       if (!IS_ERR(wh_dentry))
+               goto out; /* success */
+       /* returns with the parent is locked and wh_dentry is DGETed */
+
+ out_unpin:
+       au_unpin(pin);
+ out:
+       AuTraceErrPtr(wh_dentry);
+       return wh_dentry;
+}
+
+static int renwh_and_rmdir(struct dentry *dentry, aufs_bindex_t bindex,
+                          struct au_nhash *whlist, struct inode *dir)
+{
+       int rmdir_later, err;
+       struct dentry *h_dentry;
+       struct inode *inode, *h_inode;
+       struct super_block *sb;
+
+       LKTRTrace("%.*s, b%d\n", AuDLNPair(dentry), bindex);
+
+       inode = NULL;
+       h_inode = NULL;
+       sb = dentry->d_sb;
+       if (au_opt_test(au_mntflags(sb), UDBA_INOTIFY)) {
+               inode = dentry->d_inode;
+               h_inode = au_h_iptr(inode, bindex);
+               mutex_lock_nested(&h_inode->i_mutex, AuLsc_I_CHILD);
+       }
+       h_dentry = au_h_dptr(dentry, bindex);
+       err = au_whtmp_ren(dir, bindex, h_dentry);
+       if (inode) {
+               /* todo: bad approach? */
+               if (!err)
+                       au_hin_suspend(au_hi(inode, bindex));
+               mutex_unlock(&h_inode->i_mutex);
+       }
+       if (unlikely(err))
+               goto out;
+
+       if (!au_test_nfs(h_dentry->d_sb)) {
+               const int dirwh = au_sbi(sb)->si_dirwh;
+               rmdir_later = (dirwh <= 1);
+               if (!rmdir_later)
+                       rmdir_later = au_nhash_test_longer_wh(whlist, bindex,
+                                                             dirwh);
+               if (rmdir_later)
+                       return rmdir_later;
+       }
+
+       err = au_whtmp_rmdir(dir, bindex, h_dentry, whlist);
+       if (unlikely(err)) {
+               AuIOErr("rmdir %.*s, b%d failed, %d. ignored\n",
+                       AuDLNPair(h_dentry), bindex, err);
+               /* we do not revert the inotify watch */
+               err = 0;
+       }
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+static void epilog(struct inode *dir, struct dentry *dentry,
+                  aufs_bindex_t bindex)
+{
+       /* todo: unnecessary? */
+       d_drop(dentry);
+       dentry->d_inode->i_ctime = dir->i_ctime;
+
+       if (atomic_read(&dentry->d_count) == 1) {
+               au_set_h_dptr(dentry, au_dbstart(dentry), NULL);
+               au_update_dbstart(dentry);
+       }
+       if (au_ibstart(dir) == bindex)
+               au_cpup_attr_timesizes(dir);
+       dir->i_version++;
+}
+
+/* revert flags */
+#define AuRev_DLGT     1
+#define au_ftest_rev(flags, name)      ((flags) & AuRev_##name)
+#define au_fset_rev(flags, name)       { (flags) |= AuRev_##name; }
+#define au_fclr_rev(flags, name)       { (flags) &= ~AuRev_##name; }
+#ifndef CONFIG_AUFS_DLGT
+#undef AuRev_DLGT
+#define AuRev_DLGT     0
+#endif
+
+static int do_revert(int err, struct inode *dir, aufs_bindex_t bwh,
+                    struct dentry *wh_dentry, struct dentry *dentry,
+                    struct au_dtime *dt, unsigned int flags)
+{
+       int rerr;
+
+       rerr = au_wh_unlink_dentry(au_hi(dir, bwh), wh_dentry, dentry,
+                                  au_ftest_rev(flags, DLGT));
+       if (!rerr) {
+               au_set_dbwh(dentry, bwh);
+               au_dtime_revert(dt);
+               return 0;
+       }
+
+       AuIOErr("%.*s reverting whiteout failed(%d, %d)\n",
+               AuDLNPair(dentry), err, rerr);
+       return -EIO;
+}
+
+/* ---------------------------------------------------------------------- */
+
+int aufs_unlink(struct inode *dir, struct dentry *dentry)
+{
+       int err;
+       struct inode *inode, *h_dir;
+       struct dentry *parent, *wh_dentry, *h_dentry;
+       struct au_dtime dt;
+       aufs_bindex_t bwh, bindex, bstart;
+       unsigned char dlgt;
+       struct super_block *sb;
+       struct au_hin_ignore ign;
+       struct vfsub_args vargs;
+       struct au_pin pin;
+
+       LKTRTrace("i%lu, %.*s\n", dir->i_ino, AuDLNPair(dentry));
+       IMustLock(dir);
+       inode = dentry->d_inode;
+       if (unlikely(!inode))
+               return -ENOENT; /* possible? */
+       IMustLock(inode);
+
+       aufs_read_lock(dentry, AuLock_DW);
+       parent = dentry->d_parent; /* dir inode is locked */
+       di_write_lock_parent(parent);
+
+       bstart = au_dbstart(dentry);
+       bwh = au_dbwh(dentry);
+       bindex = -1;
+       wh_dentry = lock_hdir_create_wh(dentry, /*isdir*/0, &bindex, &dt, &pin);
+       err = PTR_ERR(wh_dentry);
+       if (IS_ERR(wh_dentry))
+               goto out;
+
+       sb = dir->i_sb;
+       dlgt = !!au_test_dlgt(au_mntflags(sb));
+       AuDebugOn(au_dbstart(dentry) != bstart);
+       h_dentry = au_h_dptr(dentry, bstart);
+       dget(h_dentry);
+
+       if (bindex == bstart) {
+               vfsub_args_init(&vargs, &ign, dlgt, 0);
+               vfsub_ign_hinode(&vargs, IN_DELETE, au_pinned_hdir(&pin));
+               h_dir = au_pinned_h_dir(&pin);
+               err = vfsub_unlink(h_dir, h_dentry, &vargs);
+       } else {
+               /* dir inode is locked */
+               AuDebugOn(!wh_dentry
+                         || wh_dentry->d_parent != au_h_dptr(parent, bindex));
+               h_dir = wh_dentry->d_parent->d_inode;
+               IMustLock(h_dir);
+               err = 0;
+       }
+
+       if (!err) {
+               drop_nlink(inode);
+#if 0 /* todo: update plink? */
+               if (!inode->i_nlink
+                   && au_opt_test(p->a.mnt_flags, PLINK)
+                   && au_plink_test(sb, inode)
+                   /* && atomic_read(&inode->i_count) == 2) */) {
+                       au_debug_on();
+                       DbgInode(inode);
+                       au_debug_off();
+               }
+#endif
+               /*
+                * although this is not a dir,
+                * set it here since we need to detect the dead inode.
+                */
+               if (!inode->i_nlink)
+                       inode->i_flags |= S_DEAD;
+               epilog(dir, dentry, bindex);
+
+               /* update target timestamps */
+               if (bindex == bstart) {
+                       au_update_fuse_h_inode(NULL, h_dentry); /*ignore*/
+                       inode->i_ctime = h_dentry->d_inode->i_ctime;
+               } else
+                       /* todo: this timestamp may be reverted later */
+                       inode->i_ctime = h_dir->i_ctime;
+               goto out_unlock; /* success */
+       }
+
+       /* revert */
+       if (wh_dentry) {
+               int rerr;
+               unsigned int rev_flags;
+
+               rev_flags = 0;
+               if (dlgt)
+                       au_fset_rev(rev_flags, DLGT);
+               rerr = do_revert(err, dir, bwh, wh_dentry, dentry, &dt,
+                                rev_flags);
+               if (rerr)
+                       err = rerr;
+       }
+
+ out_unlock:
+       au_unpin(&pin);
+       dput(wh_dentry);
+       dput(h_dentry);
+ out:
+       di_write_unlock(parent);
+       aufs_read_unlock(dentry, AuLock_DW);
+       AuTraceErr(err);
+       if (unlikely(err == -EBUSY && au_test_nfsd(current)))
+               err = -ESTALE;
+       return err;
+}
+
+int aufs_rmdir(struct inode *dir, struct dentry *dentry)
+{
+       int err, rmdir_later;
+       struct inode *inode;
+       struct dentry *parent, *wh_dentry, *h_dentry;
+       struct au_dtime dt;
+       aufs_bindex_t bwh, bindex, bstart;
+       struct au_whtmp_rmdir_args *args;
+       struct au_nhash *whlist;
+       struct super_block *sb;
+       unsigned int mnt_flags;
+       struct au_pin pin;
+
+       LKTRTrace("i%lu, %.*s\n", dir->i_ino, AuDLNPair(dentry));
+       IMustLock(dir);
+       inode = dentry->d_inode;
+       err = -ENOENT; /* possible? */
+       if (unlikely(!inode))
+               goto out;
+       IMustLock(inode);
+
+       whlist = au_nhash_new(GFP_NOFS);
+       err = PTR_ERR(whlist);
+       if (IS_ERR(whlist))
+               goto out;
+
+       err = -ENOMEM;
+       args = kmalloc(sizeof(*args), GFP_NOFS);
+       if (unlikely(!args))
+               goto out_whlist;
+
+       aufs_read_lock(dentry, AuLock_DW);
+       parent = dentry->d_parent; /* dir inode is locked */
+       di_write_lock_parent(parent);
+       err = au_test_empty(dentry, whlist);
+       if (unlikely(err))
+               goto out_args;
+
+       bstart = au_dbstart(dentry);
+       bwh = au_dbwh(dentry);
+       bindex = -1;
+       wh_dentry = lock_hdir_create_wh(dentry, /*isdir*/1, &bindex, &dt, &pin);
+       err = PTR_ERR(wh_dentry);
+       if (IS_ERR(wh_dentry))
+               goto out_args;
+
+       AuDebugOn(au_dbstart(dentry) != bstart);
+       h_dentry = au_h_dptr(dentry, bstart);
+       dget(h_dentry);
+
+       rmdir_later = 0;
+       if (bindex == bstart) {
+               err = renwh_and_rmdir(dentry, bstart, whlist, dir);
+               if (err > 0) {
+                       rmdir_later = err;
+                       err = 0;
+               }
+       } else {
+               /* dir inode is locked */
+               AuDebugOn(!wh_dentry
+                         || wh_dentry->d_parent != au_h_dptr(parent, bindex));
+               IMustLock(wh_dentry->d_parent->d_inode);
+               err = 0;
+       }
+
+       sb = dentry->d_sb;
+       mnt_flags = au_mntflags(sb);
+       if (!err) {
+               if (au_opt_test(mnt_flags, UDBA_INOTIFY) && rmdir_later)
+                       au_reset_hinotify(inode, /*flags*/0);
+               clear_nlink(inode);
+               inode->i_flags |= S_DEAD;
+               au_set_dbdiropq(dentry, -1);
+               epilog(dir, dentry, bindex);
+
+               if (rmdir_later) {
+                       au_whtmp_kick_rmdir(dir, bstart, h_dentry, whlist,
+                                           args);
+                       args = NULL;
+               }
+
+               goto out_unlock; /* success */
+       }
+
+       /* revert */
+       LKTRLabel(revert);
+       if (wh_dentry) {
+               int rerr;
+               unsigned int rev_flags;
+
+               rev_flags = 0;
+               if (au_test_dlgt(mnt_flags))
+                       au_fset_rev(rev_flags, DLGT);
+               rerr = do_revert(err, dir, bwh, wh_dentry, dentry, &dt,
+                                rev_flags);
+               if (rerr)
+                       err = rerr;
+       }
+
+ out_unlock:
+       au_unpin(&pin);
+       dput(wh_dentry);
+       dput(h_dentry);
+ out_args:
+       di_write_unlock(parent);
+       aufs_read_unlock(dentry, AuLock_DW);
+       kfree(args);
+ out_whlist:
+       au_nhash_del(whlist);
+ out:
+       AuTraceErr(err);
+       if (unlikely(err == -EBUSY && au_test_nfsd(current)))
+               err = -ESTALE;
+       return err;
+}
diff -urN linux/fs/aufs/i_op_ren.c linux-aufs/fs/aufs/i_op_ren.c
--- linux/fs/aufs/i_op_ren.c    1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/i_op_ren.c       2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,1261 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * inode operation (rename entry)
+ * todo: this is crazy monster
+ *
+ * $Id$
+ */
+
+#include "aufs.h"
+
+enum { SRC, DST };
+
+#define AuRen_ISDIR    1
+#define AuRen_ISSAMEDIR        (1 << 1)
+#define AuRen_WHSRC    (1 << 2)
+#define AuRen_WHDST    (1 << 3)
+#define AuRen_DLGT     (1 << 4)
+#define AuRen_VFSLOCK  (1 << 5)
+#define AuRen_PINNED   (1 << 6)
+#define AuRen_MNT_WRITE        (1 << 7)
+#define au_ftest_ren(flags, name)      ((flags) & AuRen_##name)
+#define au_fset_ren(flags, name)       { (flags) |= AuRen_##name; }
+#define au_fclr_ren(flags, name)       { (flags) &= ~AuRen_##name; }
+#ifndef CONFIG_AUFS_DLGT
+#undef AuRen_DLGT
+#define AuRen_DLGT     0
+#endif
+
+struct au_ren_args {
+       /* original args */
+       struct dentry *src_dentry, *dentry;
+       struct inode *src_dir, *dir;
+
+       struct dentry *h_dentry[2], *h_parent[2], *h_trap, *h_locked[2];
+       /* todo: remove them */
+       struct dentry *parent[2], *gparent[2];
+       struct au_pin pin[2];
+       struct au_nhash whlist;
+       aufs_bindex_t btgt, bstart[2];
+       /* do_rename() only */
+       unsigned char need_diropq, bycpup;
+       struct super_block *sb;
+       unsigned int flags;
+       unsigned int mnt_flags;
+       struct au_ndx ndx;
+
+       /* do_rename() only */
+#ifdef CONFIG_AUFS_BR_NFS
+       struct au_hin_ignore ign[3];
+#else
+       struct au_hin_ignore ign[2];
+#endif
+       struct vfsub_args vargs;
+       struct au_whtmp_rmdir_args *thargs;
+       struct dentry *wh_dentry[2], *h_dst, *h_src;
+};
+
+/* ---------------------------------------------------------------------- */
+
+#define RevertFailure(fmt, args...) do { \
+               AuIOErrWhck("revert failure: " fmt " (%d, %d)\n", \
+                           ##args, err, rerr); \
+               err = -EIO; \
+       } while (0)
+
+static noinline_for_stack
+void au_ren_rev_diropq(int err, struct au_ren_args *a)
+{
+       int rerr;
+       struct mutex *h_mtx;
+
+       /* lock inode simply since inotify is not set to h_inode. */
+       h_mtx = &au_h_dptr(a->src_dentry, a->btgt)->d_inode->i_mutex;
+       mutex_lock_nested(h_mtx, AuLsc_I_CHILD);
+       rerr = au_diropq_remove(a->src_dentry, a->btgt,
+                               au_ftest_ren(a->flags, DLGT));
+       mutex_unlock(h_mtx);
+       if (rerr)
+               RevertFailure("remove diropq %.*s", AuDLNPair(a->src_dentry));
+}
+
+static noinline_for_stack
+void au_ren_rev_rename(int err, struct au_ren_args *a)
+{
+       int rerr;
+       struct dentry *h_d;
+       struct qstr *name = &a->src_dentry->d_name;
+
+       h_d = au_lkup_one(name->name, a->h_parent[SRC], name->len, &a->ndx);
+       rerr = PTR_ERR(h_d);
+       if (IS_ERR(h_d)) {
+               RevertFailure("au_lkup_one %.*s", AuDLNPair(a->src_dentry));
+               return;
+       }
+
+       AuDebugOn(h_d->d_inode);
+       vfsub_args_reinit(&a->vargs);
+       vfsub_ign_hinode(&a->vargs, IN_MOVED_FROM,
+                        au_pinned_hdir(a->pin + DST));
+       vfsub_ign_hinode(&a->vargs, IN_MOVED_TO, au_pinned_hdir(a->pin + SRC));
+       rerr = vfsub_rename(au_pinned_h_dir(a->pin + DST),
+                           au_h_dptr(a->src_dentry, a->btgt),
+                           au_pinned_h_dir(a->pin + SRC), h_d, &a->vargs);
+       d_drop(h_d);
+       dput(h_d);
+       /* au_set_h_dptr(a->src_dentry, a->btgt, NULL); */
+       if (rerr)
+               RevertFailure("rename %.*s", AuDLNPair(a->src_dentry));
+}
+
+static noinline_for_stack
+void au_ren_rev_cpup(int err, struct au_ren_args *a)
+{
+       int rerr;
+
+       vfsub_args_reinit(&a->vargs);
+       vfsub_ign_hinode(&a->vargs, IN_DELETE, au_pinned_hdir(a->pin + DST));
+       rerr = vfsub_unlink(au_pinned_h_dir(a->pin + DST), a->h_dentry[DST],
+                           &a->vargs);
+       au_set_h_dptr(a->src_dentry, a->btgt, NULL);
+       au_set_dbstart(a->src_dentry, a->bstart[SRC]);
+       if (rerr)
+               RevertFailure("unlink %.*s", AuDLNPair(a->h_dentry[DST]));
+}
+
+static noinline_for_stack
+void au_ren_rev_whtmp(int err, struct au_ren_args *a)
+{
+       int rerr;
+       struct dentry *h_d;
+       struct mutex *h_mtx;
+       struct qstr *name = &a->dentry->d_name;
+
+       h_d = au_lkup_one(name->name, a->h_parent[DST], name->len, &a->ndx);
+       rerr = PTR_ERR(h_d);
+       if (IS_ERR(h_d)) {
+               RevertFailure("lookup %.*s", AuLNPair(name));
+               return;
+       }
+       if (h_d->d_inode) {
+               d_drop(h_d);
+               dput(h_d);
+               return;
+       }
+
+       h_mtx = &a->h_dst->d_inode->i_mutex;
+       mutex_lock_nested(h_mtx, AuLsc_I_CHILD);
+       au_hin_resume(au_hi(a->src_dentry->d_inode, a->btgt));
+       mutex_unlock(h_mtx);
+       vfsub_args_reinit(&a->vargs);
+       vfsub_ign_hinode(&a->vargs, IN_MOVED_TO | IN_MOVED_FROM,
+                        au_pinned_hdir(a->pin + DST));
+       rerr = vfsub_rename(au_pinned_h_dir(a->pin + DST), a->h_dst,
+                           au_pinned_h_dir(a->pin + DST), h_d, &a->vargs);
+       d_drop(h_d);
+       dput(h_d);
+       if (!rerr) {
+               au_set_h_dptr(a->dentry, a->btgt, NULL);
+               au_set_h_dptr(a->dentry, a->btgt, dget(a->h_dst));
+       } else
+               RevertFailure("rename %.*s", AuDLNPair(a->h_dst));
+}
+
+static noinline_for_stack
+void au_ren_rev_whsrc(int err, struct au_ren_args *a)
+{
+       int rerr;
+
+       rerr = au_wh_unlink_dentry(au_pinned_hdir(a->pin + SRC),
+                                  a->wh_dentry[SRC], a->src_dentry, /*dlgt*/0);
+       if (rerr)
+               RevertFailure("unlink %.*s", AuDLNPair(a->wh_dentry[SRC]));
+}
+#undef RevertFailure
+
+/* ---------------------------------------------------------------------- */
+
+static /* noinline_for_stack */
+int au_ren_or_cpup(struct au_ren_args *a)
+{
+       int err;
+
+       AuTraceEnter();
+
+       if (au_dbstart(a->src_dentry) == a->btgt) {
+               if (a->need_diropq && au_dbdiropq(a->src_dentry) == a->btgt)
+                       a->need_diropq = 0;
+               vfsub_ign_hinode(&a->vargs, IN_MOVED_FROM,
+                                au_pinned_hdir(a->pin + SRC));
+               vfsub_ign_hinode(&a->vargs, IN_MOVED_TO,
+                                au_pinned_hdir(a->pin + DST));
+               /* nfs_rename() calls d_delete() */
+               if (au_test_nfs(au_pinned_h_dir(a->pin + DST)->i_sb)
+                   && a->h_dentry[DST]->d_inode
+                   && (S_ISDIR(a->h_dentry[DST]->d_inode->i_mode)
+                       || atomic_read(&a->h_dentry[DST]->d_count) <= 2))
+                       vfsub_ign_hinode(&a->vargs, IN_DELETE,
+                                        au_pinned_hdir(a->pin + DST));
+               AuDebugOn(au_dbstart(a->src_dentry) != a->btgt);
+               err = vfsub_rename(au_pinned_h_dir(a->pin + SRC),
+                                  au_h_dptr(a->src_dentry, a->btgt),
+                                  au_pinned_h_dir(a->pin + DST),
+                                  a->h_dentry[DST], &a->vargs);
+       } else {
+               struct mutex *h_mtx = &a->h_dentry[SRC]->d_inode->i_mutex;
+
+               a->bycpup = 1;
+               mutex_lock_nested(h_mtx, AuLsc_I_CHILD);
+               au_set_dbstart(a->src_dentry, a->btgt);
+               au_set_h_dptr(a->src_dentry, a->btgt, dget(a->h_dentry[DST]));
+               err = au_sio_cpup_single(a->src_dentry, a->btgt, a->bstart[SRC],
+                                        -1, !AuCpup_DTIME, a->parent[DST]);
+               if (unlikely(err)) {
+                       au_set_h_dptr(a->src_dentry, a->btgt, NULL);
+                       au_set_dbstart(a->src_dentry, a->bstart[SRC]);
+               }
+               mutex_unlock(h_mtx);
+       }
+
+       return err;
+}
+
+static /* noinline_for_stack */
+int au_ren_del_whtmp(struct au_ren_args *a)
+{
+       int err;
+
+       AuTraceEnter();
+
+       if (au_test_nfs(a->h_dst->d_sb)
+           || !au_nhash_test_longer_wh(&a->whlist, a->btgt,
+                                       au_sbi(a->sb)->si_dirwh)) {
+               err = au_whtmp_rmdir(a->dir, a->btgt, a->h_dst, &a->whlist);
+               if (unlikely(err))
+                       AuWarn("failed removing whtmp dir %.*s (%d), "
+                              "ignored.\n", AuDLNPair(a->h_dst), err);
+       } else {
+               au_whtmp_kick_rmdir(a->dir, a->btgt, a->h_dst, &a->whlist,
+                                   a->thargs);
+               dput(a->h_dst);
+               a->thargs = NULL;
+       }
+
+       return 0;
+}
+
+static /* noinline_for_stack */
+int au_ren_diropq(struct au_ren_args *a)
+{
+       int err;
+       struct dentry *diropq;
+       struct mutex *h_mtx;
+
+       AuTraceEnter();
+
+       err = 0;
+       h_mtx = &au_h_dptr(a->src_dentry, a->btgt)->d_inode->i_mutex;
+       mutex_lock_nested(h_mtx, AuLsc_I_CHILD);
+       diropq = au_diropq_create(a->src_dentry, a->btgt,
+                                 au_ftest_ren(a->flags, DLGT));
+       mutex_unlock(h_mtx);
+       if (IS_ERR(diropq))
+               err = PTR_ERR(diropq);
+       dput(diropq);
+
+       return err;
+}
+
+static /* noinline_for_stack */
+int do_rename(struct au_ren_args *a)
+{
+       int err;
+       aufs_bindex_t bindex, bend;
+       struct dentry *h_d;
+
+       LKTRTrace("%.*s/%.*s, %.*s/%.*s, "
+                 "hd{%p, %p}, hp{%p, %p}, wh %p, btgt %d, bstart{%d, %d}, "
+                 "flags 0x%x\n",
+                 AuDLNPair(a->parent[SRC]), AuDLNPair(a->src_dentry),
+                 AuDLNPair(a->parent[DST]), AuDLNPair(a->dentry),
+                 a->h_dentry[SRC], a->h_dentry[DST],
+                 a->h_parent[SRC], a->h_parent[DST],
+                 &a->whlist, a->btgt,
+                 a->bstart[SRC], a->bstart[DST],
+                 a->flags);
+
+       /* prepare workqueue args */
+       if (au_ftest_ren(a->flags, ISDIR) && a->h_dentry[DST]->d_inode) {
+               err = -ENOMEM;
+               a->thargs = kmalloc(sizeof(*a->thargs), GFP_NOFS);
+               if (unlikely(!a->thargs))
+                       goto out;
+               a->h_dst = dget(a->h_dentry[DST]);
+       }
+
+       a->ndx.nfsmnt = au_nfsmnt(a->sb, a->btgt);
+       if (au_ftest_ren(a->flags, DLGT))
+               au_fset_ndx(a->ndx.flags, DLGT);
+
+       /* create whiteout for src_dentry */
+       if (au_ftest_ren(a->flags, WHSRC)) {
+               a->wh_dentry[SRC] = au_wh_create(a->src_dentry, a->btgt,
+                                                a->h_parent[SRC], &a->ndx);
+               err = PTR_ERR(a->wh_dentry[SRC]);
+               if (IS_ERR(a->wh_dentry[SRC]))
+                       goto out_thargs;
+       }
+
+       /* lookup whiteout for dentry */
+       if (au_ftest_ren(a->flags, WHDST)) {
+               h_d = au_wh_lkup(a->h_parent[DST], &a->dentry->d_name, &a->ndx);
+               err = PTR_ERR(h_d);
+               if (IS_ERR(h_d))
+                       goto out_whsrc;
+               if (!h_d->d_inode)
+                       dput(h_d);
+               else
+                       a->wh_dentry[DST] = h_d;
+       }
+
+       /* rename dentry to tmpwh */
+       if (a->thargs) {
+               struct au_hinode *hinode;
+
+               AuDbgDentry(a->h_dentry[DST]);
+               err = au_whtmp_ren(a->dir, a->btgt, a->h_dentry[DST]);
+               if (unlikely(err))
+                       goto out_whdst;
+               AuDbgDentry(a->h_dentry[DST]);
+               hinode = au_hi(a->dentry->d_inode, a->btgt);
+               /* todo: bad approach? */
+               mutex_lock_nested(&hinode->hi_inode->i_mutex, AuLsc_I_CHILD);
+               au_hin_suspend(hinode);
+               mutex_unlock(&hinode->hi_inode->i_mutex);
+               au_set_h_dptr(a->dentry, a->btgt, NULL);
+               AuDbgDentry(a->h_dentry[DST]);
+               err = au_lkup_neg(a->dentry, a->btgt);
+               if (unlikely(err))
+                       goto out_whtmp;
+               a->h_dentry[DST] = au_h_dptr(a->dentry, a->btgt);
+       }
+
+       /* cpup src */
+       if (a->h_dentry[DST]->d_inode && a->bstart[SRC] != a->btgt) {
+               struct mutex *h_mtx = &a->h_dentry[SRC]->d_inode->i_mutex;
+
+               mutex_lock_nested(h_mtx, AuLsc_I_CHILD);
+               err = au_sio_cpup_simple(a->src_dentry, a->btgt, -1,
+                                        !AuCpup_DTIME);
+               mutex_unlock(h_mtx);
+               if (unlikely(err))
+                       goto out_whtmp;
+       }
+
+       /* rename by vfs_rename or cpup */
+       a->need_diropq = au_ftest_ren(a->flags, ISDIR)
+               && (a->wh_dentry[DST]
+                   || au_dbdiropq(a->dentry) == a->btgt
+                   /* hide the lower to keep xino */
+                   || a->btgt < au_dbend(a->dentry)
+                   || au_opt_test(a->mnt_flags, ALWAYS_DIROPQ));
+       a->bycpup = 0;
+       vfsub_args_init(&a->vargs, a->ign, au_ftest_ren(a->flags, DLGT), 0);
+       err = au_ren_or_cpup(a);
+       if (unlikely(err))
+               goto out_whtmp;
+
+       /* make dir opaque */
+       if (a->need_diropq) {
+               err = au_ren_diropq(a);
+               if (unlikely(err))
+                       goto out_rename;
+       }
+
+       /* update target timestamps */
+       AuDebugOn(au_dbstart(a->src_dentry) != a->btgt);
+       a->h_src = au_h_dptr(a->src_dentry, a->btgt);
+       au_update_fuse_h_inode(NULL, a->h_src); /*ignore*/
+       /*
+        * fsstack_copy_attr_atime(a->src_dentry->d_inode, a->h_src->d_inode);
+        */
+       a->src_dentry->d_inode->i_ctime = a->h_src->d_inode->i_ctime;
+
+       /* remove whiteout for dentry */
+       if (a->wh_dentry[DST]) {
+               err = au_wh_unlink_dentry(au_pinned_hdir(a->pin + DST),
+                                         a->wh_dentry[DST], a->dentry,
+                                         /*dlgt*/0);
+               if (unlikely(err))
+                       goto out_diropq;
+       }
+
+       /* remove whtmp */
+       if (a->thargs)
+               /* ignore this error */
+               au_ren_del_whtmp(a);
+
+       err = 0;
+       goto out_success;
+
+ out_diropq:
+       if (a->need_diropq)
+               au_ren_rev_diropq(err, a);
+ out_rename:
+       if (!a->bycpup)
+               au_ren_rev_rename(err, a);
+       else
+               au_ren_rev_cpup(err, a);
+ out_whtmp:
+       if (a->thargs)
+               au_ren_rev_whtmp(err, a);
+ out_whdst:
+       dput(a->wh_dentry[DST]);
+       a->wh_dentry[DST] = NULL;
+ out_whsrc:
+       if (a->wh_dentry[SRC])
+               au_ren_rev_whsrc(err, a);
+       d_drop(a->src_dentry);
+       bend = au_dbend(a->src_dentry);
+       for (bindex = au_dbstart(a->src_dentry); bindex <= bend; bindex++) {
+               h_d = au_h_dptr(a->src_dentry, bindex);
+               if (h_d)
+                       d_drop(h_d);
+       }
+       d_drop(a->dentry);
+       bend = au_dbend(a->dentry);
+       for (bindex = au_dbstart(a->dentry); bindex <= bend; bindex++) {
+               h_d = au_h_dptr(a->dentry, bindex);
+               if (h_d)
+                       d_drop(h_d);
+       }
+       au_update_dbstart(a->dentry);
+       if (a->thargs)
+               d_drop(a->h_dst);
+ out_success:
+       dput(a->wh_dentry[SRC]);
+       dput(a->wh_dentry[DST]);
+ out_thargs:
+       if (a->thargs) {
+               dput(a->h_dst);
+               kfree(a->thargs);
+       }
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+/*
+ * test if @dentry dir can be rename destination or not.
+ * success means, it is a logically empty dir.
+ */
+static int may_rename_dstdir(struct dentry *dentry, aufs_bindex_t btgt,
+                            struct au_nhash *whlist)
+{
+       LKTRTrace("%.*s\n", AuDLNPair(dentry));
+
+       return au_test_empty(dentry, whlist);
+}
+
+/*
+ * test if @dentry dir can be rename source or not.
+ * if it can, return 0 and @children is filled.
+ * success means,
+ * - or, it is a logically empty dir.
+ * - or, it exists on writable branch and has no children including whiteouts
+ *       on the lower branch.
+ */
+static int may_rename_srcdir(struct dentry *dentry, aufs_bindex_t btgt)
+{
+       int err;
+       aufs_bindex_t bstart;
+
+       LKTRTrace("%.*s\n", AuDLNPair(dentry));
+
+       bstart = au_dbstart(dentry);
+       if (bstart != btgt) {
+               struct au_nhash *whlist;
+
+               whlist = au_nhash_new(GFP_NOFS);
+               err = PTR_ERR(whlist);
+               if (IS_ERR(whlist))
+                       goto out;
+               err = au_test_empty(dentry, whlist);
+               au_nhash_del(whlist);
+               goto out;
+       }
+
+       if (bstart == au_dbtaildir(dentry))
+               return 0; /* success */
+
+       err = au_test_empty_lower(dentry);
+
+ out:
+       if (/* unlikely */(err == -ENOTEMPTY)) {
+               AuWarn1("renaming dir who has child(ren) on multiple branches,"
+                       " is not supported\n");
+               err = -EXDEV;
+       }
+       AuTraceErr(err);
+       return err;
+}
+
+/* mainly for link(2) and rename(2) */
+int au_wbr(struct dentry *dentry, aufs_bindex_t btgt)
+{
+       aufs_bindex_t bdiropq, bwh;
+       struct dentry *parent;
+
+       LKTRTrace("%.*s, b%d\n", AuDLNPair(dentry), btgt);
+       parent = dentry->d_parent;
+       IMustLock(parent->d_inode); /* dir is locked */
+
+       bdiropq = au_dbdiropq(parent);
+       bwh = au_dbwh(dentry);
+       if (au_br_rdonly(au_sbr(dentry->d_sb, btgt))
+                    || (0 <= bdiropq && bdiropq < btgt)
+                    || (0 <= bwh && bwh < btgt))
+               btgt = -1;
+
+       LKTRTrace("btgt %d\n", btgt);
+       return btgt;
+}
+
+/*
+ * simple tests for rename.
+ * following the checks in vfs, plus the parent-child relationship.
+ */
+static int au_may_ren(struct au_ren_args *a)
+{
+       int err;
+       struct inode *h_inode;
+
+       AuTraceEnter();
+
+       if (a->bstart[SRC] == a->btgt) {
+               err = au_may_del(a->src_dentry, a->btgt, a->h_parent[SRC],
+                                au_ftest_ren(a->flags, ISDIR), &a->ndx);
+               if (unlikely(err))
+                       goto out;
+               err = -EINVAL;
+               if (unlikely(a->h_dentry[SRC] == a->h_trap))
+                       goto out;
+       }
+
+       err = 0;
+       if (a->bstart[DST] != a->btgt)
+               goto out;
+
+       err = -EIO;
+       h_inode = a->h_dentry[DST]->d_inode;
+       if (!a->dentry->d_inode) {
+               if (unlikely(h_inode))
+                       goto out;
+               err = au_may_add(a->dentry, a->btgt, a->h_parent[DST],
+                                au_ftest_ren(a->flags, ISDIR), &a->ndx);
+       } else {
+               if (unlikely(!h_inode || !h_inode->i_nlink))
+                       goto out;
+               err = au_may_del(a->dentry, a->btgt, a->h_parent[DST],
+                                au_ftest_ren(a->flags, ISDIR), &a->ndx);
+               if (unlikely(err))
+                       goto out;
+               err = -ENOTEMPTY;
+               if (unlikely(a->h_dentry[DST] == a->h_trap))
+                       goto out;
+               err = 0;
+       }
+
+ out:
+       if (unlikely(err == -ENOENT || err == -EEXIST))
+               err = -EIO;
+       AuTraceErr(err);
+       return err;
+}
+
+/*
+ * locking order
+ * (VFS)
+ * - src_dir and dir by lock_rename()
+ * - inode if exitsts
+ * (aufs)
+ * - lock all
+ *   + src_dentry and dentry by aufs_read_and_write_lock2() which calls,
+ *     + si_read_lock
+ *     + di_write_lock2_child()
+ *       + di_write_lock_child()
+ *        + ii_write_lock_child()
+ *       + di_write_lock_child2()
+ *        + ii_write_lock_child2()
+ *     + src_parent and parent
+ *       + di_write_lock_parent()
+ *        + ii_write_lock_parent()
+ *       + di_write_lock_parent2()
+ *        + ii_write_lock_parent2()
+ *   + if udab=inotify is specified, lock grand parents (crazy)
+ *     + di_read_lock_gparent()
+ *       + ii_read_lock_gparent()
+ *     + di_read_lock_gparent2()
+ *       + ii_read_lock_gparent2()
+ *     + mutex_lock(s_vfs_rename_mutex)
+ *     + mutex_lock_gparent()
+ *     + mutex_lock_gparent2()
+ *     + mutex_lock_parent()
+ *     + mutex_lock_parent2()
+ *   + else lower src_dir and dir by vfsub_lock_rename()
+ *   + verify the every relations between child, parent and grand parent. if any
+ *     of them failed, unlock all and return -EBUSY.
+ */
+static void au_ren_pin_init(struct au_pin *first, struct dentry *d1,
+                           struct au_pin *next, struct dentry *d2,
+                           aufs_bindex_t bindex)
+{
+       AuTraceEnter();
+
+       /* AuLsc_DI_PARENT3 is for higher gparent initially */
+       au_pin_init(first, d1, bindex, AuLsc_DI_PARENT2, AuLsc_I_PARENT2,
+                   AuPin_DI_LOCKED | AuPin_DO_GPARENT);
+       /* AuLsc_DI_PARENT4 is for lower gparent initially */
+       au_pin_init(next, d2, bindex, AuLsc_DI_PARENT3, AuLsc_I_PARENT4,
+                   AuPin_DI_LOCKED | AuPin_DO_GPARENT);
+}
+
+static void au_ren_fake_pin(struct au_ren_args *a)
+{
+       int i;
+       struct au_pin1 *p;
+       struct inode *h_i;
+
+       AuTraceEnter();
+
+       /* they increment the ref counter */
+       for (i = 0; i < 2; i++) {
+               p = a->pin[i].pin + AuPin_PARENT;
+               au_pin_set_parent(a->pin + i, a->parent[i]);
+               dput(a->parent[i]);
+               h_i = a->h_parent[i]->d_inode;
+               au_pin_set_h_dir(a->pin + i, h_i);
+               iput(h_i);
+
+               if (!a->gparent[i]) {
+                       au_pin_set_gparent(a->pin + i, NULL);
+                       au_pin_set_h_gdir(a->pin + i, NULL);
+               } else {
+                       au_pin_set_gparent(a->pin + i, a->gparent[i]);
+                       dput(a->gparent[i]);
+                       h_i = au_h_iptr(a->gparent[i]->d_inode, a->btgt);
+                       au_pin_set_h_gdir(a->pin + i, h_i);
+                       iput(h_i);
+               }
+       }
+}
+
+/* crazy */
+/* cf. i_op.c: au_do_pin() */
+static int au_ren_pin4(int higher, int lower, struct au_ren_args *a)
+{
+       int err, i, lsc;
+       struct au_pin *p;
+       struct au_pin1 *p4[4];
+       struct inode *h_dir;
+
+#if 0
+       lktr_set_pid(current->pid, LktrArrayPid);
+       LKTRTrace("i%lu, %.*s, i%lu, %.*s\n",
+                 a->src_dir->i_ino, AuDLNPair(a->src_dentry),
+                 a->dir->i_ino, AuDLNPair(a->dentry));
+       lktr_clear_pid(current->pid, LktrArrayPid);
+#endif
+       LKTRTrace("%d, %d\n", higher, lower);
+
+       err = 0;
+       p = a->pin + higher;
+       p4[0] = au_pin_gp(p); /* highest */
+       p4[1] = p->pin + AuPin_PARENT;
+       p = a->pin + lower;
+       p4[2] = au_pin_gp(p);
+       p4[3] = p->pin + AuPin_PARENT;
+
+       if (a->gparent[higher]) {
+               au_pin_do_set_parent(p4[0], a->gparent[higher]);
+               au_pin_do_set_dentry(p4[0], a->parent[higher]);
+       }
+       au_pin_do_set_parent(p4[1], a->parent[higher]);
+       if (a->gparent[lower]) {
+               au_pin_do_set_parent(p4[2], a->gparent[lower]);
+               au_pin_do_set_dentry(p4[2], a->parent[lower]);
+       }
+       au_pin_do_set_parent(p4[3], a->parent[lower]);
+
+#if 0
+       lktr_set_pid(current->pid, LktrArrayPid);
+       for (i = 0; i < 4; i++)
+               AuDbgDentry(p4[i]->parent);
+#endif
+       DiMustWriteLock(p4[3]->parent);
+       di_write_unlock(p4[1]->parent);
+       if (p4[2]->parent)
+               di_read_lock_parent2(p4[2]->parent, AuLock_IR);
+       di_write_lock_parent3(p4[1]->parent);
+       if (p4[0]->parent)
+               di_read_lock_parent4(p4[0]->parent, AuLock_IR);
+       //lktr_clear_pid(current->pid, LktrArrayPid);
+
+       vfsub_lock_rename_mutex(au_sbr_sb(a->dentry->d_sb, a->btgt));
+       au_fset_ren(a->flags, VFSLOCK);
+
+       lsc = AuLsc_I_PARENT;
+       for (i = 0; i < 4; i++, lsc++) {
+               if (p4[i]->parent) {
+                       h_dir = au_h_iptr(p4[i]->parent->d_inode, a->btgt);
+                       au_pin_do_set_h_dir(p4[i], h_dir);
+                       mutex_lock_nested(&h_dir->i_mutex, lsc);
+               }
+       }
+
+       AuTraceErr(err);
+       return err;
+}
+
+static struct dentry *au_ren_pin3(int higher, int lower, struct au_ren_args *a)
+{
+       struct dentry *h_trap;
+       struct au_pin *p;
+       int err;
+
+       LKTRTrace("%d, %d\n", higher, lower);
+
+       p = a->pin + higher;
+       AuDebugOn(!au_pin_gp(p));
+       au_fset_pin(au_pin_gp(p)->flags, VFS_RENAME);
+       err = au_do_pin(p->pin + AuPin_PARENT, au_pin_gp(p));
+       h_trap = ERR_PTR(err);
+       if (unlikely(err))
+               goto out;
+       p = a->pin + lower;
+       au_fclr_pin(p->pin[AuPin_PARENT].flags, DO_GPARENT);
+       err = au_do_pin(p->pin + AuPin_PARENT, NULL);
+       h_trap = ERR_PTR(err);
+       if (unlikely(err)) {
+               p = a->pin + higher;
+               au_do_unpin(p->pin + AuPin_PARENT, au_pin_gp(p));
+               goto out;
+       }
+       h_trap = au_pinned_h_parent(p);
+
+ out:
+       AuTraceErrPtr(h_trap);
+       return h_trap;
+}
+
+static struct dentry *au_ren_pin(struct au_ren_args *a)
+{
+       struct dentry *h_trap;
+       struct inode *h_gdir;
+       int err, i, same_gp;
+
+       //lktr_set_pid(current->pid, LktrArrayPid);
+       AuTraceEnter();
+       AuDebugOn(!au_opt_test(a->mnt_flags, UDBA_INOTIFY));
+
+       /* gdir is not locked */
+       same_gp = 0;
+       if (!IS_ROOT(a->parent[SRC]))
+               a->gparent[SRC] = dget_parent(a->parent[SRC]);
+       if (!IS_ROOT(a->parent[DST])) {
+               a->gparent[DST] = dget_parent(a->parent[DST]);
+               same_gp = (a->gparent[SRC] == a->gparent[DST]);
+       }
+
+       /*
+        * patterns
+        * - gparent[SRC] is parent[DST]
+        * - parent[SRC] is gparent[DST]
+        * - gparent[SRC] is gparent[DST]
+        * - gparent[SRC] is a descendant of parent[DST]
+        * - parent[SRC] is an ancestor of gparent[DST]
+        * - not within grand parent range
+        */
+       err = 0;
+       h_trap = ERR_PTR(-EBUSY);
+       if (a->gparent[SRC] == a->parent[DST]) {
+               //AuDbg("here\n");
+               LKTRLabel(here);
+               au_ren_pin_init(a->pin + DST, a->dentry, a->pin + SRC,
+                               a->src_dentry, a->btgt);
+               h_trap = au_ren_pin3(DST, SRC, a);
+               if (!IS_ERR(h_trap)) {
+                       h_gdir = au_pinned_h_dir(a->pin + DST);
+                       err = au_verify_parent(a->h_parent[SRC], h_gdir);
+                       if (unlikely(err))
+                               h_trap = ERR_PTR(-EBUSY);
+               }
+       } else if (a->parent[SRC] == a->gparent[DST] || same_gp) {
+               //AuDbg("here\n");
+               LKTRLabel(here);
+               au_ren_pin_init(a->pin + SRC, a->src_dentry, a->pin + DST,
+                               a->dentry, a->btgt);
+               h_trap = au_ren_pin3(SRC, DST, a);
+               if (!IS_ERR(h_trap)) {
+                       if (!same_gp)
+                               h_gdir = au_pinned_h_dir(a->pin + SRC);
+                       else
+                               h_gdir = au_pinned_h_gdir(a->pin + SRC);
+                       err = au_verify_parent(a->h_parent[DST], h_gdir);
+                       if (unlikely(err))
+                               h_trap = ERR_PTR(-EBUSY);
+               }
+       } else if (a->gparent[SRC]
+                  && (h_trap = au_test_subdir(a->gparent[SRC],
+                                              a->parent[DST]))) {
+               //AuDbg("here\n");
+               LKTRLabel(here);
+               au_ren_pin_init(a->pin + DST, a->dentry, a->pin + SRC,
+                               a->src_dentry, a->btgt);
+               if (a->gparent[DST]) {
+                       err = au_ren_pin4(DST, SRC, a);
+                       if (unlikely(err))
+                               h_trap = ERR_PTR(err);
+               } else {
+                       struct dentry *t;
+                       t = au_ren_pin3(DST, SRC, a);
+                       AuDebugOn(t == h_trap);
+               }
+#if 1
+       } else if (a->gparent[DST]
+                  && (h_trap = au_test_subdir(a->gparent[DST],
+                                              a->parent[SRC]))) {
+               /* todo: is this really necessary? */
+               //AuDbg("here\n");
+               LKTRLabel(here);
+               au_ren_pin_init(a->pin + SRC, a->src_dentry, a->pin + DST,
+                               a->dentry, a->btgt);
+               if (a->gparent[SRC]) {
+                       err = au_ren_pin4(SRC, DST, a);
+                       if (unlikely(err))
+                               h_trap = ERR_PTR(err);
+               } else {
+                       struct dentry *t;
+                       t = au_ren_pin3(SRC, DST, a);
+                       AuDebugOn(t == h_trap);
+               }
+#endif
+       } else /* if (a->gparent[DST]
+                 && (h_trap = au_test_subdir(a->gparent[DST],
+                 a->parent[SRC]))) */ {
+               //AuDbg("here\n");
+               LKTRLabel(here);
+               h_trap = NULL;
+               if (a->gparent[DST])
+                       h_trap = au_test_subdir(a->gparent[DST],
+                                               a->parent[SRC]);
+               au_ren_pin_init(a->pin + SRC, a->src_dentry, a->pin + DST,
+                               a->dentry, a->btgt);
+               err = au_ren_pin4(SRC, DST, a);
+               if (unlikely(err))
+                       h_trap = ERR_PTR(err);
+       }
+       au_fset_ren(a->flags, PINNED);
+
+       if (!IS_ERR(h_trap)) {
+               err = 0;
+               for (i = 0; !err && i < 2; i++) {
+                       h_gdir = au_pinned_h_gdir(a->pin + i);
+                       if (h_gdir)
+                               err = au_verify_parent(a->h_parent[i], h_gdir);
+               }
+               if (unlikely(err)) {
+                       h_trap = ERR_PTR(err);
+                       //AuDbg("here\n");
+               }
+       }
+
+       dput(a->gparent[SRC]);
+       dput(a->gparent[DST]);
+       memset(a->gparent, 0, sizeof(a->gparent));
+       AuTraceErrPtr(h_trap);
+       //lktr_clear_pid(current->pid, LktrArrayPid);
+       return h_trap;
+}
+
+static void au_ren_unlock(struct au_ren_args *a)
+{
+       int i;
+
+       AuTraceEnter();
+
+       if (au_ftest_ren(a->flags, MNT_WRITE))
+               au_mnt_drop_write(au_sbr_mnt(a->dentry->d_sb, a->btgt));
+       if (a->h_locked[0])
+               vfsub_unlock_rename(a->h_locked[0], a->h_locked[1]);
+       if (au_ftest_ren(a->flags, PINNED)) {
+               au_unpin(a->pin + SRC);
+               au_unpin(a->pin + DST);
+               memset(a->gparent, 0, sizeof(a->gparent));
+       }
+       if (au_ftest_ren(a->flags, VFSLOCK))
+               vfsub_unlock_rename_mutex(au_sbr_sb(a->dentry->d_sb, a->btgt));
+       for (i = 0; i < 2; i++)
+               if (a->gparent[i]) {
+                       di_read_unlock(a->gparent[i], AuLock_IR);
+                       dput(a->gparent[i]);
+               }
+}
+
+static int au_ren_lock(struct au_ren_args *a)
+{
+       int err;
+       const int hinotify = au_opt_test(a->mnt_flags, UDBA_INOTIFY);
+
+       AuTraceEnter();
+
+       err = 0;
+       if (!hinotify
+           || (au_ftest_ren(a->flags, ISSAMEDIR) && IS_ROOT(a->parent[SRC]))) {
+               au_ren_pin_init(a->pin + SRC, a->src_dentry, a->pin + DST,
+                               a->dentry, a->btgt);
+               LKTRLabel(here);
+               a->h_locked[0] = a->h_parent[SRC];
+               a->h_locked[1] = a->h_parent[DST];
+               a->h_trap = vfsub_lock_rename(a->h_locked[0], a->h_locked[1]);
+               au_ren_fake_pin(a);
+       } else if (au_ftest_ren(a->flags, ISSAMEDIR)
+                  && !IS_ROOT(a->parent[SRC])) {
+               /* this and next block should not be compiled when
+                  hinotify is disabled */
+               /* irregular/tricky rename lock */
+               LKTRLabel(here);
+               au_ren_pin_init(a->pin + SRC, a->src_dentry, a->pin + DST,
+                               a->dentry, a->btgt);
+               a->gparent[SRC] = dget_parent(a->parent[SRC]);
+               di_read_lock_parent2(a->gparent[SRC], AuLock_IR);
+               a->h_locked[0] = a->h_parent[SRC];
+               a->h_locked[1] = dget_parent(a->h_parent[SRC]);
+               a->h_trap = vfsub_lock_rename(a->h_locked[0], a->h_locked[1]);
+               err = au_verify_parent(a->h_parent[SRC],
+                                      a->h_locked[1]->d_inode);
+               dput(a->h_locked[1]);
+               if (!err)
+                       au_ren_fake_pin(a);
+       } else {
+               /* 3 or 4 dir locks. crazy */
+               LKTRLabel(here);
+               a->h_trap = au_ren_pin(a);
+               if (IS_ERR(a->h_trap))
+                       err = PTR_ERR(a->h_trap);
+       }
+
+       if (!err && au_dbstart(a->src_dentry) == a->btgt)
+               err = au_verify_parent(a->h_dentry[SRC],
+                                      a->h_parent[SRC]->d_inode);
+       if (!err && au_dbstart(a->dentry) == a->btgt)
+               err = au_verify_parent(a->h_dentry[DST],
+                                      a->h_parent[DST]->d_inode);
+       if (!err) {
+               err = au_br_want_write(au_sbr(a->dentry->d_sb, a->btgt));
+               if (unlikely(err))
+                       goto out_unlock;
+               au_fset_ren(a->flags, MNT_WRITE);
+               goto out; /* success */
+       }
+
+       err = -EBUSY;
+
+ out_unlock:
+       au_ren_unlock(a);
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+int aufs_rename(struct inode *src_dir, struct dentry *src_dentry,
+               struct inode *dir, struct dentry *dentry)
+{
+       int err;
+       aufs_bindex_t bend, bindex;
+       unsigned char do_dt_dstdir, hinotify;
+       struct inode *inode[2];
+       enum { PARENT, CHILD };
+       /* reduce stack space */
+       struct {
+               struct au_ren_args a;
+               struct au_dtime dt[2][2];
+       } *p;
+       struct au_wr_dir_args wr_dir_args = {
+               /* .force_btgt  = -1, */
+               .flags          = AuWrDir_ADD_ENTRY
+       };
+
+       LKTRTrace("i%lu, %.*s, i%lu, %.*s\n",
+                 src_dir->i_ino, AuDLNPair(src_dentry),
+                 dir->i_ino, AuDLNPair(dentry));
+       AuDebugOn(IS_ROOT(src_dentry) || IS_ROOT(dentry));
+       IMustLock(src_dir);
+       IMustLock(dir);
+       inode[DST] = dentry->d_inode;
+       if (inode[DST]) {
+               IMustLock(inode[DST]);
+               au_igrab(inode[DST]);
+       }
+
+       err = -ENOMEM;
+       BUILD_BUG_ON(sizeof(*p) > PAGE_SIZE);
+       p = kzalloc(sizeof(*p), GFP_NOFS);
+       if (unlikely(!p))
+               goto out;
+
+       err = -ENOTDIR;
+       p->a.src_dir = src_dir;
+       p->a.src_dentry = src_dentry;
+       p->a.dir = dir;
+       p->a.dentry = dentry;
+       p->a.sb = src_dentry->d_sb;
+       inode[SRC] = src_dentry->d_inode;
+       p->a.flags = 0;
+       if (S_ISDIR(inode[SRC]->i_mode)) {
+               au_fset_ren(p->a.flags, ISDIR);
+               if (unlikely(inode[DST] && !S_ISDIR(inode[DST]->i_mode)))
+                       goto out_free;
+               aufs_read_and_write_lock2(dentry, src_dentry, AuLock_DIR);
+       } else
+               aufs_read_and_write_lock2(dentry, src_dentry, 0);
+
+       p->a.mnt_flags = au_mntflags(p->a.sb);
+       if (au_test_dlgt(p->a.mnt_flags))
+               au_fset_ren(p->a.flags, DLGT);
+       p->a.parent[SRC] = src_dentry->d_parent; /* dir inode is locked */
+       p->a.parent[DST] = dentry->d_parent; /* dir inode is locked */
+       au_fset_ren(p->a.flags, ISSAMEDIR); /* temporary */
+       di_write_lock_parent(p->a.parent[DST]);
+
+       /* which branch we process */
+       p->a.bstart[SRC] = au_dbstart(src_dentry);
+       p->a.bstart[DST] = au_dbstart(dentry);
+       if (au_ftest_ren(p->a.flags, ISDIR))
+               au_fset_wrdir(wr_dir_args.flags, ISDIR);
+       wr_dir_args.force_btgt = p->a.bstart[SRC];
+       if (dentry->d_inode && p->a.bstart[DST] < p->a.bstart[SRC])
+               wr_dir_args.force_btgt = p->a.bstart[DST];
+       wr_dir_args.force_btgt = au_wbr(dentry, wr_dir_args.force_btgt);
+       err = au_wr_dir(dentry, src_dentry, &wr_dir_args);
+       p->a.btgt = err;
+       if (unlikely(err < 0))
+               goto out_unlock;
+
+       /* are they available to be renamed */
+       err = 0;
+       au_nhash_init(&p->a.whlist);
+       if (au_ftest_ren(p->a.flags, ISDIR) && inode[DST]) {
+               au_set_dbstart(dentry, p->a.bstart[DST]);
+               err = may_rename_dstdir(dentry, p->a.btgt, &p->a.whlist);
+               au_set_dbstart(dentry, p->a.btgt);
+       }
+       p->a.h_dentry[DST] = au_h_dptr(dentry, au_dbstart(dentry));
+       if (unlikely(err))
+               goto out_unlock;
+       /* todo: minor optimize,
+          their sb may be same while their bindex differs? */
+       p->a.h_dentry[SRC] = au_h_dptr(src_dentry, au_dbstart(src_dentry));
+       if (au_ftest_ren(p->a.flags, ISDIR)) {
+               err = may_rename_srcdir(src_dentry, p->a.btgt);
+               if (unlikely(err))
+                       goto out_children;
+       }
+
+       /* prepare the writable parent dir on the same branch */
+       if (p->a.bstart[DST] == p->a.btgt) {
+               au_fset_ren(p->a.flags, WHDST);
+       } else {
+               err = au_cpup_dirs(dentry, p->a.btgt);
+               if (unlikely(err))
+                       goto out_children;
+       }
+
+       if (src_dir != dir) {
+               /*
+                * this temporary unlock is safe,
+                * because both dir->i_mutex are locked.
+                */
+               di_write_unlock(p->a.parent[DST]);
+               di_write_lock_parent(p->a.parent[SRC]);
+               err = au_wr_dir_need_wh
+                       (src_dentry, au_ftest_ren(p->a.flags, ISDIR),
+                        &p->a.btgt);
+               di_write_unlock(p->a.parent[SRC]);
+               di_write_lock2_parent(p->a.parent[SRC], p->a.parent[DST],
+                                     /*isdir*/1);
+               au_fclr_ren(p->a.flags, ISSAMEDIR);
+       } else
+               err = au_wr_dir_need_wh
+                       (src_dentry, au_ftest_ren(p->a.flags, ISDIR),
+                        &p->a.btgt);
+       if (unlikely(err < 0))
+               goto out_children;
+       if (err)
+               au_fset_ren(p->a.flags, WHSRC);
+
+       hinotify = au_opt_test(p->a.mnt_flags, UDBA_INOTIFY);
+       p->a.h_parent[SRC] = au_h_dptr(p->a.parent[SRC], p->a.btgt);
+       p->a.h_parent[DST] = au_h_dptr(p->a.parent[DST], p->a.btgt);
+       err = au_ren_lock(&p->a);
+       if (unlikely(err))
+               goto out_children;
+
+       if (!au_opt_test(p->a.mnt_flags, UDBA_NONE)) {
+               p->a.ndx.nfsmnt = au_nfsmnt(p->a.sb, p->a.btgt);
+               if (au_ftest_ren(p->a.flags, DLGT))
+                       au_fset_ndx(p->a.ndx.flags, DLGT);
+               err = au_may_ren(&p->a);
+               if (unlikely(err))
+                       goto out_hdir;
+               memset(&p->a.ndx, 0, sizeof(p->a.ndx));
+       }
+
+       /* store timestamps to be revertible */
+       au_dtime_store(p->dt[PARENT] + SRC, p->a.parent[SRC],
+                      p->a.h_parent[SRC], au_pinned_hdir(p->a.pin + SRC),
+                      au_pinned_hgdir(p->a.pin + SRC)
+                      /* hgdir[SRC] */);
+       if (!au_ftest_ren(p->a.flags, ISSAMEDIR))
+               au_dtime_store(p->dt[PARENT] + DST, p->a.parent[DST],
+                              p->a.h_parent[DST],
+                              au_pinned_hdir(p->a.pin + DST),
+                              au_pinned_hgdir(p->a.pin + DST)
+                              /* hgdir[DST] */);
+       do_dt_dstdir = 0;
+       if (au_ftest_ren(p->a.flags, ISDIR)) {
+               au_dtime_store(p->dt[CHILD] + SRC, src_dentry,
+                              p->a.h_dentry[SRC], au_hi(inode[SRC], p->a.btgt),
+                              au_pinned_hdir(p->a.pin + SRC));
+               if (p->a.h_dentry[DST]->d_inode) {
+                       do_dt_dstdir = 1;
+                       au_dtime_store(p->dt[CHILD] + DST, dentry,
+                                      p->a.h_dentry[DST],
+                                      au_hi(inode[DST], p->a.btgt),
+                                      au_pinned_hdir(p->a.pin + DST));
+               }
+       }
+
+       err = do_rename(&p->a);
+       if (unlikely(err))
+               goto out_dt;
+
+       /* update dir attributes */
+       dir->i_version++;
+       if (au_ftest_ren(p->a.flags, ISDIR)) {
+               /* is this updating defined in POSIX? */
+               /* mutex_lock(&inode[SRC]->i_mutex); */
+               au_cpup_attr_timesizes(inode[SRC]);
+               /* mutex_unlock(&inode[SRC]->i_mutex); */
+
+               au_cpup_attr_nlink(dir, /*force*/1);
+               if (inode[DST]) {
+                       clear_nlink(inode[DST]);
+                       au_cpup_attr_timesizes(inode[DST]);
+               }
+       }
+       if (au_ibstart(dir) == p->a.btgt)
+               au_cpup_attr_timesizes(dir);
+
+       if (!au_ftest_ren(p->a.flags, ISSAMEDIR)) {
+               src_dir->i_version++;
+               if (au_ftest_ren(p->a.flags, ISDIR))
+                       au_cpup_attr_nlink(src_dir, /*force*/1);
+               if (au_ibstart(src_dir) == p->a.btgt)
+                       au_cpup_attr_timesizes(src_dir);
+       }
+
+       /* todo: simple d_drop(src_dentry) is not enough? */
+       /* dput/iput all lower dentries */
+       au_set_dbwh(src_dentry, -1);
+       bend = au_dbend(src_dentry);
+       for (bindex = p->a.btgt + 1; bindex <= bend; bindex++) {
+               struct dentry *hd;
+               hd = au_h_dptr(src_dentry, bindex);
+               if (hd)
+                       au_set_h_dptr(src_dentry, bindex, NULL);
+       }
+       au_set_dbend(src_dentry, p->a.btgt);
+
+       if (au_opt_test(p->a.mnt_flags, PLINK)
+           && au_plink_test(src_dentry->d_sb, inode[SRC]))
+               goto out_hdir; /* success */
+       bend = au_ibend(inode[SRC]);
+       for (bindex = p->a.btgt + 1; bindex <= bend; bindex++) {
+               struct inode *hi;
+               hi = au_h_iptr(inode[SRC], bindex);
+               if (hi) {
+                       au_xino_write0(p->a.sb, bindex, hi->i_ino, 0);
+                       /* ignore this error */
+                       au_set_h_iptr(inode[SRC], bindex, NULL, 0);
+               }
+       }
+       au_set_ibend(inode[SRC], p->a.btgt);
+       goto out_hdir; /* success */
+
+ out_dt:
+       au_dtime_revert(p->dt[PARENT] + SRC);
+       if (!au_ftest_ren(p->a.flags, ISSAMEDIR))
+               au_dtime_revert(p->dt[PARENT] + DST);
+       if (au_ftest_ren(p->a.flags, ISDIR) && err != -EIO) {
+               struct dentry *hd;
+
+               hd = p->dt[CHILD][SRC].dt_h_dentry;
+               mutex_lock_nested(&hd->d_inode->i_mutex, AuLsc_I_CHILD);
+               au_dtime_revert(p->dt[CHILD] + SRC);
+               mutex_unlock(&hd->d_inode->i_mutex);
+               if (do_dt_dstdir) {
+                       hd = p->dt[CHILD][DST].dt_h_dentry;
+                       mutex_lock_nested(&hd->d_inode->i_mutex, AuLsc_I_CHILD);
+                       au_dtime_revert(p->dt[CHILD] + DST);
+                       mutex_unlock(&hd->d_inode->i_mutex);
+               }
+       }
+ out_hdir:
+       au_ren_unlock(&p->a);
+ out_children:
+       au_nhash_fin(&p->a.whlist);
+ out_unlock:
+       if (unlikely(err && au_ftest_ren(p->a.flags, ISDIR))) {
+               au_update_dbstart(dentry);
+               d_drop(dentry);
+       }
+       if (!err) {
+               d_move(src_dentry, dentry);
+               if (inode[DST]
+                   && (inode[DST]->i_nlink == 1
+                       || au_ftest_ren(p->a.flags, ISDIR)))
+                               inode[DST]->i_flags |= S_DEAD;
+       }
+       if (au_ftest_ren(p->a.flags, ISSAMEDIR))
+               di_write_unlock(p->a.parent[DST]);
+       else
+               di_write_unlock2(p->a.parent[SRC], p->a.parent[DST]);
+       aufs_read_and_write_unlock2(dentry, src_dentry);
+ out_free:
+       kfree(p);
+ out:
+       iput(inode[DST]);
+       AuTraceErr(err);
+       //lktr_clear_pid(current->pid, LktrArrayPid);
+       if (unlikely(err == -EBUSY && au_test_nfsd(current)))
+               err = -ESTALE;
+       return err;
+}
diff -urN linux/fs/aufs/Makefile linux-aufs/fs/aufs/Makefile
--- linux/fs/aufs/Makefile      1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/Makefile 2008-10-20 03:47:24.000000000 +0200
@@ -0,0 +1,74 @@
+# AUFS Makefile for the Linux 2.6.25 and later
+# $Id$
+
+# the environment variables are not inherited since 2.6.23
+ifdef AUFS_EXTRA_CFLAGS
+ccflags-y += ${AUFS_EXTRA_CFLAGS}
+endif
+
+########################################
+
+ifdef CONFIG_AUFS_RR_SQUASHFS
+# cf. squashfs3.2-r2 and sqlzma patch.
+ccflags-y += -DSQUASHFS_MAGIC=0x73717368
+ccflags-y += -DSQUASHFS_MAGIC_SWAP=0x68737173
+ccflags-y += -DSQUASHFS_MAGIC_LZMA=0x71736873
+ccflags-y += -DSQUASHFS_MAGIC_LZMA_SWAP=0x73687371
+endif
+
+# defined in ${srctree}/fs/fuse/inode.c
+ccflags-$(CONFIG_AUFS_WORKAROUND_FUSE) += -DFUSE_SUPER_MAGIC=0x65735546
+
+# defined in ${srctree}/fs/xfs/xfs_sb.h
+# tristate
+ifdef CONFIG_XFS_FS
+ccflags-y += -DXFS_SB_MAGIC=0x58465342
+endif
+
+# defined in ${srctree}/mm/shmem.c
+# tristate
+ifdef CONFIG_TMPFS
+ccflags-y += -DTMPFS_MAGIC=0x01021994
+endif
+
+# defined in ${srctree}fs/sysfs/mount.c
+# bool
+ccflags-$(CONFIG_SYSFS) += -DSYSFS_MAGIC=0x62656572
+
+ifndef EXTRAVERSION
+EXTRAVERSION = $(shell echo ${KERNELVERSION} | cut -f3- -d. | cut -f2- -d-)
+endif
+# for -mm tree, support the latest version only
+ifneq ($(strip $(shell echo ${EXTRAVERSION} | fgrep -- mm)),)
+ccflags-y += -DCONFIG_AUFS_UNIONFS22_PATCH -DCONFIG_AUFS_UNIONFS23_PATCH
+endif
+
+-include $(dir $(lastword ${MAKEFILE_LIST}))priv.mk
+#$(warning ${ccflags-y})
+
+########################################
+
+obj-$(CONFIG_AUFS) += aufs.o
+aufs-y := module.o super.o sbinfo.o branch.o xino.o sysaufs.o opts.o \
+       wkq.o vfsub.o dcsub.o \
+       cpup.o whout.o plink.o wbr_policy.o \
+       dentry.o dinfo.o \
+       file.o f_op.o finfo.o \
+       dir.o vdir.o \
+       inode.o i_op.o i_op_add.o i_op_del.o i_op_ren.o iinfo.o \
+       misc.o
+
+aufs-$(CONFIG_SYSFS) += sysfs.o
+aufs-$(CONFIG_AUFS_BR_NFS) += br_nfs.o
+aufs-$(CONFIG_AUFS_BR_XFS) += br_xfs.o
+aufs-$(CONFIG_AUFS_WORKAROUND_FUSE) += br_fuse.o
+aufs-$(CONFIG_AUFS_DLGT) += dlgt.o
+aufs-$(CONFIG_AUFS_HINOTIFY) += hinotify.o
+aufs-$(CONFIG_AUFS_HIN_OR_DLGT) += hin_or_dlgt.o
+aufs-$(CONFIG_AUFS_GETATTR) += getattr.o
+aufs-$(CONFIG_AUFS_EXPORT) += export.o
+aufs-$(CONFIG_AUFS_ROBR) += robr.o
+# reserved for future use
+#aufs-$(CONFIG_AUFS_XATTR) += xattr.o
+aufs-$(CONFIG_AUFS_DEBUG) += debug.o
+aufs-$(CONFIG_AUFS_MAGIC_SYSRQ) += sysrq.o
diff -urN linux/fs/aufs/misc.c linux-aufs/fs/aufs/misc.c
--- linux/fs/aufs/misc.c        1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/misc.c   2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,308 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * $Id$
+ */
+
+#include "aufs.h"
+
+void *au_kzrealloc(void *p, unsigned int nused, unsigned int new_sz, gfp_t gfp)
+{
+       void *q;
+
+       LKTRTrace("p %p, nused %d, sz %d\n", p, nused, new_sz);
+       AuDebugOn(new_sz <= 0);
+       if (new_sz <= nused)
+               return p;
+
+       q = krealloc(p, new_sz, gfp);
+       if (q)
+               memset(q + nused, 0, new_sz - nused);
+       return q;
+}
+
+/* ---------------------------------------------------------------------- */
+
+struct nameidata *au_dup_nd(struct au_sbinfo *sbinfo, struct nameidata *dst,
+                           struct nameidata *src)
+{
+       LKTRTrace("src %p\n", src);
+
+       if (src) {
+               *dst = *src;
+               dst->flags &= ~LOOKUP_PARENT;
+               if (sbinfo->si_wbr_create == AuWbrCreate_TDP) {
+                       if ((dst->flags & LOOKUP_CREATE)
+                           && !(dst->intent.open.flags & O_CREAT))
+                               dst->flags &= ~LOOKUP_CREATE;
+               } else {
+                       dst->flags &= ~LOOKUP_CREATE;
+                       dst->intent.open.flags &= ~O_CREAT;
+               }
+       } else
+               dst = NULL;
+
+       return dst;
+}
+
+struct nameidata *au_fake_dm(struct nameidata *fake_nd, struct nameidata *nd,
+                            struct super_block *sb, aufs_bindex_t bindex)
+{
+       LKTRTrace("nd %p, b%d\n", nd, bindex);
+
+       if (!nd)
+               return NULL;
+
+       DiMustAnyLock(nd->path.dentry);
+
+       fake_nd->path.dentry = NULL;
+       fake_nd->path.mnt = NULL;
+
+       if (bindex <= au_dbend(nd->path.dentry))
+               fake_nd->path.dentry = au_h_dptr(nd->path.dentry, bindex);
+       if (fake_nd->path.dentry) {
+               fake_nd->path.mnt = au_sbr_mnt(sb, bindex);
+               AuDebugOn(!fake_nd->path.mnt);
+               path_get(&fake_nd->path);
+       } else
+               fake_nd = ERR_PTR(-ENOENT);
+
+       AuTraceErrPtr(fake_nd);
+       return fake_nd;
+}
+
+void au_fake_dm_release(struct nameidata *fake_nd)
+{
+       if (fake_nd)
+               path_put(&fake_nd->path);
+}
+
+int au_h_create(struct inode *h_dir, struct dentry *h_dentry, int mode,
+               struct vfsub_args *vargs, struct nameidata *nd,
+               struct vfsmount *nfsmnt)
+{
+       int err;
+
+       LKTRTrace("hi%lu, %.*s, 0%o, nd %d, nfsmnt %d\n",
+                 h_dir->i_ino, AuDLNPair(h_dentry), mode, !!nd, !!nfsmnt);
+
+       err = -ENOSYS;
+       if (!nfsmnt)
+               err = vfsub_create(h_dir, h_dentry, mode, /*nd*/NULL, vargs);
+       else {
+               struct nameidata fake_nd;
+
+               if (nd)
+                       fake_nd = *nd;
+               else
+                       memset(&fake_nd, 0, sizeof(fake_nd));
+               fake_nd.path.dentry = h_dentry;
+               fake_nd.path.mnt = nfsmnt;
+               path_get(&fake_nd.path);
+               fake_nd.flags = LOOKUP_CREATE;
+               fake_nd.intent.open.flags = O_CREAT | FMODE_READ;
+               fake_nd.intent.open.create_mode = mode;
+
+               err = vfsub_create(h_dir, h_dentry, mode, &fake_nd, vargs);
+               path_put(&fake_nd.path);
+       }
+
+       AuTraceErr(err);
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* empty_zero_page is not exported on PPC before 2.6.26 */
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 26) \
+       && (defined(CONFIG_PPC) || defined(CONFIG_PPC64))
+static char *au_zp_alloc(void)
+{
+       return (void *)get_zeroed_page(GFP_NOFS);
+}
+
+static void au_zp_free(char *p)
+{
+       if (p)
+               free_page((unsigned long)p);
+}
+#else
+static char *au_zp_alloc(void)
+{
+       return page_address(ZERO_PAGE(0));
+}
+
+static void au_zp_free(char *p)
+{
+       /* empty */
+}
+#endif
+
+int au_copy_file(struct file *dst, struct file *src, loff_t len,
+                struct au_hinode *hdir, struct super_block *sb,
+                struct vfsub_args *vargs)
+{
+       int err, all_zero, do_kfree;
+       unsigned long blksize;
+       char *buf, *zp;
+       /* reduce stack usage */
+       struct iattr *ia;
+
+       LKTRTrace("%.*s, %.*s\n",
+                 AuDLNPair(dst->f_dentry), AuDLNPair(src->f_dentry));
+       AuDebugOn(!(dst->f_mode & FMODE_WRITE));
+#ifdef CONFIG_AUFS_DEBUG
+       {
+               struct dentry *parent;
+               parent = dget_parent(dst->f_dentry);
+               IMustLock(parent->d_inode);
+               dput(parent);
+       }
+#endif
+
+       err = -ENOMEM;
+       zp = au_zp_alloc();
+       if (unlikely(!zp))
+               goto out;
+       blksize = dst->f_dentry->d_sb->s_blocksize;
+       if (!blksize || PAGE_SIZE < blksize)
+               blksize = PAGE_SIZE;
+       LKTRTrace("blksize %lu\n", blksize);
+       do_kfree = (blksize != PAGE_SIZE && blksize >= sizeof(*ia));
+       if (do_kfree)
+               buf = kmalloc(blksize, GFP_NOFS);
+       else
+               buf = (void *)__get_free_page(GFP_NOFS);
+       if (unlikely(!buf))
+               goto out;
+
+#ifdef CONFIG_AUFS_DEBUG
+       if (len > (1 << 22))
+               AuWarn("copying a large file %lld\n", (long long)len);
+#endif
+       err = 0;
+       all_zero = 0;
+       src->f_pos = 0;
+       dst->f_pos = 0;
+       while (len) {
+               size_t sz, rbytes, wbytes;
+               char *p;
+
+               LKTRTrace("len %lld\n", len);
+               sz = blksize;
+               if (len < blksize)
+                       sz = len;
+
+               /* support LSM and notify */
+               rbytes = 0;
+               /* todo: signal_pending? */
+               while (!rbytes || err == -EAGAIN || err == -EINTR) {
+                       rbytes = vfsub_read_k(src, buf, sz, &src->f_pos,
+                                             vfsub_ftest(vargs->flags, DLGT));
+                       err = rbytes;
+               }
+               if (unlikely(err < 0))
+                       break;
+
+               all_zero = 0;
+               if (len >= rbytes && rbytes == blksize) {
+#if 1
+                       all_zero = !memcmp(buf, zp, rbytes);
+#else /* reserved for future use */
+                       unsigned long long *ullp;
+                       size_t n, i;
+
+                       all_zero = 1;
+                       ullp = (void *)buf;
+                       n = rbytes / sizeof(*ullp);
+                       i = n;
+                       while (n-- > 0 && all_zero)
+                               all_zero = !*ullp++;
+                       p = (void *)ullp;
+                       i *= sizeof(*ullp);
+                       for (; all_zero && i < rbytes; i++)
+                               all_zero = !*p++;
+#endif
+               }
+               if (!all_zero) {
+                       wbytes = rbytes;
+                       p = buf;
+                       while (wbytes) {
+                               size_t b;
+                               /* support LSM and notify */
+                               vfsub_args_reinit(vargs);
+                               vfsub_ign_hinode(vargs, IN_MODIFY, hdir);
+                               b = vfsub_write_k(dst, p, wbytes, &dst->f_pos,
+                                                 vargs);
+                               err = b;
+                               /* todo: signal_pending? */
+                               if (unlikely(err == -EAGAIN || err == -EINTR))
+                                       continue;
+                               if (unlikely(err < 0))
+                                       break;
+                               wbytes -= b;
+                               p += b;
+                       }
+               } else {
+                       loff_t res;
+                       LKTRLabel(hole);
+                       res = vfsub_llseek(dst, rbytes, SEEK_CUR);
+                       err = res;
+                       if (unlikely(res < 0))
+                               break;
+               }
+               len -= rbytes;
+               err = 0;
+       }
+
+       /* the last block may be a hole */
+       if (!err && all_zero) {
+               struct dentry *h_d = dst->f_dentry;
+               struct inode *h_i = h_d->d_inode;
+
+               LKTRLabel(last hole);
+               do {
+                       /* todo: signal_pending? */
+                       vfsub_args_reinit(vargs);
+                       vfsub_ign_hinode(vargs, IN_MODIFY, hdir);
+                       err = vfsub_write_k(dst, "\0", 1, &dst->f_pos, vargs);
+               } while (err == -EAGAIN || err == -EINTR);
+               if (err == 1) {
+                       ia = (void *)buf;
+                       ia->ia_size = dst->f_pos;
+                       ia->ia_valid = ATTR_SIZE | ATTR_FILE;
+                       ia->ia_file = dst;
+                       vfsub_args_reinit(vargs);
+                       vfsub_ign_hinode(vargs, vfsub_events_notify_change(ia),
+                                        hdir);
+                       mutex_lock_nested(&h_i->i_mutex, AuLsc_I_CHILD2);
+                       err = vfsub_notify_change(h_d, ia, vargs);
+                       mutex_unlock(&h_i->i_mutex);
+               }
+       }
+       if (do_kfree)
+               kfree(buf);
+       else
+               free_page((unsigned long)buf);
+
+ out:
+       au_zp_free(zp);
+       AuTraceErr(err);
+       return err;
+}
diff -urN linux/fs/aufs/misc.h linux-aufs/fs/aufs/misc.h
--- linux/fs/aufs/misc.h        1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/misc.h   2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,244 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * $Id$
+ */
+
+#ifndef __AUFS_MISC_H__
+#define __AUFS_MISC_H__
+
+#ifdef __KERNEL__
+
+#include <linux/fs.h>
+#include <linux/namei.h>
+#include <linux/aufs_type.h>
+
+/* ---------------------------------------------------------------------- */
+
+typedef unsigned int au_gen_t;
+/* see linux/include/linux/jiffies.h */
+#define AuGenYounger(a, b)     ((int)(b) - (int)(a) < 0)
+#define AuGenOlder(a, b)       AufsGenYounger(b, a)
+
+/* ---------------------------------------------------------------------- */
+
+struct au_splhead {
+       spinlock_t              spin;
+       struct list_head        head;
+};
+
+static inline void au_spl_init(struct au_splhead *spl)
+{
+       spin_lock_init(&spl->spin);
+       INIT_LIST_HEAD(&spl->head);
+}
+
+static inline void au_spl_add(struct list_head *list, struct au_splhead *spl)
+{
+       spin_lock(&spl->spin);
+       list_add(list, &spl->head);
+       spin_unlock(&spl->spin);
+}
+
+static inline void au_spl_del(struct list_head *list, struct au_splhead *spl)
+{
+       spin_lock(&spl->spin);
+       list_del(list);
+       spin_unlock(&spl->spin);
+}
+
+/* ---------------------------------------------------------------------- */
+
+struct au_rwsem {
+       struct rw_semaphore     rwsem;
+#ifdef CONFIG_AUFS_DEBUG
+       atomic_t                rcnt;
+#endif
+};
+
+#ifdef CONFIG_AUFS_DEBUG
+#define AuDbgRcntInit(rw) do { \
+       atomic_set(&(rw)->rcnt, 0); \
+       smp_mb(); /* atomic set */ \
+} while (0)
+
+#define AuDbgRcntInc(rw)       atomic_inc_return(&(rw)->rcnt)
+#define AuDbgRcntDec(rw)       WARN_ON(atomic_dec_return(&(rw)->rcnt) < 0)
+#else
+#define AuDbgRcntInit(rw)      do {} while (0)
+#define AuDbgRcntInc(rw)       do {} while (0)
+#define AuDbgRcntDec(rw)       do {} while (0)
+#endif /* CONFIG_AUFS_DEBUG */
+
+#define au_rwsem_destroy(rw)   AuDebugOn(rwsem_is_locked(&(rw)->rwsem))
+
+static inline void au_rw_init_nolock(struct au_rwsem *rw)
+{
+       AuDbgRcntInit(rw);
+       init_rwsem(&rw->rwsem);
+}
+
+static inline void au_rw_init_wlock(struct au_rwsem *rw)
+{
+       au_rw_init_nolock(rw);
+       down_write(&rw->rwsem);
+}
+
+static inline void au_rw_init_wlock_nested(struct au_rwsem *rw,
+                                          unsigned int lsc)
+{
+       au_rw_init_nolock(rw);
+       down_write_nested(&rw->rwsem, lsc);
+}
+
+static inline void au_rw_read_lock(struct au_rwsem *rw)
+{
+       down_read(&rw->rwsem);
+       AuDbgRcntInc(rw);
+}
+
+static inline void au_rw_read_lock_nested(struct au_rwsem *rw, unsigned int lsc)
+{
+       down_read_nested(&rw->rwsem, lsc);
+       AuDbgRcntInc(rw);
+}
+
+static inline void au_rw_read_unlock(struct au_rwsem *rw)
+{
+       AuDbgRcntDec(rw);
+       up_read(&rw->rwsem);
+}
+
+static inline void au_rw_dgrade_lock(struct au_rwsem *rw)
+{
+       AuDbgRcntInc(rw);
+       downgrade_write(&rw->rwsem);
+}
+
+static inline void au_rw_write_lock(struct au_rwsem *rw)
+{
+       down_write(&rw->rwsem);
+}
+
+static inline void au_rw_write_lock_nested(struct au_rwsem *rw,
+                                          unsigned int lsc)
+{
+       down_write_nested(&rw->rwsem, lsc);
+}
+
+static inline void au_rw_write_unlock(struct au_rwsem *rw)
+{
+       up_write(&rw->rwsem);
+}
+
+/* why is not _nested version defined */
+static inline int au_rw_read_trylock(struct au_rwsem *rw)
+{
+       int ret = down_read_trylock(&rw->rwsem);
+       if (ret)
+               AuDbgRcntInc(rw);
+       return ret;
+}
+
+static inline int au_rw_write_trylock(struct au_rwsem *rw)
+{
+       return down_write_trylock(&rw->rwsem);
+}
+
+#undef AuDbgRcntInit
+#undef AuDbgRcntInc
+#undef AuDbgRcntDec
+
+/* to debug easier, do not make them inlined functions */
+#define AuRwMustNoWaiters(rw)  AuDebugOn(!list_empty(&(rw)->rwsem.wait_list))
+#define AuRwMustAnyLock(rw)    AuDebugOn(down_write_trylock(&(rw)->rwsem))
+#ifdef CONFIG_AUFS_DEBUG
+#define AuRwMustReadLock(rw) do { \
+       AuRwMustAnyLock(rw); \
+       AuDebugOn(!atomic_read(&(rw)->rcnt)); \
+} while (0)
+
+#define AuRwMustWriteLock(rw) do { \
+       AuRwMustAnyLock(rw); \
+       AuDebugOn(atomic_read(&(rw)->rcnt)); \
+} while (0)
+#else
+#define AuRwMustReadLock(rw)   AuRwMustAnyLock(rw)
+#define AuRwMustWriteLock(rw)  AuRwMustAnyLock(rw)
+#endif /* CONFIG_AUFS_DEBUG */
+
+#define AuSimpleLockRwsemFuncs(prefix, param, rwsem) \
+static inline void prefix##_read_lock(param) \
+{ au_rw_read_lock(&(rwsem)); } \
+static inline void prefix##_write_lock(param) \
+{ au_rw_write_lock(&(rwsem)); } \
+static inline int prefix##_read_trylock(param) \
+{ return au_rw_read_trylock(&(rwsem)); } \
+static inline int prefix##_write_trylock(param) \
+{ return au_rw_write_trylock(&(rwsem)); }
+/* static inline void prefix##_read_trylock_nested(param, lsc)
+{au_rw_read_trylock_nested(&(rwsem, lsc));}
+static inline void prefix##_write_trylock_nestd(param, lsc)
+{au_rw_write_trylock_nested(&(rwsem), nested);} */
+
+#define AuSimpleUnlockRwsemFuncs(prefix, param, rwsem) \
+static inline void prefix##_read_unlock(param) \
+{ au_rw_read_unlock(&(rwsem)); } \
+static inline void prefix##_write_unlock(param) \
+{ au_rw_write_unlock(&(rwsem)); } \
+static inline void prefix##_downgrade_lock(param) \
+{ au_rw_dgrade_lock(&(rwsem)); }
+
+#define AuSimpleRwsemFuncs(prefix, param, rwsem) \
+       AuSimpleLockRwsemFuncs(prefix, param, rwsem) \
+       AuSimpleUnlockRwsemFuncs(prefix, param, rwsem)
+
+/* ---------------------------------------------------------------------- */
+
+void *au_kzrealloc(void *p, unsigned int nused, unsigned int new_sz, gfp_t gfp);
+
+struct au_nd_store {
+       unsigned int            flags;
+       struct path             path;
+       struct open_intent      intent;
+};
+struct au_sbinfo;
+void au_nd_store(struct au_nd_store *store, struct nameidata *nd,
+                struct au_sbinfo *sbinfo);
+void au_nd_revert(struct au_nd_store *store, struct nameidata *nd,
+                 struct au_sbinfo *sbinfo);
+
+struct nameidata *au_dup_nd(struct au_sbinfo *sbinfo, struct nameidata *dst,
+                           struct nameidata *src);
+
+struct nameidata *au_fake_dm(struct nameidata *fake_nd, struct nameidata *nd,
+                            struct super_block *sb, aufs_bindex_t bindex);
+void au_fake_dm_release(struct nameidata *fake_nd);
+struct vfsub_args;
+int au_h_create(struct inode *h_dir, struct dentry *h_dentry, int mode,
+               struct vfsub_args *vargs, struct nameidata *nd,
+               struct vfsmount *nfsmnt);
+
+struct au_hinode;
+int au_copy_file(struct file *dst, struct file *src, loff_t len,
+                struct au_hinode *hdir, struct super_block *sb,
+                struct vfsub_args *vargs);
+
+#endif /* __KERNEL__ */
+#endif /* __AUFS_MISC_H__ */
diff -urN linux/fs/aufs/module.c linux-aufs/fs/aufs/module.c
--- linux/fs/aufs/module.c      1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/module.c 2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,269 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * module global variables and operations
+ *
+ * $Id$
+ */
+
+#include <linux/module.h>
+#include "aufs.h"
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * aufs caches
+ */
+struct kmem_cache *au_cachep[AuCache_Last];
+static int __init create_cache(void)
+{
+       au_cachep[AuCache_DINFO] = AuCache(au_dinfo);
+       if (au_cachep[AuCache_DINFO])
+               au_cachep[AuCache_ICNTNR] = AuCache(aufs_icntnr);
+       if (au_cachep[AuCache_ICNTNR])
+               au_cachep[AuCache_FINFO] = AuCache(au_finfo);
+       if (au_cachep[AuCache_FINFO])
+               au_cachep[AuCache_VDIR] = AuCache(au_vdir);
+       if (au_cachep[AuCache_VDIR])
+               au_cachep[AuCache_DEHSTR] = AuCache(au_vdir_dehstr);
+       if (au_cachep[AuCache_DEHSTR])
+               return 0;
+
+       return -ENOMEM;
+}
+
+static void destroy_cache(void)
+{
+       int i;
+       for (i = 0; i < AuCache_Last; i++)
+               if (au_cachep[i]) {
+                       kmem_cache_destroy(au_cachep[i]);
+                       au_cachep[i] = NULL;
+               }
+}
+
+/* ---------------------------------------------------------------------- */
+
+char au_esc_chars[0x20 + 3]; /* 0x01-0x20, backslash, del, and NULL */
+int au_dir_roflags;
+
+/*
+ * functions for module interface.
+ */
+MODULE_LICENSE("GPL");
+/* MODULE_LICENSE("GPL v2"); */
+MODULE_AUTHOR("Junjiro Okajima");
+MODULE_DESCRIPTION(AUFS_NAME " -- Another unionfs");
+MODULE_VERSION(AUFS_VERSION);
+
+/* it should be 'byte', but param_set_byte() prints it by "%c" */
+short aufs_nwkq = AUFS_NWKQ_DEF;
+MODULE_PARM_DESC(nwkq, "the number of workqueue thread, " AUFS_WKQ_NAME);
+module_param_named(nwkq, aufs_nwkq, short, S_IRUGO);
+
+int sysaufs_brs;
+MODULE_PARM_DESC(brs, "use <sysfs>/fs/aufs/si_*/brN");
+module_param_named(brs, sysaufs_brs, int, S_IRUGO);
+
+/* ---------------------------------------------------------------------- */
+
+static int __init aufs_init(void)
+{
+       int err, i;
+       char *p;
+
+       au_debug_init();
+#ifdef CONFIG_AUFS_INO_T_64
+       BUILD_BUG_ON(sizeof(ino_t) != sizeof(long long));
+#else
+       BUILD_BUG_ON(sizeof(ino_t) != sizeof(int));
+#endif
+
+       p = au_esc_chars;
+       for (i = 1; i <= ' '; i++)
+               *p++ = i;
+       *p++ = '\\';
+       *p++ = '\x7f';
+       *p = 0;
+
+       au_dir_roflags = au_file_roflags(O_DIRECTORY | O_LARGEFILE);
+
+       err = -EINVAL;
+       if (unlikely(aufs_nwkq <= 0))
+               goto out;
+
+       err = sysaufs_init();
+       if (unlikely(err))
+               goto out;
+       err = au_wkq_init();
+       if (unlikely(err))
+               goto out_sysaufs;
+       err = au_inotify_init();
+       if (unlikely(err))
+               goto out_wkq;
+       err = au_sysrq_init();
+       if (unlikely(err))
+               goto out_inotify;
+
+       err = create_cache();
+       if (unlikely(err))
+               goto out_sysrq;
+
+       err = register_filesystem(&aufs_fs_type);
+       if (unlikely(err))
+               goto out_cache;
+       pr_info(AUFS_NAME " " AUFS_VERSION "\n");
+       return 0; /* success */
+
+ out_cache:
+       destroy_cache();
+ out_sysrq:
+       au_sysrq_fin();
+ out_inotify:
+       au_inotify_fin();
+ out_wkq:
+       au_wkq_fin();
+ out_sysaufs:
+       sysaufs_fin();
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+static void __exit aufs_exit(void)
+{
+       unregister_filesystem(&aufs_fs_type);
+       destroy_cache();
+
+       au_sysrq_fin();
+       au_inotify_fin();
+       au_wkq_fin();
+       sysaufs_fin();
+}
+
+module_init(aufs_init);
+module_exit(aufs_exit);
+
+/* ---------------------------------------------------------------------- */
+
+/* fake Kconfig */
+#if 1
+
+#if AUFS_BRANCH_MAX > 511 && PAGE_SIZE > 4096
+#warning pagesize is larger than 4kb, \
+       CONFIG_AUFS_BRANCH_MAX_511 or smaller is recommended.
+#endif
+
+#ifdef CONFIG_AUFS_STAT
+#ifndef CONFIG_SYSFS
+#error CONFIG_AUFS_STAT requires CONFIG_SYSFS.
+#endif
+#endif /* CONFIG_AUFS_STAT */
+
+#ifdef CONFIG_AUFS_SYSAUFS
+#warning CONFIG_AUFS_SYSAUFS is unnecessary for linux-2.6.25 and later.
+#endif
+
+#ifdef CONFIG_AUFS_HINOTIFY
+#ifndef CONFIG_INOTIFY
+#error enable CONFIG_INOTIFY to use CONFIG_AUFS_HINOTIFY.
+#endif
+#endif /* CONFIG_AUFS_HINOTIFY */
+
+#ifdef CONFIG_AUFS_EXPORT
+#if !defined(CONFIG_EXPORTFS) && !defined(CONFIG_EXPORTFS_MODULE)
+#error CONFIG_AUFS_EXPORT requires CONFIG_EXPORTFS
+#endif
+#if defined(CONFIG_EXPORTFS_MODULE) && defined(CONFIG_AUFS)
+#error need CONFIG_EXPORTFS = y to link aufs statically with CONFIG_AUFS_EXPORT.
+#endif
+#endif /* CONFIG_AUFS_EXPORT */
+
+#ifdef CONFIG_AUFS_SEC_PERM_PATCH
+#ifndef CONFIG_SECURITY
+#warning AUFS_SEC_PERM_PATCH is unnecessary since SECURITY is disabled.
+#endif
+#ifdef CONFIG_AUFS
+#warning AUFS_SEC_PERM_PATCH is unnecessary since AUFS is not a module.
+#endif
+#endif
+
+#ifdef CONFIG_AUFS_LHASH_PATCH
+#if !defined(CONFIG_NFS_FS) && !defined(CONFIG_NFS_FS_MODULE)
+#warning CONFIG_AUFS_LHASH_PATCH is unnecessary since CONFIG_NFS_FS is disabled.
+#endif
+#endif
+
+#ifdef CONFIG_AUFS_PUT_FILP_PATCH
+#ifndef CONFIG_NFS_V4
+#warning AUFS_PUT_FILP_PATCH is unnecessary since NFS_V4 is disabled.
+#endif
+#ifdef CONFIG_AUFS
+#warning AUFS_PUT_FILP_PATCH is unnecessary since AUFS is not a module.
+#endif
+#endif /* CONFIG_AUFS_PUT_FILP_PATCH */
+
+#ifdef CONFIG_AUFS_FSYNC_SUPER_PATCH
+#ifdef CONFIG_AUFS
+#warning AUFS_FSYNC_SUPER_PATCH is unnecessary since AUFS is not a module.
+#endif
+#endif
+
+#ifdef CONFIG_AUFS_DENY_WRITE_ACCESS_PATCH
+#ifdef CONFIG_AUFS
+#warning AUFS_DENY_WRITE_ACCESS_PATCH is unnecessary since AUFS is not a module.
+#endif
+#endif
+
+#ifdef CONFIG_AUFS_KSIZE_PATCH
+#warning CONFIG_AUFS_KSIZE_PATCH is unnecessary for linux-2.6.22 and later.
+#endif
+
+#ifdef CONFIG_AUFS_WORKAROUND_FUSE
+#if !defined(CONFIG_FUSE_FS) && !defined(CONFIG_FUSE_FS_MODULE)
+#warning CONFIG_AUFS_WORKAROUND_FUSE is enabled while FUSE is disabled.
+#endif
+#endif
+
+#ifdef CONFIG_AUFS_DEBUG_LOCK
+#ifndef CONFIG_AUFS_MAGIC_SYSRQ
+#warning CONFIG_AUFS_DEBUG_LOCK is enabled but CONFIG_AUFS_MAGIC_SYSRQ.
+#endif
+#endif
+
+#ifdef CONFIG_AUFS_COMPAT
+#warning CONFIG_AUFS_COMPAT will be removed in the near future.
+#endif
+
+#ifdef CONFIG_AUFS_UNIONFS23_PATCH
+#ifndef CONFIG_AUFS_UNIONFS22_PATCH
+#error mis-config. AUFS_UNIONFS23_PATCH is enabled but AUFS_UNIONFS22_PATCH.
+#endif
+#ifndef CONFIG_AUFS_SPLICE_PATCH
+#error mis-config. AUFS_UNIONFS23_PATCH is enabled but AUFS_SPLICE_PATCH.
+#endif
+#endif
+
+#ifdef CONFIG_DEBUG_PROVE_LOCKING
+#if MAX_LOCKDEP_SUBCLASSES < AuLsc_I_End
+#warning lockdep will not work since aufs uses deeper locks.
+#endif
+#endif
+
+#endif
diff -urN linux/fs/aufs/module.h linux-aufs/fs/aufs/module.h
--- linux/fs/aufs/module.h      1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/module.h 2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,73 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * module initialization and module-global
+ *
+ * $Id$
+ */
+
+#ifndef __AUFS_MODULE_H__
+#define __AUFS_MODULE_H__
+
+#ifdef __KERNEL__
+
+/* module parameters */
+extern short aufs_nwkq;
+extern int sysaufs_brs;
+
+/* ---------------------------------------------------------------------- */
+
+extern char au_esc_chars[];
+extern int au_dir_roflags;
+
+/* kmem cache */
+enum {
+       AuCache_DINFO,
+       AuCache_ICNTNR,
+       AuCache_FINFO,
+       AuCache_VDIR,
+       AuCache_DEHSTR,
+#ifdef CONFIG_AUFS_HINOTIFY
+       AuCache_HINOTIFY,
+#endif
+       AuCache_Last
+};
+
+extern struct kmem_cache *au_cachep[];
+
+#define AuCacheArgs(type, sz)  (type), (sz), 0, SLAB_RECLAIM_ACCOUNT, NULL
+#define AuCache(type) \
+       kmem_cache_create(AuCacheArgs(#type, sizeof(struct type)))
+
+/* ---------------------------------------------------------------------- */
+
+#define AuCacheFuncs(name, index) \
+static inline void *au_cache_alloc_##name(void) \
+{ return kmem_cache_alloc(au_cachep[index], GFP_NOFS); } \
+static inline void au_cache_free_##name(void *p) \
+{ kmem_cache_free(au_cachep[index], p); }
+
+AuCacheFuncs(dinfo, AuCache_DINFO);
+AuCacheFuncs(icntnr, AuCache_ICNTNR);
+AuCacheFuncs(finfo, AuCache_FINFO);
+AuCacheFuncs(vdir, AuCache_VDIR);
+AuCacheFuncs(dehstr, AuCache_DEHSTR);
+
+#endif /* __KERNEL__ */
+#endif /* __AUFS_MODULE_H__ */
diff -urN linux/fs/aufs/opts.c linux-aufs/fs/aufs/opts.c
--- linux/fs/aufs/opts.c        1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/opts.c   2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,1613 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * mount options/flags
+ *
+ * $Id$
+ */
+
+#include <linux/types.h> /* a distribution requires */
+#include <linux/parser.h>
+#include "aufs.h"
+
+/* ---------------------------------------------------------------------- */
+
+enum {
+       Opt_br,
+       Opt_add, Opt_del, Opt_mod, Opt_reorder, Opt_append, Opt_prepend,
+       Opt_idel, Opt_imod, Opt_ireorder,
+       Opt_dirwh, Opt_rdcache, Opt_deblk, Opt_nhash, Opt_rendir,
+       Opt_xino, Opt_zxino, Opt_noxino,
+       Opt_trunc_xino, Opt_trunc_xino_v, Opt_notrunc_xino,
+       Opt_trunc_xino_path, Opt_itrunc_xino,
+       Opt_xinodir,
+       Opt_trunc_xib, Opt_notrunc_xib,
+       Opt_dirperm1, Opt_nodirperm1,
+       Opt_shwh, Opt_noshwh,
+       Opt_plink, Opt_noplink, Opt_list_plink, Opt_clean_plink,
+       Opt_udba,
+       /* Opt_lock, Opt_unlock, */
+       Opt_cmd, Opt_cmd_args,
+       Opt_diropq_a, Opt_diropq_w,
+       Opt_warn_perm, Opt_nowarn_perm,
+       Opt_wbr_copyup, Opt_wbr_create,
+       Opt_coo,
+       Opt_dlgt, Opt_nodlgt,
+       Opt_refrof, Opt_norefrof,
+       Opt_verbose, Opt_noverbose,
+       Opt_sum, Opt_nosum, Opt_wsum,
+       Opt_tail, Opt_ignore, Opt_ignore_silent, Opt_err
+};
+
+static match_table_t options = {
+       {Opt_br, "br=%s"},
+       {Opt_br, "br:%s"},
+
+       {Opt_add, "add=%d:%s"},
+       {Opt_add, "add:%d:%s"},
+       {Opt_add, "ins=%d:%s"},
+       {Opt_add, "ins:%d:%s"},
+       {Opt_append, "append=%s"},
+       {Opt_append, "append:%s"},
+       {Opt_prepend, "prepend=%s"},
+       {Opt_prepend, "prepend:%s"},
+
+       {Opt_del, "del=%s"},
+       {Opt_del, "del:%s"},
+       /* {Opt_idel, "idel:%d"}, */
+       {Opt_mod, "mod=%s"},
+       {Opt_mod, "mod:%s"},
+       {Opt_imod, "imod:%d:%s"},
+
+       {Opt_dirwh, "dirwh=%d"},
+       {Opt_dirwh, "dirwh:%d"},
+
+       {Opt_xino, "xino=%s"},
+       {Opt_xino, "xino:%s"},
+#if 0 /* def CONFIG_AUFS_EXPORT */ /* reserved for futur use */
+       {Opt_xinodir, "xinodir=%s"},
+       {Opt_xinodir, "xinodir:%s"},
+#endif
+       {Opt_noxino, "noxino"},
+       {Opt_trunc_xino, "trunc_xino"},
+       {Opt_trunc_xino_v, "trunc_xino_v=%d:%d"},
+       {Opt_notrunc_xino, "notrunc_xino"},
+       {Opt_trunc_xino_path, "trunc_xino=%s"},
+       {Opt_trunc_xino_path, "trunc_xino:%s"},
+       {Opt_itrunc_xino, "itrunc_xino=%d"},
+       {Opt_itrunc_xino, "itrunc_xino:%d"},
+       /* {Opt_zxino, "zxino=%s"}, */
+       {Opt_trunc_xib, "trunc_xib"},
+       {Opt_notrunc_xib, "notrunc_xib"},
+
+       {Opt_plink, "plink"},
+       {Opt_noplink, "noplink"},
+#ifdef CONFIG_AUFS_DEBUG
+       {Opt_list_plink, "list_plink"},
+#endif
+       {Opt_clean_plink, "clean_plink"},
+
+       {Opt_udba, "udba=%s"},
+
+       {Opt_diropq_a, "diropq=always"},
+       {Opt_diropq_a, "diropq=a"},
+       {Opt_diropq_w, "diropq=whiteouted"},
+       {Opt_diropq_w, "diropq=w"},
+
+       {Opt_warn_perm, "warn_perm"},
+       {Opt_nowarn_perm, "nowarn_perm"},
+
+#ifdef CONFIG_AUFS_DLGT
+       {Opt_dlgt, "dlgt"},
+       {Opt_dirperm1, "dirperm1"},
+#endif
+       {Opt_nodlgt, "nodlgt"},
+       {Opt_nodirperm1, "nodirperm1"},
+
+#ifdef CONFIG_AUFS_SHWH
+       {Opt_shwh, "shwh"},
+#endif
+       {Opt_noshwh, "noshwh"},
+
+       {Opt_rendir, "rendir=%d"},
+       {Opt_rendir, "rendir:%d"},
+
+       {Opt_refrof, "refrof"},
+       {Opt_norefrof, "norefrof"},
+
+       {Opt_verbose, "verbose"},
+       {Opt_verbose, "v"},
+       {Opt_noverbose, "noverbose"},
+       {Opt_noverbose, "quiet"},
+       {Opt_noverbose, "q"},
+       {Opt_noverbose, "silent"},
+
+       {Opt_sum, "sum"},
+       {Opt_nosum, "nosum"},
+       {Opt_wsum, "wsum"},
+
+       {Opt_rdcache, "rdcache=%d"},
+       {Opt_rdcache, "rdcache:%d"},
+
+       {Opt_coo, "coo=%s"},
+
+       {Opt_wbr_create, "create=%s"},
+       {Opt_wbr_create, "create:%s"},
+       {Opt_wbr_create, "create_policy=%s"},
+       {Opt_wbr_create, "create_policy:%s"},
+       {Opt_wbr_copyup, "cpup=%s"},
+       {Opt_wbr_copyup, "cpup:%s"},
+       {Opt_wbr_copyup, "copyup=%s"},
+       {Opt_wbr_copyup, "copyup:%s"},
+       {Opt_wbr_copyup, "copyup_policy=%s"},
+       {Opt_wbr_copyup, "copyup_policy:%s"},
+
+       /* internal use for the scripts */
+       {Opt_ignore_silent, "si=%s"},
+
+#if 0 /* reserved for future use */
+       {Opt_deblk, "deblk=%d"},
+       {Opt_deblk, "deblk:%d"},
+       {Opt_nhash, "nhash=%d"},
+       {Opt_nhash, "nhash:%d"},
+#endif
+
+       {Opt_br, "dirs=%s"},
+       {Opt_ignore, "debug=%d"},
+       {Opt_ignore, "delete=whiteout"},
+       {Opt_ignore, "delete=all"},
+       {Opt_ignore, "imap=%s"},
+
+       {Opt_err, NULL}
+};
+
+/* ---------------------------------------------------------------------- */
+
+static const char *au_parser_pattern(int val, struct match_token *token)
+{
+       while (token->pattern) {
+               if (token->token == val)
+                       return token->pattern;
+               token++;
+       }
+       BUG();
+       return "??";
+}
+
+/* ---------------------------------------------------------------------- */
+
+#define RW             "rw"
+#define RO             "ro"
+#define WH             "wh"
+#define RR             "rr"
+#define NoLinkWH       "nolwh"
+
+static match_table_t brperms = {
+       {AuBrPerm_RR, RR},
+       {AuBrPerm_RO, RO},
+       {AuBrPerm_RW, RW},
+
+       {AuBrPerm_RRWH, RR "+" WH},
+       {AuBrPerm_ROWH, RO "+" WH},
+       {AuBrPerm_RWNoLinkWH, RW "+" NoLinkWH},
+
+       {AuBrPerm_ROWH, "nfsro"},
+       {AuBrPerm_RO, NULL}
+};
+
+static noinline_for_stack int br_perm_val(char *perm)
+{
+       int val;
+       substring_t args[MAX_OPT_ARGS];
+
+       AuDebugOn(!perm || !*perm);
+       LKTRTrace("perm %s\n", perm);
+       val = match_token(perm, brperms, args);
+       AuTraceErr(val);
+       return val;
+}
+
+const char *au_optstr_br_perm(int brperm)
+{
+       return au_parser_pattern(brperm, (void *)brperms);
+}
+
+/* ---------------------------------------------------------------------- */
+
+static match_table_t udbalevel = {
+       {AuOpt_UDBA_REVAL, "reval"},
+#ifdef CONFIG_AUFS_HINOTIFY
+       {AuOpt_UDBA_INOTIFY, "inotify"},
+#endif
+       {AuOpt_UDBA_NONE, "none"},
+       {-1, NULL}
+};
+
+static noinline_for_stack int udba_val(char *str)
+{
+       substring_t args[MAX_OPT_ARGS];
+       return match_token(str, udbalevel, args);
+}
+
+const char *au_optstr_udba(int udba)
+{
+       return au_parser_pattern(udba, (void *)udbalevel);
+}
+
+/* ---------------------------------------------------------------------- */
+
+static match_table_t coolevel = {
+       {AuOpt_COO_NONE, "none"},
+       {AuOpt_COO_LEAF, "leaf"},
+       {AuOpt_COO_ALL, "all"},
+       {-1, NULL}
+};
+
+static noinline_for_stack int coo_val(char *str)
+{
+       substring_t args[MAX_OPT_ARGS];
+       return match_token(str, coolevel, args);
+}
+
+const char *au_optstr_coo(int coo)
+{
+       return au_parser_pattern(coo, (void *)coolevel);
+}
+
+/* ---------------------------------------------------------------------- */
+
+static match_table_t au_wbr_create_policy = {
+       {AuWbrCreate_TDP, "tdp"},
+       {AuWbrCreate_TDP, "top-down-parent"},
+       {AuWbrCreate_RR, "rr"},
+       {AuWbrCreate_RR, "round-robin"},
+       {AuWbrCreate_MFS, "mfs"},
+       {AuWbrCreate_MFS, "most-free-space"},
+       {AuWbrCreate_MFSV, "mfs:%d"},
+       {AuWbrCreate_MFSV, "most-free-space:%d"},
+
+       {AuWbrCreate_MFSRR, "mfsrr:%d"},
+       {AuWbrCreate_MFSRRV, "mfsrr:%d:%d"},
+       {AuWbrCreate_PMFS, "pmfs"},
+       {AuWbrCreate_PMFSV, "pmfs:%d"},
+
+       {-1, NULL}
+};
+
+/* cf. linux/lib/parser.c */
+static int au_match_ull(substring_t *s, unsigned long long *result)
+{
+       int err;
+       unsigned int len;
+       char a[32];
+
+       err = -ERANGE;
+       len = s->to - s->from;
+       if (len + 1 <= sizeof(a)) {
+               memcpy(a, s->from, len);
+               a[len] = '\0';
+#if 1
+               err = strict_strtoull(a, 0, result);
+#else
+               char *next;
+               *result = memparse(a, &next);
+               err = *result;
+               if (!IS_ERR((void *)err))
+                       err = 0;
+#endif
+       }
+       return err;
+}
+
+static int au_wbr_mfs_wmark(substring_t *arg, char *str,
+                           struct au_opt_wbr_create *create)
+{
+       int err;
+       unsigned long long ull;
+
+       err = 0;
+       if (!au_match_ull(arg, &ull))
+               create->mfsrr_watermark = ull;
+       else {
+               AuErr("bad integer in %s\n", str);
+               err = -EINVAL;
+       }
+
+       AuTraceErr(err);
+       return err;
+}
+
+static int au_wbr_mfs_sec(substring_t *arg, char *str,
+                         struct au_opt_wbr_create *create)
+{
+       int n, err;
+
+       err = 0;
+       if (!match_int(arg, &n) && 0 <= n)
+               create->mfs_second = n;
+       else {
+               AuErr("bad integer in %s\n", str);
+               err = -EINVAL;
+       }
+
+       AuTraceErr(err);
+       return err;
+}
+
+static noinline_for_stack
+int au_wbr_create_val(char *str, struct au_opt_wbr_create *create)
+{
+       int err, e;
+       substring_t args[MAX_OPT_ARGS];
+
+       err = match_token(str, au_wbr_create_policy, args);
+       create->wbr_create = err;
+       switch (err) {
+       case AuWbrCreate_MFSRRV:
+               e = au_wbr_mfs_wmark(&args[0], str, create);
+               if (!e)
+                       e = au_wbr_mfs_sec(&args[1], str, create);
+               if (unlikely(e))
+                       err = e;
+               break;
+       case AuWbrCreate_MFSRR:
+               e = au_wbr_mfs_wmark(&args[0], str, create);
+               if (unlikely(e)) {
+                       err = e;
+                       break;
+               }
+               /*FALLTHROUGH*/
+       case AuWbrCreate_MFS:
+       case AuWbrCreate_PMFS:
+               create->mfs_second = AUFS_MFS_SECOND_DEF;
+               break;
+       case AuWbrCreate_MFSV:
+       case AuWbrCreate_PMFSV:
+               e = au_wbr_mfs_sec(&args[0], str, create);
+               if (unlikely(e))
+                       err = e;
+               break;
+       }
+
+       return err;
+}
+
+const char *au_optstr_wbr_create(int wbr_create)
+{
+       return au_parser_pattern(wbr_create, (void *)au_wbr_create_policy);
+}
+
+static match_table_t au_wbr_copyup_policy = {
+       {AuWbrCopyup_TDP, "tdp"},
+       {AuWbrCopyup_TDP, "top-down-parent"},
+       {AuWbrCopyup_BUP, "bup"},
+       {AuWbrCopyup_BUP, "bottom-up-parent"},
+       {AuWbrCopyup_BU, "bu"},
+       {AuWbrCopyup_BU, "bottom-up"},
+       {-1, NULL}
+};
+
+static noinline_for_stack int au_wbr_copyup_val(char *str)
+{
+       substring_t args[MAX_OPT_ARGS];
+       return match_token(str, au_wbr_copyup_policy, args);
+}
+
+const char *au_optstr_wbr_copyup(int wbr_copyup)
+{
+       return au_parser_pattern(wbr_copyup, (void *)au_wbr_copyup_policy);
+}
+
+/* ---------------------------------------------------------------------- */
+
+static const int lkup_dirflags = LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
+
+static void dump_opts(struct au_opts *opts)
+{
+#ifdef CONFIG_AUFS_DEBUG
+       /* reduce stack space */
+       union {
+               struct au_opt_add *add;
+               struct au_opt_del *del;
+               struct au_opt_mod *mod;
+               struct au_opt_xino *xino;
+               struct au_opt_xinodir *xinodir;
+               struct au_opt_xino_itrunc *xino_itrunc;
+               struct au_opt_wbr_create *create;
+       } u;
+       struct au_opt *opt;
+
+       AuTraceEnter();
+
+       opt = opts->opt;
+       while (/* opt < opts_tail && */ opt->type != Opt_tail) {
+               switch (opt->type) {
+               case Opt_add:
+                       u.add = &opt->add;
+                       LKTRTrace("add {b%d, %s, 0x%x, %p}\n",
+                                 u.add->bindex, u.add->path, u.add->perm,
+                                 u.add->nd.path.dentry);
+                       break;
+               case Opt_del:
+               case Opt_idel:
+                       u.del = &opt->del;
+                       LKTRTrace("del {%s, %p}\n", u.del->path, u.del->h_root);
+                       break;
+               case Opt_mod:
+               case Opt_imod:
+                       u.mod = &opt->mod;
+                       LKTRTrace("mod {%s, 0x%x, %p}\n",
+                                 u.mod->path, u.mod->perm, u.mod->h_root);
+                       break;
+               case Opt_append:
+                       u.add = &opt->add;
+                       LKTRTrace("append {b%d, %s, 0x%x, %p}\n",
+                                 u.add->bindex, u.add->path, u.add->perm,
+                                 u.add->nd.path.dentry);
+                       break;
+               case Opt_prepend:
+                       u.add = &opt->add;
+                       LKTRTrace("prepend {b%d, %s, 0x%x, %p}\n",
+                                 u.add->bindex, u.add->path, u.add->perm,
+                                 u.add->nd.path.dentry);
+                       break;
+               case Opt_dirwh:
+                       LKTRTrace("dirwh %d\n", opt->dirwh);
+                       break;
+               case Opt_rdcache:
+                       LKTRTrace("rdcache %d\n", opt->rdcache);
+                       break;
+               case Opt_xino:
+                       u.xino = &opt->xino;
+                       LKTRTrace("xino {%s %.*s}\n",
+                                 u.xino->path,
+                                 AuDLNPair(u.xino->file->f_dentry));
+                       break;
+               case Opt_xinodir:
+                       u.xinodir = &opt->xinodir;
+                       LKTRTrace("xinodir {%s %.*s}\n",
+                                 u.xinodir->name,
+                                 AuDLNPair(u.xinodir->path.dentry));
+                       break;
+               case Opt_trunc_xino:
+                       LKTRLabel(trunc_xino);
+                       break;
+               case Opt_notrunc_xino:
+                       LKTRLabel(notrunc_xino);
+                       break;
+               case Opt_trunc_xino_path:
+               case Opt_itrunc_xino:
+                       u.xino_itrunc = &opt->xino_itrunc;
+                       LKTRTrace("trunc_xino %d\n", u.xino_itrunc->bindex);
+                       break;
+
+               case Opt_noxino:
+                       LKTRLabel(noxino);
+                       break;
+               case Opt_trunc_xib:
+                       LKTRLabel(trunc_xib);
+                       break;
+               case Opt_notrunc_xib:
+                       LKTRLabel(notrunc_xib);
+                       break;
+               case Opt_dirperm1:
+                       LKTRLabel(dirperm1);
+                       break;
+               case Opt_nodirperm1:
+                       LKTRLabel(nodirperm1);
+                       break;
+               case Opt_shwh:
+                       LKTRLabel(shwh);
+                       break;
+               case Opt_noshwh:
+                       LKTRLabel(noshwh);
+                       break;
+               case Opt_plink:
+                       LKTRLabel(plink);
+                       break;
+               case Opt_noplink:
+                       LKTRLabel(noplink);
+                       break;
+               case Opt_list_plink:
+                       LKTRLabel(list_plink);
+                       break;
+               case Opt_clean_plink:
+                       LKTRLabel(clean_plink);
+                       break;
+               case Opt_udba:
+                       LKTRTrace("udba %d, %s\n",
+                                 opt->udba, au_optstr_udba(opt->udba));
+                       break;
+               case Opt_diropq_a:
+                       LKTRLabel(diropq_a);
+                       break;
+               case Opt_diropq_w:
+                       LKTRLabel(diropq_w);
+                       break;
+               case Opt_warn_perm:
+                       LKTRLabel(warn_perm);
+                       break;
+               case Opt_nowarn_perm:
+                       LKTRLabel(nowarn_perm);
+                       break;
+               case Opt_dlgt:
+                       LKTRLabel(dlgt);
+                       break;
+               case Opt_nodlgt:
+                       LKTRLabel(nodlgt);
+                       break;
+               case Opt_refrof:
+                       LKTRLabel(refrof);
+                       break;
+               case Opt_norefrof:
+                       LKTRLabel(norefrof);
+                       break;
+               case Opt_verbose:
+                       LKTRLabel(verbose);
+                       break;
+               case Opt_noverbose:
+                       LKTRLabel(noverbose);
+                       break;
+               case Opt_sum:
+                       LKTRLabel(sum);
+                       break;
+               case Opt_nosum:
+                       LKTRLabel(nosum);
+                       break;
+               case Opt_wsum:
+                       LKTRLabel(wsum);
+                       break;
+               case Opt_coo:
+                       LKTRTrace("coo %d, %s\n",
+                                 opt->coo, au_optstr_coo(opt->coo));
+                       break;
+               case Opt_wbr_create:
+                       u.create = &opt->wbr_create;
+                       LKTRTrace("create %d, %s\n", u.create->wbr_create,
+                                 au_optstr_wbr_create(u.create->wbr_create));
+                       switch (u.create->wbr_create) {
+                       case AuWbrCreate_MFSV:
+                       case AuWbrCreate_PMFSV:
+                               LKTRTrace("%d sec\n", u.create->mfs_second);
+                               break;
+                       case AuWbrCreate_MFSRR:
+                               LKTRTrace("%llu watermark\n",
+                                         u.create->mfsrr_watermark);
+                               break;
+                       case AuWbrCreate_MFSRRV:
+                               LKTRTrace("%llu watermark, %d sec\n",
+                                         u.create->mfsrr_watermark,
+                                         u.create->mfs_second);
+                               break;
+                       }
+                       break;
+               case Opt_wbr_copyup:
+                       LKTRTrace("copyup %d, %s\n", opt->wbr_copyup,
+                                 au_optstr_wbr_copyup(opt->wbr_copyup));
+                       break;
+               default:
+                       BUG();
+               }
+               opt++;
+       }
+#endif
+}
+
+void au_opts_free(struct au_opts *opts)
+{
+       struct au_opt *opt;
+
+       AuTraceEnter();
+
+       opt = opts->opt;
+       while (opt->type != Opt_tail) {
+               switch (opt->type) {
+               case Opt_add:
+               case Opt_append:
+               case Opt_prepend:
+                       path_put(&opt->add.nd.path);
+                       break;
+               case Opt_del:
+               case Opt_idel:
+                       dput(opt->del.h_root);
+                       break;
+               case Opt_mod:
+               case Opt_imod:
+                       dput(opt->mod.h_root);
+                       break;
+               case Opt_xino:
+                       fput(opt->xino.file);
+                       break;
+               case Opt_xinodir:
+                       path_put(&opt->xinodir.path);
+                       break;
+               }
+               opt++;
+       }
+}
+
+static int opt_add(struct au_opt *opt, char *opt_str, unsigned long sb_flags,
+                  struct super_block *sb, aufs_bindex_t bindex)
+{
+       int err;
+       struct au_opt_add *add = &opt->add;
+       char *p;
+
+       LKTRTrace("%s, b%d\n", opt_str, bindex);
+
+       add->bindex = bindex;
+       add->perm = AuBrPerm_Last;
+       add->path = opt_str;
+       p = strchr(opt_str, '=');
+       if (p) {
+               *p++ = 0;
+               if (*p)
+                       add->perm = br_perm_val(p);
+       }
+
+       /* LSM may detect it */
+       /* do not superio. */
+       err = vfsub_path_lookup(add->path, lkup_dirflags, &add->nd);
+       if (!err) {
+               if (!p /* && add->perm == AuBrPerm_Last */) {
+                       add->perm = AuBrPerm_RO;
+                       if (au_test_def_rr(add->nd.path.dentry->d_sb))
+                               add->perm = AuBrPerm_RR;
+                       if (!bindex && !(sb_flags & MS_RDONLY))
+                               add->perm = AuBrPerm_RW;
+#ifdef CONFIG_AUFS_COMPAT
+                       add->perm = AuBrPerm_RW;
+#endif
+               }
+               opt->type = Opt_add;
+               goto out;
+       }
+       AuErr("lookup failed %s (%d)\n", add->path, err);
+       err = -EINVAL;
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+/* called without aufs lock */
+int au_opts_parse(struct super_block *sb, char *str, struct au_opts *opts)
+{
+       int err, n, token;
+       struct dentry *root;
+       struct au_opt *opt, *opt_tail;
+       char *opt_str, *p;
+       aufs_bindex_t bindex, bend;
+       unsigned char skipped;
+       union {
+               struct au_opt_del *del;
+               struct au_opt_mod *mod;
+               struct au_opt_xino *xino;
+               struct au_opt_xinodir *xinodir;
+               struct au_opt_xino_itrunc *xino_itrunc;
+               struct au_opt_wbr_create *create;
+       } u;
+       struct file *file;
+       /* reduce the stack space */
+       struct {
+               substring_t args[MAX_OPT_ARGS];
+               struct nameidata nd;
+       } *a;
+
+       LKTRTrace("%s, nopts %d\n", str, opts->max_opt);
+
+       err = -ENOMEM;
+       a = kmalloc(sizeof(*a), GFP_NOFS);
+       if (unlikely(!a))
+               goto out;
+
+       root = sb->s_root;
+       err = 0;
+       bindex = 0;
+       opt = opts->opt;
+       opt_tail = opt + opts->max_opt - 1;
+       opt->type = Opt_tail;
+       while (!err && (opt_str = strsep(&str, ",")) && *opt_str) {
+               err = -EINVAL;
+               token = match_token(opt_str, options, a->args);
+               LKTRTrace("%s, token %d, a->args[0]{%p, %p}\n",
+                         opt_str, token, a->args[0].from, a->args[0].to);
+
+               skipped = 0;
+               switch (token) {
+               case Opt_br:
+                       err = 0;
+                       while (!err && (opt_str = strsep(&a->args[0].from, ":"))
+                              && *opt_str) {
+                               err = opt_add(opt, opt_str, opts->sb_flags, sb,
+                                             bindex++);
+                               if (unlikely(!err && ++opt > opt_tail)) {
+                                       err = -E2BIG;
+                                       break;
+                               }
+                               opt->type = Opt_tail;
+                               skipped = 1;
+                       }
+                       break;
+               case Opt_add:
+                       if (unlikely(match_int(&a->args[0], &n))) {
+                               AuErr("bad integer in %s\n", opt_str);
+                               break;
+                       }
+                       bindex = n;
+                       err = opt_add(opt, a->args[1].from, opts->sb_flags, sb,
+                                     bindex);
+                       break;
+               case Opt_append:
+                       err = opt_add(opt, a->args[0].from, opts->sb_flags, sb,
+                                     /*dummy bindex*/1);
+                       if (!err)
+                               opt->type = token;
+                       break;
+               case Opt_prepend:
+                       err = opt_add(opt, a->args[0].from, opts->sb_flags, sb,
+                                     /*bindex*/0);
+                       if (!err)
+                               opt->type = token;
+                       break;
+               case Opt_del:
+                       u.del = &opt->del;
+                       u.del->path = a->args[0].from;
+                       LKTRTrace("del path %s\n", u.del->path);
+                       /* LSM may detect it */
+                       /* do not superio. */
+                       err = vfsub_path_lookup(u.del->path, lkup_dirflags,
+                                               &a->nd);
+                       if (unlikely(err)) {
+                               AuErr("lookup failed %s (%d)\n",
+                                     u.del->path, err);
+                               break;
+                       }
+                       u.del->h_root = dget(a->nd.path.dentry);
+                       path_put(&a->nd.path);
+                       opt->type = token;
+                       break;
+#if 0 /* reserved for future use */
+               case Opt_idel:
+                       u.del = &opt->del;
+                       u.del->path = "(indexed)";
+                       if (unlikely(match_int(&a->args[0], &n))) {
+                               AuErr("bad integer in %s\n", opt_str);
+                               break;
+                       }
+                       bindex = n;
+                       aufs_read_lock(root, AuLock_FLUSH);
+                       if (bindex < 0 || au_sbend(sb) < bindex) {
+                               AuErr("out of bounds, %d\n", bindex);
+                               aufs_read_unlock(root, !AuLock_IR);
+                               break;
+                       }
+                       err = 0;
+                       u.del->h_root = dget(au_h_dptr(root, bindex));
+                       opt->type = token;
+                       aufs_read_unlock(root, !AuLock_IR);
+                       break;
+#endif
+               case Opt_mod:
+                       u.mod = &opt->mod;
+                       u.mod->path = a->args[0].from;
+                       p = strchr(u.mod->path, '=');
+                       if (unlikely(!p)) {
+                               AuErr("no permssion %s\n", opt_str);
+                               break;
+                       }
+                       *p++ = 0;
+                       u.mod->perm = br_perm_val(p);
+                       LKTRTrace("mod path %s, perm 0x%x, %s\n",
+                                 u.mod->path, u.mod->perm, p);
+                       /* LSM may detect it */
+                       /* do not superio. */
+                       err = vfsub_path_lookup(u.mod->path, lkup_dirflags,
+                                               &a->nd);
+                       if (unlikely(err)) {
+                               AuErr("lookup failed %s (%d)\n",
+                                     u.mod->path, err);
+                               break;
+                       }
+                       u.mod->h_root = dget(a->nd.path.dentry);
+                       path_put(&a->nd.path);
+                       opt->type = token;
+                       break;
+#ifdef IMOD /* reserved for future use */
+               case Opt_imod:
+                       u.mod = &opt->mod;
+                       u.mod->path = "(indexed)";
+                       if (unlikely(match_int(&a->args[0], &n))) {
+                               AuErr("bad integer in %s\n", opt_str);
+                               break;
+                       }
+                       bindex = n;
+                       aufs_read_lock(root, AuLock_FLUSH);
+                       if (bindex < 0 || au_sbend(sb) < bindex) {
+                               AuErr("out of bounds, %d\n", bindex);
+                               aufs_read_unlock(root, !AuLock_IR);
+                               break;
+                       }
+                       u.mod->perm = br_perm_val(a->args[1].from);
+                       LKTRTrace("mod path %s, perm 0x%x, %s\n",
+                                 u.mod->path, u.mod->perm, a->args[1].from);
+                       err = 0;
+                       u.mod->h_root = dget(au_h_dptr(root, bindex));
+                       opt->type = token;
+                       aufs_read_unlock(root, !AuLock_IR);
+                       break;
+#endif
+               case Opt_xino:
+                       u.xino = &opt->xino;
+                       file = au_xino_create(sb, a->args[0].from, /*silent*/0);
+                       err = PTR_ERR(file);
+                       if (IS_ERR(file))
+                               break;
+                       err = -EINVAL;
+                       if (unlikely(file->f_dentry->d_sb == sb)) {
+                               fput(file);
+                               AuErr("%s must be outside\n", a->args[0].from);
+                               break;
+                       }
+                       err = 0;
+                       u.xino->file = file;
+                       u.xino->path = a->args[0].from;
+                       opt->type = token;
+                       break;
+
+#if 0 /* def CONFIG_AUFS_EXPORT */ /* reserved for futur use */
+               case Opt_xinodir:
+                       u.xinodir = &opt->xinodir;
+                       u.xinodir->name = a->args[0].from;
+                       err = vfsub_path_lookup(u.xinodir->name, lkup_dirflags,
+                                               &a->nd);
+                       if (unlikely(err)) {
+                               AuErr("lookup failed %s (%d)\n",
+                                     u.xinodir->name, err);
+                               break;
+                       }
+                       u.xinodir->path = a->nd.path;
+                       /* do not path_put() */
+                       opt->type = token;
+                       break;
+#endif
+
+               case Opt_trunc_xino_path:
+                       u.xino_itrunc = &opt->xino_itrunc;
+                       p = a->args[0].from;
+                       LKTRTrace("trunc_xino path %s\n", p);
+                       /* LSM may detect it */
+                       /* do not superio. */
+                       err = vfsub_path_lookup(p, lkup_dirflags, &a->nd);
+                       if (unlikely(err)) {
+                               AuErr("lookup failed %s (%d)\n", p , err);
+                               break;
+                       }
+                       u.xino_itrunc->bindex = -1;
+                       aufs_read_lock(root, AuLock_FLUSH);
+                       bend = au_sbend(sb);
+                       for (bindex = 0; bindex <= bend; bindex++) {
+                               if (au_h_dptr(root, bindex)
+                                   == a->nd.path.dentry) {
+                                       u.xino_itrunc->bindex = bindex;
+                                       break;
+                               }
+                       }
+                       aufs_read_unlock(root, !AuLock_IR);
+                       path_put(&a->nd.path);
+                       if (unlikely(u.xino_itrunc->bindex < 0)) {
+                               AuErr("no such branch %s\n", p);
+                               err = -EINVAL;
+                               break;
+                       }
+                       opt->type = token;
+                       break;
+
+               case Opt_itrunc_xino:
+                       u.xino_itrunc = &opt->xino_itrunc;
+                       if (unlikely(match_int(&a->args[0], &n))) {
+                               AuErr("bad integer in %s\n", opt_str);
+                               break;
+                       }
+                       u.xino_itrunc->bindex = n;
+                       aufs_read_lock(root, AuLock_FLUSH);
+                       if (n < 0 || au_sbend(sb) < n) {
+                               AuErr("out of bounds, %d\n", n);
+                               aufs_read_unlock(root, !AuLock_IR);
+                               break;
+                       }
+                       aufs_read_unlock(root, !AuLock_IR);
+                       err = 0;
+                       opt->type = token;
+                       break;
+
+               case Opt_dirwh:
+                       if (unlikely(match_int(&a->args[0], &opt->dirwh)))
+                               break;
+                       err = 0;
+                       opt->type = token;
+                       break;
+
+               case Opt_rdcache:
+                       if (unlikely(match_int(&a->args[0], &opt->rdcache)))
+                               break;
+                       err = 0;
+                       opt->type = token;
+                       break;
+
+               case Opt_shwh:
+                       if (opts->sb_flags & MS_RDONLY) {
+                               err = 0;
+                               opt->type = token;
+                       } else
+                               AuErr("shwh requires ro\n");
+                       break;
+
+               case Opt_trunc_xino:
+               case Opt_notrunc_xino:
+               case Opt_noxino:
+               case Opt_trunc_xib:
+               case Opt_notrunc_xib:
+               case Opt_dirperm1:
+               case Opt_nodirperm1:
+               case Opt_noshwh:
+               case Opt_plink:
+               case Opt_noplink:
+               case Opt_list_plink:
+               case Opt_clean_plink:
+               case Opt_diropq_a:
+               case Opt_diropq_w:
+               case Opt_warn_perm:
+               case Opt_nowarn_perm:
+               case Opt_dlgt:
+               case Opt_nodlgt:
+               case Opt_refrof:
+               case Opt_norefrof:
+               case Opt_verbose:
+               case Opt_noverbose:
+               case Opt_sum:
+               case Opt_nosum:
+               case Opt_wsum:
+                       err = 0;
+                       opt->type = token;
+                       break;
+
+               case Opt_udba:
+                       opt->udba = udba_val(a->args[0].from);
+                       if (opt->udba >= 0) {
+                               err = 0;
+                               opt->type = token;
+                       } else
+                               AuErr("wrong value, %s\n", opt_str);
+                       break;
+
+               case Opt_wbr_create:
+                       u.create = &opt->wbr_create;
+                       u.create->wbr_create
+                               = au_wbr_create_val(a->args[0].from, u.create);
+                       if (u.create->wbr_create >= 0) {
+                               err = 0;
+                               opt->type = token;
+                       } else
+                               AuErr("wrong value, %s\n", opt_str);
+                       break;
+               case Opt_wbr_copyup:
+                       opt->wbr_copyup = au_wbr_copyup_val(a->args[0].from);
+                       if (opt->wbr_copyup >= 0) {
+                               err = 0;
+                               opt->type = token;
+                       } else
+                               AuErr("wrong value, %s\n", opt_str);
+                       break;
+
+               case Opt_coo:
+                       opt->coo = coo_val(a->args[0].from);
+                       if (opt->coo >= 0) {
+                               if (opt->coo == AuOpt_COO_NONE
+                                   || !(opts->sb_flags & MS_RDONLY)) {
+                                       err = 0;
+                                       opt->type = token;
+                               } else
+                                       AuErr("bad %s for readonly mount\n",
+                                             opt_str);
+                       } else
+                               AuErr("wrong value, %s\n", opt_str);
+                       break;
+
+               case Opt_ignore:
+#ifndef CONFIG_AUFS_COMPAT
+                       AuWarn("ignored %s\n", opt_str);
+#endif
+               case Opt_ignore_silent:
+                       skipped = 1;
+                       err = 0;
+                       break;
+               case Opt_err:
+                       AuErr("unknown option %s\n", opt_str);
+                       break;
+               }
+
+               if (!err && !skipped) {
+                       if (unlikely(++opt > opt_tail)) {
+                               err = -E2BIG;
+                               opt--;
+                               opt->type = Opt_tail;
+                               break;
+                       }
+                       opt->type = Opt_tail;
+               }
+       }
+
+       kfree(a);
+       dump_opts(opts);
+       if (unlikely(err))
+               au_opts_free(opts);
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+/*
+ * returns,
+ * plus: processed without an error
+ * zero: unprocessed
+ */
+static int au_opt_simple(struct super_block *sb, struct au_opt *opt,
+                        struct au_opts *opts)
+{
+       int err;
+       struct au_sbinfo *sbinfo;
+       struct au_opt_wbr_create *create;
+
+       AuTraceEnter();
+
+       err = 1; /* handled */
+       sbinfo = au_sbi(sb);
+       switch (opt->type) {
+       case Opt_udba:
+               sbinfo->si_mntflags &= ~AuOptMask_UDBA;
+               sbinfo->si_mntflags |= opt->udba;
+               opts->given_udba |= opt->udba;
+               break;
+
+       case Opt_plink:
+               au_opt_set(sbinfo->si_mntflags, PLINK);
+               break;
+       case Opt_noplink:
+               if (au_opt_test(sbinfo->si_mntflags, PLINK))
+                       au_plink_put(sb);
+               au_opt_clr(sbinfo->si_mntflags, PLINK);
+               break;
+       case Opt_list_plink:
+               if (au_opt_test(sbinfo->si_mntflags, PLINK))
+                       au_plink_list(sb);
+               break;
+       case Opt_clean_plink:
+               if (au_opt_test(sbinfo->si_mntflags, PLINK))
+                       au_plink_put(sb);
+               break;
+
+       case Opt_diropq_a:
+               au_opt_set(sbinfo->si_mntflags, ALWAYS_DIROPQ);
+               break;
+       case Opt_diropq_w:
+               au_opt_clr(sbinfo->si_mntflags, ALWAYS_DIROPQ);
+               break;
+
+       case Opt_dlgt:
+               au_opt_set(sbinfo->si_mntflags, DLGT);
+               break;
+       case Opt_nodlgt:
+               au_opt_clr(sbinfo->si_mntflags, DLGT);
+               break;
+
+       case Opt_warn_perm:
+               au_opt_set(sbinfo->si_mntflags, WARN_PERM);
+               break;
+       case Opt_nowarn_perm:
+               au_opt_clr(sbinfo->si_mntflags, WARN_PERM);
+               break;
+
+       case Opt_refrof:
+               au_opt_set(sbinfo->si_mntflags, REFROF);
+               break;
+       case Opt_norefrof:
+               /* au_opt_set(sbinfo->si_mntflags, COO_LEAF); */
+               au_opt_clr(sbinfo->si_mntflags, REFROF);
+               break;
+
+       case Opt_verbose:
+               au_opt_set(sbinfo->si_mntflags, VERBOSE);
+               break;
+       case Opt_noverbose:
+               au_opt_clr(sbinfo->si_mntflags, VERBOSE);
+               break;
+
+       case Opt_sum:
+               au_opt_set(sbinfo->si_mntflags, SUM);
+               break;
+       case Opt_wsum:
+               au_opt_clr(sbinfo->si_mntflags, SUM);
+               au_opt_set(sbinfo->si_mntflags, SUM_W);
+       case Opt_nosum:
+               au_opt_clr(sbinfo->si_mntflags, SUM);
+               au_opt_clr(sbinfo->si_mntflags, SUM_W);
+               break;
+
+       case Opt_wbr_create:
+               create = &opt->wbr_create;
+               if (sbinfo->si_wbr_create_ops->fin) {
+                       err = sbinfo->si_wbr_create_ops->fin(sb);
+                       if (!err)
+                               err = 1;
+               }
+               sbinfo->si_wbr_create = create->wbr_create;
+               sbinfo->si_wbr_create_ops
+                       = au_wbr_create_ops + create->wbr_create;
+               switch (create->wbr_create) {
+               case AuWbrCreate_MFSRRV:
+               case AuWbrCreate_MFSRR:
+                       sbinfo->si_wbr_mfs.mfsrr_watermark
+                               = create->mfsrr_watermark;
+                       /*FALLTHROUGH*/
+               case AuWbrCreate_MFS:
+               case AuWbrCreate_MFSV:
+               case AuWbrCreate_PMFS:
+               case AuWbrCreate_PMFSV:
+                       sbinfo->si_wbr_mfs.mfs_expire = create->mfs_second * HZ;
+                       break;
+               }
+               if (sbinfo->si_wbr_create_ops->init)
+                       sbinfo->si_wbr_create_ops->init(sb); /* ignore */
+               break;
+       case Opt_wbr_copyup:
+               sbinfo->si_wbr_copyup = opt->wbr_copyup;
+               sbinfo->si_wbr_copyup_ops = au_wbr_copyup_ops + opt->wbr_copyup;
+               break;
+
+       case Opt_coo:
+               sbinfo->si_mntflags &= ~AuOptMask_COO;
+               sbinfo->si_mntflags |= opt->coo;
+               break;
+
+       case Opt_dirwh:
+               sbinfo->si_dirwh = opt->dirwh;
+               break;
+
+       case Opt_rdcache:
+               sbinfo->si_rdcache = opt->rdcache * HZ;
+               break;
+
+       case Opt_trunc_xino:
+               au_opt_set(sbinfo->si_mntflags, TRUNC_XINO);
+               break;
+       case Opt_notrunc_xino:
+               au_opt_clr(sbinfo->si_mntflags, TRUNC_XINO);
+               break;
+
+       case Opt_dirperm1:
+               au_opt_set(sbinfo->si_mntflags, DIRPERM1);
+               break;
+       case Opt_nodirperm1:
+               au_opt_clr(sbinfo->si_mntflags, DIRPERM1);
+               break;
+
+       case Opt_shwh:
+               au_opt_set(sbinfo->si_mntflags, SHWH);
+               break;
+       case Opt_noshwh:
+               au_opt_clr(sbinfo->si_mntflags, SHWH);
+               break;
+
+       case Opt_trunc_xino_path:
+       case Opt_itrunc_xino:
+               err = au_xino_trunc(sb, opt->xino_itrunc.bindex);
+               if (!err)
+                       err = 1;
+               break;
+
+       case Opt_trunc_xib:
+               au_fset_opts(opts->flags, TRUNC_XIB);
+               break;
+       case Opt_notrunc_xib:
+               au_fclr_opts(opts->flags, TRUNC_XIB);
+               break;
+
+       default:
+               err = 0;
+               break;
+       }
+
+       AuTraceErr(err);
+       return err;
+}
+
+/*
+ * returns tri-state.
+ * plus: processed without an error
+ * zero: unprocessed
+ * minus: error
+ */
+static int au_opt_br(struct super_block *sb, struct au_opt *opt,
+                    struct au_opts *opts)
+{
+       int err, do_refresh;
+
+       AuTraceEnter();
+
+       err = 0;
+       switch (opt->type) {
+       case Opt_append:
+               opt->add.bindex = au_sbend(sb) + 1;
+               if (opt->add.bindex < 0)
+                       opt->add.bindex = 0;
+               goto add;
+       case Opt_prepend:
+               opt->add.bindex = 0;
+       add:
+       case Opt_add:
+               err = au_br_add(sb, &opt->add,
+                               au_ftest_opts(opts->flags, REMOUNT));
+               if (!err) {
+                       err = 1;
+                       au_fset_opts(opts->flags, REFRESH_DIR);
+                       if (au_br_whable(opt->add.perm))
+                               au_fset_opts(opts->flags, REFRESH_NONDIR);
+               }
+               break;
+
+       case Opt_del:
+       case Opt_idel:
+               err = au_br_del(sb, &opt->del,
+                               au_ftest_opts(opts->flags, REMOUNT));
+               if (!err) {
+                       err = 1;
+                       au_fset_opts(opts->flags, TRUNC_XIB);
+                       au_fset_opts(opts->flags, REFRESH_DIR);
+                       au_fset_opts(opts->flags, REFRESH_NONDIR);
+               }
+               break;
+
+       case Opt_mod:
+       case Opt_imod:
+               err = au_br_mod(sb, &opt->mod,
+                               au_ftest_opts(opts->flags, REMOUNT),
+                               &do_refresh);
+               if (!err) {
+                       err = 1;
+                       if (do_refresh) {
+                               au_fset_opts(opts->flags, REFRESH_DIR);
+                               au_fset_opts(opts->flags, REFRESH_NONDIR);
+                       }
+               }
+               break;
+       }
+
+       AuTraceErr(err);
+       return err;
+}
+
+static int au_opt_xino(struct super_block *sb, struct au_opt *opt,
+                      struct au_opt_xino **opt_xino,
+                      struct au_opt_xinodir **opt_xinodir,
+                      struct au_opts *opts)
+{
+       int err;
+       const int remount = !!au_ftest_opts(opts->flags, REMOUNT);
+
+       AuTraceEnter();
+
+       err = 0;
+       switch (opt->type) {
+       case Opt_xino:
+               err = au_xino_set(sb, &opt->xino, remount);
+               if (!err)
+                       *opt_xino = &opt->xino;
+               break;
+#if 0 /* def CONFIG_AUFS_EXPORT */ /* reserved for futur use */
+       case Opt_xinodir:
+               err = au_xinodir_set(sb, &opt->xinodir, remount);
+               if (!err)
+                       *opt_xinodir = &opt->xinodir;
+               break;
+#endif
+       case Opt_noxino:
+               au_xino_clr(sb);
+               *opt_xino = (void *)-1;
+               break;
+       }
+
+       AuTraceErr(err);
+       return err;
+}
+
+int verify_opts(struct super_block *sb, unsigned long sb_flags,
+               unsigned int pending, int remount)
+{
+       int err;
+       aufs_bindex_t bindex, bend;
+       unsigned char do_plink, skip, do_free;
+       struct au_branch *br;
+       struct au_wbr *wbr;
+       struct dentry *root;
+       struct inode *dir, *h_dir;
+       unsigned int mnt_flags;
+
+       AuTraceEnter();
+       mnt_flags = au_mntflags(sb);
+       AuDebugOn(!(mnt_flags & AuOptMask_COO));
+       AuDebugOn(!(mnt_flags & AuOptMask_UDBA));
+
+       if (!(sb_flags & MS_RDONLY)) {
+               if (unlikely(!au_br_writable(au_sbr_perm(sb, 0))))
+                       AuWarn("first branch should be rw\n");
+               if (unlikely(au_opt_test(mnt_flags, SHWH)))
+                       AuWarn("shwh should be used with ro\n");
+       } else if (unlikely(!au_opt_test(mnt_flags, COO_NONE))) {
+               AuWarn("resetting coo for readonly mount\n");
+               au_opt_set_coo(au_sbi(sb)->si_mntflags, COO_NONE);
+       }
+
+       if (unlikely(au_opt_test((mnt_flags | pending), UDBA_INOTIFY)
+                    && !au_opt_test_xino(mnt_flags)))
+               AuWarn("udba=inotify requires xino\n");
+
+       err = 0;
+       root = sb->s_root;
+       dir = sb->s_root->d_inode;
+       do_plink = !!au_opt_test(mnt_flags, PLINK);
+       bend = au_sbend(sb);
+       for (bindex = 0; !err && bindex <= bend; bindex++) {
+               skip = 0;
+               h_dir = au_h_iptr(dir, bindex);
+               br = au_sbr(sb, bindex);
+               do_free = 0;
+               wbr = br->br_wbr;
+               if (wbr)
+                       wbr_wh_read_lock(wbr);
+               switch (br->br_perm) {
+               case AuBrPerm_RR:
+               case AuBrPerm_RO:
+               case AuBrPerm_RRWH:
+               case AuBrPerm_ROWH:
+                       do_free = !!wbr;
+                       skip = (!wbr
+                               || (!wbr->wbr_whbase
+                                   && !wbr->wbr_plink
+                                   && !wbr->wbr_tmp));
+                       break;
+
+               case AuBrPerm_RWNoLinkWH:
+                       /* skip = (!br->br_whbase && !br->br_tmp); */
+                       skip = (!wbr || !wbr->wbr_whbase);
+                       if (skip && wbr) {
+                               if (do_plink)
+                                       skip = !!wbr->wbr_plink;
+                               else
+                                       skip = !wbr->wbr_plink;
+                       }
+                       break;
+
+               case AuBrPerm_RW:
+                       /* skip = (br->br_whbase && br->br_tmp); */
+                       skip = (wbr && wbr->wbr_whbase);
+                       if (skip) {
+                               if (do_plink)
+                                       skip = !!wbr->wbr_plink;
+                               else
+                                       skip = !wbr->wbr_plink;
+                       }
+                       break;
+
+               default:
+                       BUG();
+               }
+               if (wbr)
+                       wbr_wh_read_unlock(wbr);
+
+               if (skip)
+                       continue;
+
+               mutex_lock_nested(&h_dir->i_mutex, AuLsc_I_PARENT);
+               if (wbr)
+                       wbr_wh_write_lock(wbr);
+               err = au_wh_init(au_h_dptr(root, bindex), br, br->br_mnt, sb,
+                                bindex);
+               if (wbr)
+                       wbr_wh_write_unlock(wbr);
+               mutex_unlock(&h_dir->i_mutex);
+
+               if (!err && do_free) {
+                       kfree(wbr);
+                       br->br_wbr = NULL;
+               }
+       }
+
+       AuTraceErr(err);
+       return err;
+}
+
+int au_opts_mount(struct super_block *sb, struct au_opts *opts)
+{
+       int err;
+       struct inode *dir;
+       struct au_opt *opt;
+       struct au_opt_xino *opt_xino, xino;
+       struct au_opt_xinodir *opt_xinodir;
+       aufs_bindex_t bend;
+       struct au_sbinfo *sbinfo;
+       unsigned int tmp;
+       struct au_branch *br;
+
+       AuTraceEnter();
+       SiMustWriteLock(sb);
+       DiMustWriteLock(sb->s_root);
+       dir = sb->s_root->d_inode;
+       IiMustWriteLock(dir);
+
+       err = 0;
+       opt_xino = NULL;
+       opt_xinodir = NULL;
+       opt = opts->opt;
+       while (err >= 0 && opt->type != Opt_tail)
+               err = au_opt_simple(sb, opt++, opts);
+       if (err > 0)
+               err = 0;
+       else if (unlikely(err < 0))
+               goto out;
+
+       /* disable xino, xinodir, hinotify, dlgt temporary */
+       sbinfo = au_sbi(sb);
+       tmp = sbinfo->si_mntflags;
+       au_opt_clr(sbinfo->si_mntflags, XINO);
+       au_opt_clr(sbinfo->si_mntflags, XINODIR);
+       au_opt_clr(sbinfo->si_mntflags, DLGT);
+       au_opt_set_udba(sbinfo->si_mntflags, UDBA_REVAL);
+
+       opt = opts->opt;
+       while (err >= 0 && opt->type != Opt_tail)
+               err = au_opt_br(sb, opt++, opts);
+       if (err > 0)
+               err = 0;
+       else if (unlikely(err < 0))
+               goto out;
+
+       bend = au_sbend(sb);
+       if (unlikely(bend < 0)) {
+               err = -EINVAL;
+               AuErr("no branches\n");
+               goto out;
+       }
+
+       if (au_opt_test(tmp, XINO))
+               au_opt_set(sbinfo->si_mntflags, XINO);
+       else if (au_opt_test(tmp, XINODIR))
+               au_opt_set(sbinfo->si_mntflags, XINODIR);
+       opt = opts->opt;
+       while (!err && opt->type != Opt_tail)
+               err = au_opt_xino(sb, opt++, &opt_xino, &opt_xinodir, opts);
+       if (unlikely(err))
+               goto out;
+
+       /* todo: test this error case? */
+       err = verify_opts(sb, sb->s_flags, tmp, /*remount*/0);
+       if (unlikely(err))
+               goto out;
+
+       /* enable xino */
+       if (au_opt_test(tmp, XINO) && !opt_xino) {
+               xino.file = au_xino_def(sb);
+               err = PTR_ERR(xino.file);
+               if (IS_ERR(xino.file))
+                       goto out;
+
+               br = au_xino_def_br(sbinfo);
+               err = au_xino_set(sb, &xino, /*remount*/0);
+               fput(xino.file);
+               if (unlikely(err))
+                       goto out;
+               au_xino_def_br_set(br, sbinfo);
+       }
+
+       /* restore hinotify */
+       sbinfo->si_mntflags &= ~AuOptMask_UDBA;
+       sbinfo->si_mntflags |= (tmp & AuOptMask_UDBA);
+       if (au_opt_test(tmp, UDBA_INOTIFY))
+               au_reset_hinotify(dir, au_hi_flags(dir, 1) & ~AuHi_XINO);
+
+       /* restore dlgt */
+       if (au_opt_test(tmp, DLGT))
+               au_opt_set(sbinfo->si_mntflags, DLGT);
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+int au_opts_remount(struct super_block *sb, struct au_opts *opts)
+{
+       int err, rerr;
+       struct inode *dir;
+       struct au_opt_xino *opt_xino;
+       struct au_opt_xinodir *opt_xinodir;
+       struct au_opt *opt;
+       unsigned char dlgt;
+       struct au_sbinfo *sbinfo;
+
+       AuTraceEnter();
+       SiMustWriteLock(sb);
+       DiMustWriteLock(sb->s_root);
+       dir = sb->s_root->d_inode;
+       IiMustWriteLock(dir);
+       sbinfo = au_sbi(sb);
+
+       err = 0;
+       dlgt = !!au_opt_test(sbinfo->si_mntflags, DLGT);
+       opt_xino = NULL;
+       opt_xinodir = NULL;
+       opt = opts->opt;
+       while (err >= 0 && opt->type != Opt_tail) {
+               err = au_opt_simple(sb, opt, opts);
+
+               /* disable it temporary */
+               dlgt = !!au_opt_test(sbinfo->si_mntflags, DLGT);
+               au_opt_clr(sbinfo->si_mntflags, DLGT);
+
+               if (!err)
+                       err = au_opt_br(sb, opt, opts);
+               if (!err)
+                       err = au_opt_xino(sb, opt, &opt_xino, &opt_xinodir,
+                                         opts);
+
+               /* restore it */
+               if (dlgt)
+                       au_opt_set(sbinfo->si_mntflags, DLGT);
+               opt++;
+       }
+       if (err > 0)
+               err = 0;
+       AuTraceErr(err);
+
+       /* go on even err */
+
+       /* todo: test this error case? */
+       au_opt_clr(sbinfo->si_mntflags, DLGT);
+       rerr = verify_opts(sb, opts->sb_flags, sbinfo->si_mntflags,
+                          /*remount*/1);
+       if (unlikely(dlgt))
+               au_opt_set(sbinfo->si_mntflags, DLGT);
+       if (unlikely(rerr && !err))
+               err = rerr;
+
+       if (au_ftest_opts(opts->flags, TRUNC_XIB)) {
+               rerr = au_xib_trunc(sb);
+               if (unlikely(rerr && !err))
+                       err = rerr;
+       }
+
+       /* they are handled by the caller */
+       if (!au_ftest_opts(opts->flags, REFRESH_DIR)
+           && (opts->given_udba || au_opt_test_xino(sbinfo->si_mntflags)))
+               au_fset_opts(opts->flags, REFRESH_DIR);
+
+       LKTRTrace("status 0x%x\n", opts->flags);
+       AuTraceErr(err);
+       return err;
+}
diff -urN linux/fs/aufs/opts.h linux-aufs/fs/aufs/opts.h
--- linux/fs/aufs/opts.h        1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/opts.h   2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,255 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * mount options/flags
+ *
+ * $Id$
+ */
+
+#ifndef __AUFS_OPTS_H__
+#define __AUFS_OPTS_H__
+
+#ifdef __KERNEL__
+
+#include <linux/fs.h>
+#include <linux/namei.h>
+#include <linux/aufs_type.h>
+#include "wkq.h"
+
+/* ---------------------------------------------------------------------- */
+/* mount flags */
+
+/* external inode number bitmap and translation table */
+#define AuOpt_XINO             1
+#define AuOpt_XINODIR          (1 << 1)
+#define AuOpt_TRUNC_XINO       (1 << 2)
+#define AuOpt_UDBA_NONE                (1 << 3)        /* users direct branch access */
+#define AuOpt_UDBA_REVAL       (1 << 4)
+#define AuOpt_UDBA_INOTIFY     (1 << 5)
+#define AuOpt_SHWH             (1 << 6)
+#define AuOpt_PLINK            (1 << 7)
+#define AuOpt_WARN_PERM                (1 << 8)
+#define AuOpt_DIRPERM1         (1 << 9)
+#define AuOpt_DLGT             (1 << 10)
+#define AuOpt_COO_NONE         (1 << 11)       /* copyup on open */
+#define AuOpt_COO_LEAF         (1 << 12)
+#define AuOpt_COO_ALL          (1 << 13)
+#define AuOpt_ALWAYS_DIROPQ    (1 << 14)
+#define AuOpt_REFROF           (1 << 15)
+#define AuOpt_VERBOSE          (1 << 16)
+#define AuOpt_SUM              (1 << 17)
+#define AuOpt_SUM_W            (1 << 18)       /* unimplemented */
+
+#if 1 /* ndef CONFIG_AUFS_EXPORT */ /* reserved for future use */
+#undef AuOpt_XINODIR
+#define AuOpt_XINODIR          0
+#endif
+#ifndef CONFIG_AUFS_HINOTIFY
+#undef AuOpt_UDBA_INOTIFY
+#define AuOpt_UDBA_INOTIFY     0
+#endif
+#ifndef CONFIG_AUFS_SHWH
+#undef AuOpt_SHWH
+#define AuOpt_SHWH             0
+#endif
+#ifndef CONFIG_AUFS_DLGT
+#undef AuOpt_DIRPERM1
+#define AuOpt_DIRPERM1         0
+#undef AuOpt_DLGT
+#define AuOpt_DLGT             0
+#endif
+
+/* policies to select one among multiple writable branches */
+enum {
+       AuWbrCreate_TDP,        /* top down parent */
+       AuWbrCreate_RR,         /* round robin */
+       AuWbrCreate_MFS,        /* most free space */
+       AuWbrCreate_MFSV,       /* mfs with seconds */
+       AuWbrCreate_MFSRR,      /* mfs then rr */
+       AuWbrCreate_MFSRRV,     /* mfs then rr with seconds */
+       AuWbrCreate_PMFS,       /* parent and mfs */
+       AuWbrCreate_PMFSV,      /* parent and mfs with seconds */
+
+       AuWbrCreate_Def = AuWbrCreate_TDP
+};
+
+enum {
+       AuWbrCopyup_TDP,        /* top down parent */
+       AuWbrCopyup_BUP,        /* bottom up parent */
+       AuWbrCopyup_BU,         /* bottom up */
+
+       AuWbrCopyup_Def = AuWbrCopyup_TDP
+};
+
+#define AuOptMask_COO          (AuOpt_COO_NONE \
+                                | AuOpt_COO_LEAF \
+                                | AuOpt_COO_ALL)
+#define AuOptMask_UDBA         (AuOpt_UDBA_NONE \
+                                | AuOpt_UDBA_REVAL \
+                                | AuOpt_UDBA_INOTIFY)
+
+#ifdef CONFIG_AUFS_COMPAT
+#define AuOpt_DefExtra1        AuOpt_ALWAYS_DIROPQ
+#else
+#define AuOpt_DefExtra1        0
+#endif
+
+#define AuOpt_Def      (AuOpt_XINO \
+                        | AuOpt_UDBA_REVAL \
+                        | AuOpt_WARN_PERM \
+                        | AuOpt_COO_NONE \
+                        | AuOpt_PLINK \
+                        | AuOpt_DefExtra1)
+
+/* ---------------------------------------------------------------------- */
+
+struct au_opt_add {
+       aufs_bindex_t           bindex;
+       char                    *path;
+       int                     perm;
+       struct nameidata        nd;
+};
+
+struct au_opt_del {
+       char            *path;
+       struct dentry   *h_root;
+};
+
+struct au_opt_mod {
+       char            *path;
+       int             perm;
+       struct dentry   *h_root;
+};
+
+struct au_opt_xino {
+       char            *path;
+       struct file     *file;
+};
+
+struct au_opt_xinodir {
+       char            *name;
+       struct path     path;
+};
+
+struct au_opt_xino_itrunc {
+       aufs_bindex_t   bindex;
+};
+
+struct au_opt_xino_trunc_v {
+       unsigned long long      upper;
+       int                     step;
+};
+
+struct au_opt_wbr_create {
+       int                     wbr_create;
+       int                     mfs_second;
+       unsigned long long      mfsrr_watermark;
+};
+
+struct au_opt {
+       int type;
+       union {
+               struct au_opt_xino      xino;
+               struct au_opt_xinodir   xinodir;
+               struct au_opt_xino_itrunc xino_itrunc;
+               struct au_opt_add       add;
+               struct au_opt_del       del;
+               struct au_opt_mod       mod;
+               int                     dirwh;
+               int                     rdcache;
+               int                     deblk;
+               int                     nhash;
+               int                     udba;
+               int                     coo;
+               struct au_opt_wbr_create wbr_create;
+               int                     wbr_copyup;
+       };
+};
+
+/* opts flags */
+#define AuOpts_REMOUNT         1
+#define AuOpts_REFRESH_DIR     (1 << 1)
+#define AuOpts_REFRESH_NONDIR  (1 << 2)
+#define AuOpts_TRUNC_XIB       (1 << 3)
+#define au_ftest_opts(flags, name)     ((flags) & AuOpts_##name)
+#define au_fset_opts(flags, name)      { (flags) |= AuOpts_##name; }
+#define au_fclr_opts(flags, name)      { (flags) &= ~AuOpts_##name; }
+
+struct au_opts {
+       struct au_opt   *opt;
+       int             max_opt;
+
+       unsigned int    given_udba;
+       unsigned int    flags;
+       unsigned long   sb_flags;
+};
+
+/* ---------------------------------------------------------------------- */
+
+const char *au_optstr_br_perm(int brperm);
+const char *au_optstr_udba(int udba);
+const char *au_optstr_coo(int coo);
+const char *au_optstr_wbr_copyup(int wbr_copyup);
+const char *au_optstr_wbr_create(int wbr_create);
+
+void au_opts_free(struct au_opts *opts);
+int au_opts_parse(struct super_block *sb, char *str, struct au_opts *opts);
+int verify_opts(struct super_block *sb, unsigned long sb_flags,
+               unsigned int pending, int remount);
+int au_opts_mount(struct super_block *sb, struct au_opts *opts);
+int au_opts_remount(struct super_block *sb, struct au_opts *opts);
+
+/* ---------------------------------------------------------------------- */
+
+#define au_opt_test(flags, name)       (flags & AuOpt_##name)
+
+static inline int au_opt_test_xino(unsigned int flags)
+{
+       return flags & (AuOpt_XINO | AuOpt_XINODIR);
+}
+
+#define au_opt_set(flags, name) do { \
+       BUILD_BUG_ON(AuOpt_##name & (AuOptMask_COO | AuOptMask_UDBA)); \
+       ((flags) |= AuOpt_##name); \
+} while (0)
+
+#define au_opt_set_coo(flags, name) do { \
+       (flags) &= ~AuOptMask_COO; \
+       ((flags) |= AuOpt_##name); \
+} while (0)
+
+#define au_opt_set_udba(flags, name) do { \
+       (flags) &= ~AuOptMask_UDBA; \
+       ((flags) |= AuOpt_##name); \
+} while (0)
+
+#define au_opt_clr(flags, name)                { ((flags) &= ~AuOpt_##name); }
+
+static inline int au_test_dlgt(unsigned int flags)
+{
+       return au_opt_test(flags, DLGT) && !au_test_wkq(current);
+}
+
+static inline int au_test_dirperm1(unsigned int flags)
+{
+       return au_opt_test(flags, DIRPERM1) && !au_test_wkq(current);
+}
+
+#endif /* __KERNEL__ */
+#endif /* __AUFS_OPTS_H__ */
diff -urN linux/fs/aufs/plink.c linux-aufs/fs/aufs/plink.c
--- linux/fs/aufs/plink.c       1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/plink.c  2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,364 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * pseudo-link
+ *
+ * $Id$
+ */
+
+#include "aufs.h"
+
+struct pseudo_link {
+       struct list_head list;
+       struct inode *inode;
+};
+
+#ifdef CONFIG_AUFS_DEBUG
+void au_plink_list(struct super_block *sb)
+{
+       struct au_sbinfo *sbinfo;
+       struct list_head *plink_list;
+       struct pseudo_link *plink;
+
+       AuTraceEnter();
+       SiMustAnyLock(sb);
+       sbinfo = au_sbi(sb);
+       AuDebugOn(!au_opt_test(au_mntflags(sb), PLINK));
+
+       plink_list = &sbinfo->si_plink.head;
+       spin_lock(&sbinfo->si_plink.spin);
+       list_for_each_entry(plink, plink_list, list)
+               AuDbg("%lu\n", plink->inode->i_ino);
+       spin_unlock(&sbinfo->si_plink.spin);
+}
+#endif
+
+int au_plink_test(struct super_block *sb, struct inode *inode)
+{
+       int found;
+       struct au_sbinfo *sbinfo;
+       struct list_head *plink_list;
+       struct pseudo_link *plink;
+
+       LKTRTrace("i%lu\n", inode->i_ino);
+       SiMustAnyLock(sb);
+       sbinfo = au_sbi(sb);
+       AuDebugOn(!au_opt_test(au_mntflags(sb), PLINK));
+
+       found = 0;
+       plink_list = &sbinfo->si_plink.head;
+       spin_lock(&sbinfo->si_plink.spin);
+       list_for_each_entry(plink, plink_list, list)
+               if (plink->inode == inode) {
+                       found = 1;
+                       break;
+               }
+       spin_unlock(&sbinfo->si_plink.spin);
+       return found;
+}
+
+/* 20 is max digits length of ulong 64 */
+#define PLINK_NAME_LEN ((20 + 1) * 2)
+
+static int plink_name(char *name, int len, struct inode *inode,
+                     aufs_bindex_t bindex)
+{
+       int rlen;
+       struct inode *h_inode;
+
+       LKTRTrace("i%lu, b%d\n", inode->i_ino, bindex);
+       AuDebugOn(len != PLINK_NAME_LEN);
+       h_inode = au_h_iptr(inode, bindex);
+       AuDebugOn(!h_inode);
+       rlen = snprintf(name, len, "%lu.%lu", inode->i_ino, h_inode->i_ino);
+       AuDebugOn(rlen >= len);
+       return rlen;
+}
+
+struct dentry *au_plink_lkup(struct super_block *sb, aufs_bindex_t bindex,
+                            struct inode *inode)
+{
+       struct dentry *h_dentry, *h_parent;
+       struct au_branch *br;
+       struct au_wbr *wbr;
+       struct inode *h_dir;
+       char tgtname[PLINK_NAME_LEN];
+       int len;
+       struct au_ndx ndx = {
+               .flags  = 0,
+               .nd     = NULL,
+               /* .br  = NULL */
+       };
+
+       LKTRTrace("b%d, i%lu\n", bindex, inode->i_ino);
+       br = au_sbr(sb, bindex);
+       wbr = br->br_wbr;
+       AuDebugOn(!wbr);
+       h_parent = wbr->wbr_plink;
+       AuDebugOn(!h_parent);
+       h_dir = h_parent->d_inode;
+       AuDebugOn(!h_dir);
+
+       len = plink_name(tgtname, sizeof(tgtname), inode, bindex);
+
+       /* always superio. */
+       ndx.nfsmnt = au_do_nfsmnt(br->br_mnt);
+       mutex_lock_nested(&h_dir->i_mutex, AuLsc_I_CHILD2);
+       h_dentry = au_sio_lkup_one(tgtname, h_parent, len, &ndx);
+       mutex_unlock(&h_dir->i_mutex);
+       return h_dentry;
+}
+
+static int do_whplink(char *tgt, int len, struct dentry *h_parent,
+                     struct dentry *h_dentry, struct vfsmount *nfsmnt,
+                     struct super_block *sb)
+{
+       int err, dlgt;
+       struct dentry *h_tgt;
+       struct inode *h_dir;
+       struct vfsub_args vargs;
+       struct au_ndx ndx = {
+               .nfsmnt = nfsmnt,
+               .flags  = 0,
+               .nd     = NULL,
+               /* .br  = NULL */
+       };
+
+       AuTraceEnter();
+
+       dlgt = !!au_test_dlgt(au_mntflags(sb));
+       if (dlgt)
+               au_fset_ndx(ndx.flags, DLGT);
+       h_tgt = au_lkup_one(tgt, h_parent, len, &ndx);
+       err = PTR_ERR(h_tgt);
+       if (IS_ERR(h_tgt))
+               goto out;
+
+       err = 0;
+       vfsub_args_init(&vargs, NULL, dlgt, 0);
+       /* wh.plink dir is not monitored */
+       h_dir = h_parent->d_inode;
+       if (h_tgt->d_inode && h_tgt->d_inode != h_dentry->d_inode)
+               err = vfsub_unlink(h_dir, h_tgt, &vargs);
+       if (!err && !h_tgt->d_inode) {
+               err = vfsub_link(h_dentry, h_dir, h_tgt, &vargs);
+               /* todo: unnecessary? */
+               /* inc_nlink(inode); */
+       }
+       dput(h_tgt);
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+struct do_whplink_args {
+       int *errp;
+       char *tgt;
+       int len;
+       struct dentry *h_parent;
+       struct dentry *h_dentry;
+       struct vfsmount *nfsmnt;
+       struct super_block *sb;
+};
+
+static void call_do_whplink(void *args)
+{
+       struct do_whplink_args *a = args;
+       *a->errp = do_whplink(a->tgt, a->len, a->h_parent, a->h_dentry,
+                             a->nfsmnt, a->sb);
+}
+
+static int whplink(struct dentry *h_dentry, struct inode *inode,
+                  aufs_bindex_t bindex, struct super_block *sb)
+{
+       int err, len, wkq_err;
+       struct au_branch *br;
+       struct au_wbr *wbr;
+       struct dentry *h_parent;
+       struct inode *h_dir;
+       char tgtname[PLINK_NAME_LEN];
+
+       LKTRTrace("%.*s\n", AuDLNPair(h_dentry));
+       br = au_sbr(inode->i_sb, bindex);
+       wbr = br->br_wbr;
+       AuDebugOn(!wbr);
+       h_parent = wbr->wbr_plink;
+       AuDebugOn(!h_parent);
+       h_dir = h_parent->d_inode;
+       AuDebugOn(!h_dir);
+
+       len = plink_name(tgtname, sizeof(tgtname), inode, bindex);
+
+       /* always superio. */
+       mutex_lock_nested(&h_dir->i_mutex, AuLsc_I_CHILD2);
+       if (!au_test_wkq(current)) {
+               struct do_whplink_args args = {
+                       .errp           = &err,
+                       .tgt            = tgtname,
+                       .len            = len,
+                       .h_parent       = h_parent,
+                       .h_dentry       = h_dentry,
+                       .nfsmnt         = au_do_nfsmnt(br->br_mnt),
+                       .sb             = sb
+               };
+               wkq_err = au_wkq_wait(call_do_whplink, &args, /*dlgt*/0);
+               if (unlikely(wkq_err))
+                       err = wkq_err;
+       } else
+               err = do_whplink(tgtname, len, h_parent, h_dentry,
+                                au_do_nfsmnt(br->br_mnt), sb);
+       mutex_unlock(&h_dir->i_mutex);
+
+       AuTraceErr(err);
+       return err;
+}
+
+static void do_put_plink(struct pseudo_link *plink, int do_del)
+{
+       AuTraceEnter();
+
+       iput(plink->inode);
+       if (do_del)
+               list_del(&plink->list);
+       kfree(plink);
+}
+
+void au_plink_append(struct super_block *sb, struct inode *inode,
+                    struct dentry *h_dentry, aufs_bindex_t bindex)
+{
+       struct au_sbinfo *sbinfo;
+       struct list_head *plink_list;
+       struct pseudo_link *plink;
+       int found, err, cnt;
+
+       LKTRTrace("i%lu\n", inode->i_ino);
+       SiMustAnyLock(sb);
+       sbinfo = au_sbi(sb);
+       AuDebugOn(!au_opt_test(au_mntflags(sb), PLINK));
+
+       cnt = 0;
+       found = 0;
+       plink_list = &sbinfo->si_plink.head;
+       spin_lock(&sbinfo->si_plink.spin);
+       list_for_each_entry(plink, plink_list, list) {
+               cnt++;
+               if (plink->inode == inode) {
+                       found = 1;
+                       break;
+               }
+       }
+
+       err = 0;
+       plink = NULL;
+       if (!found) {
+               plink = kmalloc(sizeof(*plink), GFP_ATOMIC);
+               if (plink) {
+                       plink->inode = au_igrab(inode);
+                       list_add(&plink->list, plink_list);
+                       cnt++;
+               } else
+                       err = -ENOMEM;
+       }
+       spin_unlock(&sbinfo->si_plink.spin);
+
+#if 0 /* todo: test here */
+       if (found)
+               return; /* success */
+#endif
+
+       if (!err)
+               err = whplink(h_dentry, inode, bindex, sb);
+
+       if (unlikely(cnt > AUFS_PLINK_WARN))
+               AuWarn1("unexpectedly many pseudo links, %d\n", cnt);
+       if (unlikely(err)) {
+               AuWarn("err %d, damaged pseudo link. ignored.\n", err);
+               if (!found && plink)
+                       do_put_plink(plink, /*do_del*/1);
+       }
+}
+
+void au_plink_put(struct super_block *sb)
+{
+       struct au_sbinfo *sbinfo;
+       struct list_head *plink_list;
+       struct pseudo_link *plink, *tmp;
+
+       AuTraceEnter();
+       SiMustWriteLock(sb);
+       sbinfo = au_sbi(sb);
+       AuDebugOn(!au_opt_test(au_mntflags(sb), PLINK));
+
+       plink_list = &sbinfo->si_plink.head;
+       /* spin_lock(&sbinfo->si_plink.spin); */
+       list_for_each_entry_safe(plink, tmp, plink_list, list)
+               do_put_plink(plink, 0);
+       INIT_LIST_HEAD(plink_list);
+       /* spin_unlock(&sbinfo->si_plink.head); */
+}
+
+void au_plink_half_refresh(struct super_block *sb, aufs_bindex_t br_id)
+{
+       struct au_sbinfo *sbinfo;
+       struct list_head *plink_list;
+       struct pseudo_link *plink, *tmp;
+       struct inode *inode;
+       aufs_bindex_t bstart, bend, bindex;
+       int do_put;
+
+       AuTraceEnter();
+       SiMustWriteLock(sb);
+       sbinfo = au_sbi(sb);
+       AuDebugOn(!au_opt_test(au_mntflags(sb), PLINK));
+
+       plink_list = &sbinfo->si_plink.head;
+       /* spin_lock(&sbinfo->si_plink.spin); */
+       list_for_each_entry_safe(plink, tmp, plink_list, list) {
+               do_put = 0;
+               inode = au_igrab(plink->inode);
+               ii_write_lock_child(inode);
+               bstart = au_ibstart(inode);
+               bend = au_ibend(inode);
+               if (bstart >= 0) {
+                       for (bindex = bstart; bindex <= bend; bindex++) {
+                               if (!au_h_iptr(inode, bindex)
+                                   || au_ii_br_id(inode, bindex) != br_id)
+                                       continue;
+                               au_set_h_iptr(inode, bindex, NULL, 0);
+                               do_put = 1;
+                               break;
+                       }
+               } else
+                       do_put_plink(plink, 1);
+
+               if (do_put) {
+                       for (bindex = bstart; bindex <= bend; bindex++)
+                               if (au_h_iptr(inode, bindex)) {
+                                       do_put = 0;
+                                       break;
+                               }
+                       if (do_put)
+                               do_put_plink(plink, 1);
+               }
+               ii_write_unlock(inode);
+               iput(inode);
+       }
+       /* spin_unlock(&sbinfo->si_plink.spin); */
+}
diff -urN linux/fs/aufs/robr.c linux-aufs/fs/aufs/robr.c
--- linux/fs/aufs/robr.c        1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/robr.c   2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,117 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * 'robr', aufs as readonly branch of another aufs
+ *
+ * $Id$
+ */
+
+#include "aufs.h"
+
+/* ---------------------------------------------------------------------- */
+
+int au_test_robr_wh(struct qstr *name, struct dentry *h_parent,
+                   struct qstr *wh_name, int try_sio, struct au_ndx *ndx)
+{
+       if (strncmp(name->name, AUFS_WH_PFX, AUFS_WH_PFX_LEN))
+               return au_wh_test(h_parent, wh_name, try_sio, ndx);
+       return -EPERM;
+}
+
+int au_test_robr_shwh(struct super_block *sb, const struct qstr *name)
+{
+       return 0;
+}
+
+/* ---------------------------------------------------------------------- */
+
+struct au_robr_lvma {
+       struct list_head list;
+       struct vm_area_struct *vma;
+};
+
+struct file *au_robr_safe_file(struct vm_area_struct *vma)
+{
+       struct file *file = vma->vm_file;
+       struct super_block *sb = file->f_dentry->d_sb;
+       struct au_robr_lvma *lvma, *entry;
+       struct au_sbinfo *sbinfo;
+       struct list_head *head;
+       unsigned char found, warn;
+
+       AuTraceEnter();
+
+       if (!file->private_data || !au_test_aufs(sb))
+               return NULL;
+
+       warn = 0;
+       found = 0;
+       sbinfo = au_sbi(sb);
+       head = &sbinfo->si_lvma.head;
+       spin_lock(&sbinfo->si_lvma.spin);
+       list_for_each_entry(entry, head, list) {
+               found = (entry->vma == vma);
+               if (unlikely(found))
+                       break;
+       }
+       if (!found) {
+               lvma = kmalloc(sizeof(*lvma), GFP_ATOMIC);
+               if (lvma) {
+                       lvma->vma = vma;
+                       list_add(&lvma->list, head);
+               } else {
+                       warn = 1;
+                       file = NULL;
+               }
+       } else
+               file = NULL;
+       spin_unlock(&sbinfo->si_lvma.spin);
+
+       if (unlikely(warn))
+               AuWarn1("no memory for lvma\n");
+       return file;
+}
+
+void au_robr_reset_file(struct vm_area_struct *vma, struct file *file)
+{
+       struct super_block *sb = file->f_dentry->d_sb;
+       struct au_robr_lvma *entry, *found;
+       struct au_sbinfo *sbinfo;
+       struct list_head *head;
+
+       AuTraceEnter();
+       AuDebugOn(!au_test_aufs(sb));
+
+       vma->vm_file = file;
+       /* smp_mb(); */ /* flush vm_file */
+
+       found = NULL;
+       sbinfo = au_sbi(sb);
+       head = &sbinfo->si_lvma.head;
+       spin_lock(&sbinfo->si_lvma.spin);
+       list_for_each_entry(entry, head, list)
+               if (entry->vma == vma) {
+                       found = entry;
+                       break;
+               }
+       AuDebugOn(!found);
+       list_del(&found->list);
+       spin_unlock(&sbinfo->si_lvma.spin);
+       kfree(found);
+}
diff -urN linux/fs/aufs/sbinfo.c linux-aufs/fs/aufs/sbinfo.c
--- linux/fs/aufs/sbinfo.c      1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/sbinfo.c 2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,221 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * superblock private data
+ *
+ * $Id$
+ */
+
+#include <linux/smp_lock.h>
+#include "aufs.h"
+
+/*
+ * they are necessary regardless sysfs is disabled.
+ */
+void au_si_free(struct kobject *kobj)
+{
+       struct au_sbinfo *sbinfo;
+       struct super_block *sb;
+
+       LKTRTrace("kobj %p\n", kobj);
+       sbinfo = container_of(kobj, struct au_sbinfo, si_kobj);
+       LKTRTrace("sbinfo %p\n", sbinfo);
+       AuDebugOn(!list_empty(&sbinfo->si_plink.head));
+
+       sb = sbinfo->si_sb;
+       si_write_lock(sb);
+       au_xino_clr(sb);
+       au_br_free(sbinfo);
+       kfree(sbinfo->si_branch);
+       au_export_put(sbinfo);
+       mutex_destroy(&sbinfo->si_xib_mtx);
+       si_write_unlock(sb);
+       au_rwsem_destroy(&sbinfo->si_rwsem);
+
+       kfree(sbinfo);
+}
+
+int au_si_alloc(struct super_block *sb)
+{
+       int err;
+       struct au_sbinfo *sbinfo;
+
+       AuTraceEnter();
+
+       err = -ENOMEM;
+       sbinfo = kmalloc(sizeof(*sbinfo), GFP_NOFS);
+       if (unlikely(!sbinfo))
+               goto out;
+       sbinfo->si_branch = kzalloc(sizeof(*sbinfo->si_branch), GFP_NOFS);
+       if (unlikely(!sbinfo->si_branch))
+               goto out_sbinfo;
+
+       memset(&sbinfo->si_kobj, 0, sizeof(sbinfo->si_kobj));
+       err = sysaufs_si_init(sbinfo);
+       if (unlikely(err))
+               goto out_br;
+
+       au_rw_init_wlock(&sbinfo->si_rwsem);
+       //au_dbg_locked_si_reg(sb, 1);
+       sbinfo->si_generation = 0;
+       sbinfo->au_si_status = 0;
+       sbinfo->si_bend = -1;
+       sbinfo->si_last_br_id = 0;
+
+       sbinfo->si_wbr_copyup = AuWbrCopyup_Def;
+       sbinfo->si_wbr_create = AuWbrCreate_Def;
+       sbinfo->si_wbr_copyup_ops = au_wbr_copyup_ops + AuWbrCopyup_Def;
+       sbinfo->si_wbr_create_ops = au_wbr_create_ops + AuWbrCreate_Def;
+
+       sbinfo->si_mntflags = AuOpt_Def;
+
+       sbinfo->si_xread = NULL;
+       sbinfo->si_xwrite = NULL;
+       sbinfo->si_xib = NULL;
+       mutex_init(&sbinfo->si_xib_mtx);
+       sbinfo->si_xib_buf = NULL;
+       au_xino_def_br_set(NULL, sbinfo);
+       /* leave si_xib_last_pindex and si_xib_next_bit */
+
+       au_nwt_init(&sbinfo->si_nowait);
+
+       sbinfo->si_rdcache = AUFS_RDCACHE_DEF * HZ;
+       sbinfo->si_dirwh = AUFS_DIRWH_DEF;
+
+       au_spl_init(&sbinfo->si_plink);
+
+       au_robr_lvma_init(sbinfo);
+
+       /* leave other members for sysaufs and si_mnt. */
+       sbinfo->si_sb = sb;
+
+       sb->s_fs_info = sbinfo;
+
+       au_debug_sbinfo_init(sbinfo);
+       return 0; /* success */
+
+ out_br:
+       kfree(sbinfo->si_branch);
+ out_sbinfo:
+       kfree(sbinfo);
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+struct au_branch *au_sbr(struct super_block *sb, aufs_bindex_t bindex)
+{
+       struct au_branch *br;
+
+       SiMustAnyLock(sb);
+       AuDebugOn(bindex < 0 || au_sbend(sb) < bindex);
+       br = au_sbi(sb)->si_branch[0 + bindex];
+       AuDebugOn(!br);
+       return br;
+}
+
+au_gen_t au_sigen_inc(struct super_block *sb)
+{
+       au_gen_t gen;
+
+       SiMustWriteLock(sb);
+       gen = ++au_sbi(sb)->si_generation;
+       au_update_digen(sb->s_root);
+       au_update_iigen(sb->s_root->d_inode);
+       sb->s_root->d_inode->i_version++;
+       return gen;
+}
+
+int au_find_bindex(struct super_block *sb, struct au_branch *br)
+{
+       aufs_bindex_t bindex, bend;
+
+       bend = au_sbend(sb);
+       for (bindex = 0; bindex <= bend; bindex++)
+               if (au_sbr(sb, bindex) == br)
+                       return bindex;
+       return -1;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* dentry and super_block lock. call at entry point */
+void aufs_read_lock(struct dentry *dentry, int flags)
+{
+       si_read_lock(dentry->d_sb, flags);
+       if (au_ftest_lock(flags, DW))
+               di_write_lock_child(dentry);
+       else
+               di_read_lock_child(dentry, flags);
+}
+
+void aufs_read_unlock(struct dentry *dentry, int flags)
+{
+       if (au_ftest_lock(flags, DW))
+               di_write_unlock(dentry);
+       else
+               di_read_unlock(dentry, flags);
+       si_read_unlock(dentry->d_sb);
+}
+
+void aufs_write_lock(struct dentry *dentry)
+{
+       si_write_lock(dentry->d_sb);
+       di_write_lock_child(dentry);
+}
+
+void aufs_write_unlock(struct dentry *dentry)
+{
+       di_write_unlock(dentry);
+       si_write_unlock(dentry->d_sb);
+}
+
+void aufs_read_and_write_lock2(struct dentry *d1, struct dentry *d2, int flags)
+{
+       AuDebugOn(d1 == d2 || d1->d_sb != d2->d_sb);
+       si_read_lock(d1->d_sb, flags);
+       di_write_lock2_child(d1, d2, au_ftest_lock(flags, DIR));
+}
+
+void aufs_read_and_write_unlock2(struct dentry *d1, struct dentry *d2)
+{
+       AuDebugOn(d1 == d2 || d1->d_sb != d2->d_sb);
+       di_write_unlock2(d1, d2);
+       si_read_unlock(d1->d_sb);
+}
+
+/* ---------------------------------------------------------------------- */
+
+aufs_bindex_t au_new_br_id(struct super_block *sb)
+{
+       aufs_bindex_t br_id;
+       struct au_sbinfo *sbinfo;
+
+       AuTraceEnter();
+       SiMustWriteLock(sb);
+
+       sbinfo = au_sbi(sb);
+       while (1) {
+               br_id = ++sbinfo->si_last_br_id;
+               if (br_id && au_br_index(sb, br_id) < 0)
+                       return br_id;
+       }
+}
diff -urN linux/fs/aufs/super.c linux-aufs/fs/aufs/super.c
--- linux/fs/aufs/super.c       1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/super.c  2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,939 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * mount and super_block operations
+ *
+ * $Id$
+ */
+
+#include <linux/module.h>
+#include <linux/buffer_head.h>
+#include <linux/seq_file.h>
+#include <linux/smp_lock.h>
+#include <linux/statfs.h>
+
+#include "aufs.h"
+
+/*
+ * super_operations
+ */
+static struct inode *aufs_alloc_inode(struct super_block *sb)
+{
+       struct aufs_icntnr *c;
+
+       AuTraceEnter();
+
+       c = au_cache_alloc_icntnr();
+       if (c) {
+               inode_init_once(&c->vfs_inode);
+               c->vfs_inode.i_version = 1; /* sigen(sb); */
+               c->iinfo.ii_hinode = NULL;
+               return &c->vfs_inode;
+       }
+       return NULL;
+}
+
+static void aufs_destroy_inode(struct inode *inode)
+{
+       int err;
+
+       LKTRTrace("i%lu\n", inode->i_ino);
+
+       if (!inode->i_nlink || IS_DEADDIR(inode)) {
+               /* todo: move this lock into xigen_inc() */
+               /* in nowait task or remount, sbi is write-locked */
+               struct super_block *sb = inode->i_sb;
+               const int locked = si_noflush_read_trylock(sb);
+
+               err = au_xigen_inc(inode);
+               if (unlikely(err))
+                       AuWarn1("failed resetting i_generation, %d\n", err);
+               if (locked)
+                       si_read_unlock(sb);
+       }
+
+       au_iinfo_fin(inode);
+       au_cache_free_icntnr(container_of(inode, struct aufs_icntnr,
+                                         vfs_inode));
+}
+
+struct inode *au_iget_locked(struct super_block *sb, ino_t ino)
+{
+       struct inode *inode;
+       int err;
+
+       LKTRTrace("i%lu\n", (unsigned long)ino);
+
+       inode = iget_locked(sb, ino);
+       if (unlikely(!inode)) {
+               inode = ERR_PTR(-ENOMEM);
+               goto out;
+       }
+       AuDebugOn(IS_ERR(inode));
+       if (!(inode->i_state & I_NEW))
+               goto out;
+
+       err = au_xigen_new(inode);
+       if (!err)
+               err = au_iinfo_init(inode);
+       if (!err)
+               inode->i_version++;
+       else {
+               iget_failed(inode);
+               inode = ERR_PTR(err);
+       }
+
+ out:
+       /* never return NULL */
+       AuDebugOn(!inode);
+       AuTraceErrPtr(inode);
+       return inode;
+}
+
+/* lock free root dinfo */
+static int au_show_brs(struct seq_file *seq, struct super_block *sb)
+{
+       int err;
+       aufs_bindex_t bindex, bend;
+       struct path path;
+       struct au_hdentry *hd;
+
+       AuTraceEnter();
+
+       err = 0;
+       bend = au_sbend(sb);
+       hd = au_di(sb->s_root)->di_hdentry;
+       for (bindex = 0; !err && bindex <= bend; bindex++) {
+               path.mnt = au_sbr_mnt(sb, bindex);
+               path.dentry = hd[bindex].hd_dentry;
+               err = seq_path(seq, &path, au_esc_chars);
+               if (err > 0) {
+                       const char *p = au_optstr_br_perm(au_sbr_perm(sb,
+                                                                     bindex));
+                       err = seq_printf(seq, "=%s", p);
+               }
+               if (!err && bindex != bend)
+                       err = seq_putc(seq, ':');
+       }
+
+       AuTraceErr(err);
+       return err;
+}
+
+static void au_show_wbr_create(struct seq_file *m, int v,
+                              struct au_sbinfo *sbinfo)
+{
+       const char *pat;
+
+       AuDebugOn(v == AuWbrCreate_Def);
+
+       seq_printf(m, ",create=");
+       pat = au_optstr_wbr_create(v);
+       switch (v) {
+       case AuWbrCreate_TDP:
+       case AuWbrCreate_RR:
+       case AuWbrCreate_MFS:
+       case AuWbrCreate_PMFS:
+               seq_printf(m, pat);
+               break;
+       case AuWbrCreate_MFSV:
+               seq_printf(m, /*pat*/"mfs:%lu",
+                          sbinfo->si_wbr_mfs.mfs_expire / HZ);
+               break;
+       case AuWbrCreate_PMFSV:
+               seq_printf(m, /*pat*/"pmfs:%lu",
+                          sbinfo->si_wbr_mfs.mfs_expire / HZ);
+               break;
+       case AuWbrCreate_MFSRR:
+               seq_printf(m, /*pat*/"mfsrr:%llu",
+                          sbinfo->si_wbr_mfs.mfsrr_watermark);
+               break;
+       case AuWbrCreate_MFSRRV:
+               seq_printf(m, /*pat*/"mfsrr:%llu:%lu",
+                          sbinfo->si_wbr_mfs.mfsrr_watermark,
+                          sbinfo->si_wbr_mfs.mfs_expire / HZ);
+               break;
+       }
+}
+
+/* seq_file will re-call me in case of too long string */
+static int aufs_show_options(struct seq_file *m, struct vfsmount *mnt)
+{
+       int err, n;
+       unsigned int mnt_flags, v;
+       struct path path;
+       struct super_block *sb;
+       struct au_sbinfo *sbinfo;
+       struct file *xino;
+
+       AuTraceEnter();
+
+       sb = mnt->mnt_sb;
+       /* lock free root dinfo */
+       si_noflush_read_lock(sb);
+       sbinfo = au_sbi(sb);
+       seq_printf(m, ",si=%lx", au_si_mask ^ (unsigned long)sbinfo);
+       mnt_flags = au_mntflags(sb);
+       if (au_opt_test(mnt_flags, XINO)) {
+               seq_puts(m, ",xino=");
+               xino = sbinfo->si_xib;
+               path.mnt = xino->f_vfsmnt;
+               path.dentry = xino->f_dentry;
+               err = seq_path(m, &path, au_esc_chars);
+               if (unlikely(err <= 0))
+                       goto out;
+               err = 0;
+#define Deleted "\\040(deleted)"
+               m->count -= sizeof(Deleted) - 1;
+               AuDebugOn(memcmp(m->buf + m->count, Deleted,
+                                sizeof(Deleted) - 1));
+#undef Deleted
+#ifdef CONFIG_AUFS_EXPORT /* reserved for future use */
+       } else if (au_opt_test(mnt_flags, XINODIR)) {
+               seq_puts(m, ",xinodir=");
+               seq_path(m, &sbinfo->si_xinodir, au_esc_chars);
+#endif
+       } else
+               seq_puts(m, ",noxino");
+
+#define AuBool(name, str) do { \
+       v = au_opt_test(mnt_flags, name); \
+       if (v != au_opt_test(AuOpt_Def, name)) \
+               seq_printf(m, ",%s" #str, v ? "" : "no"); \
+} while (0)
+
+#define AuStr(name, str) do { \
+       v = mnt_flags & AuOptMask_##name; \
+       if (v != (AuOpt_Def & AuOptMask_##name)) \
+               seq_printf(m, "," #str "=%s", au_optstr_##str(v)); \
+} while (0)
+
+#ifdef CONFIG_AUFS_COMPAT
+#define AuStr_BrOpt    "dirs="
+#else
+#define AuStr_BrOpt    "br:"
+#endif
+
+       AuBool(TRUNC_XINO, trunc_xino);
+       AuBool(DIRPERM1, dirperm1);
+       AuBool(SHWH, shwh);
+       AuBool(PLINK, plink);
+       AuStr(UDBA, udba);
+
+       v = sbinfo->si_wbr_create;
+       if (v != AuWbrCreate_Def)
+               au_show_wbr_create(m, v, sbinfo);
+
+       v = sbinfo->si_wbr_copyup;
+       if (v != AuWbrCopyup_Def)
+               seq_printf(m, ",cpup=%s", au_optstr_wbr_copyup(v));
+
+       v = au_opt_test(mnt_flags, ALWAYS_DIROPQ);
+       if (v != au_opt_test(AuOpt_Def, ALWAYS_DIROPQ))
+               seq_printf(m, ",diropq=%c", v ? 'a' : 'w');
+       AuBool(REFROF, refrof);
+       AuBool(DLGT, dlgt);
+       AuBool(WARN_PERM, warn_perm);
+       AuBool(VERBOSE, verbose);
+       AuBool(SUM, sum);
+       /* AuBool(SUM_W, wsum); */
+
+       n = sbinfo->si_dirwh;
+       if (n != AUFS_DIRWH_DEF)
+               seq_printf(m, ",dirwh=%d", n);
+       n = sbinfo->si_rdcache / HZ;
+       if (n != AUFS_RDCACHE_DEF)
+               seq_printf(m, ",rdcache=%d", n);
+
+       AuStr(COO, coo);
+
+ out:
+       if (!sysaufs_brs) {
+               seq_puts(m, "," AuStr_BrOpt);
+               au_show_brs(m, sb);
+       }
+       si_read_unlock(sb);
+       return 0;
+
+#undef AuBool
+#undef AuStr
+#undef AuStr_BrOpt
+}
+
+static u64 au_add_till_max(u64 a, u64 b)
+{
+       u64 old;
+
+       old = a;
+       a += b;
+       if (old < a)
+               return a;
+       return ULLONG_MAX;
+}
+
+static int au_statfs_sum(struct super_block *sb, struct kstatfs *buf, int dlgt)
+{
+       int err;
+       aufs_bindex_t bend, bindex, i;
+       unsigned char shared;
+       u64 blocks, bfree, bavail, files, ffree;
+       struct super_block *h_sb;
+
+       AuTraceEnter();
+
+       blocks = 0;
+       bfree = 0;
+       bavail = 0;
+       files = 0;
+       ffree = 0;
+
+       err = 0;
+       bend = au_sbend(sb);
+       for (bindex = bend; bindex >= 0; bindex--) {
+               h_sb = au_sbr_sb(sb, bindex);
+               shared = 0;
+               for (i = bindex + 1; !shared && i <= bend; i++)
+                       shared = au_sbr_sb(sb, i) == h_sb;
+               if (shared)
+                       continue;
+
+               err = vfsub_statfs(h_sb->s_root, buf, dlgt);
+               if (unlikely(err))
+                       goto out;
+
+               blocks = au_add_till_max(blocks, buf->f_blocks);
+               bfree = au_add_till_max(bfree, buf->f_bfree);
+               bavail = au_add_till_max(bavail, buf->f_bavail);
+               files = au_add_till_max(files, buf->f_files);
+               ffree = au_add_till_max(ffree, buf->f_ffree);
+       }
+
+       buf->f_blocks = blocks;
+       buf->f_bfree = bfree;
+       buf->f_bavail = bavail;
+       buf->f_files = files;
+       buf->f_ffree = ffree;
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+/* todo: in case of round-robin policy, return the sum of all rw branches? */
+static int aufs_statfs(struct dentry *dentry, struct kstatfs *buf)
+{
+       int err;
+       unsigned int mnt_flags;
+       unsigned char dlgt;
+       struct super_block *sb;
+
+       AuTraceEnter();
+
+       /* lock free root dinfo */
+       sb = dentry->d_sb;
+       si_noflush_read_lock(sb);
+       mnt_flags = au_mntflags(sb);
+       dlgt = !!au_test_dlgt(mnt_flags);
+       if (!au_opt_test(mnt_flags, SUM))
+               err = vfsub_statfs(au_sbr_sb(sb, 0)->s_root, buf, dlgt);
+       else
+               err = au_statfs_sum(sb, buf, dlgt);
+       si_read_unlock(sb);
+       if (!err) {
+               buf->f_type = AUFS_SUPER_MAGIC;
+               buf->f_namelen -= AUFS_WH_PFX_LEN;
+               memset(&buf->f_fsid, 0, sizeof(buf->f_fsid));
+       }
+       /* buf->f_bsize = buf->f_blocks = buf->f_bfree = buf->f_bavail = -1; */
+
+       AuTraceErr(err);
+       return err;
+}
+
+static void au_fsync_br(struct super_block *sb)
+{
+#ifdef CONFIG_AUFS_FSYNC_SUPER_PATCH
+       aufs_bindex_t bend, bindex;
+       int brperm;
+       struct au_branch *br;
+       struct super_block *h_sb;
+
+       AuTraceEnter();
+
+       si_write_lock(sb);
+       bend = au_sbend(sb);
+       for (bindex = 0; bindex < bend; bindex++) {
+               br = au_sbr(sb, bindex);
+               brperm = br->br_perm;
+               if (brperm == AuBrPerm_RR || brperm == AuBrPerm_RRWH)
+                       continue;
+               h_sb = br->br_mnt->mnt_sb;
+               if (bdev_read_only(h_sb->s_bdev))
+                       continue;
+
+               lockdep_off();
+               down_write(&h_sb->s_umount);
+               shrink_dcache_sb(h_sb);
+               fsync_super(h_sb);
+               up_write(&h_sb->s_umount);
+               lockdep_on();
+       }
+       si_write_unlock(sb);
+#endif
+}
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 26)
+/* this IS NOT for super_operations */
+static void aufs_umount_begin(struct super_block *arg)
+#define AuUmountBeginSb(arg)   (arg)
+#else
+/* this IS for super_operations */
+static void aufs_umount_begin(struct vfsmount *arg, int flags)
+#define AuUmountBeginSb(arg)   ((arg)->mnt_sb)
+#endif
+{
+       struct super_block *sb = AuUmountBeginSb(arg);
+       struct au_sbinfo *sbinfo;
+
+       AuTraceEnter();
+       /* dont trust BKL */
+       AuDebugOn(!kernel_locked());
+
+       sbinfo = au_sbi(sb);
+       if (!sbinfo)
+               return;
+
+       au_fsync_br(sb);
+
+       si_write_lock(sb);
+       if (au_opt_test(au_mntflags(sb), PLINK))
+               au_plink_put(sb);
+       au_mnt_reset(sbinfo);
+#if 0 /* reserved for future use */
+       if (sbinfo->si_wbr_create_ops->fin)
+               sbinfo->si_wbr_create_ops->fin(sb);
+#endif
+       si_write_unlock(sb);
+}
+
+/* final actions when unmounting a file system */
+static void aufs_put_super(struct super_block *sb)
+{
+       struct au_sbinfo *sbinfo;
+
+       AuTraceEnter();
+
+       sbinfo = au_sbi(sb);
+       if (!sbinfo)
+               return;
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 26)
+       aufs_umount_begin(sb);
+#endif
+       kobject_put(&sbinfo->si_kobj);
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * refresh dentry and inode at remount time.
+ */
+static int do_refresh(struct dentry *dentry, mode_t type,
+                     unsigned int dir_flags)
+{
+       int err;
+       struct dentry *parent;
+       struct inode *inode;
+
+       LKTRTrace("%.*s, 0%o\n", AuDLNPair(dentry), type);
+       inode = dentry->d_inode;
+       AuDebugOn(!inode);
+
+       di_write_lock_child(dentry);
+       parent = dget_parent(dentry);
+       di_read_lock_parent(parent, AuLock_IR);
+       /* returns a number of positive dentries */
+       err = au_refresh_hdentry(dentry, type);
+       if (err >= 0) {
+               err = au_refresh_hinode(inode, dentry);
+               if (!err && type == S_IFDIR)
+                       au_reset_hinotify(inode, dir_flags);
+       }
+       if (unlikely(err))
+               AuErr("unrecoverable error %d, %.*s\n", err, AuDLNPair(dentry));
+       di_read_unlock(parent, AuLock_IR);
+       dput(parent);
+       di_write_unlock(dentry);
+
+       AuTraceErr(err);
+       return err;
+}
+
+static int test_dir(struct dentry *dentry, void *arg)
+{
+       return S_ISDIR(dentry->d_inode->i_mode);
+}
+
+/* todo: merge with refresh_nondir()? */
+static int refresh_dir(struct dentry *root, au_gen_t sgen)
+{
+       int err, i, j, ndentry, e;
+       struct au_dcsub_pages dpages;
+       struct au_dpage *dpage;
+       struct dentry **dentries;
+       struct inode *inode;
+       const unsigned int flags = au_hi_flags(root->d_inode, /*isdir*/1);
+
+       LKTRTrace("sgen %d\n", sgen);
+       SiMustWriteLock(root->d_sb);
+       /* dont trust BKL */
+       AuDebugOn(au_digen(root) != sgen || !kernel_locked());
+
+       err = 0;
+       list_for_each_entry(inode, &root->d_sb->s_inodes, i_sb_list)
+               if (S_ISDIR(inode->i_mode) && au_iigen(inode) != sgen) {
+                       ii_write_lock_child(inode);
+                       e = au_refresh_hinode_self(inode);
+                       ii_write_unlock(inode);
+                       if (unlikely(e)) {
+                               LKTRTrace("e %d, i%lu\n", e, inode->i_ino);
+                               if (!err)
+                                       err = e;
+                               /* go on even if err */
+                       }
+               }
+
+       e = au_dpages_init(&dpages, GFP_NOFS);
+       if (unlikely(e)) {
+               if (!err)
+                       err = e;
+               goto out;
+       }
+       e = au_dcsub_pages(&dpages, root, test_dir, NULL);
+       if (unlikely(e)) {
+               if (!err)
+                       err = e;
+               goto out_dpages;
+       }
+
+       for (i = 0; !e && i < dpages.ndpage; i++) {
+               dpage = dpages.dpages + i;
+               dentries = dpage->dentries;
+               ndentry = dpage->ndentry;
+               for (j = 0; !e && j < ndentry; j++) {
+                       struct dentry *d;
+                       d = dentries[j];
+#ifdef CONFIG_AUFS_DEBUG
+                       {
+                               struct dentry *parent;
+                               parent = dget_parent(d);
+                               AuDebugOn(!S_ISDIR(d->d_inode->i_mode)
+                                         || IS_ROOT(d)
+                                         || au_digen(parent) != sgen);
+                               dput(parent);
+                       }
+#endif
+                       if (au_digen(d) != sgen) {
+                               e = do_refresh(d, S_IFDIR, flags);
+                               if (unlikely(e && !err))
+                                       err = e;
+                               /* break on err */
+                       }
+               }
+       }
+
+ out_dpages:
+       au_dpages_free(&dpages);
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+static int test_nondir(struct dentry *dentry, void *arg)
+{
+       return !S_ISDIR(dentry->d_inode->i_mode);
+}
+
+static int refresh_nondir(struct dentry *root, au_gen_t sgen, int do_dentry)
+{
+       int err, i, j, ndentry, e;
+       struct au_dcsub_pages dpages;
+       struct au_dpage *dpage;
+       struct dentry **dentries;
+       struct inode *inode;
+
+       LKTRTrace("sgen %d\n", sgen);
+       SiMustWriteLock(root->d_sb);
+       /* dont trust BKL */
+       AuDebugOn(au_digen(root) != sgen || !kernel_locked());
+
+       err = 0;
+       list_for_each_entry(inode, &root->d_sb->s_inodes, i_sb_list)
+               if (!S_ISDIR(inode->i_mode) && au_iigen(inode) != sgen) {
+                       ii_write_lock_child(inode);
+                       e = au_refresh_hinode_self(inode);
+                       ii_write_unlock(inode);
+                       if (unlikely(e)) {
+                               LKTRTrace("e %d, i%lu\n", e, inode->i_ino);
+                               if (!err)
+                                       err = e;
+                               /* go on even if err */
+                       }
+               }
+
+       if (!do_dentry)
+               goto out;
+
+       e = au_dpages_init(&dpages, GFP_NOFS);
+       if (unlikely(e)) {
+               if (!err)
+                       err = e;
+               goto out;
+       }
+       e = au_dcsub_pages(&dpages, root, test_nondir, NULL);
+       if (unlikely(e)) {
+               if (!err)
+                       err = e;
+               goto out_dpages;
+       }
+
+       for (i = 0; i < dpages.ndpage; i++) {
+               dpage = dpages.dpages + i;
+               dentries = dpage->dentries;
+               ndentry = dpage->ndentry;
+               for (j = 0; j < ndentry; j++) {
+                       struct dentry *d;
+                       d = dentries[j];
+#ifdef CONFIG_AUFS_DEBUG
+                       {
+                               struct dentry *parent;
+                               parent = dget_parent(d);
+                               AuDebugOn(S_ISDIR(d->d_inode->i_mode)
+                                         || au_digen(parent) != sgen);
+                               dput(parent);
+                       }
+#endif
+                       inode = d->d_inode;
+                       if (inode && au_digen(d) != sgen) {
+                               e = do_refresh(d, inode->i_mode & S_IFMT, 0);
+                               if (unlikely(e && !err))
+                                       err = e;
+                               /* go on even err */
+                       }
+               }
+       }
+
+ out_dpages:
+       au_dpages_free(&dpages);
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+/* stop extra interpretation of errno in mount(8), and strange error messages */
+static int cvt_err(int err)
+{
+       AuTraceErr(err);
+
+       switch (err) {
+       case -ENOENT:
+       case -ENOTDIR:
+       case -EEXIST:
+       case -EIO:
+               err = -EINVAL;
+       }
+       return err;
+}
+
+/* protected by s_umount */
+static int aufs_remount_fs(struct super_block *sb, int *flags, char *data)
+{
+       int err, rerr;
+       au_gen_t sigen;
+       struct dentry *root;
+       struct inode *inode;
+       struct au_opts opts;
+       struct au_sbinfo *sbinfo;
+       unsigned char dlgt;
+
+       LKTRTrace("flags 0x%x, data %s, len %lu\n",
+                 *flags, data ? data : "NULL",
+                 (unsigned long)(data ? strlen(data) : 0));
+
+       au_fsync_br(sb);
+
+       err = 0;
+       root = sb->s_root;
+       if (!data || !*data) {
+               aufs_write_lock(root);
+               err = verify_opts(sb, *flags, /*pending*/0, /*remount*/1);
+               aufs_write_unlock(root);
+               goto out; /* success */
+       }
+
+       err = -ENOMEM;
+       memset(&opts, 0, sizeof(opts));
+       opts.opt = (void *)__get_free_page(GFP_NOFS);
+       if (unlikely(!opts.opt))
+               goto out;
+       opts.max_opt = PAGE_SIZE / sizeof(*opts.opt);
+       opts.flags = AuOpts_REMOUNT;
+       opts.sb_flags = *flags;
+
+       /* parse it before aufs lock */
+       err = au_opts_parse(sb, data, &opts);
+       if (unlikely(err))
+               goto out_opts;
+
+       sbinfo = au_sbi(sb);
+       inode = root->d_inode;
+       mutex_lock(&inode->i_mutex);
+       aufs_write_lock(root);
+
+       /* au_do_opts() may return an error */
+       err = au_opts_remount(sb, &opts);
+       au_opts_free(&opts);
+
+       if (au_ftest_opts(opts.flags, REFRESH_DIR)
+           || au_ftest_opts(opts.flags, REFRESH_NONDIR)) {
+               dlgt = !!au_opt_test(sbinfo->si_mntflags, DLGT);
+               au_opt_clr(sbinfo->si_mntflags, DLGT);
+               au_sigen_inc(sb);
+               au_reset_hinotify(inode, au_hi_flags(inode, /*isdir*/1));
+               sigen = au_sigen(sb);
+               au_fclr_si(sbinfo, FAILED_REFRESH_DIRS);
+
+               DiMustNoWaiters(root);
+               IiMustNoWaiters(root->d_inode);
+               di_write_unlock(root);
+
+               rerr = refresh_dir(root, sigen);
+               if (unlikely(rerr)) {
+                       au_fset_si(sbinfo, FAILED_REFRESH_DIRS);
+                       AuWarn("Refreshing directories failed, ignores (%d)\n",
+                              rerr);
+               }
+
+               if (au_ftest_opts(opts.flags, REFRESH_NONDIR)) {
+                       rerr = refresh_nondir(root, sigen, !rerr);
+                       if (unlikely(rerr))
+                               AuWarn("Refreshing non-directories failed,"
+                                      " ignores (%d)\n", rerr);
+               }
+
+               /* aufs_write_lock() calls ..._child() */
+               di_write_lock_child(root);
+
+               au_cpup_attr_all(inode, /*force*/1);
+               if (dlgt)
+                       au_opt_set(sbinfo->si_mntflags, DLGT);
+       }
+
+       aufs_write_unlock(root);
+       mutex_unlock(&inode->i_mutex);
+
+ out_opts:
+       free_page((unsigned long)opts.opt);
+ out:
+       err = cvt_err(err);
+       AuTraceErr(err);
+       return err;
+}
+
+static struct super_operations aufs_sop = {
+       .alloc_inode    = aufs_alloc_inode,
+       .destroy_inode  = aufs_destroy_inode,
+       .drop_inode     = generic_delete_inode,
+
+       .show_options   = aufs_show_options,
+       .statfs         = aufs_statfs,
+
+       .put_super      = aufs_put_super,
+       .remount_fs     = aufs_remount_fs,
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 26)
+       .umount_begin   = aufs_umount_begin
+#endif
+};
+
+/* ---------------------------------------------------------------------- */
+
+static int alloc_root(struct super_block *sb)
+{
+       int err;
+       struct inode *inode;
+       struct dentry *root;
+
+       AuTraceEnter();
+
+       err = -ENOMEM;
+       inode = au_iget_locked(sb, AUFS_ROOT_INO);
+       err = PTR_ERR(inode);
+       if (IS_ERR(inode))
+               goto out;
+       inode->i_op = &aufs_dir_iop;
+       inode->i_fop = &aufs_dir_fop;
+       inode->i_mode = S_IFDIR;
+       unlock_new_inode(inode);
+       root = d_alloc_root(inode);
+       if (unlikely(!root))
+               goto out_iput;
+       err = PTR_ERR(root);
+       if (IS_ERR(root))
+               goto out_iput;
+
+       err = au_alloc_dinfo(root);
+       if (!err) {
+               sb->s_root = root;
+               return 0; /* success */
+       }
+       dput(root);
+       goto out; /* do not iput */
+
+ out_iput:
+       iget_failed(inode);
+       iput(inode);
+ out:
+       AuTraceErr(err);
+       return err;
+
+}
+
+static int aufs_fill_super(struct super_block *sb, void *raw_data, int silent)
+{
+       int err;
+       struct dentry *root;
+       struct inode *inode;
+       struct au_opts opts;
+       char *arg = raw_data;
+
+       if (unlikely(!arg || !*arg)) {
+               err = -EINVAL;
+               AuErr("no arg\n");
+               goto out;
+       }
+       LKTRTrace("%s, silent %d\n", arg, silent);
+
+       err = -ENOMEM;
+       memset(&opts, 0, sizeof(opts));
+       opts.opt = (void *)__get_free_page(GFP_NOFS);
+       if (unlikely(!opts.opt))
+               goto out;
+       opts.max_opt = PAGE_SIZE / sizeof(*opts.opt);
+       opts.sb_flags = sb->s_flags;
+
+       err = au_si_alloc(sb);
+       if (unlikely(err))
+               goto out_opts;
+       SiMustWriteLock(sb);
+
+       /* all timestamps always follow the ones on the branch */
+       sb->s_flags |= MS_NOATIME | MS_NODIRATIME;
+       sb->s_op = &aufs_sop;
+       sb->s_magic = AUFS_SUPER_MAGIC;
+       au_export_init(sb);
+
+       err = alloc_root(sb);
+       if (unlikely(err)) {
+               AuDebugOn(sb->s_root);
+               si_write_unlock(sb);
+               goto out_info;
+       }
+       root = sb->s_root;
+       DiMustWriteLock(root);
+       inode = root->d_inode;
+       inode->i_nlink = 2;
+
+       /*
+        * actually we can parse options regardless aufs lock here.
+        * but at remount time, parsing must be done before aufs lock.
+        * so we follow the same rule.
+        */
+       ii_write_lock_parent(inode);
+       au_dbg_locked_si_reg(sb, 1);
+       aufs_write_unlock(root);
+       err = au_opts_parse(sb, arg, &opts);
+       if (unlikely(err))
+               goto out_root;
+
+       /* lock vfs_inode first, then aufs. */
+       mutex_lock(&inode->i_mutex);
+       inode->i_op = &aufs_dir_iop;
+       inode->i_fop = &aufs_dir_fop;
+       aufs_write_lock(root);
+
+       sb->s_maxbytes = 0;
+       err = au_opts_mount(sb, &opts);
+       au_opts_free(&opts);
+       if (unlikely(err))
+               goto out_unlock;
+       AuDebugOn(!sb->s_maxbytes);
+
+       aufs_write_unlock(root);
+       mutex_unlock(&inode->i_mutex);
+       goto out_opts; /* success */
+
+ out_unlock:
+       aufs_write_unlock(root);
+       mutex_unlock(&inode->i_mutex);
+ out_root:
+       dput(root);
+       sb->s_root = NULL;
+ out_info:
+       kobject_put(&au_sbi(sb)->si_kobj);
+       sb->s_fs_info = NULL;
+ out_opts:
+       free_page((unsigned long)opts.opt);
+ out:
+       AuTraceErr(err);
+       err = cvt_err(err);
+       AuTraceErr(err);
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static int aufs_get_sb(struct file_system_type *fs_type, int flags,
+                      const char *dev_name, void *raw_data,
+                      struct vfsmount *mnt)
+{
+       int err;
+       struct super_block *sb;
+
+       /* all timestamps always follow the ones on the branch */
+       /* mnt->mnt_flags |= MNT_NOATIME | MNT_NODIRATIME; */
+       err = get_sb_nodev(fs_type, flags, raw_data, aufs_fill_super, mnt);
+       if (!err) {
+               sb = mnt->mnt_sb;
+               au_mnt_init(au_sbi(sb), mnt);
+               si_write_lock(sb);
+               sysaufs_brs_add(sb, 0);
+               si_write_unlock(sb);
+       }
+       return err;
+}
+
+struct file_system_type aufs_fs_type = {
+       .name           = AUFS_FSTYPE,
+       .fs_flags       =
+               FS_RENAME_DOES_D_MOVE   /* a race between rename and others*/
+               | FS_REVAL_DOT,         /* for NFS branch and udba */
+       .get_sb         = aufs_get_sb,
+       .kill_sb        = generic_shutdown_super,
+       /* no need to __module_get() and module_put(). */
+       .owner          = THIS_MODULE,
+};
diff -urN linux/fs/aufs/super.h linux-aufs/fs/aufs/super.h
--- linux/fs/aufs/super.h       1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/super.h  2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,579 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * super_block operations
+ *
+ * $Id$
+ */
+
+#ifndef __AUFS_SUPER_H__
+#define __AUFS_SUPER_H__
+
+#ifdef __KERNEL__
+
+#include <linux/fs.h>
+#include <linux/cramfs_fs.h>
+#include <linux/kobject.h>
+#include <linux/magic.h>
+#include <linux/mount.h>
+#include <linux/aufs_type.h>
+#include "misc.h"
+#include "wkq.h"
+
+typedef ssize_t (*au_readf_t)(struct file *, char __user *, size_t, loff_t *);
+typedef ssize_t (*au_writef_t)(struct file *, const char __user *, size_t,
+                              loff_t *);
+
+struct au_wbr_copyup_operations {
+       int (*copyup)(struct dentry *dentry);
+};
+
+struct au_wbr_create_operations {
+       int (*create)(struct dentry *dentry, int isdir);
+       int (*init)(struct super_block *sb);
+       int (*fin)(struct super_block *sb);
+};
+
+struct au_wbr_mfs {
+       struct mutex    mfs_lock; /* protect this structure */
+       unsigned long   mfs_jiffy;
+       unsigned long   mfs_expire;
+       aufs_bindex_t   mfs_bindex;
+
+       unsigned long long      mfsrr_bytes;
+       unsigned long long      mfsrr_watermark;
+};
+
+/* sbinfo status flags */
+/*
+ * set true when refresh_dirs() failed at remount time.
+ * then try refreshing dirs at access time again.
+ * if it is false, refreshing dirs at access time is unnecesary
+ */
+#define AuSi_FAILED_REFRESH_DIRS       1
+#define au_ftest_si(sbinfo, name)      ((sbinfo)->au_si_status & AuSi_##name)
+#define au_fset_si(sbinfo, name) \
+       { (sbinfo)->au_si_status |= AuSi_##name; }
+#define au_fclr_si(sbinfo, name) \
+       { (sbinfo)->au_si_status &= ~AuSi_##name; }
+
+struct au_branch;
+struct au_sbinfo {
+       /* nowait tasks in the system-wide workqueue */
+       struct au_nowait_tasks  si_nowait;
+
+       struct au_rwsem         si_rwsem;
+
+       /* branch management */
+       au_gen_t                si_generation;
+
+       /* see above flags */
+       unsigned char           au_si_status;
+
+       aufs_bindex_t           si_bend;
+       aufs_bindex_t           si_last_br_id;
+       struct au_branch        **si_branch;
+
+       /* policy to select a writable branch */
+       unsigned char           si_wbr_copyup;
+       unsigned char           si_wbr_create;
+       struct au_wbr_copyup_operations *si_wbr_copyup_ops;
+       struct au_wbr_create_operations *si_wbr_create_ops;
+
+       /* round robin */
+       atomic_t                si_wbr_rr_next;
+
+       /* most free space */
+       struct au_wbr_mfs       si_wbr_mfs;
+
+       /* mount flags */
+       /* include/asm-ia64/siginfo.h defines a macro named si_flags */
+       unsigned int            si_mntflags;
+
+       /* external inode number (bitmap and translation table) */
+       au_readf_t              si_xread;
+       au_writef_t             si_xwrite;
+       struct file             *si_xib;
+       struct mutex            si_xib_mtx; /* protect xib members */
+       unsigned long           *si_xib_buf;
+       unsigned long           si_xib_last_pindex;
+       int                     si_xib_next_bit;
+       /* reserved for future use */
+       /* unsigned long long   si_xib_limit; */        /* Max xib file size */
+
+#ifdef CONFIG_AUFS_HINOTIFY
+       struct au_branch        *si_xino_def_br;
+#endif
+
+#ifdef CONFIG_AUFS_EXPORT
+       /* i_generation */
+       struct file             *si_xigen;
+       atomic_t                si_xigen_next;
+#endif
+
+       /* readdir cache time, max, in HZ */
+       unsigned long           si_rdcache;
+
+       /*
+        * If the number of whiteouts are larger than si_dirwh, leave all of
+        * them after au_whtmp_ren to reduce the cost of rmdir(2).
+        * future fsck.aufs or kernel thread will remove them later.
+        * Otherwise, remove all whiteouts and the dir in rmdir(2).
+        */
+       unsigned int            si_dirwh;
+
+       /*
+        * rename(2) a directory with all children.
+        */
+       /* reserved for future use */
+       /* int                  si_rendir; */
+
+       /* pseudo_link list */ /* todo: dirty? */
+       struct au_splhead       si_plink;
+
+#if defined(CONFIG_AUFS_EXPORT) && LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 26)
+       /* dirty, for export, async ops, and sysfs */
+       spinlock_t              si_mntcache_lock;
+       struct vfsmount         *si_mntcache;   /* no get/put */
+#endif
+
+       /*
+        * sysfs and lifetime management.
+        * this is not a small structure and it may be a waste of memory in case
+        * of sysfs is disabled, particulary when many aufs-es are mounted.
+        */
+       struct kobject          si_kobj;
+
+#ifdef CONFIG_AUFS_ROBR
+       /* locked vma list for mmap() */ /* todo: dirty? */
+       struct au_splhead       si_lvma;
+#endif
+
+#ifdef CONFIG_AUFS_EXPORT /* reserved for future use */
+       struct path             si_xinodir;
+#endif
+
+       /* dirty, necessary for unmounting, sysfs and sysrq */
+       struct super_block      *si_sb;
+
+#ifdef CONFIG_AUFS_DEBUG_LOCK
+       struct au_splhead       si_dbg_lock[AuDbgLock_Last];
+#endif
+};
+
+/* ---------------------------------------------------------------------- */
+
+/* policy to select one among writable branches */
+#define AuWbrCopyup(sbinfo, args...) \
+       ((sbinfo)->si_wbr_copyup_ops->copyup(args))
+#define AuWbrCreate(sbinfo, args...) \
+       ((sbinfo)->si_wbr_create_ops->create(args))
+
+/* flags for si_read_lock()/aufs_read_lock()/di_read_lock() */
+#define AuLock_DW              1               /* write-lock dentry */
+#define AuLock_IR              (1 << 1)        /* read-lock inode */
+#define AuLock_IW              (1 << 2)        /* write-lock inode */
+#define AuLock_FLUSH           (1 << 3)        /* wait for 'nowait' tasks */
+#define AuLock_DIR             (1 << 4)        /* target is a dir */
+#define au_ftest_lock(flags, name)     ((flags) & AuLock_##name)
+#define au_fset_lock(flags, name)      { (flags) |= AuLock_##name; }
+#define au_fclr_lock(flags, name)      { (flags) &= ~AuLock_##name; }
+
+/* ---------------------------------------------------------------------- */
+
+/* super.c */
+extern struct file_system_type aufs_fs_type;
+struct inode *au_iget_locked(struct super_block *sb, ino_t ino);
+
+/* sbinfo.c */
+void au_si_free(struct kobject *kobj);
+int au_si_alloc(struct super_block *sb);
+struct au_branch *au_sbr(struct super_block *sb, aufs_bindex_t bindex);
+au_gen_t au_sigen_inc(struct super_block *sb);
+int au_find_bindex(struct super_block *sb, struct au_branch *br);
+
+void aufs_read_lock(struct dentry *dentry, int flags);
+void aufs_read_unlock(struct dentry *dentry, int flags);
+void aufs_write_lock(struct dentry *dentry);
+void aufs_write_unlock(struct dentry *dentry);
+void aufs_read_and_write_lock2(struct dentry *d1, struct dentry *d2, int isdir);
+void aufs_read_and_write_unlock2(struct dentry *d1, struct dentry *d2);
+
+aufs_bindex_t au_new_br_id(struct super_block *sb);
+
+/* wbr_policy.c */
+extern struct au_wbr_copyup_operations au_wbr_copyup_ops[];
+extern struct au_wbr_create_operations au_wbr_create_ops[];
+int au_cpdown_dirs(struct dentry *dentry, aufs_bindex_t bdst);
+
+/* ---------------------------------------------------------------------- */
+
+#if defined(CONFIG_AUFS_EXPORT) && LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 26)
+static inline void au_mnt_init(struct au_sbinfo *sbinfo, struct vfsmount *mnt)
+{
+       spin_lock_init(&sbinfo->si_mntcache_lock);
+       sbinfo->si_mntcache = mnt;
+}
+
+static inline void au_mnt_reset(struct au_sbinfo *sbinfo)
+{
+       spin_lock(&sbinfo->si_mntcache_lock);
+       sbinfo->si_mntcache = NULL;
+       spin_unlock(&sbinfo->si_mntcache_lock);
+}
+#else
+static inline void au_mnt_init(struct au_sbinfo *sbinfo, struct vfsmount *mnt)
+{
+       /* emptr */
+}
+
+static inline void au_mnt_reset(struct au_sbinfo *sbinfo)
+{
+       /* emptr */
+}
+#endif /* EXPORT && < 2.6.26 */
+
+/* ---------------------------------------------------------------------- */
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 26)
+static inline int au_mnt_want_write(struct vfsmount *h_mnt)
+{
+       return mnt_want_write(h_mnt);
+}
+
+static inline void au_mnt_drop_write(struct vfsmount *h_mnt)
+{
+       mnt_drop_write(h_mnt);
+}
+#else
+static inline int au_mnt_want_write(struct vfsmount *h_mnt)
+{
+       return 0;
+}
+
+static inline void au_mnt_drop_write(struct vfsmount *h_mnt)
+{
+       /* empty */
+}
+#endif
+
+/* ---------------------------------------------------------------------- */
+
+static inline struct au_sbinfo *au_sbi(struct super_block *sb)
+{
+       return sb->s_fs_info;
+}
+
+static inline const char *au_sbtype(struct super_block *sb)
+{
+       return sb->s_type->name;
+}
+
+static inline int au_test_aufs(struct super_block *sb)
+{
+       return sb->s_magic == AUFS_SUPER_MAGIC;
+}
+
+static inline int au_test_nfs(struct super_block *sb)
+{
+#ifdef CONFIG_AUFS_BR_NFS
+       return sb->s_magic == NFS_SUPER_MAGIC;
+#else
+       return 0;
+#endif
+}
+
+static inline int au_test_nfs4(struct super_block *sb)
+{
+#ifdef CONFIG_AUFS_BR_NFS_V4
+       return au_test_nfs(sb) && !strcmp(sb->s_type->name, "nfs4");
+#else
+       return 0;
+#endif
+}
+
+static inline int au_test_fuse(struct super_block *sb)
+{
+#ifdef CONFIG_AUFS_WORKAROUND_FUSE
+       return sb->s_magic == FUSE_SUPER_MAGIC;
+#else
+       return 0;
+#endif
+}
+
+static inline int au_test_xfs(struct super_block *sb)
+{
+#ifdef CONFIG_AUFS_BR_XFS
+       return sb->s_magic == XFS_SB_MAGIC;
+#else
+       return 0;
+#endif
+}
+
+static inline int au_test_tmpfs(struct super_block *sb)
+{
+#ifdef CONFIG_TMPFS
+       return sb->s_magic == TMPFS_MAGIC;
+#else
+       return 0;
+#endif
+}
+
+static inline int au_test_ecryptfs(struct super_block *sb)
+{
+#if defined(CONFIG_ECRYPT_FS) || defined(CONFIG_ECRYPT_FS_MODULE)
+       /* why don't they use s_magic? */
+       return !strcmp(sb->s_type->name, "ecryptfs");
+#else
+       return 0;
+#endif
+}
+
+/* ---------------------------------------------------------------------- */
+
+#ifdef CONFIG_AUFS_HINOTIFY
+static inline void au_xino_def_br_set(struct au_branch *br,
+                                     struct au_sbinfo *sbinfo)
+{
+       sbinfo->si_xino_def_br = br;
+}
+
+static inline struct au_branch *au_xino_def_br(struct au_sbinfo *sbinfo)
+{
+       return sbinfo->si_xino_def_br;
+}
+#else
+static inline void au_xino_def_br_set(struct au_branch *br,
+                                     struct au_sbinfo *sbinfo)
+{
+       /* empty */
+}
+
+static inline struct au_branch *au_xino_def_br(struct au_sbinfo *sbinfo)
+{
+       return NULL;
+}
+#endif
+
+/* ---------------------------------------------------------------------- */
+
+#ifdef CONFIG_AUFS_EXPORT
+void au_export_init(struct super_block *sb);
+
+static inline int au_test_nfsd(struct task_struct *tsk)
+{
+       return !tsk->mm && !strcmp(tsk->comm, "nfsd");
+}
+
+static inline void au_export_put(struct au_sbinfo *sbinfo)
+{
+       path_put(&sbinfo->si_xinodir);
+}
+
+int au_xigen_inc(struct inode *inode);
+int au_xigen_new(struct inode *inode);
+int au_xigen_set(struct super_block *sb, struct file *base);
+void au_xigen_clr(struct super_block *sb);
+#else
+static inline void au_export_init(struct super_block *sb)
+{
+       /* nothing */
+}
+
+static inline int au_test_nfsd(struct task_struct *tsk)
+{
+       return 0;
+}
+
+static inline void au_export_put(struct au_sbinfo *sbinfo)
+{
+       /* nothing */
+}
+
+static inline int au_xigen_inc(struct inode *inode)
+{
+       return 0;
+}
+
+static inline int au_xigen_new(struct inode *inode)
+{
+       return 0;
+}
+
+static inline int au_xigen_set(struct super_block *sb, struct file *base)
+{
+       return 0;
+}
+
+static inline void au_xigen_clr(struct super_block *sb)
+{
+       /* empty */
+}
+#endif /* CONFIG_AUFS_EXPORT */
+
+#ifdef CONFIG_AUFS_ROBR
+static inline int au_test_nested(struct super_block *h_sb)
+{
+       return 0;
+}
+
+static inline void au_robr_lvma_init(struct au_sbinfo *sbinfo)
+{
+       au_spl_init(&sbinfo->si_lvma);
+}
+#else
+static inline int au_test_nested(struct super_block *h_sb)
+{
+       int err = 0;
+       if (unlikely(au_test_aufs(h_sb))) {
+               err = -EINVAL;
+               AuTraceErr(err);
+       }
+       return err;
+}
+
+static inline void au_robr_lvma_init(struct au_sbinfo *sbinfo)
+{
+       /* empty */
+}
+#endif /* CONFIG_AUFS_ROBR */
+
+/* ---------------------------------------------------------------------- */
+
+/* lock superblock. mainly for entry point functions */
+/*
+ * si_do_noflush_read_lock, si_do_noflush_write_lock,
+ * si_do_read_unlock, si_do_write_unlock, si_do_downgrade_lock
+ */
+AuSimpleLockRwsemFuncs(si_do_noflush, struct super_block *sb,
+                      au_sbi(sb)->si_rwsem);
+AuSimpleUnlockRwsemFuncs(si_do, struct super_block *sb, au_sbi(sb)->si_rwsem);
+
+static inline void si_noflush_read_lock(struct super_block *sb)
+{
+       au_dbg_locking_si_reg(sb, 0);
+       si_do_noflush_read_lock(sb);
+       au_dbg_locking_si_unreg(sb, 0);
+       au_dbg_locked_si_reg(sb, 0);
+}
+
+static inline void si_noflush_write_lock(struct super_block *sb)
+{
+       au_dbg_locking_si_reg(sb, 1);
+       si_do_noflush_write_lock(sb);
+       au_dbg_locking_si_unreg(sb, 1);
+       au_dbg_locked_si_reg(sb, 1);
+}
+
+static inline int si_noflush_read_trylock(struct super_block *sb)
+{
+       int locked;
+
+       au_dbg_locking_si_reg(sb, 0);
+       locked = si_do_noflush_read_trylock(sb);
+       au_dbg_locking_si_unreg(sb, 0);
+       if (locked)
+               au_dbg_locked_si_reg(sb, 0);
+       return locked;
+}
+
+static inline int si_noflush_write_trylock(struct super_block *sb)
+{
+       int locked;
+
+       au_dbg_locking_si_reg(sb, 1);
+       locked = si_do_noflush_write_trylock(sb);
+       au_dbg_locking_si_unreg(sb, 1);
+       if (locked)
+               au_dbg_locked_si_reg(sb, 1);
+       return locked;
+}
+
+static inline void si_read_unlock(struct super_block *sb)
+{
+       si_do_read_unlock(sb);
+       au_dbg_locked_si_unreg(sb, 0);
+}
+
+static inline void si_write_unlock(struct super_block *sb)
+{
+       si_do_write_unlock(sb);
+       au_dbg_locked_si_unreg(sb, 1);
+}
+
+static inline void si_downgrade_lock(struct super_block *sb)
+{
+       si_do_downgrade_lock(sb);
+}
+
+static inline void si_read_lock(struct super_block *sb, int flags)
+{
+       if (/* !au_test_nfsd(current) &&  */au_ftest_lock(flags, FLUSH))
+               au_nwt_flush(&au_sbi(sb)->si_nowait);
+       si_noflush_read_lock(sb);
+}
+
+static inline void si_write_lock(struct super_block *sb)
+{
+       //WARN_ON(au_test_nfsd(current));
+       au_nwt_flush(&au_sbi(sb)->si_nowait);
+       si_noflush_write_lock(sb);
+}
+
+static inline int si_read_trylock(struct super_block *sb, int flags)
+{
+       if (/* !au_test_nfsd(current) &&  */au_ftest_lock(flags, FLUSH))
+               au_nwt_flush(&au_sbi(sb)->si_nowait);
+       return si_noflush_read_trylock(sb);
+}
+
+static inline int si_write_trylock(struct super_block *sb, int flags)
+{
+       if (/* !au_test_nfsd(current) &&  */au_ftest_lock(flags, FLUSH))
+               au_nwt_flush(&au_sbi(sb)->si_nowait);
+       return si_noflush_write_trylock(sb);
+}
+
+/* to debug easier, do not make them inlined functions */
+#define SiMustReadLock(sb)     AuRwMustReadLock(&au_sbi(sb)->si_rwsem)
+#define SiMustWriteLock(sb)    AuRwMustWriteLock(&au_sbi(sb)->si_rwsem)
+#define SiMustAnyLock(sb)      AuRwMustAnyLock(&au_sbi(sb)->si_rwsem)
+
+/* ---------------------------------------------------------------------- */
+
+static inline aufs_bindex_t au_sbend(struct super_block *sb)
+{
+       SiMustAnyLock(sb);
+       return au_sbi(sb)->si_bend;
+}
+
+static inline unsigned int au_mntflags(struct super_block *sb)
+{
+       SiMustAnyLock(sb);
+       return au_sbi(sb)->si_mntflags;
+}
+
+static inline au_gen_t au_sigen(struct super_block *sb)
+{
+       SiMustAnyLock(sb);
+       return au_sbi(sb)->si_generation;
+}
+
+#endif /* __KERNEL__ */
+#endif /* __AUFS_SUPER_H__ */
diff -urN linux/fs/aufs/sysaufs.c linux-aufs/fs/aufs/sysaufs.c
--- linux/fs/aufs/sysaufs.c     1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/sysaufs.c        2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,109 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * sysfs interface and lifetime management
+ * they are necessary regardless sysfs is disabled.
+ *
+ * $Id$
+ */
+
+#include <linux/fs.h>
+#include <linux/module.h>
+#include <linux/random.h>
+#include <linux/sysfs.h>
+#include "aufs.h"
+
+/* ---------------------------------------------------------------------- */
+
+unsigned long au_si_mask;
+
+/* ---------------------------------------------------------------------- */
+
+struct kset *au_kset;
+
+#define AuSbiAttr(_name) { \
+       .attr   = { .name = __stringify(_name), .mode = 0444 }, \
+       .show   = sysaufs_sbi_##_name,                          \
+}
+
+static struct au_sbi_attr au_sbi_attr_xino = AuSbiAttr(xino);
+#ifdef CONFIG_AUFS_EXPORT
+static struct au_sbi_attr au_sbi_attr_xigen = AuSbiAttr(xigen);
+#endif
+struct attribute *au_sbi_attrs[] = {
+       &au_sbi_attr_xino.attr,
+#ifdef CONFIG_AUFS_EXPORT
+       &au_sbi_attr_xigen.attr,
+#endif
+       NULL,
+};
+
+static struct sysfs_ops au_sbi_ops = {
+       .show   = sysaufs_sbi_show
+};
+
+static struct kobj_type au_sbi_ktype = {
+       .release        = au_si_free,
+       .sysfs_ops      = &au_sbi_ops,
+       .default_attrs  = au_sbi_attrs
+};
+
+/* ---------------------------------------------------------------------- */
+
+int sysaufs_si_init(struct au_sbinfo *sbinfo)
+{
+       int err;
+
+       sbinfo->si_kobj.kset = au_kset;
+       /* some people doesn't like to show a pointer in kernel */
+       err = kobject_init_and_add(&sbinfo->si_kobj, &au_sbi_ktype,
+                                  NULL/*&au_kset->kobj*/,
+                                  SysaufsSb_PREFIX "%lx",
+                                  au_si_mask ^ (unsigned long)sbinfo);
+       AuTraceErr(err);
+       return err;
+}
+
+
+/* ---------------------------------------------------------------------- */
+
+void sysaufs_fin(void)
+{
+       sysfs_remove_group(&au_kset->kobj, au_attr_group);
+       kset_unregister(au_kset);
+}
+
+int __init sysaufs_init(void)
+{
+       int err;
+
+       get_random_bytes(&au_si_mask, sizeof(au_si_mask));
+
+       au_kset = kset_create_and_add(AUFS_NAME, NULL, fs_kobj);
+       err = PTR_ERR(au_kset);
+       if (IS_ERR(au_kset))
+               goto out;
+       err = sysfs_create_group(&au_kset->kobj, au_attr_group);
+       if (unlikely(err))
+               kset_unregister(au_kset);
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
diff -urN linux/fs/aufs/sysaufs.h linux-aufs/fs/aufs/sysaufs.h
--- linux/fs/aufs/sysaufs.h     1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/sysaufs.h        2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,119 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * sysfs interface and lifetime management
+ *
+ * $Id$
+ */
+
+#ifndef __SYSAUFS_H__
+#define __SYSAUFS_H__
+
+#ifdef __KERNEL__
+
+#include <linux/fs.h>
+#include <linux/sysfs.h>
+#include "module.h"
+#include "super.h"
+
+#define SysaufsSb_PREFIX       "si_"   /* followed by %p */
+
+struct au_sbi_attr {
+       struct attribute attr;
+       int (*show)(struct seq_file *seq, struct super_block *sb);
+};
+
+/* ---------------------------------------------------------------------- */
+
+/* sysaufs.c */
+extern unsigned long au_si_mask;
+extern struct kset *au_kset;
+extern struct attribute *au_sbi_attrs[];
+int sysaufs_si_init(struct au_sbinfo *sbinfo);
+int __init sysaufs_init(void);
+void sysaufs_fin(void);
+
+/* ---------------------------------------------------------------------- */
+
+struct au_branch;
+#ifdef CONFIG_SYSFS
+/* sysfs.c */
+extern struct attribute_group *au_attr_group;
+extern struct kobj_type *au_ktype;
+
+int sysaufs_sbi_xino(struct seq_file *seq, struct super_block *sb);
+#ifdef CONFIG_AUFS_EXPORT
+int sysaufs_sbi_xigen(struct seq_file *seq, struct super_block *sb);
+#endif
+int sysaufs_sbi_mntpnt1(struct seq_file *seq, struct super_block *sb);
+ssize_t sysaufs_sbi_show(struct kobject *kobj, struct attribute *attr,
+                        char *buf);
+
+void sysaufs_br_init(struct au_branch *br);
+void sysaufs_brs_add(struct super_block *sb, aufs_bindex_t bindex);
+void sysaufs_brs_del(struct super_block *sb, aufs_bindex_t bindex);
+#else
+#define au_attr_group  NULL
+#define au_ktype       NULL
+
+static inline
+int sysaufs_sbi_xino(struct seq_file *seq, struct super_block *sb)
+{
+       return 0;
+}
+
+#ifdef CONFIG_AUFS_EXPORT
+static inline
+int sysaufs_sbi_xigen(struct seq_file *seq, struct super_block *sb)
+{
+       return 0;
+}
+#endif
+
+static inline
+int sysaufs_sbi_mntpnt1(struct seq_file *seq, struct super_block *sb)
+{
+       return 0;
+}
+
+static inline
+ssize_t sysaufs_sbi_show(struct kobject *kobj, struct attribute *attr,
+                        char *buf)
+{
+       return 0;
+}
+
+static inline void sysaufs_br_init(struct au_branch *br)
+{
+       /* empty */
+}
+
+static inline void sysaufs_brs_add(struct super_block *sb, aufs_bindex_t bindex)
+{
+       /* nothing */
+}
+
+static inline void sysaufs_brs_del(struct super_block *sb, aufs_bindex_t bindex)
+{
+       /* nothing */
+}
+#endif /* CONFIG_SYSFS */
+
+#endif /* __KERNEL__ */
+#endif /* __SYSAUFS_H__ */
diff -urN linux/fs/aufs/sysfs.c linux-aufs/fs/aufs/sysfs.c
--- linux/fs/aufs/sysfs.c       1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/sysfs.c  2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,533 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * sysfs interface
+ *
+ * $Id$
+ */
+
+#include <linux/fs.h>
+#include <linux/module.h>
+#include <linux/seq_file.h>
+#include <linux/sysfs.h>
+#include "aufs.h"
+
+
+#ifdef CONFIG_AUFS_LOCAL
+static ssize_t config_show(struct kobject *kobj, struct kobj_attribute *attr,
+                          char *buf)
+{
+#define conf_bool(name)        "CONFIG_AUFS_" #name "=y\n"
+       static const char opt[] =
+#ifdef CONFIG_AUFS
+               "CONFIG_AUFS=y\n"
+#else
+               "CONFIG_AUFS=m\n"
+#endif
+#ifdef CONFIG_AUFS_BRANCH_MAX_127
+               conf_bool(BRANCH_MAX_127)
+#elif defined(CONFIG_AUFS_BRANCH_MAX_511)
+               conf_bool(BRANCH_MAX_511)
+#elif defined(CONFIG_AUFS_BRANCH_MAX_1023)
+               conf_bool(BRANCH_MAX_1023)
+#elif defined(CONFIG_AUFS_BRANCH_MAX_32767)
+               conf_bool(BRANCH_MAX_32767)
+#endif
+#ifdef CONFIG_AUFS_STAT
+               conf_bool(STAT)
+#endif
+#ifdef CONFIG_AUFS_HINOTIFY
+               conf_bool(HINOTIFY)
+#endif
+#ifdef CONFIG_AUFS_EXPORT
+               conf_bool(EXPORT)
+#endif
+#ifdef CONFIG_AUFS_INO_T_64
+               conf_bool(INO_T_64)
+#endif
+#ifdef CONFIG_AUFS_ROBR
+               conf_bool(ROBR)
+#endif
+#ifdef CONFIG_AUFS_DLGT
+               conf_bool(DLGT)
+#endif
+#ifdef CONFIG_AUFS_HIN_OR_DLGT
+               conf_bool(HIN_OR_DLGT)
+#endif
+#ifdef CONFIG_AUFS_SHWH
+               conf_bool(SHWH)
+#endif
+#ifdef CONFIG_AUFS_RR_SQUASHFS
+               conf_bool(RR_SQUASHFS)
+#endif
+#ifdef CONFIG_AUFS_SEC_PERM_PATCH
+               conf_bool(SEC_PERM_PATCH)
+#endif
+#ifdef CONFIG_AUFS_SPLICE_PATCH
+               conf_bool(SPLICE_PATCH)
+#endif
+#ifdef CONFIG_AUFS_LHASH_PATCH
+               conf_bool(LHASH_PATCH)
+#endif
+#ifdef CONFIG_AUFS_PUT_FILP_PATCH
+               conf_bool(PUT_FILP_PATCH)
+#endif
+#ifdef CONFIG_AUFS_BR_NFS
+               conf_bool(BR_NFS)
+#endif
+#ifdef CONFIG_AUFS_BR_NFS_V4
+               conf_bool(BR_NFS_V4)
+#endif
+#ifdef CONFIG_AUFS_BR_XFS
+               conf_bool(BR_XFS)
+#endif
+#ifdef CONFIG_AUFS_FSYNC_SUPER_PATCH
+               conf_bool(FSYNC_SUPER_PATCH)
+#endif
+#ifdef CONFIG_AUFS_DENY_WRITE_ACCESS_PATCH
+               conf_bool(DENY_WRITE_ACCESS_PATCH)
+#endif
+#ifdef CONFIG_AUFS_KSIZE_PATCH
+               conf_bool(KSIZE_PATCH)
+#endif
+#ifdef CONFIG_AUFS_WORKAROUND_FUSE
+               conf_bool(WORKAROUND_FUSE)
+#endif
+#ifdef CONFIG_AUFS_GETATTR
+               conf_bool(GETATTR)
+#endif
+#ifdef CONFIG_AUFS_DEBUG
+               conf_bool(DEBUG)
+#endif
+#ifdef CONFIG_AUFS_MAGIC_SYSRQ
+               conf_bool(MAGIC_SYSRQ)
+#endif
+#ifdef CONFIG_AUFS_DEBUG_LOCK
+               conf_bool(DEBUG_LOCK)
+#endif
+#ifdef CONFIG_AUFS_COMPAT
+               conf_bool(COMPAT)
+#endif
+#ifdef CONFIG_AUFS_UNIONFS22_PATCH
+               conf_bool(UNIONFS22_PATCH)
+#endif
+#ifdef CONFIG_AUFS_UNIONFS23_PATCH
+               conf_bool(UNIONFS23_PATCH)
+#endif
+               ;
+#undef conf_bool
+
+       char *p = buf;
+       const char *end = buf + PAGE_SIZE;
+
+       p += snprintf(p, end - p, "%s", opt);
+#ifdef DbgUdbaRace
+       if (p < end)
+               p += snprintf(p, end - p, "DbgUdbaRace=%d\n", DbgUdbaRace);
+#endif
+       if (p < end)
+               return p - buf;
+       else
+               return -EFBIG;
+}
+
+static struct kobj_attribute au_config_attr = __ATTR_RO(config);
+#endif
+
+#ifdef CONFIG_AUFS_STAT
+static ssize_t stat_show(struct kobject *kobj, struct kobj_attribute *attr,
+                        char *buf)
+{
+       char *p = buf;
+       const char *end = buf + PAGE_SIZE;
+       int i;
+
+       p += snprintf(p, end - p, "wkq max_busy:");
+       for (i = 0; p < end && i < aufs_nwkq; i++)
+               p += snprintf(p, end - p, " %u", au_wkq[i].max_busy);
+       if (p < end)
+               p += snprintf(p, end - p, ", %u(generic)\n",
+                             au_wkq[aufs_nwkq].max_busy);
+
+       if (p < end)
+               return p - buf;
+       else
+               return -EFBIG;
+}
+
+static struct kobj_attribute au_stat_attr = __ATTR_RO(stat);
+#endif
+
+#ifdef CONFIG_AUFS_DEBUG
+static ssize_t debug_show(struct kobject *kobj, struct kobj_attribute *attr,
+                         char *buf)
+{
+       return sprintf(buf, "%d\n", au_debug_test());
+}
+
+static ssize_t debug_store(struct kobject *kobj, struct kobj_attribute *attr,
+                          const char *buf, size_t sz)
+{
+       LKTRTrace("%.*s\n", (unsigned int)sz, buf);
+
+       if (unlikely(!sz || (*buf != '0' && *buf != '1')))
+               return -EOPNOTSUPP;
+
+       if (*buf == '0')
+               au_debug_off();
+       else if (*buf == '1')
+               au_debug_on();
+       return sz;
+}
+
+static struct kobj_attribute au_debug_attr = __ATTR(debug, S_IRUGO | S_IWUSR,
+                                                   debug_show, debug_store);
+#endif
+
+static struct attribute *au_attr[] = {
+#ifdef CONFIG_AUFS_LOCAL
+       &au_config_attr.attr,
+#endif
+#ifdef CONFIG_AUFS_STAT
+       &au_stat_attr.attr,
+#endif
+#ifdef CONFIG_AUFS_DEBUG
+       &au_debug_attr.attr,
+#endif
+       NULL,   /* need to NULL terminate the list of attributes */
+};
+
+static struct attribute_group au_attr_group_body = {
+       .attrs = au_attr
+};
+
+struct attribute_group *au_attr_group = &au_attr_group_body;
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * they are copied from linux/lib/kobject.c,
+ * and will be exported in the future.
+ */
+static ssize_t au_attr_show(struct kobject *kobj, struct attribute *attr,
+                           char *buf)
+{
+       struct kobj_attribute *kattr;
+       ssize_t ret = -EIO;
+
+       kattr = container_of(attr, struct kobj_attribute, attr);
+       if (kattr->show)
+               ret = kattr->show(kobj, kattr, buf);
+       return ret;
+}
+
+#ifdef CONFIG_AUFS_DEBUG
+static ssize_t au_attr_store(struct kobject *kobj, struct attribute *attr,
+                            const char *buf, size_t count)
+{
+       struct kobj_attribute *kattr;
+       ssize_t ret = -EIO;
+
+       kattr = container_of(attr, struct kobj_attribute, attr);
+       if (kattr->store)
+               ret = kattr->store(kobj, kattr, buf, count);
+       return ret;
+}
+#endif
+
+static struct sysfs_ops sysaufs_ops = {
+       .show   = au_attr_show,
+#ifdef CONFIG_AUFS_DEBUG
+       .store  = au_attr_store
+#endif
+};
+
+static struct kobj_type au_ktype_body = {
+       .sysfs_ops = &sysaufs_ops
+};
+struct kobj_type *au_ktype = &au_ktype_body;
+
+/* ---------------------------------------------------------------------- */
+
+static noinline_for_stack
+int sysaufs_sbi_xi(struct seq_file *seq, struct file *xf, int dlgt,
+                  int print_path)
+{
+       int err;
+       struct kstat st;
+       struct path path;
+
+       err = vfsub_getattr(xf->f_vfsmnt, xf->f_dentry, &st, dlgt);
+       if (!err) {
+               seq_printf(seq, "%llux%lu %lld",
+                          st.blocks, st.blksize, (long long)st.size);
+               if (print_path) {
+                       path.dentry = xf->f_dentry;
+                       path.mnt = xf->f_vfsmnt;
+                       seq_putc(seq, ' ');
+                       seq_path(seq, &path, au_esc_chars);
+               }
+               seq_putc(seq, '\n');
+       } else
+               seq_printf(seq, "err %d\n", err);
+
+       AuTraceErr(err);
+       return err;
+}
+
+int sysaufs_sbi_xino(struct seq_file *seq, struct super_block *sb)
+{
+       int err;
+       unsigned int mnt_flags;
+       aufs_bindex_t bend, bindex;
+       unsigned char dlgt, xinodir;
+       struct kstat st;
+       struct path path;
+       struct au_sbinfo *sbinfo;
+       struct file *xf;
+
+       AuTraceEnter();
+
+       sbinfo = au_sbi(sb);
+       mnt_flags = au_mntflags(sb);
+       xinodir = !!au_opt_test(mnt_flags, XINODIR);
+       if (!au_opt_test_xino(mnt_flags)) {
+#ifdef CONFIG_AUFS_DEBUG
+               AuDebugOn(sbinfo->si_xib);
+               bend = au_sbend(sb);
+               for (bindex = 0; bindex <= bend; bindex++)
+                       AuDebugOn(au_sbr(sb, bindex)->br_xino.xi_file);
+#endif
+               err = 0;
+               goto out; /* success */
+       }
+
+       dlgt = !!au_test_dlgt(mnt_flags);
+       err = sysaufs_sbi_xi(seq, sbinfo->si_xib, dlgt, xinodir);
+
+       bend = au_sbend(sb);
+       for (bindex = 0; !err && bindex <= bend; bindex++) {
+               xf = au_sbr(sb, bindex)->br_xino.xi_file;
+               if (!xf)
+                       continue;
+               seq_printf(seq, "%d: ", bindex);
+               err = vfsub_getattr(xf->f_vfsmnt, xf->f_dentry, &st, dlgt);
+               if (!err) {
+                       seq_printf(seq, "%ld, %llux%lu %lld",
+                                  (long)file_count(xf), st.blocks, st.blksize,
+                                  (long long)st.size);
+                       if (xinodir) {
+                               path.dentry = xf->f_dentry;
+                               path.mnt = xf->f_vfsmnt;
+                               seq_putc(seq, ' ');
+                               seq_path(seq, &path, au_esc_chars);
+                       }
+                       seq_putc(seq, '\n');
+               } else
+                       seq_printf(seq, "err %d\n", err);
+       }
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+#ifdef CONFIG_AUFS_EXPORT
+int sysaufs_sbi_xigen(struct seq_file *seq, struct super_block *sb)
+{
+       int err;
+       unsigned int mnt_flags;
+       struct au_sbinfo *sbinfo;
+
+       AuTraceEnter();
+
+       err = 0;
+       sbinfo = au_sbi(sb);
+       mnt_flags = au_mntflags(sb);
+       if (au_opt_test_xino(mnt_flags))
+               err = sysaufs_sbi_xi(seq, sbinfo->si_xigen,
+                                    !!au_opt_test(mnt_flags, DLGT),
+                                    !!au_opt_test(mnt_flags, XINODIR));
+
+       AuTraceErr(err);
+       return err;
+}
+#endif
+
+/*
+ * the lifetime of branch is independent from the entry under sysfs.
+ * sysfs handles the lifetime of the entry, and never call ->show() after it is
+ * unlinked.
+ */
+#define SysaufsBr_PREFIX "br"
+static int sysaufs_sbi_br(struct seq_file *seq, struct super_block *sb,
+                         aufs_bindex_t bindex)
+{
+       int err;
+       struct dentry *root;
+       struct au_branch *br;
+       struct path path;
+
+       LKTRTrace("b%d\n", bindex);
+
+       err = -ENOENT;
+       if (unlikely(au_sbend(sb) < bindex))
+               goto out;
+
+       err = 0;
+       root = sb->s_root;
+       di_read_lock_parent(root, !AuLock_IR);
+       br = au_sbr(sb, bindex);
+       path.mnt = br->br_mnt;
+       path.dentry = au_h_dptr(root, bindex);
+       seq_path(seq, &path, au_esc_chars);
+       di_read_unlock(root, !AuLock_IR);
+       seq_printf(seq, "=%s\n", au_optstr_br_perm(br->br_perm));
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static struct seq_file *au_seq(char *p, ssize_t len)
+{
+       struct seq_file *seq;
+
+       seq = kzalloc(sizeof(*seq), GFP_NOFS);
+       if (seq) {
+               /* todo: necessary? */
+               /* mutex_init(&seq.lock); */
+               seq->buf = p;
+               seq->size = len;
+               return seq; /* success */
+       }
+
+       seq = ERR_PTR(-ENOMEM);
+       AuTraceErrPtr(seq);
+       return seq;
+}
+
+/* todo: file size may exceed PAGE_SIZE */
+ssize_t sysaufs_sbi_show(struct kobject *kobj, struct attribute *attr,
+                        char *buf)
+{
+       ssize_t err;
+       long l;
+       struct au_sbinfo *sbinfo;
+       struct super_block *sb;
+       struct seq_file *seq;
+       char *name;
+       struct attribute **cattr;
+
+       LKTRTrace("%s/%s\n", kobject_name(kobj), attr->name);
+
+       sbinfo = container_of(kobj, struct au_sbinfo, si_kobj);
+       sb = sbinfo->si_sb;
+       si_noflush_read_lock(sb);
+
+       seq = au_seq(buf, PAGE_SIZE);
+       err = PTR_ERR(seq);
+       if (IS_ERR(seq))
+               goto out;
+
+       name = (void *)attr->name;
+       cattr = au_sbi_attrs;
+       while (*cattr) {
+               if (!strcmp(name, (*cattr)->name)) {
+                       err = container_of(*cattr, struct au_sbi_attr, attr)
+                               ->show(seq, sb);
+                       goto out_seq;
+               }
+               cattr++;
+       }
+
+       if (!strncmp(name, SysaufsBr_PREFIX, sizeof(SysaufsBr_PREFIX) - 1)) {
+               name += sizeof(SysaufsBr_PREFIX) - 1;
+               err = strict_strtol(name, 10, &l);
+               if (!err)
+                       err = sysaufs_sbi_br(seq, sb, (aufs_bindex_t)l);
+               goto out_seq;
+       }
+       BUG();
+
+ out_seq:
+       if (!err) {
+               err = seq->count;
+               /* sysfs limit */
+               if (unlikely(err == PAGE_SIZE))
+                       err = -EFBIG;
+       }
+       kfree(seq);
+ out:
+       si_read_unlock(sb);
+       AuTraceErr(err);
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+void sysaufs_br_init(struct au_branch *br)
+{
+       br->br_attr.name = br->br_name;
+       br->br_attr.mode = S_IRUGO;
+       br->br_attr.owner = THIS_MODULE;
+}
+
+void sysaufs_brs_del(struct super_block *sb, aufs_bindex_t bindex)
+{
+       struct au_sbinfo *sbinfo;
+       aufs_bindex_t bend;
+
+       LKTRTrace("b%d\n", bindex);
+
+       if (!sysaufs_brs)
+               return;
+
+       sbinfo = au_sbi(sb);
+       bend = au_sbend(sb);
+       for (; bindex <= bend; bindex++)
+               sysfs_remove_file(&sbinfo->si_kobj,
+                                 &au_sbr(sb, bindex)->br_attr);
+}
+
+void sysaufs_brs_add(struct super_block *sb, aufs_bindex_t bindex)
+{
+       int err;
+       struct kobject *kobj;
+       aufs_bindex_t bend;
+       struct au_branch *br;
+
+       LKTRTrace("b%d\n", bindex);
+
+       if (!sysaufs_brs)
+               return;
+
+       kobj = &au_sbi(sb)->si_kobj;
+       bend = au_sbend(sb);
+       for (; bindex <= bend; bindex++) {
+               br = au_sbr(sb, bindex);
+               snprintf(br->br_name, sizeof(br->br_name),
+                        SysaufsBr_PREFIX "%d", bindex);
+               err = sysfs_create_file(kobj, &br->br_attr);
+               if (unlikely(err))
+                       AuWarn("failed %s under sysfs(%d)\n", br->br_name, err);
+       }
+}
diff -urN linux/fs/aufs/sysrq.c linux-aufs/fs/aufs/sysrq.c
--- linux/fs/aufs/sysrq.c       1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/sysrq.c  2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,280 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * magic sysrq hanlder
+ *
+ * $Id$
+ */
+
+#include <linux/fs.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+/* #include <linux/sysrq.h> */
+#include "aufs.h"
+
+#ifdef CONFIG_AUFS_DEBUG_LOCK
+struct au_dbg_lock {
+       struct list_head list;
+       union {
+               struct super_block      *sb;
+               struct dentry           *dentry;
+               struct inode            *inode;
+               void                    *any;
+       };
+       int flags;
+       unsigned int lsc;
+       pid_t pid;
+};
+
+static void au_dbg_reg(struct au_splhead *spl, void *any, int flags,
+                      unsigned int lsc)
+{
+       struct au_dbg_lock *p = kmalloc(sizeof(*p), GFP_NOFS);
+
+       if (p) {
+               p->any = any;
+               p->flags = flags;
+               p->lsc = lsc;
+               p->pid = current->pid;
+               spin_lock(&spl->spin);
+               list_add(&p->list, &spl->head);
+               spin_unlock(&spl->spin);
+       }
+       WARN_ON(!p);
+}
+
+static void au_dbg_unreg(struct au_splhead *spl, void *any, int flags)
+{
+       struct au_dbg_lock *p, *tmp, *found;
+       struct list_head *head = &spl->head;
+       const pid_t pid = current->pid;
+
+       found = NULL;
+       spin_lock(&spl->spin);
+       list_for_each_entry_safe(p, tmp, head, list)
+               if (p->any == any && p->pid == pid) {
+                       list_del(&p->list);
+                       found = p;
+                       break;
+               }
+       spin_unlock(&spl->spin);
+       kfree(found);
+       WARN_ON(!found);
+}
+
+/* ---------------------------------------------------------------------- */
+
+void au_dbg_locking_si_reg(struct super_block *sb, int flags)
+{
+       au_dbg_reg(au_sbi(sb)->si_dbg_lock + AuDbgLock_SI_LOCKING, sb, flags,
+                  -1);
+}
+
+void au_dbg_locking_si_unreg(struct super_block *sb, int flags)
+{
+       au_dbg_unreg(au_sbi(sb)->si_dbg_lock + AuDbgLock_SI_LOCKING, sb, flags);
+}
+
+void au_dbg_locked_si_reg(struct super_block *sb, int flags)
+{
+       au_dbg_reg(au_sbi(sb)->si_dbg_lock + AuDbgLock_SI_LOCKED, sb, flags,
+                  -1);
+}
+
+void au_dbg_locked_si_unreg(struct super_block *sb, int flags)
+{
+       au_dbg_unreg(au_sbi(sb)->si_dbg_lock + AuDbgLock_SI_LOCKED, sb, flags);
+}
+
+void au_dbg_locking_di_reg(struct dentry *d, int flags, unsigned int lsc)
+{
+       au_dbg_reg(au_sbi(d->d_sb)->si_dbg_lock + AuDbgLock_DI_LOCKING, d,
+                  flags, lsc);
+}
+
+void au_dbg_locking_di_unreg(struct dentry *d, int flags)
+{
+       au_dbg_unreg(au_sbi(d->d_sb)->si_dbg_lock + AuDbgLock_DI_LOCKING, d,
+                    flags);
+}
+
+void au_dbg_locked_di_reg(struct dentry *d, int flags, unsigned int lsc)
+{
+       au_dbg_reg(au_sbi(d->d_sb)->si_dbg_lock + AuDbgLock_DI_LOCKED, d, flags,
+                  lsc);
+}
+
+void au_dbg_locked_di_unreg(struct dentry *d, int flags)
+{
+       au_dbg_unreg(au_sbi(d->d_sb)->si_dbg_lock + AuDbgLock_DI_LOCKED, d,
+                    flags);
+}
+
+void au_dbg_locking_ii_reg(struct inode *i, int flags, unsigned int lsc)
+{
+       au_dbg_reg(au_sbi(i->i_sb)->si_dbg_lock + AuDbgLock_II_LOCKING, i,
+                  flags, lsc);
+}
+
+void au_dbg_locking_ii_unreg(struct inode *i, int flags)
+{
+       au_dbg_unreg(au_sbi(i->i_sb)->si_dbg_lock + AuDbgLock_II_LOCKING, i,
+                    flags);
+}
+
+void au_dbg_locked_ii_reg(struct inode *i, int flags, unsigned int lsc)
+{
+       au_dbg_reg(au_sbi(i->i_sb)->si_dbg_lock + AuDbgLock_II_LOCKED, i, flags,
+                  lsc);
+}
+
+void au_dbg_locked_ii_unreg(struct inode *i, int flags)
+{
+       au_dbg_unreg(au_sbi(i->i_sb)->si_dbg_lock + AuDbgLock_II_LOCKED, i,
+                    flags);
+}
+#endif /* CONFIG_AUFS_DEBUG_LOCK */
+
+/* ---------------------------------------------------------------------- */
+
+static void sysrq_sb(struct super_block *sb)
+{
+       char *plevel;
+       struct inode *i;
+       struct au_sbinfo *sbinfo;
+       struct file *file;
+
+       plevel = au_plevel;
+       au_plevel = KERN_WARNING;
+       au_debug_on();
+
+       sbinfo = au_sbi(sb);
+       pr_warning("si=%lx\n", au_si_mask ^ (unsigned long)sbinfo);
+       pr_warning(AUFS_NAME ": superblock\n");
+       au_dpri_sb(sb);
+       pr_warning(AUFS_NAME ": root dentry\n");
+       au_dpri_dentry(sb->s_root);
+       pr_warning(AUFS_NAME ": root inode\n");
+       au_dpri_inode(sb->s_root->d_inode);
+       pr_warning(AUFS_NAME ": isolated inode\n");
+       list_for_each_entry(i, &sb->s_inodes, i_sb_list)
+               if (list_empty(&i->i_dentry))
+                       au_dpri_inode(i);
+       pr_warning(AUFS_NAME ": files\n");
+       list_for_each_entry(file, &sb->s_files, f_u.fu_list)
+               if (au_test_aufs_file(file))
+                       au_dpri_file(file);
+
+#ifdef CONFIG_AUFS_DEBUG_LOCK
+       {
+               struct au_dbg_lock *p;
+               struct list_head *head;
+
+               pr_warning(AUFS_NAME ": locking si\n");
+               head = &sbinfo->si_dbg_lock[AuDbgLock_SI_LOCKING].head;
+               list_for_each_entry(p, head, list)
+                       pr_warning("pid: %d, 0x%x\n", p->pid, p->flags);
+               pr_warning(AUFS_NAME ": locked si\n");
+               head = &sbinfo->si_dbg_lock[AuDbgLock_SI_LOCKED].head;
+               list_for_each_entry(p, head, list)
+                       pr_warning("pid: %d, 0x%x\n", p->pid, p->flags);
+               pr_warning(AUFS_NAME ": locking di\n");
+               head = &sbinfo->si_dbg_lock[AuDbgLock_DI_LOCKING].head;
+               list_for_each_entry(p, head, list) {
+                       pr_warning("pid: %d, 0x%x, %d\n",
+                                  p->pid, p->flags, p->lsc);
+                       au_dpri_dentry(p->dentry);
+               }
+               pr_warning(AUFS_NAME ": locked di\n");
+               head = &sbinfo->si_dbg_lock[AuDbgLock_DI_LOCKED].head;
+               list_for_each_entry(p, head, list) {
+                       pr_warning("pid: %d, 0x%x, %d\n",
+                                  p->pid, p->flags, p->lsc);
+                       au_dpri_dentry(p->dentry);
+               }
+               pr_warning(AUFS_NAME ": locking ii\n");
+               head = &sbinfo->si_dbg_lock[AuDbgLock_II_LOCKING].head;
+               list_for_each_entry(p, head, list) {
+                       pr_warning("pid: %d, %d\n", p->pid, p->lsc);
+                       au_dpri_inode(p->inode);
+               }
+               pr_warning(AUFS_NAME ": locked ii\n");
+               head = &sbinfo->si_dbg_lock[AuDbgLock_II_LOCKED].head;
+               list_for_each_entry(p, head, list) {
+                       pr_warning("pid: %d, %d\n", p->pid, p->lsc);
+                       au_dpri_inode(p->inode);
+               }
+       }
+#endif
+
+       au_plevel = plevel;
+       au_debug_off();
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* module parameter */
+static char *aufs_sysrq_key = "a";
+module_param_named(sysrq, aufs_sysrq_key, charp, S_IRUGO);
+MODULE_PARM_DESC(sysrq, "MagicSysRq key for " AUFS_NAME);
+
+static void au_sysrq(int key, struct tty_struct *tty)
+{
+       struct kobject *kobj;
+       struct au_sbinfo *sbinfo;
+
+       /* spin_lock(&au_kset->list_lock); */
+       list_for_each_entry(kobj, &au_kset->list, entry) {
+               sbinfo = container_of(kobj, struct au_sbinfo, si_kobj);
+               sysrq_sb(sbinfo->si_sb);
+       }
+       /* spin_unlock(&au_kset->list_lock); */
+}
+
+static struct sysrq_key_op au_sysrq_op = {
+       .handler        = au_sysrq,
+       .help_msg       = "Aufs",
+       .action_msg     = "Aufs",
+       /* todo: test mask? */
+       .enable_mask    = SYSRQ_ENABLE_DUMP
+};
+
+/* ---------------------------------------------------------------------- */
+
+int __init au_sysrq_init(void)
+{
+       int err;
+       char key;
+
+       err = -1;
+       key = *aufs_sysrq_key;
+       if ('a' <= key && key <= 'z')
+               err = register_sysrq_key(key, &au_sysrq_op);
+       if (unlikely(err))
+               AuErr("err %d, sysrq=%c\n", err, key);
+       return err;
+}
+
+void au_sysrq_fin(void)
+{
+       int err;
+       err = unregister_sysrq_key(*aufs_sysrq_key, &au_sysrq_op);
+       if (unlikely(err))
+               AuErr("err %d (ignored)\n", err);
+}
diff -urN linux/fs/aufs/vdir.c linux-aufs/fs/aufs/vdir.c
--- linux/fs/aufs/vdir.c        1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/vdir.c   2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,941 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * virtual or vertical directory
+ *
+ * $Id$
+ */
+
+#include "aufs.h"
+
+static int calc_size(int namelen)
+{
+       int sz;
+
+       sz = sizeof(struct au_vdir_de) + namelen;
+       if (sizeof(ino_t) == sizeof(long)) {
+               const int mask = sizeof(ino_t) - 1;
+               if (sz & mask) {
+                       sz += sizeof(ino_t);
+                       sz &= ~mask;
+               }
+       }
+
+       AuDebugOn(sz % sizeof(ino_t));
+       return sz;
+}
+
+static int set_deblk_end(union au_vdir_deblk_p *p,
+                        union au_vdir_deblk_p *deblk_end)
+{
+       if (calc_size(0) <= deblk_end->p - p->p) {
+               p->de->de_str.len = 0;
+               /* smp_mb(); */
+               return 0;
+       }
+       return -1; /* error */
+}
+
+/* returns true or false */
+static int is_deblk_end(union au_vdir_deblk_p *p,
+                       union au_vdir_deblk_p *deblk_end)
+{
+       if (calc_size(0) <= deblk_end->p - p->p)
+               return !p->de->de_str.len;
+       return 1;
+}
+
+static au_vdir_deblk_t *last_deblk(struct au_vdir *vdir)
+{
+       return vdir->vd_deblk[vdir->vd_nblk - 1];
+}
+
+void au_nhash_init(struct au_nhash *nhash)
+{
+       int i;
+       for (i = 0; i < AuSize_NHASH; i++)
+               INIT_HLIST_HEAD(nhash->heads + i);
+}
+
+struct au_nhash *au_nhash_new(gfp_t gfp)
+{
+       struct au_nhash *nhash;
+
+       nhash = kmalloc(sizeof(*nhash), gfp);
+       if (nhash) {
+               au_nhash_init(nhash);
+               return nhash;
+       }
+       return ERR_PTR(-ENOMEM);
+}
+
+void au_nhash_del(struct au_nhash *nhash)
+{
+       au_nhash_fin(nhash);
+       kfree(nhash);
+}
+
+void au_nhash_move(struct au_nhash *dst, struct au_nhash *src)
+{
+       int i;
+
+       AuTraceEnter();
+
+       *dst = *src;
+       for (i = 0; i < AuSize_NHASH; i++) {
+               struct hlist_head *h;
+               h = dst->heads + i;
+               if (h->first)
+                       h->first->pprev = &h->first;
+               INIT_HLIST_HEAD(src->heads + i);
+       }
+       /* smp_mb(); */
+}
+
+/* ---------------------------------------------------------------------- */
+
+void au_nhash_fin(struct au_nhash *whlist)
+{
+       int i;
+       struct hlist_head *head;
+       struct au_vdir_wh *tpos;
+       struct hlist_node *pos, *n;
+
+       AuTraceEnter();
+
+       for (i = 0; i < AuSize_NHASH; i++) {
+               head = whlist->heads + i;
+               hlist_for_each_entry_safe(tpos, pos, n, head, wh_hash) {
+                       /* hlist_del(pos); */
+                       kfree(tpos);
+               }
+       }
+}
+
+int au_nhash_test_longer_wh(struct au_nhash *whlist, aufs_bindex_t btgt,
+                           int limit)
+{
+       int n, i;
+       struct hlist_head *head;
+       struct au_vdir_wh *tpos;
+       struct hlist_node *pos;
+
+       LKTRTrace("limit %d\n", limit);
+
+       n = 0;
+       for (i = 0; i < AuSize_NHASH; i++) {
+               head = whlist->heads + i;
+               hlist_for_each_entry(tpos, pos, head, wh_hash)
+                       if (tpos->wh_bindex == btgt && ++n > limit)
+                               return 1;
+       }
+       return 0;
+}
+
+static unsigned int au_name_hash(const unsigned char *name, unsigned int len)
+{
+       return full_name_hash(name, len) % AuSize_NHASH;
+}
+
+/* returns found(true) or not */
+int au_nhash_test_known_wh(struct au_nhash *whlist, char *name, int namelen)
+{
+       struct hlist_head *head;
+       struct au_vdir_wh *tpos;
+       struct hlist_node *pos;
+       struct au_vdir_destr *str;
+
+       LKTRTrace("%.*s\n", namelen, name);
+
+       head = whlist->heads + au_name_hash(name, namelen);
+       hlist_for_each_entry(tpos, pos, head, wh_hash) {
+               str = &tpos->wh_str;
+               LKTRTrace("%.*s\n", str->len, str->name);
+               if (str->len == namelen && !memcmp(str->name, name, namelen))
+                       return 1;
+       }
+       return 0;
+}
+
+int au_nhash_append_wh(struct au_nhash *whlist, char *name, int namelen,
+                      ino_t ino, unsigned int d_type, aufs_bindex_t bindex,
+                      unsigned char shwh)
+{
+       int err;
+       struct au_vdir_destr *str;
+       struct au_vdir_wh *wh;
+
+       LKTRTrace("%.*s\n", namelen, name);
+
+       err = -ENOMEM;
+       wh = kmalloc(sizeof(*wh) + namelen, GFP_NOFS);
+       if (unlikely(!wh))
+               goto out;
+       err = 0;
+       wh->wh_bindex = bindex;
+       if (shwh)
+               au_shwh_init_wh(wh, ino, d_type);
+       str = &wh->wh_str;
+       str->len = namelen;
+       memcpy(str->name, name, namelen);
+       hlist_add_head(&wh->wh_hash,
+                      whlist->heads + au_name_hash(name, namelen));
+       /* smp_mb(); */
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+void au_vdir_free(struct au_vdir *vdir)
+{
+       au_vdir_deblk_t **deblk;
+
+       AuTraceEnter();
+
+       deblk = vdir->vd_deblk;
+       while (vdir->vd_nblk--) {
+               kfree(*deblk);
+               deblk++;
+       }
+       kfree(vdir->vd_deblk);
+       au_cache_free_vdir(vdir);
+}
+
+static int append_deblk(struct au_vdir *vdir)
+{
+       int err, sz, i;
+       au_vdir_deblk_t **o;
+       union au_vdir_deblk_p p, deblk_end;
+
+       AuTraceEnter();
+
+       err = -ENOMEM;
+       sz = sizeof(*o) * vdir->vd_nblk;
+       o = au_kzrealloc(vdir->vd_deblk, sz, sz + sizeof(*o), GFP_NOFS);
+       if (unlikely(!o))
+               goto out;
+       vdir->vd_deblk = o;
+       p.deblk = kmalloc(sizeof(*p.deblk), GFP_NOFS);
+       if (p.deblk) {
+               i = vdir->vd_nblk++;
+               vdir->vd_deblk[i] = p.deblk;
+               vdir->vd_last.i = i;
+               vdir->vd_last.p.p = p.p;
+               deblk_end.deblk = p.deblk + 1;
+               err = set_deblk_end(&p, &deblk_end);
+               AuDebugOn(err);
+       }
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+static struct au_vdir *alloc_vdir(void)
+{
+       struct au_vdir *vdir;
+       int err;
+
+       AuTraceEnter();
+
+       err = -ENOMEM;
+       vdir = au_cache_alloc_vdir();
+       if (unlikely(!vdir))
+               goto out;
+       vdir->vd_deblk = kzalloc(sizeof(*vdir->vd_deblk), GFP_NOFS);
+       if (unlikely(!vdir->vd_deblk))
+               goto out_free;
+
+       vdir->vd_nblk = 0;
+       vdir->vd_version = 0;
+       vdir->vd_jiffy = 0;
+       err = append_deblk(vdir);
+       if (!err)
+               return vdir; /* success */
+
+       kfree(vdir->vd_deblk);
+
+ out_free:
+       au_cache_free_vdir(vdir);
+ out:
+       vdir = ERR_PTR(err);
+       AuTraceErrPtr(vdir);
+       return vdir;
+}
+
+static int reinit_vdir(struct au_vdir *vdir)
+{
+       int err;
+       union au_vdir_deblk_p p, deblk_end;
+
+       AuTraceEnter();
+
+       while (vdir->vd_nblk > 1) {
+               kfree(vdir->vd_deblk[vdir->vd_nblk - 1]);
+               vdir->vd_deblk[vdir->vd_nblk - 1] = NULL;
+               vdir->vd_nblk--;
+       }
+       p.deblk = vdir->vd_deblk[0];
+       deblk_end.deblk = p.deblk + 1;
+       err = set_deblk_end(&p, &deblk_end);
+       AuDebugOn(err);
+       vdir->vd_version = 0;
+       vdir->vd_jiffy = 0;
+       vdir->vd_last.i = 0;
+       vdir->vd_last.p.deblk = vdir->vd_deblk[0];
+       /* smp_mb(); */
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static void free_dehlist(struct au_nhash *dehlist)
+{
+       int i;
+       struct hlist_head *head;
+       struct au_vdir_dehstr *tpos;
+       struct hlist_node *pos, *n;
+
+       AuTraceEnter();
+
+       for (i = 0; i < AuSize_NHASH; i++) {
+               head = dehlist->heads + i;
+               hlist_for_each_entry_safe(tpos, pos, n, head, hash) {
+                       /* hlist_del(pos); */
+                       au_cache_free_dehstr(tpos);
+               }
+       }
+}
+
+/* returns found(true) or not */
+static int test_known(struct au_nhash *delist, char *name, int namelen)
+{
+       struct hlist_head *head;
+       struct au_vdir_dehstr *tpos;
+       struct hlist_node *pos;
+       struct au_vdir_destr *str;
+
+       LKTRTrace("%.*s\n", namelen, name);
+
+       head = delist->heads + au_name_hash(name, namelen);
+       hlist_for_each_entry(tpos, pos, head, hash) {
+               str = tpos->str;
+               LKTRTrace("%.*s\n", str->len, str->name);
+               if (str->len == namelen && !memcmp(str->name, name, namelen))
+                       return 1;
+       }
+       return 0;
+
+}
+
+static int append_de(struct au_vdir *vdir, char *name, int namelen, ino_t ino,
+                    unsigned int d_type, struct au_nhash *delist)
+{
+       int err, sz;
+       union au_vdir_deblk_p p, *room, deblk_end;
+       struct au_vdir_dehstr *dehstr;
+
+       LKTRTrace("%.*s %d, i%lu, dt%u\n",
+                 namelen, name, namelen, (unsigned long)ino, d_type);
+
+       p.deblk = last_deblk(vdir);
+       deblk_end.deblk = p.deblk + 1;
+       room = &vdir->vd_last.p;
+       AuDebugOn(room->p < p.p || deblk_end.p <= room->p
+                 || !is_deblk_end(room, &deblk_end));
+
+       sz = calc_size(namelen);
+       if (unlikely(sz > deblk_end.p - room->p)) {
+               err = append_deblk(vdir);
+               if (unlikely(err))
+                       goto out;
+               p.deblk = last_deblk(vdir);
+               deblk_end.deblk = p.deblk + 1;
+               /* smp_mb(); */
+               AuDebugOn(room->p != p.p);
+       }
+
+       err = -ENOMEM;
+       dehstr = au_cache_alloc_dehstr();
+       if (unlikely(!dehstr))
+               goto out;
+       dehstr->str = &room->de->de_str;
+       hlist_add_head(&dehstr->hash,
+                      delist->heads + au_name_hash(name, namelen));
+
+       room->de->de_ino = ino;
+       room->de->de_type = d_type;
+       room->de->de_str.len = namelen;
+       memcpy(room->de->de_str.name, name, namelen);
+
+       err = 0;
+       room->p += sz;
+       if (unlikely(set_deblk_end(room, &deblk_end)))
+               err = append_deblk(vdir);
+       /* smp_mb(); */
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static int au_ino(struct super_block *sb, aufs_bindex_t bindex, ino_t h_ino,
+                 unsigned int d_type, ino_t *ino)
+{
+       int err;
+       struct au_xino_entry xinoe;
+       struct mutex *mtx;
+       const int isdir = (d_type == DT_DIR);
+
+       /* prevent hardlinks from race condition */
+       mtx = NULL;
+       if (!isdir) {
+               mtx = &au_sbr(sb, bindex)->br_xino.xi_nondir_mtx;
+               mutex_lock(mtx);
+       }
+       err = au_xino_read(sb, bindex, h_ino, &xinoe);
+       if (unlikely(err))
+               goto out;
+
+       if (!xinoe.ino) {
+               err = -EIO;
+               xinoe.ino = au_xino_new_ino(sb);
+               if (unlikely(!xinoe.ino))
+                       goto out;
+
+#if 0 /* reserved for future use */
+               struct inode *h_inode;
+               xinoe.h_gen = AuXino_INVALID_HGEN;
+               h_inode = ilookup(au_sbr_sb(sb, bindex), h_ino);
+               if (h_inode) {
+                       if (!is_bad_inode(h_inode)) {
+                               xinoe.h_gen = h_inode->i_generation;
+                               WARN_ON(xinoe.h_gen == AuXino_INVALID_HGEN);
+                       }
+                       iput(h_inode);
+               }
+#endif
+               err = au_xino_write(sb, bindex, h_ino, &xinoe);
+               if (unlikely(err))
+                       goto out;
+       }
+
+       *ino = xinoe.ino;
+
+ out:
+       if (!isdir)
+               mutex_unlock(mtx);
+       AuTraceErr(err);
+       return err;
+}
+
+static int au_wh_ino(struct super_block *sb, aufs_bindex_t bindex, ino_t h_ino,
+                    unsigned int d_type, ino_t *ino)
+{
+#ifdef CONFIG_AUFS_SHWH
+       return au_ino(sb, bindex, h_ino, d_type, ino);
+#else
+       return 0;
+#endif
+}
+
+#define AuFillVdir_CALLED      1
+#define AuFillVdir_SHWH                (1 << 1)
+#define au_ftest_fillvdir(flags, name) ((flags) & AuFillVdir_##name)
+#define au_fset_fillvdir(flags, name)  { (flags) |= AuFillVdir_##name; }
+#define au_fclr_fillvdir(flags, name)  { (flags) &= ~AuFillVdir_##name; }
+#ifndef CONFIG_AUFS_SHWH
+#undef AuFillVdir_SHWH
+#define AuFillVdir_SHWH                0
+#endif
+
+struct fillvdir_arg {
+       struct file             *file;
+       struct au_vdir          *vdir;
+       struct au_nhash         *delist;
+       struct au_nhash         *whlist;
+       aufs_bindex_t           bindex;
+       unsigned int            flags;
+       int                     err;
+};
+
+static int fillvdir(void *__arg, const char *__name, int namelen, loff_t offset,
+                   u64 h_ino, unsigned int d_type)
+{
+       struct fillvdir_arg *arg = __arg;
+       char *name = (void *)__name;
+       aufs_bindex_t bindex, bend;
+       struct super_block *sb;
+       ino_t ino;
+
+       LKTRTrace("%.*s, namelen %d, i%llu, dt%u\n",
+                 namelen, name, namelen, (unsigned long long)h_ino, d_type);
+
+       sb = arg->file->f_dentry->d_sb;
+       bend = arg->bindex;
+       arg->err = 0;
+       au_fset_fillvdir(arg->flags, CALLED);
+       /* smp_mb(); */
+       if (namelen <= AUFS_WH_PFX_LEN
+           || memcmp(name, AUFS_WH_PFX, AUFS_WH_PFX_LEN)) {
+               for (bindex = 0; bindex < bend; bindex++)
+                       if (test_known(arg->delist + bindex, name, namelen)
+                           || au_nhash_test_known_wh(arg->whlist + bindex,
+                                                     name, namelen))
+                               goto out; /* already exists or whiteouted */
+
+               ino = 1; /* why does gcc warns? */
+               arg->err = au_ino(sb, bend, h_ino, d_type, &ino);
+               if (!arg->err)
+                       arg->err = append_de(arg->vdir, name, namelen, ino,
+                                            d_type, arg->delist + bend);
+       } else {
+               name += AUFS_WH_PFX_LEN;
+               namelen -= AUFS_WH_PFX_LEN;
+               for (bindex = 0; bindex < bend; bindex++)
+                       if (au_nhash_test_known_wh(arg->whlist + bend, name,
+                                                  namelen))
+                               goto out; /* already whiteouted */
+
+               ino = 1; /* dummy */
+               if (au_ftest_fillvdir(arg->flags, SHWH))
+                       arg->err = au_wh_ino(sb, bend, h_ino, d_type, &ino);
+               if (!arg->err)
+                       arg->err = au_nhash_append_wh
+                               (arg->whlist + bend, name, namelen, ino, d_type,
+                                bend, au_ftest_fillvdir(arg->flags, SHWH));
+       }
+
+ out:
+       if (!arg->err)
+               arg->vdir->vd_jiffy = jiffies;
+       /* smp_mb(); */
+       AuTraceErr(arg->err);
+       return arg->err;
+}
+
+static int au_handle_shwh(struct super_block *sb, struct au_vdir *vdir,
+                         aufs_bindex_t bstart, aufs_bindex_t bend,
+                         struct au_nhash *_whlist, struct au_nhash *_delist)
+{
+#ifdef CONFIG_AUFS_SHWH
+       int err, i;
+       struct hlist_head *head;
+       struct au_vdir_wh *tpos;
+       struct hlist_node *pos, *n;
+       char *p, *o;
+       struct au_nhash *whlist, *delist;
+       struct au_vdir_destr *destr;
+       aufs_bindex_t bindex;
+
+       AuTraceEnter();
+       AuDebugOn(!au_opt_test(au_mntflags(sb), SHWH));
+
+       err = -ENOMEM;
+       o = p = __getname();
+       if (unlikely(!p))
+               goto out;
+
+       err = 0;
+       memcpy(p, AUFS_WH_PFX, AUFS_WH_PFX_LEN);
+       p += AUFS_WH_PFX_LEN;
+       for (bindex = bstart; !err && bindex <= bend; bindex++) {
+               whlist = _whlist + bindex;
+               delist = _delist + bindex;
+
+               for (i = 0; i < AuSize_NHASH; i++) {
+                       head = whlist->heads + i;
+                       hlist_for_each_entry_safe(tpos, pos, n, head, wh_hash) {
+                               destr = &tpos->wh_str;
+                               memcpy(p, destr->name, destr->len);
+                               err = append_de(vdir, o,
+                                               destr->len + AUFS_WH_PFX_LEN,
+                                               tpos->wh_ino, tpos->wh_type,
+                                               delist);
+                               if (unlikely(err))
+                                       break;
+                       }
+               }
+       }
+
+       __putname(o);
+
+ out:
+       AuTraceErr(err);
+       return err;
+#else
+       return 0;
+#endif
+}
+
+static int au_do_read_vdir(struct fillvdir_arg *arg)
+{
+       int err;
+       unsigned int mnt_flags;
+       loff_t offset;
+       aufs_bindex_t bend, bindex, bstart;
+       unsigned char dlgt, shwh;
+       struct super_block *sb;
+       struct file *hf;
+
+       AuTraceEnter();
+
+       err = -ENOMEM;
+       bend = au_fbend(arg->file);
+       arg->delist = kmalloc(sizeof(*arg->delist) * (bend + 1), GFP_NOFS);
+       if (unlikely(!arg->delist))
+               goto out;
+       arg->whlist = kmalloc(sizeof(*arg->whlist) * (bend + 1), GFP_NOFS);
+       if (unlikely(!arg->whlist))
+               goto out_delist;
+       err = 0;
+       for (bindex = 0; bindex <= bend; bindex++) {
+               au_nhash_init(arg->delist + bindex);
+               au_nhash_init(arg->whlist + bindex);
+       }
+
+       sb = arg->file->f_dentry->d_sb;
+       mnt_flags = au_mntflags(sb);
+       dlgt = !!au_test_dlgt(mnt_flags);
+       arg->flags = 0;
+       shwh = 0;
+       if (au_opt_test(mnt_flags, SHWH)) {
+               shwh = 1;
+               au_fset_fillvdir(arg->flags, SHWH);
+       }
+       bstart = au_fbstart(arg->file);
+       for (bindex = bstart; !err && bindex <= bend; bindex++) {
+               hf = au_h_fptr(arg->file, bindex);
+               if (!hf)
+                       continue;
+
+               offset = vfsub_llseek(hf, 0, SEEK_SET);
+               err = offset;
+               if (unlikely(offset))
+                       break;
+               arg->bindex = bindex;
+               do {
+                       arg->err = 0;
+                       au_fclr_fillvdir(arg->flags, CALLED);
+                       /* smp_mb(); */
+                       err = vfsub_readdir(hf, fillvdir, arg, dlgt);
+                       if (err >= 0)
+                               err = arg->err;
+               } while (!err && au_ftest_fillvdir(arg->flags, CALLED));
+       }
+
+       if (!err && shwh)
+               err = au_handle_shwh(sb, arg->vdir, bstart, bend, arg->whlist,
+                                    arg->delist);
+
+       for (bindex = bstart; bindex <= bend; bindex++) {
+               free_dehlist(arg->delist + bindex);
+               au_nhash_fin(arg->whlist + bindex);
+       }
+       kfree(arg->whlist);
+
+ out_delist:
+       kfree(arg->delist);
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+static int read_vdir(struct file *file, int may_read)
+{
+       int err;
+       unsigned long expire;
+       struct fillvdir_arg arg;
+       unsigned char do_read;
+       struct dentry *dentry;
+       struct inode *inode;
+       struct au_vdir *vdir, *allocated;
+       struct super_block *sb;
+
+       dentry = file->f_dentry;
+       LKTRTrace("%.*s, may %d\n", AuDLNPair(dentry), may_read);
+       FiMustWriteLock(file);
+       inode = dentry->d_inode;
+       IMustLock(inode);
+       IiMustWriteLock(inode);
+       AuDebugOn(!S_ISDIR(inode->i_mode));
+
+       err = 0;
+       allocated = NULL;
+       do_read = 0;
+       sb = inode->i_sb;
+       expire = au_sbi(sb)->si_rdcache;
+       vdir = au_ivdir(inode);
+       if (!vdir) {
+               AuDebugOn(au_fvdir_cache(file));
+               do_read = 1;
+               vdir = alloc_vdir();
+               err = PTR_ERR(vdir);
+               if (IS_ERR(vdir))
+                       goto out;
+               err = 0;
+               allocated = vdir;
+       } else if (may_read
+                  && (inode->i_version != vdir->vd_version
+                      || time_after(jiffies, vdir->vd_jiffy + expire))) {
+               LKTRTrace("iver %llu, vdver %lu, exp %lu\n",
+                         (unsigned long long)inode->i_version,
+                         vdir->vd_version, vdir->vd_jiffy + expire);
+               do_read = 1;
+               err = reinit_vdir(vdir);
+               if (unlikely(err))
+                       goto out;
+       }
+
+       if (!do_read)
+               return 0; /* success */
+
+       arg.file = file;
+       arg.vdir = vdir;
+       err = au_do_read_vdir(&arg);
+       if (!err) {
+               /* todo: necessary? */
+               /* file->f_pos = 0; */
+               vdir->vd_version = inode->i_version;
+               vdir->vd_last.i = 0;
+               vdir->vd_last.p.deblk = vdir->vd_deblk[0];
+               if (allocated)
+                       au_set_ivdir(inode, allocated);
+       } else if (allocated)
+               au_vdir_free(allocated);
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+static int copy_vdir(struct au_vdir *tgt, struct au_vdir *src)
+{
+       int err, i, rerr, n;
+
+       AuTraceEnter();
+       AuDebugOn(tgt->vd_nblk != 1);
+
+       err = -ENOMEM;
+       if (tgt->vd_nblk < src->vd_nblk) {
+               au_vdir_deblk_t **p;
+               p = au_kzrealloc(tgt->vd_deblk, sizeof(*p) * tgt->vd_nblk,
+                                sizeof(*p) * src->vd_nblk, GFP_NOFS);
+               if (unlikely(!p))
+                       goto out;
+               tgt->vd_deblk = p;
+       }
+
+       tgt->vd_nblk = src->vd_nblk;
+       n = src->vd_nblk;
+       memcpy(tgt->vd_deblk[0], src->vd_deblk[0], AuSize_DEBLK);
+       /* tgt->vd_last.i = 0; */
+       /* tgt->vd_last.p.deblk = tgt->vd_deblk[0]; */
+       tgt->vd_version = src->vd_version;
+       tgt->vd_jiffy = src->vd_jiffy;
+
+       for (i = 1; i < n; i++) {
+               tgt->vd_deblk[i] = kmalloc(AuSize_DEBLK, GFP_NOFS);
+               if (tgt->vd_deblk[i])
+                       memcpy(tgt->vd_deblk[i], src->vd_deblk[i],
+                              AuSize_DEBLK);
+               else
+                       goto out;
+       }
+       /* smp_mb(); */
+       return 0; /* success */
+
+ out:
+       rerr = reinit_vdir(tgt);
+       BUG_ON(rerr);
+       AuTraceErr(err);
+       return err;
+}
+
+int au_vdir_init(struct file *file)
+{
+       int err;
+       struct dentry *dentry;
+       struct inode *inode;
+       struct au_vdir *vdir_cache, *allocated;
+
+       dentry = file->f_dentry;
+       LKTRTrace("%.*s, pos %lld\n", AuDLNPair(dentry), file->f_pos);
+       FiMustWriteLock(file);
+       inode = dentry->d_inode;
+       IiMustWriteLock(inode);
+       AuDebugOn(!S_ISDIR(inode->i_mode));
+
+       err = read_vdir(file, !file->f_pos);
+       if (unlikely(err))
+               goto out;
+
+       allocated = NULL;
+       vdir_cache = au_fvdir_cache(file);
+       if (!vdir_cache) {
+               vdir_cache = alloc_vdir();
+               err = PTR_ERR(vdir_cache);
+               if (IS_ERR(vdir_cache))
+                       goto out;
+               allocated = vdir_cache;
+       } else if (!file->f_pos && vdir_cache->vd_version != file->f_version) {
+               err = reinit_vdir(vdir_cache);
+               if (unlikely(err))
+                       goto out;
+       } else
+               return 0; /* success */
+
+       err = copy_vdir(vdir_cache, au_ivdir(inode));
+       if (!err) {
+               file->f_version = inode->i_version;
+               if (allocated)
+                       au_set_fvdir_cache(file, allocated);
+       } else if (allocated)
+               au_vdir_free(allocated);
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+static loff_t calc_offset(struct au_vdir *vdir)
+{
+       loff_t offset;
+       union au_vdir_deblk_p p;
+
+       p.deblk = vdir->vd_deblk[vdir->vd_last.i];
+       offset = vdir->vd_last.p.p - p.p;
+       offset += sizeof(*p.deblk) * vdir->vd_last.i;
+       return offset;
+}
+
+/* returns true or false */
+static int seek_vdir(struct file *file)
+{
+       int valid, i, n;
+       struct dentry *dentry;
+       struct au_vdir *vdir_cache;
+       loff_t offset;
+       union au_vdir_deblk_p p, deblk_end;
+
+       dentry = file->f_dentry;
+       LKTRTrace("%.*s, pos %lld\n", AuDLNPair(dentry), file->f_pos);
+       vdir_cache = au_fvdir_cache(file);
+       AuDebugOn(!vdir_cache);
+
+       valid = 1;
+       offset = calc_offset(vdir_cache);
+       LKTRTrace("offset %lld\n", offset);
+       if (file->f_pos == offset)
+               goto out;
+
+       vdir_cache->vd_last.i = 0;
+       vdir_cache->vd_last.p.deblk = vdir_cache->vd_deblk[0];
+       if (!file->f_pos)
+               goto out;
+
+       valid = 0;
+       i = file->f_pos / AuSize_DEBLK;
+       LKTRTrace("i %d\n", i);
+       if (i >= vdir_cache->vd_nblk)
+               goto out;
+
+       n = vdir_cache->vd_nblk;
+       for (; i < n; i++) {
+               p.deblk = vdir_cache->vd_deblk[i];
+               deblk_end.deblk = p.deblk + 1;
+               offset = i;
+               offset *= AuSize_DEBLK;
+               while (!is_deblk_end(&p, &deblk_end) && offset < file->f_pos) {
+                       int l;
+                       l = calc_size(p.de->de_str.len);
+                       offset += l;
+                       p.p += l;
+               }
+               if (!is_deblk_end(&p, &deblk_end)) {
+                       valid = 1;
+                       vdir_cache->vd_last.i = i;
+                       vdir_cache->vd_last.p = p;
+                       break;
+               }
+       }
+
+ out:
+       /* smp_mb(); */
+       AuTraceErr(!valid);
+       return valid;
+}
+
+int au_vdir_fill_de(struct file *file, void *dirent, filldir_t filldir)
+{
+       int err, l;
+       struct dentry *dentry;
+       struct au_vdir *vdir_cache;
+       struct au_vdir_de *de;
+       union au_vdir_deblk_p deblk_end;
+
+       dentry = file->f_dentry;
+       LKTRTrace("%.*s, pos %lld\n", AuDLNPair(dentry), file->f_pos);
+       vdir_cache = au_fvdir_cache(file);
+       AuDebugOn(!vdir_cache);
+
+       if (!seek_vdir(file))
+               return 0;
+
+       while (1) {
+               deblk_end.deblk
+                       = vdir_cache->vd_deblk[vdir_cache->vd_last.i] + 1;
+               while (!is_deblk_end(&vdir_cache->vd_last.p, &deblk_end)) {
+                       de = vdir_cache->vd_last.p.de;
+                       LKTRTrace("%.*s, off%lld, i%lu, dt%d\n",
+                                 de->de_str.len, de->de_str.name,
+                                 file->f_pos, (unsigned long)de->de_ino,
+                                 de->de_type);
+                       err = filldir(dirent, de->de_str.name, de->de_str.len,
+                                     file->f_pos, de->de_ino, de->de_type);
+                       if (unlikely(err)) {
+                               AuTraceErr(err);
+                               /* todo: ignore the error caused by udba? */
+                               /* return err; */
+                               return 0;
+                       }
+
+                       l = calc_size(de->de_str.len);
+                       vdir_cache->vd_last.p.p += l;
+                       file->f_pos += l;
+               }
+               if (vdir_cache->vd_last.i < vdir_cache->vd_nblk - 1) {
+                       vdir_cache->vd_last.i++;
+                       vdir_cache->vd_last.p.deblk
+                               = vdir_cache->vd_deblk[vdir_cache->vd_last.i];
+                       file->f_pos = sizeof(*vdir_cache->vd_last.p.deblk)
+                               * vdir_cache->vd_last.i;
+                       continue;
+               }
+               break;
+       }
+
+       /* smp_mb(); */
+       return 0;
+}
diff -urN linux/fs/aufs/vfsub.c linux-aufs/fs/aufs/vfsub.c
--- linux/fs/aufs/vfsub.c       1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/vfsub.c  2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,686 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * sub-routines for VFS
+ *
+ * $Id$
+ */
+
+#include <linux/uaccess.h>
+#include "aufs.h"
+
+/* ---------------------------------------------------------------------- */
+
+void vfsub_args_init(struct vfsub_args *vargs, struct au_hin_ignore *ign,
+                    int dlgt, int force_unlink)
+{
+       do_vfsub_args_reinit(vargs, ign);
+       vargs->flags = 0;
+       if (dlgt)
+               vfsub_fset(vargs->flags, DLGT);
+       if (force_unlink)
+               vfsub_fset(vargs->flags, FORCE_UNLINK);
+}
+
+/* ---------------------------------------------------------------------- */
+
+struct file *vfsub_filp_open(const char *path, int oflags, int mode)
+{
+       struct file *err;
+
+       LKTRTrace("%s\n", path);
+
+       lockdep_off();
+       err = filp_open(path, oflags, mode);
+       lockdep_on();
+       if (!IS_ERR(err))
+               au_update_fuse_h_inode(err->f_vfsmnt, err->f_dentry); /*ignore*/
+       return err;
+}
+
+int vfsub_path_lookup(const char *name, unsigned int flags,
+                     struct nameidata *nd)
+{
+       int err;
+
+       LKTRTrace("%s\n", name);
+
+       /* lockdep_off(); */
+       err = path_lookup(name, flags, nd);
+       /* lockdep_on(); */
+       if (!err)
+               au_update_fuse_h_inode(nd->path.mnt, nd->path.dentry);
+       /*ignore*/
+       return err;
+}
+
+struct dentry *vfsub_lookup_one_len(const char *name, struct dentry *parent,
+                                   int len)
+{
+       struct dentry *d;
+
+       LKTRTrace("%.*s/%.*s\n", AuDLNPair(parent), len, name);
+       IMustLock(parent->d_inode);
+
+       d = lookup_one_len(name, parent, len);
+       if (!IS_ERR(d))
+               au_update_fuse_h_inode(NULL, d); /*ignore*/
+       return d;
+}
+
+#ifdef CONFIG_AUFS_LHASH_PATCH
+struct dentry *vfsub__lookup_hash(struct qstr *name, struct dentry *parent,
+                                 struct nameidata *nd)
+{
+       struct dentry *d;
+
+       LKTRTrace("%.*s/%.*s, nd %d\n",
+                 AuDLNPair(parent), AuLNPair(name), !!nd);
+       if (nd)
+               LKTRTrace("nd{0x%x}\n", nd->flags);
+       IMustLock(parent->d_inode);
+
+       d = __lookup_hash(name, parent, nd);
+       if (!IS_ERR(d))
+               au_update_fuse_h_inode(NULL, d); /*ignore*/
+       return d;
+}
+#endif
+
+/* ---------------------------------------------------------------------- */
+
+int do_vfsub_create(struct inode *dir, struct dentry *dentry, int mode,
+                   struct nameidata *nd)
+{
+       int err;
+       struct vfsmount *mnt;
+
+       LKTRTrace("i%lu, %.*s, 0x%x\n", dir->i_ino, AuDLNPair(dentry), mode);
+       IMustLock(dir);
+
+       err = vfs_create(dir, dentry, mode, nd);
+       if (!err) {
+               mnt = NULL;
+               if (nd)
+                       mnt = nd->path.mnt;
+               /* dir inode is locked */
+               au_update_fuse_h_inode(mnt, dentry->d_parent); /*ignore*/
+               au_update_fuse_h_inode(mnt, dentry); /*ignore*/
+       }
+       return err;
+}
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 27)
+#define VfsubSymlinkArgs       dir, dentry, symname
+#else
+#define VfsubSymlinkArgs       dir, dentry, symname, mode
+#endif
+
+int do_vfsub_symlink(struct inode *dir, struct dentry *dentry,
+                    const char *symname, int mode)
+{
+       int err;
+
+       LKTRTrace("i%lu, %.*s, %s, 0x%x\n",
+                 dir->i_ino, AuDLNPair(dentry), symname, mode);
+       IMustLock(dir);
+
+       err = vfs_symlink(VfsubSymlinkArgs);
+       if (!err) {
+               /* dir inode is locked */
+               au_update_fuse_h_inode(NULL, dentry->d_parent); /*ignore*/
+               au_update_fuse_h_inode(NULL, dentry); /*ignore*/
+       }
+       return err;
+}
+
+int do_vfsub_mknod(struct inode *dir, struct dentry *dentry, int mode,
+                  dev_t dev)
+{
+       int err;
+
+       LKTRTrace("i%lu, %.*s, 0x%x\n", dir->i_ino, AuDLNPair(dentry), mode);
+       IMustLock(dir);
+
+       err = vfs_mknod(dir, dentry, mode, dev);
+       if (!err) {
+               /* dir inode is locked */
+               au_update_fuse_h_inode(NULL, dentry->d_parent); /*ignore*/
+               au_update_fuse_h_inode(NULL, dentry); /*ignore*/
+       }
+       return err;
+}
+
+int do_vfsub_link(struct dentry *src_dentry, struct inode *dir,
+                 struct dentry *dentry)
+{
+       int err;
+
+       LKTRTrace("%.*s, i%lu, %.*s\n",
+                 AuDLNPair(src_dentry), dir->i_ino, AuDLNPair(dentry));
+       IMustLock(dir);
+
+       lockdep_off();
+       err = vfs_link(src_dentry, dir, dentry);
+       lockdep_on();
+       if (!err) {
+               LKTRTrace("src_i %p, dst_i %p\n",
+                         src_dentry->d_inode, dentry->d_inode);
+               /* fuse has different memory inode for the same inumber */
+               au_update_fuse_h_inode(NULL, src_dentry); /*ignore*/
+               /* dir inode is locked */
+               au_update_fuse_h_inode(NULL, dentry->d_parent); /*ignore*/
+               au_update_fuse_h_inode(NULL, dentry); /*ignore*/
+       }
+       return err;
+}
+
+int do_vfsub_rename(struct inode *src_dir, struct dentry *src_dentry,
+                   struct inode *dir, struct dentry *dentry)
+{
+       int err;
+
+       LKTRTrace("i%lu, %.*s, i%lu, %.*s\n",
+                 src_dir->i_ino, AuDLNPair(src_dentry),
+                 dir->i_ino, AuDLNPair(dentry));
+       IMustLock(dir);
+       IMustLock(src_dir);
+       AuDebugOn(src_dir != dir && !vfsub_is_rename_mutex_locked(dir->i_sb));
+
+       lockdep_off();
+       err = vfs_rename(src_dir, src_dentry, dir, dentry);
+       lockdep_on();
+       if (!err) {
+               /* dir inode is locked */
+               au_update_fuse_h_inode(NULL, dentry->d_parent); /*ignore*/
+               au_update_fuse_h_inode(NULL, src_dentry->d_parent); /*ignore*/
+               au_update_fuse_h_inode(NULL, src_dentry); /*ignore*/
+       }
+       return err;
+}
+
+int do_vfsub_mkdir(struct inode *dir, struct dentry *dentry, int mode)
+{
+       int err;
+
+       LKTRTrace("i%lu, %.*s, 0x%x\n", dir->i_ino, AuDLNPair(dentry), mode);
+       IMustLock(dir);
+
+       err = vfs_mkdir(dir, dentry, mode);
+       if (!err) {
+               /* dir inode is locked */
+               au_update_fuse_h_inode(NULL, dentry->d_parent); /*ignore*/
+               au_update_fuse_h_inode(NULL, dentry); /*ignore*/
+       }
+       return err;
+}
+
+int do_vfsub_rmdir(struct inode *dir, struct dentry *dentry)
+{
+       int err;
+
+       LKTRTrace("i%lu, %.*s\n", dir->i_ino, AuDLNPair(dentry));
+       IMustLock(dir);
+
+       lockdep_off();
+       err = vfs_rmdir(dir, dentry);
+       lockdep_on();
+       /* dir inode is locked */
+       if (!err)
+               au_update_fuse_h_inode(NULL, dentry->d_parent); /*ignore*/
+       return err;
+}
+
+int do_vfsub_unlink(struct inode *dir, struct dentry *dentry)
+{
+       int err;
+
+       LKTRTrace("i%lu, %.*s\n", dir->i_ino, AuDLNPair(dentry));
+       IMustLock(dir);
+
+       /* vfs_unlink() locks inode */
+       lockdep_off();
+       err = vfs_unlink(dir, dentry);
+       lockdep_on();
+       /* dir inode is locked */
+       if (!err)
+               au_update_fuse_h_inode(NULL, dentry->d_parent); /*ignore*/
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+ssize_t do_vfsub_read_u(struct file *file, char __user *ubuf, size_t count,
+                       loff_t *ppos)
+{
+       ssize_t err;
+
+       LKTRTrace("%.*s, cnt %zu, pos %lld\n",
+                 AuDLNPair(file->f_dentry), count, *ppos);
+
+       /* todo: always off, regardless nfs branch? */
+       au_br_nfs_lockdep_off(file->f_vfsmnt->mnt_sb);
+       err = vfs_read(file, ubuf, count, ppos);
+       au_br_nfs_lockdep_on(file->f_vfsmnt->mnt_sb);
+       if (err >= 0)
+               au_update_fuse_h_inode(file->f_vfsmnt, file->f_dentry);
+       /*ignore*/
+       return err;
+}
+
+/* todo: kernel_read()? */
+ssize_t do_vfsub_read_k(struct file *file, void *kbuf, size_t count,
+                       loff_t *ppos)
+{
+       ssize_t err;
+       mm_segment_t oldfs;
+
+       oldfs = get_fs();
+       set_fs(KERNEL_DS);
+       err = do_vfsub_read_u(file, (char __user *)kbuf, count, ppos);
+       set_fs(oldfs);
+       return err;
+}
+
+ssize_t do_vfsub_write_u(struct file *file, const char __user *ubuf,
+                        size_t count, loff_t *ppos)
+{
+       ssize_t err;
+
+       LKTRTrace("%.*s, cnt %zu, pos %lld\n",
+                 AuDLNPair(file->f_dentry), count, *ppos);
+
+       lockdep_off();
+       err = vfs_write(file, ubuf, count, ppos);
+       lockdep_on();
+       if (err >= 0)
+               au_update_fuse_h_inode(file->f_vfsmnt, file->f_dentry);
+       /*ignore*/
+       return err;
+}
+
+ssize_t do_vfsub_write_k(struct file *file, void *kbuf, size_t count,
+                        loff_t *ppos)
+{
+       ssize_t err;
+       mm_segment_t oldfs;
+
+       oldfs = get_fs();
+       set_fs(KERNEL_DS);
+       err = do_vfsub_write_u(file, (const char __user *)kbuf, count, ppos);
+       set_fs(oldfs);
+       return err;
+}
+
+int do_vfsub_readdir(struct file *file, filldir_t filldir, void *arg)
+{
+       int err;
+
+       LKTRTrace("%.*s\n", AuDLNPair(file->f_dentry));
+
+       lockdep_off();
+       err = vfs_readdir(file, filldir, arg);
+       lockdep_on();
+       if (err >= 0)
+               au_update_fuse_h_inode(file->f_vfsmnt, file->f_dentry);
+       /*ignore*/
+       return err;
+}
+
+#ifdef CONFIG_AUFS_SPLICE_PATCH
+long do_vfsub_splice_to(struct file *in, loff_t *ppos,
+                       struct pipe_inode_info *pipe, size_t len,
+                       unsigned int flags)
+{
+       long err;
+
+       LKTRTrace("%.*s, pos %lld, len %zu, 0x%x\n",
+                 AuDLNPair(in->f_dentry), *ppos, len, flags);
+
+       lockdep_off();
+       err = vfs_splice_to(in, ppos, pipe, len, flags);
+       lockdep_on();
+       if (err >= 0)
+               au_update_fuse_h_inode(in->f_vfsmnt, in->f_dentry); /*ignore*/
+       return err;
+}
+
+long do_vfsub_splice_from(struct pipe_inode_info *pipe, struct file *out,
+                         loff_t *ppos, size_t len, unsigned int flags)
+{
+       long err;
+
+       LKTRTrace("%.*s, pos %lld, len %zu, 0x%x\n",
+                 AuDLNPair(out->f_dentry), *ppos, len, flags);
+
+       lockdep_off();
+       err = vfs_splice_from(pipe, out, ppos, len, flags);
+       lockdep_on();
+       if (err >= 0)
+               au_update_fuse_h_inode(out->f_vfsmnt, out->f_dentry); /*ignore*/
+       return err;
+}
+#endif
+
+/* ---------------------------------------------------------------------- */
+
+struct au_vfsub_mkdir_args {
+       int *errp;
+       struct inode *dir;
+       struct dentry *dentry;
+       int mode;
+       struct vfsub_args *vargs;
+};
+
+static void au_call_vfsub_mkdir(void *args)
+{
+       struct au_vfsub_mkdir_args *a = args;
+       *a->errp = vfsub_mkdir(a->dir, a->dentry, a->mode, a->vargs);
+}
+
+int vfsub_sio_mkdir(struct au_hinode *hdir, struct dentry *dentry, int mode,
+                   int dlgt)
+{
+       int err, do_sio, wkq_err;
+       struct inode *dir = hdir->hi_inode;
+       struct au_hin_ignore ign;
+       struct vfsub_args vargs;
+
+       LKTRTrace("i%lu, %.*s\n", dir->i_ino, AuDLNPair(dentry));
+
+       vfsub_args_init(&vargs, &ign, dlgt, /*force_unlink*/0);
+       vfsub_ign_hinode(&vargs, IN_CREATE, hdir);
+       do_sio = au_test_h_perm_sio(dir, MAY_EXEC | MAY_WRITE, dlgt);
+       if (!do_sio)
+               err = vfsub_mkdir(dir, dentry, mode, &vargs);
+       else {
+               struct au_vfsub_mkdir_args args = {
+                       .errp   = &err,
+                       .dir    = dir,
+                       .dentry = dentry,
+                       .mode   = mode,
+                       .vargs  = &vargs
+               };
+               vfsub_fclr(vargs.flags, DLGT);
+               wkq_err = au_wkq_wait(au_call_vfsub_mkdir, &args, /*dlgt*/0);
+               if (unlikely(wkq_err))
+                       err = wkq_err;
+       }
+
+       AuTraceErr(err);
+       return err;
+}
+
+struct au_vfsub_rmdir_args {
+       int *errp;
+       struct inode *dir;
+       struct dentry *dentry;
+       struct vfsub_args *vargs;
+};
+
+static void au_call_vfsub_rmdir(void *args)
+{
+       struct au_vfsub_rmdir_args *a = args;
+       *a->errp = vfsub_rmdir(a->dir, a->dentry, a->vargs);
+}
+
+int vfsub_sio_rmdir(struct au_hinode *hdir, struct dentry *dentry, int dlgt)
+{
+       int err, do_sio, wkq_err;
+       struct inode *dir = hdir->hi_inode;
+       struct au_hin_ignore ign;
+       struct vfsub_args vargs;
+
+       LKTRTrace("i%lu, %.*s\n", dir->i_ino, AuDLNPair(dentry));
+
+       vfsub_args_init(&vargs, &ign, dlgt, /*force_unlink*/0);
+       vfsub_ign_hinode(&vargs, IN_DELETE, hdir);
+       do_sio = au_test_h_perm_sio(dir, MAY_EXEC | MAY_WRITE, dlgt);
+       if (!do_sio)
+               err = vfsub_rmdir(dir, dentry, &vargs);
+       else {
+               struct au_vfsub_rmdir_args args = {
+                       .errp           = &err,
+                       .dir            = dir,
+                       .dentry         = dentry,
+                       .vargs          = &vargs
+               };
+               vfsub_fclr(vargs.flags, DLGT);
+               wkq_err = au_wkq_wait(au_call_vfsub_rmdir, &args, /*dlgt*/0);
+               if (unlikely(wkq_err))
+                       err = wkq_err;
+       }
+
+       AuTraceErr(err);
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+struct notify_change_args {
+       int *errp;
+       struct dentry *h_dentry;
+       struct iattr *ia;
+       struct vfsub_args *vargs;
+};
+
+static void call_notify_change(void *args)
+{
+       struct notify_change_args *a = args;
+       struct inode *h_inode;
+
+       LKTRTrace("%.*s, ia_valid 0x%x\n",
+                 AuDLNPair(a->h_dentry), a->ia->ia_valid);
+       h_inode = a->h_dentry->d_inode;
+       IMustLock(h_inode);
+
+       *a->errp = -EPERM;
+       if (!IS_IMMUTABLE(h_inode) && !IS_APPEND(h_inode)) {
+               vfsub_ignore(a->vargs);
+               lockdep_off();
+               *a->errp = notify_change(a->h_dentry, a->ia);
+               lockdep_on();
+               if (!*a->errp)
+                       au_update_fuse_h_inode(NULL, a->h_dentry); /*ignore*/
+               else
+                       vfsub_unignore(a->vargs);
+               au_dbg_hin_list(a->vargs);
+       }
+       AuTraceErr(*a->errp);
+}
+
+#ifdef CONFIG_AUFS_DLGT
+static void vfsub_notify_change_dlgt(struct notify_change_args *args,
+                                    unsigned int flags)
+{
+       if (!vfsub_ftest(flags, DLGT))
+               call_notify_change(args);
+       else {
+               int wkq_err;
+               wkq_err = au_wkq_wait(call_notify_change, args, /*dlgt*/1);
+               if (unlikely(wkq_err))
+                       *args->errp = wkq_err;
+       }
+}
+#else
+static void vfsub_notify_change_dlgt(struct notify_change_args *args,
+                                    unsigned int flags)
+{
+       call_notify_change(args);
+}
+#endif
+
+int vfsub_notify_change(struct dentry *dentry, struct iattr *ia,
+                       struct vfsub_args *vargs)
+{
+       int err;
+       struct notify_change_args args = {
+               .errp           = &err,
+               .h_dentry       = dentry,
+               .ia             = ia,
+               .vargs          = vargs
+       };
+
+       vfsub_notify_change_dlgt(&args, vargs->flags);
+
+       AuTraceErr(err);
+       return err;
+}
+
+int vfsub_sio_notify_change(struct au_hinode *hdir, struct dentry *dentry,
+                           struct iattr *ia)
+{
+       int err, wkq_err;
+       struct au_hin_ignore ign;
+       struct vfsub_args vargs;
+       __u32 events;
+       struct notify_change_args args = {
+               .errp           = &err,
+               .h_dentry       = dentry,
+               .ia             = ia,
+               .vargs          = &vargs
+       };
+
+       LKTRTrace("%.*s, 0x%x\n", AuDLNPair(dentry), ia->ia_valid);
+
+       vfsub_args_init(&vargs, &ign, /*dlgt*/0, /*force_unlink*/0);
+       events = vfsub_events_notify_change(ia);
+       if (events)
+               vfsub_ign_hinode(&vargs, events, hdir);
+       wkq_err = au_wkq_wait(call_notify_change, &args, /*dlgt*/0);
+       if (unlikely(wkq_err))
+               err = wkq_err;
+
+       AuTraceErr(err);
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+struct unlink_args {
+       int *errp;
+       struct inode *dir;
+       struct dentry *dentry;
+       struct vfsub_args *vargs;
+};
+
+static void call_unlink(void *args)
+{
+       struct unlink_args *a = args;
+       struct inode *h_inode;
+       const int stop_sillyrename = (au_test_nfs(a->dentry->d_sb)
+                                     && atomic_read(&a->dentry->d_count) == 1);
+
+       LKTRTrace("%.*s, stop_silly %d, cnt %d\n",
+                 AuDLNPair(a->dentry), stop_sillyrename,
+                 atomic_read(&a->dentry->d_count));
+
+       if (!stop_sillyrename)
+               dget(a->dentry);
+       h_inode = a->dentry->d_inode;
+       if (h_inode)
+               atomic_inc_return(&h_inode->i_count);
+       vfsub_ignore(a->vargs);
+       *a->errp = do_vfsub_unlink(a->dir, a->dentry);
+       if (unlikely(*a->errp || (a->dentry->d_flags & DCACHE_NFSFS_RENAMED)))
+               vfsub_unignore(a->vargs);
+       au_dbg_hin_list(a->vargs);
+       if (!stop_sillyrename)
+               dput(a->dentry);
+       if (h_inode)
+               iput(h_inode);
+
+       AuTraceErr(*a->errp);
+}
+
+/*
+ * @dir: must be locked.
+ * @dentry: target dentry.
+ */
+int vfsub_unlink(struct inode *dir, struct dentry *dentry,
+                struct vfsub_args *vargs)
+{
+       int err;
+       struct unlink_args args = {
+               .errp   = &err,
+               .dir    = dir,
+               .dentry = dentry,
+               .vargs  = vargs
+       };
+
+       if (!vfsub_ftest(vargs->flags, DLGT)
+           && !vfsub_ftest(vargs->flags, FORCE_UNLINK))
+               call_unlink(&args);
+       else {
+               int wkq_err;
+               wkq_err = au_wkq_wait(call_unlink, &args,
+                                     vfsub_ftest(vargs->flags, DLGT));
+               if (unlikely(wkq_err))
+                       err = wkq_err;
+       }
+
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+struct statfs_args {
+       int *errp;
+       void *arg;
+       struct kstatfs *buf;
+};
+
+static void call_statfs(void *args)
+{
+       struct statfs_args *a = args;
+       *a->errp = vfs_statfs(a->arg, a->buf);
+}
+
+#ifdef CONFIG_AUFS_DLGT
+static void vfsub_statfs_dlgt(struct statfs_args *args, int dlgt)
+{
+       if (!dlgt)
+               call_statfs(args);
+       else {
+               int wkq_err;
+               wkq_err = au_wkq_wait(call_statfs, args, /*dlgt*/1);
+               if (unlikely(wkq_err))
+                       *args->errp = wkq_err;
+       }
+}
+#else
+static void vfsub_statfs_dlgt(struct statfs_args *args, int dlgt)
+{
+       call_statfs(args);
+}
+#endif
+
+int vfsub_statfs(void *arg, struct kstatfs *buf, int dlgt)
+{
+       int err;
+       struct statfs_args args = {
+               .errp   = &err,
+               .arg    = arg,
+               .buf    = buf
+       };
+
+       vfsub_statfs_dlgt(&args, dlgt);
+
+       return err;
+}
diff -urN linux/fs/aufs/vfsub.h linux-aufs/fs/aufs/vfsub.h
--- linux/fs/aufs/vfsub.h       1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/vfsub.h  2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,530 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * sub-routines for VFS
+ *
+ * $Id$
+ */
+
+#ifndef __AUFS_VFSUB_H__
+#define __AUFS_VFSUB_H__
+
+#ifdef __KERNEL__
+
+#include <linux/fs.h>
+#include <linux/fs_stack.h>
+#include <linux/inotify.h>
+#include <linux/namei.h>
+#include <linux/security.h>
+#include <linux/splice.h>
+
+/* ---------------------------------------------------------------------- */
+
+/* vfsub flags */
+#define Vfsub_DLGT             1               /* operation with delegation */
+#define Vfsub_FORCE_UNLINK     (1 << 1)        /* force unlinking */
+#define vfsub_ftest(flags, name)       ((flags) & Vfsub_##name)
+#define vfsub_fset(flags, name)                { (flags) |= Vfsub_##name; }
+#define vfsub_fclr(flags, name)                { (flags) &= ~Vfsub_##name; }
+#ifndef CONFIG_AUFS_DLGT
+#undef Vfsub_DLGT
+#define Vfsub_DLGT     0
+#endif
+
+struct au_hin_ignore;
+struct vfsub_args {
+#ifdef CONFIG_AUFS_HINOTIFY
+       /* inotify events to be ignored */
+       int                     nignore;
+       struct au_hin_ignore    *ignore;
+#endif
+
+       unsigned int            flags;
+};
+
+struct au_hinode;
+#ifdef CONFIG_AUFS_HINOTIFY
+static inline
+void do_vfsub_args_reinit(struct vfsub_args *vargs, struct au_hin_ignore *ign)
+{
+       vargs->nignore = 0;
+       vargs->ignore = ign;
+}
+
+static inline void vfsub_args_reinit(struct vfsub_args *vargs)
+{
+       vargs->nignore = 0;
+}
+
+__u32 vfsub_events_notify_change(struct iattr *ia);
+void vfsub_ign_hinode(struct vfsub_args *vargs, __u32 events,
+                     struct au_hinode *hinode);
+void vfsub_ignore(struct vfsub_args *vargs);
+void vfsub_unignore(struct vfsub_args *vargs);
+#else
+static inline
+void do_vfsub_args_reinit(struct vfsub_args *vargs, struct au_hin_ignore *ign)
+{
+       /* empty */
+}
+
+static inline void vfsub_args_reinit(struct vfsub_args *vargs)
+{
+       /* empty */
+}
+
+static inline __u32 vfsub_events_notify_change(struct iattr *ia)
+{
+       return 0;
+}
+
+static inline void vfsub_ign_hinode(struct vfsub_args *vargs, __u32 events,
+                                   struct au_hinode *hinode)
+{
+       /* empty */
+}
+
+static inline void vfsub_ignore(struct vfsub_args *vargs)
+{
+       /* empty */
+}
+
+static inline void vfsub_unignore(struct vfsub_args *vargs)
+{
+       /* empty */
+}
+#endif /* CONFIG_AUFS_HINOTIFY */
+
+void vfsub_args_init(struct vfsub_args *vargs, struct au_hin_ignore *ign,
+                    int dlgt, int force_unlink);
+
+/* ---------------------------------------------------------------------- */
+
+/* inotify_inode_watched() is not exported */
+static inline int au_test_inotify(struct inode *inode)
+{
+#ifdef CONFIG_INOTIFY
+       return !list_empty(&inode->inotify_watches);
+#endif
+       return 0;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* lock subclass for hidden inode */
+/* default MAX_LOCKDEP_SUBCLASSES(8) is not enough */
+/* reduce? gave up. */
+enum {
+       AuLsc_I_Begin = I_MUTEX_QUOTA, /* 4 */
+       AuLsc_I_PARENT,         /* hidden inode, parent first */
+       AuLsc_I_PARENT2,        /* copyup dirs */
+       AuLsc_I_PARENT3,        /* rename with hinotify */
+       AuLsc_I_PARENT4,        /* ditto */
+       AuLsc_I_CHILD,
+       AuLsc_I_CHILD2,
+       AuLsc_I_End
+};
+
+#define IMustLock(i)   MtxMustLock(&(i)->i_mutex)
+
+static inline void vfsub_lock_rename_mutex(struct super_block *sb)
+{
+       lockdep_off();
+       mutex_lock(&sb->s_vfs_rename_mutex);
+       lockdep_on();
+}
+
+static inline void vfsub_unlock_rename_mutex(struct super_block *sb)
+{
+       lockdep_off();
+       mutex_unlock(&sb->s_vfs_rename_mutex);
+       lockdep_on();
+}
+
+static inline int vfsub_is_rename_mutex_locked(struct super_block *sb)
+{
+       int res;
+
+       lockdep_off();
+       res = mutex_is_locked(&sb->s_vfs_rename_mutex);
+       lockdep_on();
+
+       return res;
+}
+
+static inline
+struct dentry *vfsub_lock_rename(struct dentry *d1, struct dentry *d2)
+{
+       struct dentry *d;
+
+       lockdep_off();
+       d = lock_rename(d1, d2);
+       lockdep_on();
+       return d;
+}
+
+static inline void vfsub_unlock_rename(struct dentry *d1, struct dentry *d2)
+{
+       lockdep_off();
+       unlock_rename(d1, d2);
+       lockdep_on();
+}
+
+static inline int au_verify_parent(struct dentry *dentry, struct inode *dir)
+{
+       IMustLock(dir);
+       return /* !dir->i_nlink || */ dentry->d_parent->d_inode != dir;
+}
+
+/* ---------------------------------------------------------------------- */
+
+#ifdef CONFIG_AUFS_WORKAROUND_FUSE
+/* br_fuse.c */
+int au_update_fuse_h_inode(struct vfsmount *h_mnt, struct dentry *h_dentry);
+#else
+static inline
+int au_update_fuse_h_inode(struct vfsmount *h_mnt, struct dentry *h_dentry)
+{
+       return 0;
+}
+#endif
+
+#ifdef CONFIG_AUFS_BR_XFS
+/* br_xfs.c */
+dev_t au_h_rdev(struct inode *h_inode, struct vfsmount *h_mnt,
+               struct dentry *h_dentry);
+#else
+static inline
+dev_t au_h_rdev(struct inode *h_inode, struct vfsmount *h_mnt,
+               struct dentry *h_dentry)
+{
+       return h_inode->i_rdev;
+}
+#endif
+
+/* simple abstractions, for future use */
+static inline
+int do_vfsub_permission(struct inode *inode, int mask, struct nameidata *nd)
+{
+       LKTRTrace("i%lu, mask 0x%x, nd %d\n", inode->i_ino, mask, !!nd);
+       IMustLock(inode);
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 27)
+       return inode_permission(inode, mask);
+#else
+       return permission(inode, mask, nd);
+#endif
+}
+
+static inline
+int vfsub_security_inode_permission(struct inode *inode, int mask,
+                                   struct nameidata *nd)
+{
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 27)
+       mask &= MAY_READ | MAY_WRITE | MAY_EXEC | MAY_APPEND;
+       return security_inode_permission(inode, mask);
+#else
+       return security_inode_permission(inode, mask, nd);
+#endif
+}
+
+/* ---------------------------------------------------------------------- */
+
+struct file *vfsub_filp_open(const char *path, int oflags, int mode);
+int vfsub_path_lookup(const char *name, unsigned int flags,
+                     struct nameidata *nd);
+struct dentry *vfsub_lookup_one_len(const char *name, struct dentry *parent,
+                                   int len);
+
+#ifdef CONFIG_AUFS_LHASH_PATCH
+struct dentry *vfsub__lookup_hash(struct qstr *name, struct dentry *parent,
+                                 struct nameidata *nd);
+#endif
+
+/* ---------------------------------------------------------------------- */
+
+int do_vfsub_create(struct inode *dir, struct dentry *dentry, int mode,
+                   struct nameidata *nd);
+int do_vfsub_symlink(struct inode *dir, struct dentry *dentry,
+                    const char *symname, int mode);
+int do_vfsub_mknod(struct inode *dir, struct dentry *dentry, int mode,
+                  dev_t dev);
+int do_vfsub_link(struct dentry *src_dentry, struct inode *dir,
+                 struct dentry *dentry);
+int do_vfsub_rename(struct inode *src_dir, struct dentry *src_dentry,
+                   struct inode *dir, struct dentry *dentry);
+int do_vfsub_mkdir(struct inode *dir, struct dentry *dentry, int mode);
+int do_vfsub_rmdir(struct inode *dir, struct dentry *dentry);
+int do_vfsub_unlink(struct inode *dir, struct dentry *dentry);
+
+/* ---------------------------------------------------------------------- */
+
+ssize_t do_vfsub_read_u(struct file *file, char __user *ubuf, size_t count,
+                       loff_t *ppos);
+/* todo: kernel_read()? */
+ssize_t do_vfsub_read_k(struct file *file, void *kbuf, size_t count,
+                       loff_t *ppos);
+ssize_t do_vfsub_write_u(struct file *file, const char __user *ubuf,
+                        size_t count, loff_t *ppos);
+ssize_t do_vfsub_write_k(struct file *file, void *kbuf, size_t count,
+                        loff_t *ppos);
+int do_vfsub_readdir(struct file *file, filldir_t filldir, void *arg);
+
+/* ---------------------------------------------------------------------- */
+
+#ifndef CONFIG_AUFS_UNIONFS22_PATCH
+static inline void vfsub_copy_inode_size(struct inode *inode,
+                                        struct inode *h_inode)
+{
+       spin_lock(&inode->i_lock);
+       fsstack_copy_inode_size(inode, h_inode);
+       spin_unlock(&inode->i_lock);
+}
+#else
+static inline void vfsub_copy_inode_size(struct inode *inode,
+                                        struct inode *h_inode)
+{
+       fsstack_copy_inode_size(inode, h_inode);
+}
+#endif
+
+#ifndef CONFIG_AUFS_UNIONFS23_PATCH
+#define vfs_splice_to          do_splice_to
+#define vfs_splice_from                do_splice_from
+#endif
+
+#ifdef CONFIG_AUFS_SPLICE_PATCH
+long do_vfsub_splice_to(struct file *in, loff_t *ppos,
+                       struct pipe_inode_info *pipe, size_t len,
+                       unsigned int flags);
+long do_vfsub_splice_from(struct pipe_inode_info *pipe, struct file *out,
+                         loff_t *ppos, size_t len, unsigned int flags);
+#else
+static inline
+long do_vfsub_splice_to(struct file *in, loff_t *ppos,
+                       struct pipe_inode_info *pipe, size_t len,
+                       unsigned int flags)
+{
+       return -ENOSYS;
+}
+
+static inline
+long do_vfsub_splice_from(struct pipe_inode_info *pipe, struct file *out,
+                         loff_t *ppos, size_t len, unsigned int flags)
+{
+       return -ENOSYS;
+}
+#endif /* CONFIG_AUFS_SPLICE_PATCH */
+
+/* ---------------------------------------------------------------------- */
+
+static inline loff_t vfsub_llseek(struct file *file, loff_t offset, int origin)
+{
+       loff_t err;
+
+       LKTRTrace("%.*s\n", AuDLNPair(file->f_dentry));
+
+       lockdep_off();
+       err = vfs_llseek(file, offset, origin);
+       lockdep_on();
+       return err;
+}
+
+static inline int do_vfsub_getattr(struct vfsmount *mnt, struct dentry *dentry,
+                                  struct kstat *st)
+{
+       LKTRTrace("%.*s\n", AuDLNPair(dentry));
+       return vfs_getattr(mnt, dentry, st);
+}
+
+/* ---------------------------------------------------------------------- */
+
+#ifdef CONFIG_AUFS_HIN_OR_DLGT
+/* hin_or_dlgt.c */
+int vfsub_permission(struct inode *inode, int mask, struct nameidata *nd,
+                    int dlgt);
+
+int vfsub_create(struct inode *dir, struct dentry *dentry, int mode,
+                struct nameidata *nd, struct vfsub_args *vargs);
+int vfsub_symlink(struct inode *dir, struct dentry *dentry, const char *symname,
+                 int mode, struct vfsub_args *vargs);
+int vfsub_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev,
+               struct vfsub_args *vargs);
+int vfsub_link(struct dentry *src_dentry, struct inode *dir,
+              struct dentry *dentry, struct vfsub_args *vargs);
+int vfsub_rename(struct inode *src_dir, struct dentry *src_dentry,
+                struct inode *dir, struct dentry *dentry,
+                struct vfsub_args *vargs);
+int vfsub_mkdir(struct inode *dir, struct dentry *dentry, int mode,
+               struct vfsub_args *vargs);
+int vfsub_rmdir(struct inode *dir, struct dentry *dentry,
+               struct vfsub_args *vargs);
+
+ssize_t vfsub_read_u(struct file *file, char __user *ubuf, size_t count,
+                    loff_t *ppos, int dlgt);
+ssize_t vfsub_read_k(struct file *file, void *kbuf, size_t count, loff_t *ppos,
+                    int dlgt);
+ssize_t vfsub_write_u(struct file *file, const char __user *ubuf, size_t count,
+                     loff_t *ppos, struct vfsub_args *vargs);
+ssize_t vfsub_write_k(struct file *file, void *kbuf, size_t count, loff_t *ppos,
+                     struct vfsub_args *vargs);
+int vfsub_readdir(struct file *file, filldir_t filldir, void *arg, int dlgt);
+long vfsub_splice_to(struct file *in, loff_t *ppos,
+                    struct pipe_inode_info *pipe, size_t len,
+                    unsigned int flags, int dlgt);
+long vfsub_splice_from(struct pipe_inode_info *pipe, struct file *out,
+                      loff_t *ppos, size_t len, unsigned int flags,
+                      struct vfsub_args *vargs);
+
+int vfsub_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *st,
+                 int dlgt);
+#else
+
+static inline
+int vfsub_permission(struct inode *inode, int mask, struct nameidata *nd,
+                    int dlgt)
+{
+       return do_vfsub_permission(inode, mask, nd);
+}
+
+static inline
+int vfsub_create(struct inode *dir, struct dentry *dentry, int mode,
+                struct nameidata *nd, struct vfsub_args *vargs)
+{
+       return do_vfsub_create(dir, dentry, mode, nd);
+}
+
+static inline
+int vfsub_symlink(struct inode *dir, struct dentry *dentry, const char *symname,
+                 int mode, struct vfsub_args *vargs)
+{
+       return do_vfsub_symlink(dir, dentry, symname, mode);
+}
+
+static inline
+int vfsub_mknod(struct inode *dir, struct dentry *dentry, int mode, dev_t dev,
+               struct vfsub_args *vargs)
+{
+       return do_vfsub_mknod(dir, dentry, mode, dev);
+}
+
+static inline
+int vfsub_link(struct dentry *src_dentry, struct inode *dir,
+              struct dentry *dentry, struct vfsub_args *vargs)
+{
+       return do_vfsub_link(src_dentry, dir, dentry);
+}
+
+static inline
+int vfsub_rename(struct inode *src_dir, struct dentry *src_dentry,
+                struct inode *dir, struct dentry *dentry,
+                struct vfsub_args *vargs)
+{
+       return do_vfsub_rename(src_dir, src_dentry, dir, dentry);
+}
+
+static inline
+int vfsub_mkdir(struct inode *dir, struct dentry *dentry, int mode,
+               struct vfsub_args *vargs)
+{
+       return do_vfsub_mkdir(dir, dentry, mode);
+}
+
+static inline
+int vfsub_rmdir(struct inode *dir, struct dentry *dentry,
+               struct vfsub_args *vargs)
+{
+       return do_vfsub_rmdir(dir, dentry);
+}
+
+static inline
+ssize_t vfsub_read_u(struct file *file, char __user *ubuf, size_t count,
+                    loff_t *ppos, int dlgt)
+{
+       return do_vfsub_read_u(file, ubuf, count, ppos);
+}
+
+static inline
+ssize_t vfsub_read_k(struct file *file, void *kbuf, size_t count, loff_t *ppos,
+                    int dlgt)
+{
+       return do_vfsub_read_k(file, kbuf, count, ppos);
+}
+
+static inline
+ssize_t vfsub_write_u(struct file *file, const char __user *ubuf, size_t count,
+                     loff_t *ppos, struct vfsub_args *vargs)
+{
+       return do_vfsub_write_u(file, ubuf, count, ppos);
+}
+
+static inline
+ssize_t vfsub_write_k(struct file *file, void *kbuf, size_t count, loff_t *ppos,
+                     struct vfsub_args *vargs)
+{
+       return do_vfsub_write_k(file, kbuf, count, ppos);
+}
+
+static inline
+int vfsub_readdir(struct file *file, filldir_t filldir, void *arg, int dlgt)
+{
+       return do_vfsub_readdir(file, filldir, arg);
+}
+
+static inline
+long vfsub_splice_to(struct file *in, loff_t *ppos,
+                    struct pipe_inode_info *pipe, size_t len,
+                    unsigned int flags, int dlgt)
+{
+       return do_vfsub_splice_to(in, ppos, pipe, len, flags);
+}
+
+static inline
+long vfsub_splice_from(struct pipe_inode_info *pipe, struct file *out,
+                      loff_t *ppos, size_t len, unsigned int flags,
+                      struct vfsub_args *vargs)
+{
+       return do_vfsub_splice_from(pipe, out, ppos, len, flags);
+}
+
+static inline
+int vfsub_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *st,
+                 int dlgt)
+{
+       return do_vfsub_getattr(mnt, dentry, st);
+}
+#endif /* HIN_OR_DLGT */
+
+/* ---------------------------------------------------------------------- */
+
+int vfsub_sio_mkdir(struct au_hinode *hdir, struct dentry *dentry, int mode,
+                   int dlgt);
+int vfsub_sio_rmdir(struct au_hinode *hdir, struct dentry *dentry, int dlgt);
+int vfsub_sio_notify_change(struct au_hinode *hdir, struct dentry *dentry,
+                           struct iattr *ia);
+
+/* ---------------------------------------------------------------------- */
+
+int vfsub_notify_change(struct dentry *dentry, struct iattr *ia,
+                       struct vfsub_args *vargs);
+int vfsub_unlink(struct inode *dir, struct dentry *dentry,
+                struct vfsub_args *vargs);
+int vfsub_statfs(void *arg, struct kstatfs *buf, int dlgt);
+
+#endif /* __KERNEL__ */
+#endif /* __AUFS_VFSUB_H__ */
diff -urN linux/fs/aufs/wbr_policy.c linux-aufs/fs/aufs/wbr_policy.c
--- linux/fs/aufs/wbr_policy.c  1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/wbr_policy.c     2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,696 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * policies for selecting one among multiple writable branches
+ *
+ * $Id$
+ */
+
+#include <linux/statfs.h>
+#include "aufs.h"
+
+static int au_cpdown_attr(struct au_hinode *hdir, struct dentry *h_dst,
+                         struct dentry *h_src)
+{
+       int err, sbits;
+       struct iattr ia;
+       struct inode *h_idst, *h_isrc;
+
+       LKTRTrace("%.*s\n", AuDLNPair(h_dst));
+       h_idst = h_dst->d_inode;
+       /* todo? IMustLock(h_idst); */
+       h_isrc = h_src->d_inode;
+       /* todo? IMustLock(h_isrc); */
+
+       ia.ia_valid = ATTR_FORCE | ATTR_MODE | ATTR_UID | ATTR_GID;
+       ia.ia_mode = h_isrc->i_mode;
+       ia.ia_uid = h_isrc->i_uid;
+       ia.ia_gid = h_isrc->i_gid;
+       sbits = !!(ia.ia_mode & (S_ISUID | S_ISGID));
+       au_cpup_attr_flags(h_idst, h_isrc);
+       err = vfsub_sio_notify_change(hdir, h_dst, &ia);
+
+       /* is this nfs only? */
+       if (!err && sbits && au_test_nfs(h_dst->d_sb)) {
+               ia.ia_valid = ATTR_FORCE | ATTR_MODE;
+               ia.ia_mode = h_isrc->i_mode;
+               err = vfsub_sio_notify_change(hdir, h_dst, &ia);
+       }
+
+       AuTraceErr(err);
+       return err;
+}
+
+struct au_cpdown_dir_args {
+       struct dentry *parent;
+       unsigned int parent_opq; /* bit-flags */
+};
+
+static int au_cpdown_dir(struct dentry *dentry, aufs_bindex_t bdst,
+                        struct dentry *h_parent, void *arg)
+{
+       int err, rerr;
+       struct au_cpdown_dir_args *args = arg;
+       aufs_bindex_t bend, bopq, bstart;
+       unsigned char parent_opq, whed, dlgt, do_opq, made_dir, diropq;
+       struct dentry *h_dentry, *opq_dentry, *wh_dentry, *parent;
+       struct inode *h_dir, *h_inode, *inode, *dir;
+
+       LKTRTrace("%.*s, b%d\n", AuDLNPair(dentry), bdst);
+       bstart = au_dbstart(dentry);
+       AuDebugOn(bstart <= bdst
+                 && bdst <= au_dbend(dentry)
+                 && au_h_dptr(dentry, bdst));
+       AuDebugOn(!h_parent);
+       /* todo: safe? */
+       parent = dget_parent(dentry);
+       dir = parent->d_inode;
+       dput(parent);
+       h_dir = h_parent->d_inode;
+       AuDebugOn(!h_dir);
+       AuDebugOn(h_dir != au_h_iptr(dir, bdst));
+       IMustLock(h_dir);
+
+       err = au_lkup_neg(dentry, bdst);
+       if (unlikely(err < 0))
+               goto out;
+       h_dentry = au_h_dptr(dentry, bdst);
+       dlgt = !!au_test_dlgt(au_mntflags(dentry->d_sb));
+       err = vfsub_sio_mkdir(au_hi(dir, bdst), h_dentry,
+                             S_IRWXU | S_IRUGO | S_IXUGO, dlgt);
+       if (unlikely(err))
+               goto out_put;
+
+       made_dir = 1;
+       bend = au_dbend(dentry);
+       bopq = au_dbdiropq(dentry);
+       whed = (au_dbwh(dentry) == bdst);
+       if (!args->parent_opq)
+               args->parent_opq |= (bopq <= bdst);
+       parent_opq = (args->parent_opq && args->parent == dentry);
+       do_opq = 0;
+       diropq = 0;
+       h_inode = h_dentry->d_inode;
+       mutex_lock_nested(&h_inode->i_mutex, AuLsc_I_CHILD);
+       if (whed || (parent_opq && do_opq)) {
+               opq_dentry = au_diropq_create(dentry, bdst, dlgt);
+               err = PTR_ERR(opq_dentry);
+               if (IS_ERR(opq_dentry)) {
+                       mutex_unlock(&h_inode->i_mutex);
+                       goto out_dir;
+               }
+               dput(opq_dentry);
+               diropq = 1;
+       }
+
+       err = au_cpdown_attr(au_hi(dir, bdst), h_dentry,
+                            au_h_dptr(dentry, bstart));
+       mutex_unlock(&h_inode->i_mutex);
+       if (unlikely(err))
+               goto out_opq;
+
+       wh_dentry = NULL;
+       if (whed) {
+               wh_dentry = au_wh_lkup(h_parent, &dentry->d_name, /*ndx*/NULL);
+               err = PTR_ERR(wh_dentry);
+               if (IS_ERR(wh_dentry))
+                       goto out_opq;
+               err = 0;
+               if (wh_dentry->d_inode)
+                       err = au_wh_unlink_dentry(au_hi(dir, bdst), wh_dentry,
+                                                 dentry, dlgt);
+               dput(wh_dentry);
+               if (unlikely(err))
+                       goto out_opq;
+       }
+
+       inode = dentry->d_inode;
+       if (au_ibend(inode) < bdst)
+               au_set_ibend(inode, bdst);
+       au_set_h_iptr(inode, bdst, au_igrab(h_inode), au_hi_flags(inode, 1));
+       goto out; /* success */
+
+       /* revert */
+ out_opq:
+       if (diropq) {
+               mutex_lock_nested(&h_inode->i_mutex, AuLsc_I_CHILD);
+               rerr = au_diropq_remove(dentry, bdst, dlgt);
+               mutex_unlock(&h_inode->i_mutex);
+               if (unlikely(rerr)) {
+                       AuIOErr("failed removing diropq for %.*s b%d (%d)\n",
+                               AuDLNPair(dentry), bdst, rerr);
+                       err = -EIO;
+                       goto out;
+               }
+       }
+ out_dir:
+       if (made_dir) {
+               rerr = vfsub_sio_rmdir(au_hi(dir, bdst), h_dentry, dlgt);
+               if (unlikely(rerr)) {
+                       AuIOErr("failed removing %.*s b%d (%d)\n",
+                               AuDLNPair(dentry), bdst, rerr);
+                       err = -EIO;
+               }
+       }
+ out_put:
+       au_set_h_dptr(dentry, bdst, NULL);
+       if (au_dbend(dentry) == bdst)
+               au_update_dbend(dentry);
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+int au_cpdown_dirs(struct dentry *dentry, aufs_bindex_t bdst)
+{
+       int err;
+       struct au_cpdown_dir_args args = {
+               .parent         = dget_parent(dentry),
+               .parent_opq     = 0
+       };
+
+       LKTRTrace("%.*s, b%d\n", AuDLNPair(dentry), bdst);
+
+       err = au_cp_dirs(dentry, bdst, au_cpdown_dir, &args);
+       dput(args.parent);
+
+       AuTraceErr(err);
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* policies for create */
+
+static int au_wbr_bu(struct super_block *sb, aufs_bindex_t bindex)
+{
+       for (; bindex >= 0; bindex--)
+               if (!au_br_rdonly(au_sbr(sb, bindex)))
+                       return bindex;
+       return -EROFS;
+}
+
+/* top down parent */
+static int au_wbr_create_tdp(struct dentry *dentry, int isdir)
+{
+       int err;
+       struct super_block *sb;
+       aufs_bindex_t bstart, bindex;
+       unsigned char dirperm1;
+       struct dentry *parent, *h_parent;
+       struct inode *h_dir;
+
+       LKTRTrace("%.*s, dir %d\n", AuDLNPair(dentry), isdir);
+
+       sb = dentry->d_sb;
+       dirperm1 = !!au_test_dirperm1(au_mntflags(sb));
+       bstart = au_dbstart(dentry);
+       AuDebugOn(bstart < 0);
+       err = bstart;
+       /* todo: can 'err' be an illegal? */
+       if (/* err >= 0 && */ !au_br_rdonly(au_sbr(sb, bstart)))
+               goto out;
+
+       err = -EROFS;
+       parent = dget_parent(dentry);
+       for (bindex = au_dbstart(parent); bindex < bstart; bindex++) {
+               h_parent = au_h_dptr(parent, bindex);
+               if (!h_parent)
+                       continue;
+               h_dir = h_parent->d_inode;
+               if (!h_dir)
+                       continue;
+
+               if (!au_br_rdonly(au_sbr(sb, bindex))
+                   && (!dirperm1
+                       || au_test_h_perm(h_dir, MAY_WRITE | MAY_EXEC,
+                                         /*dlgt*/0))) {
+                               err = bindex;
+                               break;
+               }
+       }
+       dput(parent);
+
+       /* bottom up here */
+       if (unlikely(err < 0))
+               err = au_wbr_bu(sb, bstart - 1);
+
+ out:
+       LKTRTrace("b%d\n", err);
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* an exception for the policy other than tdp */
+static int au_wbr_create_exp(struct dentry *dentry)
+{
+       int err;
+       struct dentry *parent;
+       aufs_bindex_t bwh, bdiropq;
+
+       LKTRTrace("%.*s\n", AuDLNPair(dentry));
+
+       err = -1;
+       bwh = au_dbwh(dentry);
+       parent = dget_parent(dentry);
+       bdiropq = au_dbdiropq(parent);
+       if (bwh >= 0) {
+               if (bdiropq >= 0)
+                       err = min(bdiropq, bwh);
+               else
+                       err = bwh;
+               LKTRTrace("%d\n", err);
+       } else if (bdiropq >= 0) {
+               err = bdiropq;
+               LKTRTrace("%d\n", err);
+       }
+       dput(parent);
+
+       if (err >= 0 && au_br_rdonly(au_sbr(dentry->d_sb, err)))
+               err = -1;
+
+       LKTRTrace("%d\n", err);
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* round robin */
+static int au_wbr_create_init_rr(struct super_block *sb)
+{
+       int err;
+
+       err = au_wbr_bu(sb, au_sbend(sb));
+       atomic_set(&au_sbi(sb)->si_wbr_rr_next, -err); /* less important */
+
+       LKTRTrace("b%d\n", err);
+       return err;
+}
+
+static int au_wbr_create_rr(struct dentry *dentry, int isdir)
+{
+       int err, nbr;
+       struct super_block *sb;
+       atomic_t *next;
+       unsigned int u;
+       aufs_bindex_t bindex, bend;
+
+       LKTRTrace("%.*s, dir %d\n", AuDLNPair(dentry), isdir);
+
+       sb = dentry->d_sb;
+       next = NULL;
+       err = au_wbr_create_exp(dentry);
+       if (err >= 0)
+               goto out;
+
+       next = &au_sbi(sb)->si_wbr_rr_next;
+       bend = au_sbend(sb);
+       nbr = bend + 1;
+       for (bindex = 0; bindex <= bend; bindex++) {
+               if (!isdir) {
+                       err = atomic_dec_return(next) + 1;
+                       /* modulo for 0 is meaningless */
+                       if (unlikely(!err))
+                               err = atomic_dec_return(next) + 1;
+               } else
+                       err = atomic_read(next);
+               LKTRTrace("%d\n", err);
+               u = err;
+               err = u % nbr;
+               LKTRTrace("%d\n", err);
+               if (!au_br_rdonly(au_sbr(sb, err)))
+                       break;
+               err = -EROFS;
+       }
+
+ out:
+       LKTRTrace("%d\n", err);
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* most free space */
+static void *au_wbr_statfs_arg(struct au_branch *br, struct super_block *sb,
+                              aufs_bindex_t bindex)
+{
+       struct super_block *h_sb;
+
+       h_sb = br->br_mnt->mnt_sb;
+
+       if (!au_test_nfs(h_sb))
+               return h_sb->s_root;
+
+       /* sigh,,, why nfs s_root has wrong inode? */
+       return au_di(sb->s_root)->di_hdentry[0 + bindex].hd_dentry;
+}
+
+static void au_mfs(struct dentry *dentry)
+{
+       struct super_block *sb;
+       aufs_bindex_t bindex, bend;
+       unsigned char dlgt;
+       int err;
+       struct kstatfs st;
+       unsigned long long b, bavail;
+       void *arg;
+       struct au_branch *br;
+       struct au_wbr_mfs *mfs;
+
+       LKTRTrace("%.*s\n", AuDLNPair(dentry));
+
+       bavail = 0;
+       sb = dentry->d_sb;
+       mfs = &au_sbi(sb)->si_wbr_mfs;
+       mfs->mfs_bindex = -EROFS;
+       mfs->mfsrr_bytes = 0;
+       dlgt = !!au_test_dlgt(au_mntflags(sb));
+       bend = au_sbend(sb);
+       for (bindex = 0; bindex <= bend; bindex++) {
+               br = au_sbr(sb, bindex);
+               if (au_br_rdonly(br))
+                       continue;
+               AuDebugOn(!br->br_wbr);
+               arg = au_wbr_statfs_arg(br, sb, bindex);
+               if (!arg)
+                       continue;
+
+               err = vfsub_statfs(arg, &st, dlgt);
+               LKTRTrace("b%d, %d, %llu\n",
+                         bindex, err, (unsigned long long)st.f_bavail);
+               if (unlikely(err)) {
+                       AuWarn1("failed statfs, b%d, %d\n", bindex, err);
+                       continue;
+               }
+
+               /* when the available size is equal, select lower one */
+               b = st.f_bavail * st.f_bsize;
+               br->br_wbr->wbr_bytes = b;
+               if (b >= bavail) {
+                       bavail = b;
+                       mfs->mfs_bindex = bindex;
+                       mfs->mfs_jiffy = jiffies;
+               }
+       }
+
+       mfs->mfsrr_bytes = bavail;
+       LKTRTrace("b%d\n", mfs->mfs_bindex);
+}
+
+static int au_wbr_create_mfs(struct dentry *dentry, int isdir)
+{
+       int err;
+       struct super_block *sb;
+       struct au_wbr_mfs *mfs;
+
+       LKTRTrace("%.*s\n", AuDLNPair(dentry));
+
+       sb = dentry->d_sb;
+       err = au_wbr_create_exp(dentry);
+       if (err >= 0)
+               goto out;
+
+       mfs = &au_sbi(sb)->si_wbr_mfs;
+       mutex_lock(&mfs->mfs_lock);
+       if (unlikely(time_after(jiffies, mfs->mfs_jiffy + mfs->mfs_expire)
+                    || mfs->mfs_bindex < 0
+                    || au_br_rdonly(au_sbr(sb, mfs->mfs_bindex))))
+               au_mfs(dentry);
+       mutex_unlock(&mfs->mfs_lock);
+       err = mfs->mfs_bindex;
+
+ out:
+       LKTRTrace("b%d\n", err);
+       return err;
+}
+
+static int au_wbr_create_init_mfs(struct super_block *sb)
+{
+       struct au_wbr_mfs *mfs;
+
+       mfs = &au_sbi(sb)->si_wbr_mfs;
+       LKTRTrace("expire %lu\n", mfs->mfs_expire);
+
+       mutex_init(&mfs->mfs_lock);
+       mfs->mfs_jiffy = 0;
+       mfs->mfs_bindex = -EROFS;
+
+       return 0;
+}
+
+static int au_wbr_create_fin_mfs(struct super_block *sb)
+{
+       AuTraceEnter();
+       mutex_destroy(&au_sbi(sb)->si_wbr_mfs.mfs_lock);
+       return 0;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* most free space and then round robin */
+static int au_wbr_create_mfsrr(struct dentry *dentry, int isdir)
+{
+       int err;
+       struct au_wbr_mfs *mfs;
+
+       LKTRTrace("%.*s, %d\n", AuDLNPair(dentry), isdir);
+
+       err = au_wbr_create_mfs(dentry, isdir);
+       if (err >= 0) {
+               mfs = &au_sbi(dentry->d_sb)->si_wbr_mfs;
+               LKTRTrace("%llu bytes, %llu wmark\n",
+                         mfs->mfsrr_bytes, mfs->mfsrr_watermark);
+               if (mfs->mfsrr_bytes < mfs->mfsrr_watermark)
+                       err = au_wbr_create_rr(dentry, isdir);
+       }
+
+       LKTRTrace("b%d\n", err);
+       return err;
+}
+
+static int au_wbr_create_init_mfsrr(struct super_block *sb)
+{
+       int err;
+
+       au_wbr_create_init_mfs(sb); /* ignore */
+       err = au_wbr_create_init_rr(sb);
+
+       AuTraceErr(err);
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* top down parent and most free space */
+static int au_wbr_create_pmfs(struct dentry *dentry, int isdir)
+{
+       int err, e2;
+       struct super_block *sb;
+       struct dentry *parent, *h_parent;
+       aufs_bindex_t bindex, bstart, bend;
+       unsigned char dirperm1;
+       struct au_branch *br;
+       unsigned long long b;
+       struct inode *h_dir;
+
+       LKTRTrace("%.*s, %d\n", AuDLNPair(dentry), isdir);
+
+       err = au_wbr_create_tdp(dentry, isdir);
+       if (unlikely(err < 0))
+               goto out;
+       parent = dget_parent(dentry);
+       bstart = au_dbstart(parent);
+       bend = au_dbtaildir(parent);
+       if (bstart == bend)
+               goto out_parent; /* success */
+
+       e2 = au_wbr_create_mfs(dentry, isdir);
+       if (e2 < 0)
+               goto out_parent; /* success */
+
+       /* when the available size is equal, select upper one */
+       sb = dentry->d_sb;
+       br = au_sbr(sb, err);
+       AuDebugOn(!br->br_wbr);
+       dirperm1 = !!au_test_dirperm1(au_mntflags(sb));
+       b = br->br_wbr->wbr_bytes;
+       LKTRTrace("b%d, %llu\n", err, b);
+
+       if (dirperm1) {
+               for (bindex = bstart; bindex <= bend; bindex++) {
+                       h_parent = au_h_dptr(parent, bindex);
+                       if (!h_parent)
+                               continue;
+                       h_dir = h_parent->d_inode;
+                       if (!h_dir)
+                               continue;
+
+                       br = au_sbr(sb, bindex);
+                       if (!au_br_rdonly(br)
+                           && au_test_h_perm(h_dir, MAY_WRITE | MAY_EXEC,
+                                             /*dlgt*/0)
+                           && br->br_wbr->wbr_bytes > b) {
+                               b = br->br_wbr->wbr_bytes;
+                               err = bindex;
+                               LKTRTrace("b%d, %llu\n", err, b);
+                       }
+               }
+               if (err >= 0)
+                       goto out_parent;
+       }
+       for (bindex = bstart; bindex <= bend; bindex++) {
+               h_parent = au_h_dptr(parent, bindex);
+               if (!h_parent || !h_parent->d_inode)
+                       continue;
+
+               br = au_sbr(sb, bindex);
+               if (!au_br_rdonly(br) && br->br_wbr->wbr_bytes > b) {
+                       b = br->br_wbr->wbr_bytes;
+                       err = bindex;
+                       LKTRTrace("b%d, %llu\n", err, b);
+               }
+       }
+
+ out_parent:
+       dput(parent);
+ out:
+       LKTRTrace("b%d\n", err);
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* policies for copyup */
+
+/* top down parent */
+static int au_wbr_copyup_tdp(struct dentry *dentry)
+{
+       return au_wbr_create_tdp(dentry, /*isdir, anything is ok*/0);
+}
+
+/* bottom up parent */
+static int au_wbr_copyup_bup(struct dentry *dentry)
+{
+       int err;
+       struct dentry *parent, *h_parent;
+       aufs_bindex_t bindex, bstart;
+       unsigned char dirperm1;
+       struct super_block *sb;
+       struct inode *h_dir;
+
+       LKTRTrace("%.*s\n", AuDLNPair(dentry));
+
+       err = -EROFS;
+       sb = dentry->d_sb;
+       dirperm1 = !!au_test_dirperm1(au_mntflags(sb));
+       parent = dget_parent(dentry);
+       bstart = au_dbstart(parent);
+       for (bindex = au_dbstart(dentry); bindex >= bstart; bindex--) {
+               h_parent = au_h_dptr(parent, bindex);
+               if (!h_parent)
+                       continue;
+               h_dir = h_parent->d_inode;
+               if (!h_dir)
+                       continue;
+
+               if (!au_br_rdonly(au_sbr(sb, bindex))
+                   && (!dirperm1
+                       || au_test_h_perm(h_dir, MAY_WRITE | MAY_EXEC,
+                                         /*dlgt*/0))) {
+                       err = bindex;
+                       break;
+               }
+       }
+       dput(parent);
+
+       /* bottom up here */
+       if (unlikely(err < 0))
+               err = au_wbr_bu(sb, bstart - 1);
+
+       LKTRTrace("b%d\n", err);
+       return err;
+}
+
+/* bottom up */
+static int au_wbr_copyup_bu(struct dentry *dentry)
+{
+       int err;
+
+       LKTRTrace("%.*s\n", AuDLNPair(dentry));
+
+       err = au_wbr_bu(dentry->d_sb, au_dbstart(dentry));
+
+       LKTRTrace("b%d\n", err);
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+struct au_wbr_copyup_operations au_wbr_copyup_ops[] = {
+       [AuWbrCopyup_TDP] = {
+               .copyup = au_wbr_copyup_tdp
+       },
+       [AuWbrCopyup_BUP] = {
+               .copyup = au_wbr_copyup_bup
+       },
+       [AuWbrCopyup_BU] = {
+               .copyup = au_wbr_copyup_bu
+       }
+};
+
+struct au_wbr_create_operations au_wbr_create_ops[] = {
+       [AuWbrCreate_TDP] = {
+               .create = au_wbr_create_tdp
+       },
+       [AuWbrCreate_RR] = {
+               .create = au_wbr_create_rr,
+               .init   = au_wbr_create_init_rr
+       },
+       [AuWbrCreate_MFS] = {
+               .create = au_wbr_create_mfs,
+               .init   = au_wbr_create_init_mfs,
+               .fin    = au_wbr_create_fin_mfs
+       },
+       [AuWbrCreate_MFSV] = {
+               .create = au_wbr_create_mfs,
+               .init   = au_wbr_create_init_mfs,
+               .fin    = au_wbr_create_fin_mfs
+       },
+       [AuWbrCreate_MFSRR] = {
+               .create = au_wbr_create_mfsrr,
+               .init   = au_wbr_create_init_mfsrr,
+               .fin    = au_wbr_create_fin_mfs
+       },
+       [AuWbrCreate_MFSRRV] = {
+               .create = au_wbr_create_mfsrr,
+               .init   = au_wbr_create_init_mfsrr,
+               .fin    = au_wbr_create_fin_mfs
+       },
+       [AuWbrCreate_PMFS] = {
+               .create = au_wbr_create_pmfs,
+               .init   = au_wbr_create_init_mfs,
+               .fin    = au_wbr_create_fin_mfs
+       },
+       [AuWbrCreate_PMFSV] = {
+               .create = au_wbr_create_pmfs,
+               .init   = au_wbr_create_init_mfs,
+               .fin    = au_wbr_create_fin_mfs
+       }
+};
diff -urN linux/fs/aufs/whout.c linux-aufs/fs/aufs/whout.c
--- linux/fs/aufs/whout.c       1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/whout.c  2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,1160 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * whiteout for logical deletion and opaque directory
+ *
+ * $Id$
+ */
+
+#include <linux/fs.h>
+#include <linux/namei.h>
+#include "aufs.h"
+
+#define WH_MASK                        S_IRUGO
+
+/* If a directory contains this file, then it is opaque.  We start with the
+ * .wh. flag so that it is blocked by lookup.
+ */
+static struct qstr diropq_name = {
+       .name = AUFS_WH_DIROPQ,
+       .len = sizeof(AUFS_WH_DIROPQ) - 1
+};
+
+/*
+ * generate whiteout name, which is NOT terminated by NULL.
+ * @name: original d_name.name
+ * @len: original d_name.len
+ * @wh: whiteout qstr
+ * returns zero when succeeds, otherwise error.
+ * succeeded value as wh->name should be freed by au_wh_name_free().
+ */
+int au_wh_name_alloc(const char *name, int len, struct qstr *wh)
+{
+       char *p;
+
+       AuDebugOn(!name || !len || !wh);
+
+       if (unlikely(len > PATH_MAX - AUFS_WH_PFX_LEN))
+               return -ENAMETOOLONG;
+
+       wh->len = len + AUFS_WH_PFX_LEN;
+       p = kmalloc(wh->len, GFP_NOFS);
+       wh->name = p;
+       if (p) {
+               memcpy(p, AUFS_WH_PFX, AUFS_WH_PFX_LEN);
+               memcpy(p + AUFS_WH_PFX_LEN, name, len);
+               /* smp_mb(); */
+               return 0;
+       }
+       return -ENOMEM;
+}
+
+void au_wh_name_free(struct qstr *wh)
+{
+       AuDebugOn(!wh || !wh->name);
+       kfree(wh->name);
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * test if the @wh_name exists under @h_parent.
+ * @try_sio specifies the necessary of super-io.
+ */
+int au_wh_test(struct dentry *h_parent, struct qstr *wh_name, int try_sio,
+              struct au_ndx *ndx)
+{
+       int err;
+       struct dentry *wh_dentry;
+       struct inode *h_dir;
+       unsigned int flags;
+
+       LKTRTrace("%.*s/%.*s, ndx{%p, 0x%x}\n", AuDLNPair(h_parent),
+                 wh_name->len, wh_name->name, ndx->nfsmnt, ndx->flags);
+       h_dir = h_parent->d_inode;
+       AuDebugOn(!S_ISDIR(h_dir->i_mode));
+
+       flags = 0;
+       if (ndx && ndx->nd) {
+               flags = ndx->nd->flags;
+               ndx->nd->flags &= ~(LOOKUP_OPEN | LOOKUP_CREATE);
+       }
+
+       if (!try_sio)
+               wh_dentry = au_lkup_one(wh_name->name, h_parent,
+                                       wh_name->len, ndx);
+       else
+               wh_dentry = au_sio_lkup_one(wh_name->name, h_parent,
+                                           wh_name->len, ndx);
+       if (flags)
+               ndx->nd->flags = flags;
+       err = PTR_ERR(wh_dentry);
+       if (IS_ERR(wh_dentry))
+               goto out;
+
+       err = 0;
+       if (!wh_dentry->d_inode)
+               goto out_wh; /* success */
+
+       err = 1;
+       if (S_ISREG(wh_dentry->d_inode->i_mode))
+               goto out_wh; /* success */
+
+       err = -EIO;
+       AuIOErr("%.*s Invalid whiteout entry type 0%o.\n",
+               AuDLNPair(wh_dentry), wh_dentry->d_inode->i_mode);
+
+ out_wh:
+       dput(wh_dentry);
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+/*
+ * test if the @h_dentry sets opaque or not.
+ */
+int au_diropq_test(struct dentry *h_dentry, struct au_ndx *ndx)
+{
+       int err, try_sio;
+       struct inode *h_dir;
+
+       LKTRTrace("dentry %.*s\n", AuDLNPair(h_dentry));
+       h_dir = h_dentry->d_inode;
+       AuDebugOn(!S_ISDIR(h_dir->i_mode));
+
+       try_sio = au_test_h_perm_sio(h_dir, MAY_EXEC,
+                                    au_ftest_ndx(ndx->flags, DLGT));
+       err = au_wh_test(h_dentry, &diropq_name, try_sio, ndx);
+       AuTraceErr(err);
+       return err;
+}
+
+/*
+ * returns a negative dentry whose name is unique and temporary.
+ */
+struct dentry *au_whtmp_lkup(struct dentry *h_parent, struct qstr *prefix,
+                            struct au_ndx *ndx)
+{
+#define HEX_LEN 4
+       struct dentry *dentry;
+       int len, i;
+       char defname[AUFS_WH_PFX_LEN * 2 + DNAME_INLINE_LEN_MIN + 1
+                    + HEX_LEN + 1], *name, *p;
+       static unsigned char cnt;
+
+       LKTRTrace("hp %.*s, prefix %.*s\n",
+                 AuDLNPair(h_parent), prefix->len, prefix->name);
+       AuDebugOn(!h_parent->d_inode);
+
+       name = defname;
+       len = sizeof(defname) - DNAME_INLINE_LEN_MIN + prefix->len - 1;
+       if (unlikely(prefix->len > DNAME_INLINE_LEN_MIN)) {
+               dentry = ERR_PTR(-ENAMETOOLONG);
+               if (unlikely(len >= PATH_MAX))
+                       goto out;
+               dentry = ERR_PTR(-ENOMEM);
+               name = kmalloc(len + 1, GFP_NOFS);
+               if (unlikely(!name))
+                       goto out;
+       }
+
+       /* doubly whiteout-ed */
+       memcpy(name, AUFS_WH_PFX AUFS_WH_PFX, AUFS_WH_PFX_LEN * 2);
+       p = name + AUFS_WH_PFX_LEN * 2;
+       memcpy(p, prefix->name, prefix->len);
+       p += prefix->len;
+       *p++ = '.';
+       AuDebugOn(name + len + 1 - p <= HEX_LEN);
+
+       for (i = 0; i < 3; i++) {
+               sprintf(p, "%.*d", HEX_LEN, cnt++);
+               dentry = au_sio_lkup_one(name, h_parent, len, ndx);
+               if (IS_ERR(dentry) || !dentry->d_inode)
+                       goto out_name;
+               dput(dentry);
+       }
+       /* AuWarn("could not get random name\n"); */
+       dentry = ERR_PTR(-EEXIST);
+       AuDbg("%.*s\n", len, name);
+       BUG();
+
+ out_name:
+       if (name != defname)
+               kfree(name);
+ out:
+       AuTraceErrPtr(dentry);
+       return dentry;
+#undef HEX_LEN
+}
+
+/*
+ * rename the @dentry of @bindex to the whiteouted temporary name.
+ */
+int au_whtmp_ren(struct inode *dir, aufs_bindex_t bindex,
+                struct dentry *h_dentry)
+{
+       int err, dlgt;
+       struct inode *h_dir;
+       struct dentry *h_parent, *tmp_dentry;
+       struct super_block *sb;
+       unsigned int mnt_flags;
+       struct au_hin_ignore ign;
+       struct vfsub_args vargs;
+       struct au_ndx ndx = {
+               .flags  = 0,
+               .nd     = NULL,
+               /* .br  = NULL */
+       };
+
+       LKTRTrace("%.*s\n", AuDLNPair(h_dentry));
+       AuDebugOn(!h_dentry->d_inode);
+       h_parent = h_dentry->d_parent; /* dir inode is locked */
+       h_dir = h_parent->d_inode;
+       IMustLock(h_dir);
+
+       sb = dir->i_sb;
+       mnt_flags = au_mntflags(sb);
+       dlgt = !!au_test_dlgt(mnt_flags);
+       if (dlgt)
+               au_fset_ndx(ndx.flags, DLGT);
+       ndx.nfsmnt = au_nfsmnt(sb, bindex);
+       tmp_dentry = au_whtmp_lkup(h_parent, &h_dentry->d_name, &ndx);
+       err = PTR_ERR(tmp_dentry);
+       if (IS_ERR(tmp_dentry))
+               goto out;
+
+       /* under the same dir, no need to lock_rename() */
+       vfsub_args_init(&vargs, &ign, dlgt, 0);
+       AuDebugOn(!S_ISDIR(h_dentry->d_inode->i_mode));
+       vfsub_ign_hinode(&vargs, IN_MOVED_FROM | IN_MOVED_TO,
+                        au_hi(dir, bindex));
+       err = vfsub_rename(h_dir, h_dentry, h_dir, tmp_dentry, &vargs);
+       AuTraceErr(err);
+       dput(tmp_dentry);
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static int do_unlink_wh(struct au_hinode *hdir, struct inode *h_dir,
+                       struct dentry *wh_dentry, const int dlgt)
+{
+       int err;
+       struct au_hin_ignore ign;
+       struct vfsub_args vargs;
+
+       AuDebugOn(hdir && h_dir);
+       AuDebugOn(!hdir && !h_dir);
+       if (!h_dir)
+               h_dir = hdir->hi_inode;
+       LKTRTrace("hi%lu, wh %.*s\n", h_dir->i_ino, AuDLNPair(wh_dentry));
+       AuDebugOn(!wh_dentry->d_inode || !S_ISREG(wh_dentry->d_inode->i_mode));
+
+       /*
+        * forces superio when the dir has a sticky bit.
+        * this may be a violation of unix fs semantics.
+        */
+       vfsub_args_init(&vargs, &ign, dlgt,
+                       (h_dir->i_mode & S_ISVTX)
+                       && wh_dentry->d_inode->i_uid != current_fsuid());
+       vfsub_ign_hinode(&vargs, IN_DELETE, hdir);
+       err = vfsub_unlink(h_dir, wh_dentry, &vargs);
+       AuTraceErr(err);
+       return err;
+}
+
+int au_wh_unlink_dentry(struct au_hinode *hdir, struct dentry *wh_dentry,
+                       struct dentry *dentry, int dlgt)
+{
+       int err;
+
+       LKTRTrace("i%lu, wh %.*s, d %p\n",
+                 hdir->hi_inode->i_ino, AuDLNPair(wh_dentry), dentry);
+       AuDebugOn((dentry && au_dbwh(dentry) < 0)
+                 || !wh_dentry->d_inode
+                 || !S_ISREG(wh_dentry->d_inode->i_mode));
+
+       err = do_unlink_wh(hdir, /*h_dir*/NULL, wh_dentry, dlgt);
+       if (!err && dentry)
+               au_set_dbwh(dentry, -1);
+
+       AuTraceErr(err);
+       return err;
+}
+
+static int unlink_wh_name(struct dentry *h_parent, struct qstr *wh,
+                         struct au_ndx *ndx)
+{
+       int err;
+       struct dentry *wh_dentry;
+
+       LKTRTrace("%.*s/%.*s\n", AuDLNPair(h_parent), AuLNPair(wh));
+
+       /* au_test_h_perm() is already done */
+       wh_dentry = au_lkup_one(wh->name, h_parent, wh->len, ndx);
+       if (IS_ERR(wh_dentry))
+               err = PTR_ERR(wh_dentry);
+       else {
+               err = 0;
+               if (wh_dentry->d_inode && S_ISREG(wh_dentry->d_inode->i_mode))
+                       err = do_unlink_wh(/*hdir*/NULL, h_parent->d_inode,
+                                          wh_dentry,
+                                          au_ftest_ndx(ndx->flags, DLGT));
+               dput(wh_dentry);
+       }
+
+       AuTraceErr(err);
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static void clean_wh(struct inode *h_dir, struct path *whpath,
+                    struct au_hinode *hdir, struct vfsub_args *vargs)
+{
+       int err;
+
+       AuTraceEnter();
+
+       if (!whpath->dentry->d_inode)
+               return;
+
+       err = au_mnt_want_write(whpath->mnt);
+       if (!err) {
+               vfsub_args_reinit(vargs);
+               vfsub_ign_hinode(vargs, IN_DELETE, hdir);
+               err = vfsub_unlink(h_dir, whpath->dentry, vargs);
+               au_mnt_drop_write(whpath->mnt);
+       }
+       if (unlikely(err))
+               AuWarn("failed unlink %.*s (%d), ignored.\n",
+                      AuDLNPair(whpath->dentry), err);
+}
+
+static void au_whdir_clean(struct inode *h_dir, struct path *whpath,
+                          struct au_hinode *hdir, struct vfsub_args *vargs)
+{
+       int err;
+
+       AuTraceEnter();
+
+       if (!whpath->dentry->d_inode)
+               return;
+
+       err = au_mnt_want_write(whpath->mnt);
+       if (!err) {
+               vfsub_args_reinit(vargs);
+               vfsub_ign_hinode(vargs, IN_DELETE, hdir);
+               err = vfsub_rmdir(h_dir, whpath->dentry, vargs);
+               au_mnt_drop_write(whpath->mnt);
+       }
+       if (unlikely(err))
+               AuWarn("failed rmdir %.*s (%d), ignored.\n",
+                      AuDLNPair(whpath->dentry), err);
+}
+
+static int test_linkable(struct inode *h_dir)
+{
+       if (h_dir->i_op && h_dir->i_op->link)
+               return 0;
+       return -ENOSYS;
+}
+
+/* todo: should this mkdir be done in /sbin/mount.aufs script? */
+static int au_whdir(struct inode *h_dir, struct path *path,
+                   struct au_hinode *hdir, struct vfsub_args *vargs)
+{
+       int err;
+
+       err = -EEXIST;
+       if (!path->dentry->d_inode) {
+               int mode = S_IRWXU;
+               if (au_test_nfs(path->dentry->d_sb))
+                       mode |= S_IXUGO;
+               err = au_mnt_want_write(path->mnt);
+               if (!err) {
+                       vfsub_args_reinit(vargs);
+                       vfsub_ign_hinode(vargs, IN_CREATE, hdir);
+                       err = vfsub_mkdir(h_dir, path->dentry, mode, vargs);
+                       au_mnt_drop_write(path->mnt);
+               }
+       } else if (S_ISDIR(path->dentry->d_inode->i_mode))
+               err = 0;
+       else
+               AuErr("unknown %.*s exists\n", AuDLNPair(path->dentry));
+
+       return err;
+}
+
+/*
+ * initialize the whiteout base file/dir for @br.
+ */
+int au_wh_init(struct dentry *h_root, struct au_branch *br,
+              struct vfsmount *h_mnt, struct super_block *sb,
+              aufs_bindex_t bindex)
+{
+       int err, i;
+       const unsigned int mnt_flags = au_mntflags(sb);
+       const unsigned char do_plink = !!au_opt_test(mnt_flags, PLINK),
+               do_hinotify = au_opt_test(mnt_flags, UDBA_INOTIFY);
+       struct path path = {
+               .mnt = h_mnt
+       };
+       struct au_hin_ignore ign;
+       struct vfsub_args vargs;
+       struct inode *h_dir;
+       struct au_hinode *hdir;
+       struct au_wbr *wbr = br->br_wbr;
+       struct vfsmount *nfsmnt = au_do_nfsmnt(h_mnt);
+       static const struct qstr base_name[] = {
+               [AuBrWh_BASE] = {
+                       .name   = AUFS_BASE_NAME,
+                       .len    = sizeof(AUFS_BASE_NAME) - 1
+               },
+               [AuBrWh_PLINK] = {
+                       .name   = AUFS_PLINKDIR_NAME,
+                       .len    = sizeof(AUFS_PLINKDIR_NAME) - 1
+               },
+               [AuBrWh_TMP] = {
+                       .name   = AUFS_TMPDIR_NAME,
+                       .len    = sizeof(AUFS_TMPDIR_NAME) - 1
+               }
+       };
+       struct {
+               const struct qstr *name;
+               struct dentry *dentry;
+       } base[] = {
+               [AuBrWh_BASE] = {
+                       .name   = base_name + AuBrWh_BASE,
+                       .dentry = NULL
+               },
+               [AuBrWh_PLINK] = {
+                       .name   = base_name + AuBrWh_PLINK,
+                       .dentry = NULL
+               },
+               [AuBrWh_TMP] = {
+                       .name   = base_name + AuBrWh_TMP,
+                       .dentry = NULL
+               }
+       };
+       struct au_ndx ndx = {
+               .nfsmnt = nfsmnt,
+               .flags  = 0, /* always no dlgt */
+               .nd     = NULL,
+               /* .br  = NULL */
+       };
+
+       LKTRTrace("nfsmnt %p\n", nfsmnt);
+       WbrWhMustWriteLock(wbr);
+       SiMustWriteLock(sb);
+       h_dir = h_root->d_inode;
+
+       for (i = 0; i < AuBrWh_Last; i++) {
+               /* doubly whiteouted */
+               struct dentry *d;
+               d = au_wh_lkup(h_root, (void *)base[i].name, &ndx);
+               err = PTR_ERR(d);
+               if (IS_ERR(d))
+                       goto out;
+               base[i].dentry = d;
+               if (!au_test_ecryptfs(d->d_sb))
+                       AuDebugOn(wbr
+                                 && wbr->wbr_wh[i]
+                                 && wbr->wbr_wh[i] != base[i].dentry);
+               else
+                       /* ecryptfs problem?: it returns different dentry */
+                       AuDebugOn(wbr
+                                 && wbr->wbr_wh[i]
+                                 && !!wbr->wbr_wh[i] != !!base[i].dentry);
+       }
+
+       if (wbr)
+               for (i = 0; i < AuBrWh_Last; i++) {
+                       dput(wbr->wbr_wh[i]);
+                       wbr->wbr_wh[i] = NULL;
+               }
+
+       err = 0;
+       hdir = NULL;
+       if (bindex >= 0 && do_hinotify)
+               hdir = au_hi(sb->s_root->d_inode, bindex);
+       vfsub_args_init(&vargs, &ign, au_test_dlgt(mnt_flags), 0);
+
+       switch (br->br_perm) {
+       case AuBrPerm_RR:
+       case AuBrPerm_RO:
+       case AuBrPerm_RRWH:
+       case AuBrPerm_ROWH:
+               path.dentry = base[AuBrWh_BASE].dentry;
+               clean_wh(h_dir, &path, hdir, &vargs);
+               path.dentry = base[AuBrWh_PLINK].dentry;
+               au_whdir_clean(h_dir, &path, hdir, &vargs);
+               path.dentry = base[AuBrWh_TMP].dentry;
+               au_whdir_clean(h_dir, &path, hdir, &vargs);
+               break;
+
+       case AuBrPerm_RWNoLinkWH:
+               path.dentry = base[AuBrWh_BASE].dentry;
+               clean_wh(h_dir, &path, hdir, &vargs);
+               path.dentry = base[AuBrWh_PLINK].dentry;
+               if (do_plink) {
+                       err = test_linkable(h_dir);
+                       if (unlikely(err))
+                               goto out_nolink;
+
+                       err = au_whdir(h_dir, &path, hdir, &vargs);
+                       if (unlikely(err))
+                               goto out_err;
+                       wbr->wbr_plink = dget(base[AuBrWh_PLINK].dentry);
+               } else
+                       au_whdir_clean(h_dir, &path, hdir, &vargs);
+               path.dentry = base[AuBrWh_TMP].dentry;
+               err = au_whdir(h_dir, &path, hdir, &vargs);
+               if (unlikely(err))
+                       goto out_err;
+               wbr->wbr_tmp = dget(base[AuBrWh_TMP].dentry);
+               break;
+
+       case AuBrPerm_RW:
+               /*
+                * for the moment, aufs supports the branch filesystem
+                * which does not support link(2).
+                * testing on FAT which does not support i_op->setattr() fully
+                * either, copyup failed.
+                * finally, such filesystem will not be used as the writable
+                * branch.
+                */
+               err = test_linkable(h_dir);
+               if (unlikely(err))
+                       goto out_nolink;
+
+               err = -EEXIST;
+               /*
+                * todo: should this create be done
+                * in /sbin/mount.aufs script?
+                */
+               if (!base[AuBrWh_BASE].dentry->d_inode) {
+                       err = au_mnt_want_write(h_mnt);
+                       if (!err) {
+                               vfsub_args_reinit(&vargs);
+                               vfsub_ign_hinode(&vargs, IN_CREATE, hdir);
+                               err = au_h_create
+                                       (h_dir, base[AuBrWh_BASE].dentry,
+                                        WH_MASK, &vargs, /*nd*/NULL, nfsmnt);
+                               au_mnt_drop_write(h_mnt);
+                       }
+               } else if (S_ISREG(base[AuBrWh_BASE].dentry->d_inode->i_mode))
+                       err = 0;
+               else
+                       AuErr("unknown %.*s/%.*s exists\n",
+                             AuDLNPair(h_root),
+                             AuDLNPair(base[AuBrWh_BASE].dentry));
+               if (unlikely(err))
+                       goto out_err;
+
+               path.dentry = base[AuBrWh_PLINK].dentry;
+               if (do_plink) {
+                       err = au_whdir(h_dir, &path, hdir, &vargs);
+                       if (unlikely(err))
+                               goto out_err;
+                       wbr->wbr_plink = dget(base[AuBrWh_PLINK].dentry);
+               } else
+                       au_whdir_clean(h_dir, &path, hdir, &vargs);
+               wbr->wbr_whbase = dget(base[AuBrWh_BASE].dentry);
+
+               path.dentry = base[AuBrWh_TMP].dentry;
+               err = au_whdir(h_dir, &path, hdir, &vargs);
+               if (unlikely(err))
+                       goto out_err;
+               wbr->wbr_tmp = dget(base[AuBrWh_TMP].dentry);
+               break;
+
+       default:
+               BUG();
+       }
+
+ out:
+       for (i = 0; i < AuBrWh_Last; i++)
+               dput(base[i].dentry);
+       AuTraceErr(err);
+       return err;
+ out_nolink:
+       AuErr("%.*s doesn't support link(2), use noplink and rw+nolwh\n",
+             AuDLNPair(h_root));
+       goto out;
+ out_err:
+       AuErr("an error(%d) on the writable branch %.*s(%s)\n",
+             err, AuDLNPair(h_root), au_sbtype(h_root->d_sb));
+       goto out;
+}
+
+struct reinit_br_wh {
+       struct super_block *sb;
+       struct au_branch *br;
+};
+
+static void reinit_br_wh(void *arg)
+{
+       int err;
+       struct reinit_br_wh *a = arg;
+       struct au_wbr *wbr;
+       struct inode *h_dir, *dir;
+       struct dentry *h_root;
+       aufs_bindex_t bindex;
+       struct au_hin_ignore ign;
+       struct vfsub_args vargs;
+
+       AuTraceEnter();
+       AuDebugOn(current_fsuid());
+
+       err = 0;
+       wbr = a->br->br_wbr;
+       /* big aufs lock */
+       si_noflush_write_lock(a->sb);
+       if (!au_br_writable(a->br->br_perm))
+               goto out;
+       bindex = au_br_index(a->sb, a->br->br_id);
+       if (unlikely(bindex < 0))
+               goto out;
+
+       AuDebugOn(!wbr);
+       AuDebugOn(!wbr->wbr_whbase || !wbr->wbr_whbase->d_inode);
+
+       dir = a->sb->s_root->d_inode;
+       ii_read_lock_parent(dir);
+       h_root = dget_parent(wbr->wbr_whbase);
+       h_dir = h_root->d_inode;
+       AuDebugOn(!h_dir->i_op || !h_dir->i_op->link);
+       mutex_lock_nested(&h_dir->i_mutex, AuLsc_I_PARENT);
+       wbr_wh_write_lock(wbr);
+       if (!au_verify_parent(wbr->wbr_whbase, h_dir)) {
+               err = au_br_want_write(a->br);
+               if (!err) {
+                       vfsub_args_init(&vargs, &ign, /*dlgt*/0, 0);
+                       vfsub_ign_hinode(&vargs, IN_DELETE, au_hi(dir, bindex));
+                       err = vfsub_unlink(h_dir, wbr->wbr_whbase, &vargs);
+                       au_br_drop_write(a->br);
+               }
+       } else {
+               AuWarn("%.*s is moved, ignored\n", AuDLNPair(wbr->wbr_whbase));
+               err = 0;
+       }
+       dput(wbr->wbr_whbase);
+       wbr->wbr_whbase = NULL;
+       if (!err)
+               err = au_wh_init(h_root, a->br, a->br->br_mnt, a->sb, bindex);
+       wbr_wh_write_unlock(wbr);
+       mutex_unlock(&h_dir->i_mutex);
+       dput(h_root);
+       ii_read_unlock(dir);
+
+ out:
+       if (wbr)
+               atomic_dec_return(&wbr->wbr_wh_running);
+       au_br_put(a->br);
+       au_nwt_done(&au_sbi(a->sb)->si_nowait);
+       si_write_unlock(a->sb);
+       kfree(arg);
+       if (unlikely(err))
+               AuIOErr("err %d\n", err);
+}
+
+static void kick_reinit_br_wh(struct super_block *sb, struct au_branch *br)
+{
+       int do_dec, wkq_err;
+       struct reinit_br_wh *arg;
+
+       AuTraceEnter();
+       AuDebugOn(!br->br_wbr);
+
+       do_dec = 1;
+       if (atomic_inc_return(&br->br_wbr->wbr_wh_running) != 1)
+               goto out;
+
+       /* ignore ENOMEM */
+       arg = kmalloc(sizeof(*arg), GFP_NOFS);
+       if (arg) {
+               /*
+                * dec(wh_running), kfree(arg) and au_br_put()
+                * in reinit function
+                */
+               arg->sb = sb;
+               arg->br = br;
+               au_br_get(br);
+               wkq_err = au_wkq_nowait(reinit_br_wh, arg, sb, /*dlgt*/0);
+               if (unlikely(wkq_err)) {
+                       atomic_dec_return(&br->br_wbr->wbr_wh_running);
+                       au_br_put(br);
+                       kfree(arg);
+               }
+               do_dec = 0;
+       }
+
+ out:
+       if (do_dec)
+               atomic_dec_return(&br->br_wbr->wbr_wh_running);
+}
+
+/*
+ * create the whiteout @wh.
+ */
+static int link_or_create_wh(struct super_block *sb, aufs_bindex_t bindex,
+                            struct dentry *wh, struct inode *dir)
+{
+       int err, dlgt;
+       struct au_branch *br;
+       struct au_wbr *wbr;
+       struct dentry *h_parent;
+       struct inode *h_dir;
+       struct au_hin_ignore ign;
+       struct vfsub_args vargs;
+
+       LKTRTrace("%.*s\n", AuDLNPair(wh));
+       h_parent = wh->d_parent; /* dir inode is locked */
+       h_dir = h_parent->d_inode;
+       IMustLock(h_dir);
+       br = au_sbr(sb, bindex);
+       wbr = br->br_wbr;
+       AuDebugOn(!wbr);
+
+       dlgt = !!au_test_dlgt(au_mntflags(sb));
+       wbr_wh_read_lock(wbr);
+       if (wbr->wbr_whbase) {
+               vfsub_args_init(&vargs, &ign, dlgt, 0);
+               if (dir)
+                       vfsub_ign_hinode(&vargs, IN_CREATE, au_hi(dir, bindex));
+               err = vfsub_link(wbr->wbr_whbase, h_dir, wh, &vargs);
+               if (!err || err != -EMLINK)
+                       goto out;
+
+               /* link count full. re-initialize br_whbase. */
+               kick_reinit_br_wh(sb, br);
+       }
+
+       /* return this error in this context */
+       vfsub_args_init(&vargs, &ign, dlgt, 0);
+       if (dir)
+               vfsub_ign_hinode(&vargs, IN_CREATE, au_hi(dir, bindex));
+       err = au_h_create(h_dir, wh, WH_MASK, &vargs, /*nd*/NULL,
+                         au_do_nfsmnt(br->br_mnt));
+
+ out:
+       wbr_wh_read_unlock(wbr);
+       AuTraceErr(err);
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * create or remove the diropq.
+ */
+static struct dentry *do_diropq(struct dentry *dentry, aufs_bindex_t bindex,
+                               unsigned int flags)
+{
+       struct dentry *opq_dentry, *h_dentry;
+       struct inode *h_dir;
+       int err, dlgt;
+       struct super_block *sb;
+       struct au_ndx ndx = {
+               .flags  = 0,
+               .nd     = NULL,
+               /* .br  = NULL */
+       };
+
+       LKTRTrace("%.*s, bindex %d, flags 0x%x\n",
+                 AuDLNPair(dentry), bindex, flags);
+       h_dentry = au_h_dptr(dentry, bindex);
+       AuDebugOn(!h_dentry);
+       h_dir = h_dentry->d_inode;
+       AuDebugOn(!h_dir || !S_ISDIR(h_dir->i_mode));
+
+       /* already checked by au_test_h_perm(). */
+       sb = dentry->d_sb;
+       ndx.nfsmnt = au_nfsmnt(sb, bindex);
+       dlgt = 0;
+       if (au_ftest_diropq(flags, DLGT)) {
+               dlgt = 1;
+               au_fset_ndx(ndx.flags, DLGT);
+       }
+       opq_dentry = au_lkup_one(diropq_name.name, h_dentry, diropq_name.len,
+                                &ndx);
+       if (IS_ERR(opq_dentry))
+               goto out;
+
+       if (au_ftest_diropq(flags, CREATE)) {
+               AuDebugOn(opq_dentry->d_inode);
+               err = link_or_create_wh(dentry->d_sb, bindex, opq_dentry,
+                                       dentry->d_inode);
+               if (!err) {
+                       au_set_dbdiropq(dentry, bindex);
+                       goto out; /* success */
+               }
+       } else {
+               AuDebugOn(/* !S_ISDIR(dentry->d_inode->i_mode)
+                          * ||  */!opq_dentry->d_inode);
+               err = do_unlink_wh(au_hi(dentry->d_inode, bindex),
+                                  /*h_dir*/NULL, opq_dentry, dlgt);
+               if (!err)
+                       au_set_dbdiropq(dentry, -1);
+       }
+       dput(opq_dentry);
+       opq_dentry = ERR_PTR(err);
+
+ out:
+       AuTraceErrPtr(opq_dentry);
+       return opq_dentry;
+}
+
+struct do_diropq_args {
+       struct dentry **errp;
+       struct dentry *dentry;
+       aufs_bindex_t bindex;
+       unsigned int flags;
+};
+
+static void call_do_diropq(void *args)
+{
+       struct do_diropq_args *a = args;
+       *a->errp = do_diropq(a->dentry, a->bindex, a->flags);
+}
+
+struct dentry *au_diropq_sio(struct dentry *dentry, aufs_bindex_t bindex,
+                            unsigned int flags)
+{
+       struct dentry *diropq, *h_dentry;
+
+       LKTRTrace("%.*s, bindex %d, flags 0x%x\n",
+                 AuDLNPair(dentry), bindex, flags);
+
+       h_dentry = au_h_dptr(dentry, bindex);
+       if (!au_test_h_perm_sio(h_dentry->d_inode, MAY_EXEC | MAY_WRITE,
+                               au_ftest_diropq(flags, DLGT)))
+               diropq = do_diropq(dentry, bindex, flags);
+       else {
+               int wkq_err;
+               struct do_diropq_args args = {
+                       .errp           = &diropq,
+                       .dentry         = dentry,
+                       .bindex         = bindex,
+                       .flags          = flags
+               };
+               wkq_err = au_wkq_wait(call_do_diropq, &args, /*dlgt*/0);
+               if (unlikely(wkq_err))
+                       diropq = ERR_PTR(wkq_err);
+       }
+
+       AuTraceErrPtr(diropq);
+       return diropq;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * lookup whiteout dentry.
+ * @h_parent: hidden parent dentry which must exist and be locked
+ * @base_name: name of dentry which will be whiteouted
+ * returns dentry for whiteout.
+ */
+struct dentry *au_wh_lkup(struct dentry *h_parent, struct qstr *base_name,
+                         struct au_ndx *ndx)
+{
+       int err;
+       struct qstr wh_name;
+       struct dentry *wh_dentry;
+
+       LKTRTrace("%.*s/%.*s\n", AuDLNPair(h_parent), AuLNPair(base_name));
+
+       err = au_wh_name_alloc(base_name->name, base_name->len, &wh_name);
+       wh_dentry = ERR_PTR(err);
+       if (!err) {
+               /* do not superio. */
+               wh_dentry = au_lkup_one(wh_name.name, h_parent,
+                                       wh_name.len, ndx);
+               au_wh_name_free(&wh_name);
+       }
+       AuTraceErrPtr(wh_dentry);
+       return wh_dentry;
+}
+
+/*
+ * link/create a whiteout for @dentry on @bindex.
+ */
+struct dentry *au_wh_create(struct dentry *dentry, aufs_bindex_t bindex,
+                           struct dentry *h_parent, struct au_ndx *ndx)
+{
+       struct dentry *wh_dentry;
+       struct inode *dir;
+       int err;
+       struct super_block *sb;
+
+       LKTRTrace("%.*s/%.*s on b%d\n", AuDLNPair(h_parent),
+                 AuDLNPair(dentry), bindex);
+
+       sb = dentry->d_sb;
+       wh_dentry = au_wh_lkup(h_parent, &dentry->d_name, ndx);
+       if (!IS_ERR(wh_dentry) && !wh_dentry->d_inode) {
+               dir = dentry->d_parent->d_inode; /* dir is locked */
+               IMustLock(dir);
+               err = link_or_create_wh(sb, bindex, wh_dentry, dir);
+               if (!err)
+                       au_set_dbwh(dentry, bindex);
+               else {
+                       dput(wh_dentry);
+                       wh_dentry = ERR_PTR(err);
+               }
+       }
+
+       AuTraceErrPtr(wh_dentry);
+       return wh_dentry;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/* Delete all whiteouts in this directory on branch bindex. */
+static int del_wh_children(struct dentry *h_dentry, struct au_nhash *whlist,
+                          aufs_bindex_t bindex, struct au_ndx *ndx)
+{
+       int err, i;
+       struct qstr wh_name;
+       char *p;
+       struct inode *h_inode;
+       struct hlist_head *head;
+       struct au_vdir_wh *tpos;
+       struct hlist_node *pos;
+       struct au_vdir_destr *str;
+
+       LKTRTrace("%.*s\n", AuDLNPair(h_dentry));
+       h_inode = h_dentry->d_inode;
+       AuDebugOn(IS_RDONLY(h_inode));
+
+       err = -ENOMEM;
+       p = __getname();
+       wh_name.name = p;
+       if (unlikely(!wh_name.name))
+               goto out;
+       memcpy(p, AUFS_WH_PFX, AUFS_WH_PFX_LEN);
+       p += AUFS_WH_PFX_LEN;
+
+       /* already checked by au_test_h_perm(). */
+       err = 0;
+       for (i = 0; !err && i < AuSize_NHASH; i++) {
+               head = whlist->heads + i;
+               hlist_for_each_entry(tpos, pos, head, wh_hash) {
+                       if (tpos->wh_bindex != bindex)
+                               continue;
+                       str = &tpos->wh_str;
+                       if (str->len + AUFS_WH_PFX_LEN <= PATH_MAX) {
+                               memcpy(p, str->name, str->len);
+                               wh_name.len = AUFS_WH_PFX_LEN + str->len;
+                               err = unlink_wh_name(h_dentry, &wh_name, ndx);
+                               if (!err)
+                                       continue;
+                               break;
+                       }
+                       AuIOErr("whiteout name too long %.*s\n",
+                               str->len, str->name);
+                       err = -EIO;
+                       break;
+               }
+       }
+       __putname(wh_name.name);
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+struct del_wh_children_args {
+       int *errp;
+       struct dentry *h_dentry;
+       struct au_nhash *whlist;
+       aufs_bindex_t bindex;
+       struct au_ndx *ndx;
+};
+
+static void call_del_wh_children(void *args)
+{
+       struct del_wh_children_args *a = args;
+       *a->errp = del_wh_children(a->h_dentry, a->whlist, a->bindex, a->ndx);
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * rmdir the whiteouted temporary named dir @h_dentry.
+ * @whlist: whiteouted children.
+ */
+int au_whtmp_rmdir(struct inode *dir, aufs_bindex_t bindex,
+                  struct dentry *wh_dentry, struct au_nhash *whlist)
+{
+       int err, dlgt;
+       struct inode *wh_inode, *h_dir;
+       struct super_block *sb;
+       unsigned int mnt_flags;
+       struct au_hin_ignore ign;
+       struct vfsub_args vargs;
+       struct au_ndx ndx = {
+               .flags  = 0,
+               .nd     = NULL,
+               /* .br  = NULL */
+       };
+
+       LKTRTrace("i%lu, %.*s, b%d\n",
+                 dir->i_ino, AuDLNPair(wh_dentry), bindex);
+       /* IMustLock(dir); */
+       IiMustAnyLock(dir);
+       h_dir = wh_dentry->d_parent->d_inode; /* dir inode is locked */
+       IMustLock(h_dir);
+
+       sb = dir->i_sb;
+       mnt_flags = au_mntflags(sb);
+       dlgt = !!au_test_dlgt(mnt_flags);
+       if (dlgt)
+               au_fset_ndx(ndx.flags, DLGT);
+       ndx.nfsmnt = au_nfsmnt(sb, bindex);
+       wh_inode = wh_dentry->d_inode;
+       mutex_lock_nested(&wh_inode->i_mutex, AuLsc_I_CHILD);
+
+       /*
+        * someone else might change some whiteouts while we were sleeping.
+        * it means this whlist may have an obsoleted entry.
+        */
+       if (!au_test_h_perm_sio(wh_inode, MAY_EXEC | MAY_WRITE, dlgt))
+               err = del_wh_children(wh_dentry, whlist, bindex, &ndx);
+       else {
+               int wkq_err;
+               /* ugly */
+               unsigned int flags = ndx.flags;
+               struct del_wh_children_args args = {
+                       .errp           = &err,
+                       .h_dentry       = wh_dentry,
+                       .whlist         = whlist,
+                       .bindex         = bindex,
+                       .ndx            = &ndx
+               };
+
+               ndx.flags = 0;
+               wkq_err = au_wkq_wait(call_del_wh_children, &args, /*dlgt*/0);
+               if (unlikely(wkq_err))
+                       err = wkq_err;
+               ndx.flags = flags;
+       }
+       mutex_unlock(&wh_inode->i_mutex);
+
+       if (!err) {
+               vfsub_args_init(&vargs, &ign, dlgt, 0);
+               vfsub_ign_hinode(&vargs, IN_DELETE, au_hi(dir, bindex));
+               err = vfsub_rmdir(h_dir, wh_dentry, &vargs);
+               /* d_drop(h_dentry); */
+       }
+
+       if (!err) {
+               if (au_ibstart(dir) == bindex) {
+                       au_cpup_attr_timesizes(dir);
+                       /* au_cpup_attr_nlink(dir); */
+                       drop_nlink(dir);
+               }
+               return 0; /* success */
+       }
+
+       AuWarn("failed removing %.*s(%d), ignored\n",
+              AuDLNPair(wh_dentry), err);
+       return err;
+}
+
+static void au_whtmp_rmdir_free_args(struct au_whtmp_rmdir_args *args)
+{
+       au_nhash_fin(&args->whlist);
+       dput(args->wh_dentry);
+       iput(args->dir);
+       kfree(args);
+}
+
+static void call_rmdir_whtmp(void *args)
+{
+       int err;
+       struct au_whtmp_rmdir_args *a = args;
+       struct super_block *sb;
+       struct dentry *h_parent;
+       struct inode *h_dir;
+
+       LKTRTrace("%.*s, b%d, dir i%lu\n",
+                 AuDLNPair(a->wh_dentry), a->bindex, a->dir->i_ino);
+
+       /* rmdir by nfsd may cause deadlock with this i_mutex */
+       /* mutex_lock(&a->dir->i_mutex); */
+       sb = a->dir->i_sb;
+       si_noflush_read_lock(sb);
+       err = au_test_ro(sb, a->bindex, NULL);
+       if (unlikely(err))
+               goto out;
+
+       err = -EIO;
+       ii_write_lock_parent(a->dir);
+       h_parent = dget_parent(a->wh_dentry);
+       h_dir = h_parent->d_inode;
+       mutex_lock_nested(&h_dir->i_mutex, AuLsc_I_PARENT);
+       if (!au_verify_parent(a->wh_dentry, h_dir)) {
+               err = au_br_want_write(au_sbr(sb, a->bindex));
+               if (!err) {
+                       err = au_whtmp_rmdir(a->dir, a->bindex, a->wh_dentry,
+                                            &a->whlist);
+                       au_br_drop_write(au_sbr(sb, a->bindex));
+               }
+       }
+       mutex_unlock(&h_dir->i_mutex);
+       dput(h_parent);
+       ii_write_unlock(a->dir);
+
+ out:
+       /* mutex_unlock(&a->dir->i_mutex); */
+       au_nwt_done(&au_sbi(sb)->si_nowait);
+       si_read_unlock(sb);
+       au_whtmp_rmdir_free_args(a);
+       if (unlikely(err))
+               AuIOErr("err %d\n", err);
+}
+
+void au_whtmp_kick_rmdir(struct inode *dir, aufs_bindex_t bindex,
+                        struct dentry *wh_dentry, struct au_nhash *whlist,
+                        struct au_whtmp_rmdir_args *args)
+{
+       int wkq_err;
+
+       LKTRTrace("%.*s\n", AuDLNPair(wh_dentry));
+       IMustLock(dir);
+
+       /* all post-process will be done in do_rmdir_whtmp(). */
+       args->dir = au_igrab(dir);
+       args->bindex = bindex;
+       args->wh_dentry = dget(wh_dentry);
+       au_nhash_init(&args->whlist);
+       au_nhash_move(&args->whlist, whlist);
+       wkq_err = au_wkq_nowait(call_rmdir_whtmp, args, dir->i_sb, /*dlgt*/0);
+       if (unlikely(wkq_err)) {
+               AuWarn("rmdir error %.*s (%d), ignored\n",
+                      AuDLNPair(wh_dentry), wkq_err);
+               au_whtmp_rmdir_free_args(args);
+       }
+}
diff -urN linux/fs/aufs/whout.h linux-aufs/fs/aufs/whout.h
--- linux/fs/aufs/whout.h       1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/whout.h  2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,137 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * whiteout for logical deletion and opaque directory
+ *
+ * $Id$
+ */
+
+#ifndef __AUFS_WHOUT_H__
+#define __AUFS_WHOUT_H__
+
+#ifdef __KERNEL__
+
+#include <linux/fs.h>
+#include <linux/aufs_type.h>
+#include "dir.h"
+#include "opts.h"
+#include "super.h"
+
+int au_wh_name_alloc(const char *name, int len, struct qstr *wh);
+void au_wh_name_free(struct qstr *wh);
+
+struct au_ndx;
+int au_wh_test(struct dentry *h_parent, struct qstr *wh_name, int try_sio,
+              struct au_ndx *ndx);
+int au_diropq_test(struct dentry *h_dentry, struct au_ndx *ndx);
+
+struct dentry *au_whtmp_lkup(struct dentry *h_parent, struct qstr *prefix,
+                            struct au_ndx *ndx);
+int au_whtmp_ren(struct inode *dir, aufs_bindex_t bindex,
+                struct dentry *h_dentry);
+int au_wh_unlink_dentry(struct au_hinode *dir, struct dentry *wh_dentry,
+                       struct dentry *dentry, int dlgt);
+
+struct au_branch;
+int au_wh_init(struct dentry *h_parent, struct au_branch *br,
+              struct vfsmount *nfsmnt, struct super_block *sb,
+              aufs_bindex_t bindex);
+
+/* diropq flags */
+#define AuDiropq_CREATE        1
+#define AuDiropq_DLGT  (1 << 1)
+#define au_ftest_diropq(flags, name)   ((flags) & AuDiropq_##name)
+#define au_fset_diropq(flags, name)    { (flags) |= AuDiropq_##name; }
+#define au_fclr_diropq(flags, name)    { (flags) &= ~AuDiropq_##name; }
+#ifndef CONFIG_AUFS_DLGT
+#undef AuDiropq_DLGT
+#define AuDiropq_DLGT  0
+#endif
+
+struct dentry *au_diropq_sio(struct dentry *dentry, aufs_bindex_t bindex,
+                            unsigned int flags);
+
+struct dentry *au_wh_lkup(struct dentry *h_parent, struct qstr *base_name,
+                         struct au_ndx *ndx);
+struct dentry *au_wh_create(struct dentry *dentry, aufs_bindex_t bindex,
+                           struct dentry *h_parent, struct au_ndx *ndx);
+
+/* real rmdir the whiteout-ed dir */
+struct au_whtmp_rmdir_args {
+       struct inode *dir;
+       aufs_bindex_t bindex;
+       struct dentry *wh_dentry;
+       struct au_nhash whlist;
+};
+
+struct au_nhash;
+int au_whtmp_rmdir(struct inode *dir, aufs_bindex_t bindex,
+                  struct dentry *wh_dentry, struct au_nhash *whlist);
+void au_whtmp_kick_rmdir(struct inode *dir, aufs_bindex_t bindex,
+                        struct dentry *wh_dentry, struct au_nhash *whlist,
+                        struct au_whtmp_rmdir_args *args);
+
+/* ---------------------------------------------------------------------- */
+
+static inline
+struct dentry *au_diropq_create(struct dentry *dentry, aufs_bindex_t bindex,
+                               int dlgt)
+{
+       unsigned int flags = AuDiropq_CREATE;
+       if (dlgt)
+               au_fset_diropq(flags, DLGT);
+       return au_diropq_sio(dentry, bindex, flags);
+}
+
+static inline
+int au_diropq_remove(struct dentry *dentry, aufs_bindex_t bindex, int dlgt)
+{
+       unsigned int flags = !AuDiropq_CREATE;
+       if (dlgt)
+               au_fset_diropq(flags, DLGT);
+       return PTR_ERR(au_diropq_sio(dentry, bindex, flags));
+}
+
+/* ---------------------------------------------------------------------- */
+
+#ifdef CONFIG_AUFS_ROBR
+/* robr.c */
+int au_test_robr_wh(struct qstr *name, struct dentry *h_parent,
+                   struct qstr *wh_name, int try_sio, struct au_ndx *ndx);
+int au_test_robr_shwh(struct super_block *sb, const struct qstr *name);
+#else
+static inline
+int au_test_robr_wh(struct qstr *name, struct dentry *h_parent,
+                   struct qstr *wh_name, int try_sio, struct au_ndx *ndx)
+{
+       return au_wh_test(h_parent, wh_name, try_sio, ndx);
+}
+
+static inline
+int au_test_robr_shwh(struct super_block *sb, const struct qstr *name)
+{
+       if (unlikely(!au_opt_test(au_mntflags(sb), SHWH)
+                    && !strncmp(name->name, AUFS_WH_PFX, AUFS_WH_PFX_LEN)))
+               return -EPERM;
+       return 0;
+}
+#endif /* CONFIG_AUFS_ROBR */
+
+#endif /* __KERNEL__ */
+#endif /* __AUFS_WHOUT_H__ */
diff -urN linux/fs/aufs/wkq.c linux-aufs/fs/aufs/wkq.c
--- linux/fs/aufs/wkq.c 1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/wkq.c    2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,343 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * workqueue for asynchronous/super-io/delegated operations
+ *
+ * $Id$
+ */
+
+#include <linux/module.h>
+#include "aufs.h"
+
+struct au_wkq *au_wkq;
+
+
+
+struct au_wkinfo {
+       struct work_struct wk;
+       struct super_block *sb;
+
+       unsigned int flags;
+       struct cred cred;
+
+       au_wkq_func_t func;
+       void *args;
+
+       atomic_t *busyp;
+       struct completion *comp;
+};
+
+/* ---------------------------------------------------------------------- */
+
+#ifdef CONFIG_AUFS_DLGT
+static void cred_store(struct cred *cred)
+{
+       cred = get_current_cred();
+}
+
+static void cred_revert(struct cred *cred)
+{
+       AuDebugOn(!au_test_wkq(current));
+       revert_creds(cred);
+}
+
+static void cred_switch(struct cred *old, struct cred *new)
+{
+       cred_store(old);
+       cred_revert(new);
+}
+
+static void dlgt_cred_store(unsigned int flags, struct au_wkinfo *wkinfo)
+{
+       if (au_ftest_wkq(flags, DLGT))
+               cred_store(&wkinfo->cred);
+}
+
+static void dlgt_func(struct au_wkinfo *wkinfo)
+{
+       if (!au_ftest_wkq(wkinfo->flags, DLGT))
+               wkinfo->func(wkinfo->args);
+       else {
+               struct cred cred;
+               cred_switch(&cred, &wkinfo->cred);
+               wkinfo->func(wkinfo->args);
+               cred_revert(&cred);
+       }
+}
+#else
+static void dlgt_cred_store(unsigned int flags, struct au_wkinfo *wkinfo)
+{
+       /* empty */
+}
+
+static void dlgt_func(struct au_wkinfo *wkinfo)
+{
+       wkinfo->func(wkinfo->args);
+}
+#endif /* CONFIG_AUFS_DLGT */
+
+/* ---------------------------------------------------------------------- */
+
+static void update_busy(struct au_wkq *wkq, struct au_wkinfo *wkinfo)
+{
+#ifdef CONFIG_AUFS_STAT
+       unsigned int new, old;
+
+       do {
+               new = atomic_read(wkinfo->busyp);
+               old = wkq->max_busy;
+               if (new <= old)
+                       break;
+       } while (cmpxchg(&wkq->max_busy, old, new) == old);
+#endif
+}
+
+static int enqueue(struct au_wkq *wkq, struct au_wkinfo *wkinfo)
+{
+       AuTraceEnter();
+
+       wkinfo->busyp = &wkq->busy;
+       update_busy(wkq, wkinfo);
+       if (au_ftest_wkq(wkinfo->flags, WAIT))
+               return !queue_work(wkq->q, &wkinfo->wk);
+       else
+               return !schedule_work(&wkinfo->wk);
+}
+
+static void do_wkq(struct au_wkinfo *wkinfo)
+{
+       unsigned int idle, n;
+       int i, idle_idx;
+
+       AuTraceEnter();
+
+       while (1) {
+               if (au_ftest_wkq(wkinfo->flags, WAIT)) {
+                       idle_idx = 0;
+                       idle = UINT_MAX;
+                       for (i = 0; i < aufs_nwkq; i++) {
+                               n = atomic_inc_return(&au_wkq[i].busy);
+                               if (n == 1 && !enqueue(au_wkq + i, wkinfo))
+                                       return; /* success */
+
+                               if (n < idle) {
+                                       idle_idx = i;
+                                       idle = n;
+                               }
+                               atomic_dec_return(&au_wkq[i].busy);
+                       }
+               } else
+                       idle_idx = aufs_nwkq;
+
+               atomic_inc_return(&au_wkq[idle_idx].busy);
+               if (!enqueue(au_wkq + idle_idx, wkinfo))
+                       return; /* success */
+
+               /* impossible? */
+               AuWarn1("failed to queue_work()\n");
+               yield();
+       }
+}
+
+static void wkq_func(struct work_struct *wk)
+{
+       struct au_wkinfo *wkinfo = container_of(wk, struct au_wkinfo, wk);
+
+       LKTRTrace("wkinfo{0x%x, %p, %p, %p}\n",
+                 wkinfo->flags, wkinfo->func, wkinfo->busyp, wkinfo->comp);
+
+       dlgt_func(wkinfo);
+       atomic_dec_return(wkinfo->busyp);
+       if (au_ftest_wkq(wkinfo->flags, WAIT))
+               complete(wkinfo->comp);
+       else {
+               kobject_put(&au_sbi(wkinfo->sb)->si_kobj);
+               module_put(THIS_MODULE);
+               kfree(wkinfo);
+       }
+}
+
+#if defined(CONFIG_4KSTACKS) || defined(Test4KSTACKS)
+#define AuWkqCompDeclare(name) struct completion *comp = NULL
+
+static int au_wkq_comp_alloc(struct au_wkinfo *wkinfo, struct completion **comp)
+{
+       *comp = kmalloc(sizeof(**comp), GFP_NOFS);
+       if (*comp) {
+               init_completion(*comp);
+               wkinfo->comp = *comp;
+               return 0;
+       }
+       return -ENOMEM;
+}
+
+static void au_wkq_comp_free(struct completion *comp)
+{
+       kfree(comp);
+}
+
+#else
+
+/* no braces */
+#define AuWkqCompDeclare(name) \
+       DECLARE_COMPLETION_ONSTACK(_ ## name); \
+       struct completion *comp = &_ ## name
+
+static int au_wkq_comp_alloc(struct au_wkinfo *wkinfo, struct completion **comp)
+{
+       wkinfo->comp = *comp;
+       return 0;
+}
+
+static void au_wkq_comp_free(struct completion *comp)
+{
+       /* empty */
+}
+#endif /* 4KSTACKS */
+
+static void au_wkq_run(struct au_wkinfo *wkinfo)
+{
+#if 1 /* tmp debug */
+       if (au_test_wkq(current))
+               au_dbg_blocked();
+#endif
+       AuDebugOn(au_test_wkq(current));
+
+       INIT_WORK(&wkinfo->wk, wkq_func);
+       dlgt_cred_store(wkinfo->flags, wkinfo);
+       do_wkq(wkinfo);
+}
+
+int au_wkq_wait(au_wkq_func_t func, void *args, int dlgt)
+{
+       int err;
+       AuWkqCompDeclare(comp);
+       struct au_wkinfo wkinfo = {
+               .flags  = AuWkq_WAIT,
+               .func   = func,
+               .args   = args
+       };
+
+       LKTRTrace("dlgt %d\n", dlgt);
+
+       err = au_wkq_comp_alloc(&wkinfo, &comp);
+       if (!err) {
+               if (dlgt)
+                       au_fset_wkq(wkinfo.flags, DLGT);
+               au_wkq_run(&wkinfo);
+               /* no timeout, no interrupt */
+               wait_for_completion(wkinfo.comp);
+               au_wkq_comp_free(comp);
+       }
+
+       AuTraceErr(err);
+       return err;
+
+}
+
+int au_wkq_nowait(au_wkq_func_t func, void *args, struct super_block *sb,
+                 int dlgt)
+{
+       int err;
+       struct au_wkinfo *wkinfo;
+
+       LKTRTrace("dlgt %d\n", dlgt);
+       AuDebugOn(!sb);
+
+       atomic_inc_return(&au_sbi(sb)->si_nowait.nw_len);
+
+       /*
+        * wkq_func() must free this wkinfo.
+        * it highly depends upon the implementation of workqueue.
+        */
+       err = 0;
+       wkinfo = kmalloc(sizeof(*wkinfo), GFP_NOFS);
+       if (wkinfo) {
+               wkinfo->sb = sb;
+               wkinfo->flags = !AuWkq_WAIT;
+               wkinfo->func = func;
+               wkinfo->args = args;
+               wkinfo->comp = NULL;
+               if (dlgt)
+                       au_fset_wkq(wkinfo->flags, DLGT);
+               kobject_get(&au_sbi(sb)->si_kobj);
+               __module_get(THIS_MODULE);
+
+               au_wkq_run(wkinfo);
+       } else {
+               err = -ENOMEM;
+               atomic_dec_return(&au_sbi(sb)->si_nowait.nw_len);
+       }
+
+       AuTraceErr(err);
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+void au_wkq_fin(void)
+{
+       int i;
+
+       AuTraceEnter();
+
+       for (i = 0; i < aufs_nwkq; i++)
+               if (au_wkq[i].q && !IS_ERR(au_wkq[i].q))
+                       destroy_workqueue(au_wkq[i].q);
+       kfree(au_wkq);
+}
+
+int __init au_wkq_init(void)
+{
+       int err, i;
+       struct au_wkq *nowaitq;
+
+       LKTRTrace("%d\n", aufs_nwkq);
+
+       /* '+1' is for accounting  of nowait queue */
+       err = -ENOMEM;
+       au_wkq = kcalloc(aufs_nwkq + 1, sizeof(*au_wkq), GFP_NOFS);
+       if (unlikely(!au_wkq))
+               goto out;
+
+       err = 0;
+       for (i = 0; i < aufs_nwkq; i++) {
+               au_wkq[i].q = create_singlethread_workqueue(AUFS_WKQ_NAME);
+               if (au_wkq[i].q && !IS_ERR(au_wkq[i].q)) {
+                       atomic_set(&au_wkq[i].busy, 0);
+                       au_wkq_max_busy_init(au_wkq + i);
+                       continue;
+               }
+
+               err = PTR_ERR(au_wkq[i].q);
+               au_wkq_fin();
+               break;
+       }
+
+       /* nowait accounting */
+       nowaitq = au_wkq + aufs_nwkq;
+       atomic_set(&nowaitq->busy, 0);
+       au_wkq_max_busy_init(nowaitq);
+       nowaitq->q = NULL;
+       /* smp_mb(); */ /* atomic_set */
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
diff -urN linux/fs/aufs/wkq.h linux-aufs/fs/aufs/wkq.h
--- linux/fs/aufs/wkq.h 1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/wkq.h    2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,128 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * workqueue for asynchronous/super-io/delegated operations
+ *
+ * $Id$
+ */
+
+#ifndef __AUFS_WKQ_H__
+#define __AUFS_WKQ_H__
+
+#ifdef __KERNEL__
+
+#include <linux/fs.h>
+#include <linux/sched.h>
+#include <linux/workqueue.h>
+#include <linux/aufs_type.h>
+
+/* ---------------------------------------------------------------------- */
+
+/* internal workqueue named AUFS_WKQ_NAME */
+struct au_wkq {
+       struct workqueue_struct *q;
+
+       /* balancing */
+       atomic_t                busy;
+
+       /* accounting */
+#ifdef CONFIG_AUFS_STAT
+       unsigned int            max_busy;
+#endif
+};
+
+/*
+ * in the next operation, wait for the 'nowait' tasks in system-wide workqueue
+ */
+struct au_nowait_tasks {
+       atomic_t                nw_len;
+       wait_queue_head_t       nw_wq;
+};
+
+/* ---------------------------------------------------------------------- */
+
+extern struct au_wkq *au_wkq;
+typedef void (*au_wkq_func_t)(void *args);
+
+/* wkq flags */
+#define AuWkq_WAIT     1
+#define AuWkq_DLGT     (1 << 1)
+#define au_ftest_wkq(flags, name)      ((flags) & AuWkq_##name)
+#define au_fset_wkq(flags, name)       { (flags) |= AuWkq_##name; }
+#define au_fclr_wkq(flags, name)       { (flags) &= ~AuWkq_##name; }
+#ifndef CONFIG_AUFS_DLGT
+#undef AuWkq_DLGT
+#define AuWkq_DLGT     0
+#endif
+
+int au_wkq_wait(au_wkq_func_t func, void *args, int dlgt);
+int au_wkq_nowait(au_wkq_func_t func, void *args, struct super_block *sb,
+                 int dlgt);
+int __init au_wkq_init(void);
+void au_wkq_fin(void);
+
+/* ---------------------------------------------------------------------- */
+
+static inline int au_test_nowait_wkq(struct task_struct *tsk)
+{
+       static const char *p = "events";
+       return !tsk->mm && !strncmp(tsk->comm, p, strlen(p));
+}
+
+static inline int au_test_wkq(struct task_struct *tsk)
+{
+       return !tsk->mm && !strcmp(tsk->comm, AUFS_WKQ_NAME);
+#if 0 /* reserved for future use, per-cpu workqueue */
+       return !tsk->mm
+               && !memcmp(tsk->comm, AUFS_WKQ_NAME "/",
+                          sizeof(AUFS_WKQ_NAME));
+#endif
+}
+
+static inline void au_wkq_max_busy_init(struct au_wkq *wkq)
+{
+#ifdef CONFIG_AUFS_STAT
+       wkq->max_busy = 0;
+#endif
+}
+
+/* todo: memory barrier? */
+static inline void au_nwt_init(struct au_nowait_tasks *nwt)
+{
+       atomic_set(&nwt->nw_len, 0);
+       smp_mb(); /* atomic_set */
+       init_waitqueue_head(&nwt->nw_wq);
+}
+
+static inline void au_nwt_done(struct au_nowait_tasks *nwt)
+{
+       AuTraceEnter();
+
+       if (!atomic_dec_return(&nwt->nw_len))
+               wake_up_all(&nwt->nw_wq);
+}
+
+static inline int au_nwt_flush(struct au_nowait_tasks *nwt)
+{
+       wait_event(nwt->nw_wq, !atomic_read(&nwt->nw_len));
+       return 0;
+}
+
+#endif /* __KERNEL__ */
+#endif /* __AUFS_WKQ_H__ */
diff -urN linux/fs/aufs/xino.c linux-aufs/fs/aufs/xino.c
--- linux/fs/aufs/xino.c        1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/fs/aufs/xino.c   2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,1268 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ * external inode number translation table and bitmap
+ *
+ * $Id$
+ */
+
+#include <linux/uaccess.h>
+#include "aufs.h"
+
+/* ---------------------------------------------------------------------- */
+
+ssize_t xino_fread(au_readf_t func, struct file *file, void *buf, size_t size,
+                  loff_t *pos)
+{
+       ssize_t err;
+       mm_segment_t oldfs;
+
+       LKTRTrace("%.*s, sz %zu, *pos %lld\n",
+                 AuDLNPair(file->f_dentry), size, *pos);
+
+       oldfs = get_fs();
+       set_fs(KERNEL_DS);
+       do {
+               /* todo: signal_pending? */
+               err = func(file, (char __user *)buf, size, pos);
+       } while (err == -EAGAIN || err == -EINTR);
+       set_fs(oldfs);
+
+#if 0 /* reserved for future use */
+       if (err > 0)
+               fsnotify_access(file->f_dentry);
+#endif
+
+       AuTraceErr(err);
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static ssize_t do_xino_fwrite(au_writef_t func, struct file *file, void *buf,
+                             size_t size, loff_t *pos)
+{
+       ssize_t err;
+       mm_segment_t oldfs;
+
+       lockdep_off();
+       oldfs = get_fs();
+       set_fs(KERNEL_DS);
+       do {
+               /* todo: signal_pending? */
+               err = func(file, (const char __user *)buf, size, pos);
+       } while (err == -EAGAIN || err == -EINTR);
+       set_fs(oldfs);
+       lockdep_on();
+
+       if (err >= 0)
+               au_update_fuse_h_inode(file->f_vfsmnt, file->f_dentry);
+       /*ignore*/
+
+#if 0 /* reserved for future use */
+       if (err > 0)
+               fsnotify_modify(file->f_dentry);
+#endif
+
+       AuTraceErr(err);
+       return err;
+}
+
+struct do_xino_fwrite_args {
+       ssize_t *errp;
+       au_writef_t func;
+       struct file *file;
+       void *buf;
+       size_t size;
+       loff_t *pos;
+};
+
+static void call_do_xino_fwrite(void *args)
+{
+       struct do_xino_fwrite_args *a = args;
+       *a->errp = do_xino_fwrite(a->func, a->file, a->buf, a->size, a->pos);
+}
+
+ssize_t xino_fwrite(au_writef_t func, struct file *file, void *buf, size_t size,
+                   loff_t *pos)
+{
+       ssize_t err;
+
+       LKTRTrace("%.*s, sz %zu, *pos %lld\n",
+                 AuDLNPair(file->f_dentry), size, *pos);
+
+       /* todo: signal block and no wkq? */
+       /*
+        * it breaks RLIMIT_FSIZE and normal user's limit,
+        * users should care about quota and real 'filesystem full.'
+        */
+       if (!au_test_wkq(current)) {
+               int wkq_err;
+               struct do_xino_fwrite_args args = {
+                       .errp   = &err,
+                       .func   = func,
+                       .file   = file,
+                       .buf    = buf,
+                       .size   = size,
+                       .pos    = pos
+               };
+               wkq_err = au_wkq_wait(call_do_xino_fwrite, &args, /*dlgt*/0);
+               if (unlikely(wkq_err))
+                       err = wkq_err;
+       } else
+               err = do_xino_fwrite(func, file, buf, size, pos);
+
+       AuTraceErr(err);
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+struct xino_do_trunc_args {
+       struct super_block *sb;
+       struct au_branch *br;
+};
+
+static void xino_do_trunc(void *_args)
+{
+       struct xino_do_trunc_args *args = _args;
+       struct super_block *sb;
+       aufs_bindex_t bindex;
+       int err;
+       struct file *file;
+       struct inode *dir;
+       struct au_sbinfo *sbinfo;
+
+       err = 0;
+       sb = args->sb;
+       dir = sb->s_root->d_inode;
+       si_noflush_write_lock(sb);
+       ii_read_lock_parent(dir);
+       bindex = au_br_index(sb, args->br->br_id);
+       AuDebugOn(bindex < 0);
+       err = au_xino_trunc(sb, bindex);
+       if (unlikely(err))
+               goto out;
+
+       file = args->br->br_xino.xi_file;
+       au_update_fuse_h_inode(args->br->br_mnt, file->f_dentry); /*ignore*/
+       if (file->f_dentry->d_inode->i_blocks >= args->br->br_xino_upper)
+               args->br->br_xino_upper += AUFS_XINO_TRUNC_STEP;
+
+ out:
+       ii_read_unlock(dir);
+       if (unlikely(err))
+               AuWarn("err b%d, (%d)\n", bindex, err);
+       atomic_dec_return(&args->br->br_xino_running);
+       au_br_put(args->br);
+       sbinfo = au_sbi(sb);
+       au_nwt_done(&sbinfo->si_nowait);
+       si_write_unlock(sb);
+       kfree(args);
+}
+
+static void xino_try_trunc(struct super_block *sb, struct au_branch *br)
+{
+       struct xino_do_trunc_args *args;
+       struct au_sbinfo *sbinfo;
+       struct file *file = br->br_xino.xi_file;
+       int wkq_err;
+
+       au_update_fuse_h_inode(br->br_mnt, file->f_dentry); /*ignore*/
+       if (file->f_dentry->d_inode->i_blocks < br->br_xino_upper)
+               return;
+       if (atomic_inc_return(&br->br_xino_running) > 1)
+               goto out;
+
+       /* lock and kfree() will be called in trunc_xino() */
+       args = kmalloc(sizeof(*args), GFP_NOFS);
+       if (unlikely(!args)) {
+               AuErr1("no memory\n");
+               goto out_args;
+       }
+
+       sbinfo = au_sbi(sb);
+       au_br_get(br);
+       args->sb = sb;
+       args->br = br;
+       wkq_err = au_wkq_nowait(xino_do_trunc, args, sb, /*dlgt*/0);
+       if (!wkq_err)
+               return; /* success */
+
+       AuErr("wkq %d\n", wkq_err);
+       au_br_put(br);
+
+ out_args:
+       kfree(args);
+ out:
+       atomic_dec_return(&br->br_xino_running);
+}
+
+/* ---------------------------------------------------------------------- */
+
+static int au_xino_do_write(au_writef_t write, struct file *file,
+                           ino_t h_ino, struct au_xino_entry *xinoe)
+{
+       loff_t pos;
+       ssize_t sz;
+
+       AuTraceEnter();
+
+       pos = h_ino;
+       if (unlikely(Au_LOFF_MAX / sizeof(*xinoe) - 1 < pos)) {
+               AuIOErr1("too large hi%lu\n", (unsigned long)h_ino);
+               return -EFBIG;
+       }
+       pos *= sizeof(*xinoe);
+       sz = xino_fwrite(write, file, xinoe, sizeof(*xinoe), &pos);
+       if (sz == sizeof(*xinoe))
+               return 0; /* success */
+
+       AuIOErr("write failed (%zd)\n", sz);
+       return -EIO;
+}
+
+/*
+ * write @ino to the xinofile for the specified branch{@sb, @bindex}
+ * at the position of @_ino.
+ * when @ino is zero, it is written to the xinofile and means no entry.
+ */
+int au_xino_write(struct super_block *sb, aufs_bindex_t bindex, ino_t h_ino,
+                 struct au_xino_entry *xinoe)
+{
+       int err;
+       struct file *file;
+       struct au_branch *br;
+       unsigned int mnt_flags;
+
+       LKTRTrace("b%d, hi%lu, i%lu\n",
+                 bindex, (unsigned long)h_ino, (unsigned long)xinoe->ino);
+       BUILD_BUG_ON(sizeof(long long) != sizeof(Au_LOFF_MAX)
+                    || ((loff_t)-1) > 0);
+
+       mnt_flags = au_mntflags(sb);
+       if (!au_opt_test_xino(mnt_flags))
+               return 0;
+
+       br = au_sbr(sb, bindex);
+       file = br->br_xino.xi_file;
+       AuDebugOn(!file);
+
+       err = au_xino_do_write(au_sbi(sb)->si_xwrite, file, h_ino, xinoe);
+       if (!err) {
+               if (au_opt_test(mnt_flags, TRUNC_XINO)
+                   && au_test_trunc_xino(br->br_mnt->mnt_sb))
+                       xino_try_trunc(sb, br);
+               return 0; /* success */
+       }
+
+       AuIOErr("write failed (%d)\n", err);
+       return -EIO;
+}
+
+/* ---------------------------------------------------------------------- */
+
+static const int page_bits = (int)PAGE_SIZE * BITS_PER_BYTE;
+static ino_t xib_calc_ino(unsigned long pindex, int bit)
+{
+       ino_t ino;
+
+       AuDebugOn(bit < 0 || page_bits <= bit);
+       ino = AUFS_FIRST_INO + pindex * page_bits + bit;
+       return ino;
+}
+
+static void xib_calc_bit(ino_t ino, unsigned long *pindex, int *bit)
+{
+       AuDebugOn(ino < AUFS_FIRST_INO);
+       ino -= AUFS_FIRST_INO;
+       *pindex = ino / page_bits;
+       *bit = ino % page_bits;
+}
+
+static int xib_pindex(struct super_block *sb, unsigned long pindex)
+{
+       int err;
+       struct au_sbinfo *sbinfo;
+       loff_t pos;
+       ssize_t sz;
+       struct file *xib;
+       unsigned long *p;
+
+       LKTRTrace("pindex %lu\n", pindex);
+       sbinfo = au_sbi(sb);
+       MtxMustLock(&sbinfo->si_xib_mtx);
+       AuDebugOn(pindex > ULONG_MAX / PAGE_SIZE
+                 || !au_opt_test_xino(sbinfo->si_mntflags));
+
+       if (pindex == sbinfo->si_xib_last_pindex)
+               return 0;
+
+       xib = sbinfo->si_xib;
+       p = sbinfo->si_xib_buf;
+       pos = sbinfo->si_xib_last_pindex;
+       pos *= PAGE_SIZE;
+       sz = xino_fwrite(sbinfo->si_xwrite, xib, p, PAGE_SIZE, &pos);
+       if (unlikely(sz != PAGE_SIZE))
+               goto out;
+
+       pos = pindex;
+       pos *= PAGE_SIZE;
+       if (i_size_read(xib->f_dentry->d_inode) >= pos + PAGE_SIZE)
+               sz = xino_fread(sbinfo->si_xread, xib, p, PAGE_SIZE, &pos);
+       else {
+               memset(p, 0, PAGE_SIZE);
+               sz = xino_fwrite(sbinfo->si_xwrite, xib, p, PAGE_SIZE, &pos);
+       }
+       if (sz == PAGE_SIZE) {
+               sbinfo->si_xib_last_pindex = pindex;
+               return 0; /* success */
+       }
+
+ out:
+       AuIOErr1("write failed (%zd)\n", sz);
+       err = sz;
+       if (sz >= 0)
+               err = -EIO;
+       AuTraceErr(err);
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+int au_xino_write0(struct super_block *sb, aufs_bindex_t bindex, ino_t h_ino,
+                  ino_t ino)
+{
+       int err, bit;
+       unsigned long pindex;
+       struct au_sbinfo *sbinfo;
+       struct au_xino_entry xinoe = {
+               .ino    = 0
+       };
+
+       LKTRTrace("b%d, hi%lu, i%lu\n",
+                 bindex, (unsigned long)h_ino, (unsigned long)ino);
+
+       if (!au_opt_test_xino(au_mntflags(sb)))
+               return 0;
+
+       err = 0;
+       sbinfo = au_sbi(sb);
+       if (ino) {
+               AuDebugOn(ino < AUFS_FIRST_INO);
+               xib_calc_bit(ino, &pindex, &bit);
+               AuDebugOn(page_bits <= bit);
+               mutex_lock(&sbinfo->si_xib_mtx);
+               err = xib_pindex(sb, pindex);
+               if (!err) {
+                       clear_bit(bit, sbinfo->si_xib_buf);
+                       sbinfo->si_xib_next_bit = bit;
+               }
+               mutex_unlock(&sbinfo->si_xib_mtx);
+       }
+
+       if (!err)
+               err = au_xino_write(sb, bindex, h_ino, &xinoe);
+       return err;
+}
+
+ino_t au_xino_new_ino(struct super_block *sb)
+{
+       ino_t ino;
+       struct au_sbinfo *sbinfo;
+       int free_bit, err;
+       unsigned long *p, pindex, ul, pend;
+       struct file *file;
+
+       AuTraceEnter();
+
+       if (!au_opt_test_xino(au_mntflags(sb)))
+               return iunique(sb, AUFS_FIRST_INO);
+
+       sbinfo = au_sbi(sb);
+       mutex_lock(&sbinfo->si_xib_mtx);
+       p = sbinfo->si_xib_buf;
+       free_bit = sbinfo->si_xib_next_bit;
+       if (free_bit < page_bits && !test_bit(free_bit, p))
+               goto out; /* success */
+       free_bit = find_first_zero_bit(p, page_bits);
+       if (free_bit < page_bits)
+               goto out; /* success */
+
+       pindex = sbinfo->si_xib_last_pindex;
+       for (ul = pindex - 1; ul < ULONG_MAX; ul--) {
+               err = xib_pindex(sb, ul);
+               if (unlikely(err))
+                       goto out_err;
+               free_bit = find_first_zero_bit(p, page_bits);
+               if (free_bit < page_bits)
+                       goto out; /* success */
+       }
+
+       file = sbinfo->si_xib;
+       pend = i_size_read(file->f_dentry->d_inode) / PAGE_SIZE;
+       for (ul = pindex + 1; ul <= pend; ul++) {
+               err = xib_pindex(sb, ul);
+               if (unlikely(err))
+                       goto out_err;
+               free_bit = find_first_zero_bit(p, page_bits);
+               if (free_bit < page_bits)
+                       goto out; /* success */
+       }
+       BUG();
+
+ out:
+       set_bit(free_bit, p);
+       sbinfo->si_xib_next_bit++;
+       pindex = sbinfo->si_xib_last_pindex;
+       mutex_unlock(&sbinfo->si_xib_mtx);
+       ino = xib_calc_ino(pindex, free_bit);
+       LKTRTrace("i%lu\n", (unsigned long)ino);
+       return ino;
+ out_err:
+       mutex_unlock(&sbinfo->si_xib_mtx);
+       LKTRTrace("i0\n");
+       return 0;
+}
+
+/*
+ * read @ino from xinofile for the specified branch{@sb, @bindex}
+ * at the position of @h_ino.
+ * if @ino does not exist and @do_new is true, get new one.
+ */
+int au_xino_read(struct super_block *sb, aufs_bindex_t bindex, ino_t h_ino,
+                struct au_xino_entry *xinoe)
+{
+       int err;
+       struct file *file;
+       loff_t pos;
+       ssize_t sz;
+       struct au_sbinfo *sbinfo;
+
+       LKTRTrace("b%d, hi%lu\n", bindex, (unsigned long)h_ino);
+
+       xinoe->ino = 0;
+       if (!au_opt_test_xino(au_mntflags(sb)))
+               return 0; /* no ino */
+
+       err = 0;
+       sbinfo = au_sbi(sb);
+       pos = h_ino;
+       if (unlikely(Au_LOFF_MAX / sizeof(*xinoe) - 1 < pos)) {
+               AuIOErr1("too large hi%lu\n", (unsigned long)h_ino);
+               return -EFBIG;
+       }
+       pos *= sizeof(*xinoe);
+
+       file = au_sbr(sb, bindex)->br_xino.xi_file;
+       AuDebugOn(!file);
+       if (i_size_read(file->f_dentry->d_inode) < pos + sizeof(*xinoe))
+               return 0; /* no ino */
+
+       sz = xino_fread(sbinfo->si_xread, file, xinoe, sizeof(*xinoe), &pos);
+       if (sz == sizeof(*xinoe))
+               return 0; /* success */
+
+       err = sz;
+       if (unlikely(sz >= 0)) {
+               err = -EIO;
+               AuIOErr("xino read error (%zd)\n", sz);
+       }
+
+       AuTraceErr(err);
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+struct file *au_xino_create(struct super_block *sb, char *fname, int silent)
+{
+       struct file *file;
+       int err;
+       struct dentry *h_parent;
+       struct inode *h_dir;
+       struct vfsub_args vargs;
+
+       LKTRTrace("%s\n", fname);
+
+       /*
+        * at mount-time, and the xino file is the default path,
+        * hinotify is disabled so we have no inotify events to ignore.
+        * when a user specified the xino, we cannot get au_hdir to be ignored.
+        */
+       vfsub_args_init(&vargs, /*ign*/NULL, /*dlgt*/0, 0);
+       file = vfsub_filp_open(fname, O_RDWR | O_CREAT | O_EXCL | O_LARGEFILE,
+                              S_IRUGO | S_IWUGO);
+       if (IS_ERR(file)) {
+               if (!silent)
+                       AuErr("open %s(%ld)\n", fname, PTR_ERR(file));
+               return file;
+       }
+
+       /* keep file count */
+       h_parent = dget_parent(file->f_dentry);
+       h_dir = h_parent->d_inode;
+       mutex_lock_nested(&h_dir->i_mutex, AuLsc_I_PARENT);
+       /* mnt_want_write() is unnecessary here */
+       err = vfsub_unlink(h_dir, file->f_dentry, &vargs);
+       mutex_unlock(&h_dir->i_mutex);
+       dput(h_parent);
+       if (unlikely(err)) {
+               if (!silent)
+                       AuErr("unlink %s(%d)\n", fname, err);
+               goto out;
+       }
+
+       if (sb != file->f_dentry->d_sb)
+               return file; /* success */
+
+       if (!silent)
+               AuErr("%s must be outside\n", fname);
+       err = -EINVAL;
+
+ out:
+       fput(file);
+       file = ERR_PTR(err);
+       return file;
+}
+
+/*
+ * find another branch who is on the same filesystem of the specified
+ * branch{@btgt}. search until @bend.
+ */
+static int is_sb_shared(struct super_block *sb, aufs_bindex_t btgt,
+                       aufs_bindex_t bend)
+{
+       aufs_bindex_t bindex;
+       struct super_block *tgt_sb = au_sbr_sb(sb, btgt);
+
+       for (bindex = 0; bindex < btgt; bindex++)
+               if (unlikely(tgt_sb == au_sbr_sb(sb, bindex)))
+                       return bindex;
+       for (bindex++; bindex <= bend; bindex++)
+               if (unlikely(tgt_sb == au_sbr_sb(sb, bindex)))
+                       return bindex;
+       return -1;
+}
+
+/*
+ * create a new xinofile at the same place/path as @base_file.
+ */
+struct file *au_xino_create2(struct super_block *sb, struct file *base_file,
+                            struct file *copy_src)
+{
+       struct file *file;
+       int err;
+       struct dentry *base, *dentry, *parent;
+       struct inode *dir, *inode;
+       struct qstr *name;
+       struct au_hinode *hdir;
+       struct au_branch *br;
+       aufs_bindex_t bindex;
+       struct au_hin_ignore ign;
+       struct vfsub_args vargs;
+       struct au_ndx ndx = {
+               .nfsmnt = NULL,
+               .flags  = 0,
+               .nd     = NULL,
+               /* .br  = NULL */
+       };
+
+       base = base_file->f_dentry;
+       LKTRTrace("%.*s\n", AuDLNPair(base));
+       parent = base->d_parent; /* dir inode is locked */
+       dir = parent->d_inode;
+       IMustLock(dir);
+
+       file = ERR_PTR(-EINVAL);
+       if (unlikely(au_test_nfs(parent->d_sb)
+                   || au_test_ecryptfs(parent->d_sb)))
+               goto out;
+
+       /* do not superio, nor NFS. */
+       name = &base->d_name;
+       dentry = au_lkup_one(name->name, parent, name->len, &ndx);
+       if (IS_ERR(dentry)) {
+               file = (void *)dentry;
+               AuErr("%.*s lookup err %ld\n", AuLNPair(name), PTR_ERR(dentry));
+               goto out;
+       }
+
+       hdir = NULL;
+       br = au_xino_def_br(au_sbi(sb));
+       if (br) {
+               bindex = au_find_bindex(sb, br);
+               if (bindex >= 0)
+                       hdir = au_hi(sb->s_root->d_inode, bindex);
+       }
+       vfsub_args_init(&vargs, &ign, 0, 0);
+       vfsub_ign_hinode(&vargs, IN_CREATE, hdir);
+       /* no need to mnt_want_write() since we call dentry_open() later */
+       err = vfsub_create(dir, dentry, S_IRUGO | S_IWUGO, NULL, &vargs);
+       if (unlikely(err)) {
+               file = ERR_PTR(err);
+               AuErr("%.*s create err %d\n", AuLNPair(name), err);
+               goto out_dput;
+       }
+       file = dentry_open(dget(dentry), mntget(base_file->f_vfsmnt),
+                          O_RDWR | O_CREAT | O_EXCL | O_LARGEFILE, base_file->f_cred);
+       if (IS_ERR(file)) {
+               AuErr("%.*s open err %ld\n", AuLNPair(name), PTR_ERR(file));
+               goto out_dput;
+       }
+       vfsub_args_reinit(&vargs);
+       vfsub_ign_hinode(&vargs, IN_DELETE, hdir);
+       err = vfsub_unlink(dir, dentry, &vargs);
+       if (unlikely(err)) {
+               AuErr("%.*s unlink err %d\n", AuLNPair(name), err);
+               goto out_fput;
+       }
+
+       if (copy_src) {
+               inode = copy_src->f_dentry->d_inode;
+               err = au_copy_file(file, copy_src, i_size_read(inode),
+                                  hdir, sb, &vargs);
+               if (unlikely(err)) {
+                       AuErr("%.*s copy err %d\n", AuLNPair(name), err);
+                       goto out_fput;
+               }
+       }
+       goto out_dput; /* success */
+
+ out_fput:
+       fput(file);
+       file = ERR_PTR(err);
+ out_dput:
+       dput(dentry);
+ out:
+       AuTraceErrPtr(file);
+       return file;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * initialize the xinofile for the specified branch{@sb, @bindex}
+ * at the place/path where @base_file indicates.
+ * test whether another branch is on the same filesystem or not,
+ * if @do_test is true.
+ */
+int au_xino_br(struct super_block *sb, struct au_branch *br, ino_t h_ino,
+              struct file *base_file, int do_test)
+{
+       int err;
+       struct au_branch *shared_br;
+       aufs_bindex_t bshared, bend, bindex;
+       unsigned char do_create;
+       struct inode *dir;
+       struct au_xino_entry xinoe;
+       struct dentry *parent;
+       struct file *file;
+       struct super_block *tgt_sb;
+
+       LKTRTrace("base_file %p, do_test %d\n", base_file, do_test);
+       SiMustWriteLock(sb);
+       AuDebugOn(!au_opt_test_xino(au_mntflags(sb)));
+       AuDebugOn(br->br_xino.xi_file);
+
+       do_create = 1;
+       bshared = -1;
+       shared_br = NULL;
+       bend = au_sbend(sb);
+       if (do_test) {
+               tgt_sb = br->br_mnt->mnt_sb;
+               for (bindex = 0; bindex <= bend; bindex++)
+                       if (tgt_sb == au_sbr_sb(sb, bindex)) {
+                               bshared = bindex;
+                               break;
+                       }
+       }
+       if (bshared >= 0) {
+               shared_br = au_sbr(sb, bshared);
+               do_create = !shared_br->br_xino.xi_file;
+       }
+
+       if (do_create) {
+               parent = dget_parent(base_file->f_dentry);
+               dir = parent->d_inode;
+               mutex_lock_nested(&dir->i_mutex, AuLsc_I_PARENT);
+               /* mnt_want_write() is unnecessary here */
+               file = au_xino_create2(sb, base_file, NULL);
+               mutex_unlock(&dir->i_mutex);
+               dput(parent);
+               err = PTR_ERR(file);
+               if (IS_ERR(file))
+                       goto out;
+               br->br_xino.xi_file = file;
+       } else {
+               br->br_xino.xi_file = shared_br->br_xino.xi_file;
+               get_file(br->br_xino.xi_file);
+       }
+
+       xinoe.ino = AUFS_ROOT_INO;
+#if 0 /* reserved for future use */
+       xinoe.h_gen = h_inode->i_generation;
+       WARN_ON(xinoe.h_gen == AuXino_INVALID_HGEN);
+#endif
+       err = au_xino_do_write(au_sbi(sb)->si_xwrite, br->br_xino.xi_file,
+                              h_ino, &xinoe);
+       if (!err)
+               return 0; /* success */
+
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+/* too slow */
+static int do_xib_restore(struct super_block *sb, struct file *file, void *page)
+{
+       int err, bit;
+       struct au_sbinfo *sbinfo;
+       au_readf_t func;
+       loff_t pos, pend;
+       ssize_t sz;
+       struct au_xino_entry *xinoe;
+       unsigned long pindex;
+
+       AuTraceEnter();
+       SiMustWriteLock(sb);
+
+       err = 0;
+       sbinfo = au_sbi(sb);
+       func = sbinfo->si_xread;
+       pend = i_size_read(file->f_dentry->d_inode);
+#ifdef CONFIG_AUFS_DEBUG
+       if (unlikely(pend > (1 << 22)))
+               AuWarn("testing a large xino file %lld\n", (long long)pend);
+#endif
+       pos = 0;
+       while (pos < pend) {
+               sz = xino_fread(func, file, page, PAGE_SIZE, &pos);
+               err = sz;
+               if (unlikely(sz <= 0))
+                       goto out;
+
+               err = 0;
+               for (xinoe = page; sz > 0; xinoe++, sz -= sizeof(xinoe)) {
+                       if (unlikely(xinoe->ino < AUFS_FIRST_INO))
+                               continue;
+
+                       xib_calc_bit(xinoe->ino, &pindex, &bit);
+                       AuDebugOn(page_bits <= bit);
+                       err = xib_pindex(sb, pindex);
+                       if (!err)
+                               set_bit(bit, sbinfo->si_xib_buf);
+                       else
+                               goto out;
+               }
+       }
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+static int xib_restore(struct super_block *sb)
+{
+       int err;
+       aufs_bindex_t bindex, bend;
+       void *page;
+
+       AuTraceEnter();
+
+       err = -ENOMEM;
+       page = (void *)__get_free_page(GFP_NOFS);
+       if (unlikely(!page))
+               goto out;
+
+       err = 0;
+       bend = au_sbend(sb);
+       for (bindex = 0; !err && bindex <= bend; bindex++)
+               if (!bindex || is_sb_shared(sb, bindex, bindex - 1) < 0)
+                       err = do_xib_restore
+                               (sb, au_sbr(sb, bindex)->br_xino.xi_file, page);
+               else
+                       LKTRTrace("b%d\n", bindex);
+       free_page((unsigned long)page);
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+int au_xib_trunc(struct super_block *sb)
+{
+       int err;
+       unsigned int mnt_flags;
+       ssize_t sz;
+       loff_t pos;
+       struct au_sbinfo *sbinfo;
+       unsigned long *p;
+       struct dentry *parent;
+       struct inode *dir;
+       struct file *file;
+
+       AuTraceEnter();
+       SiMustWriteLock(sb);
+
+       err = 0;
+       mnt_flags = au_mntflags(sb);
+       if (!au_opt_test_xino(mnt_flags))
+               goto out;
+
+       sbinfo = au_sbi(sb);
+       if (i_size_read(sbinfo->si_xib->f_dentry->d_inode) <= PAGE_SIZE)
+               goto out;
+       parent = dget_parent(sbinfo->si_xib->f_dentry);
+       dir = parent->d_inode;
+       mutex_lock_nested(&dir->i_mutex, AuLsc_I_PARENT);
+       /* mnt_want_write() is unnecessary here */
+       file = au_xino_create2(sb, sbinfo->si_xib, NULL);
+       mutex_unlock(&dir->i_mutex);
+       dput(parent);
+       err = PTR_ERR(file);
+       if (IS_ERR(file))
+               goto out;
+       fput(sbinfo->si_xib);
+       sbinfo->si_xib = file;
+
+       p = sbinfo->si_xib_buf;
+       memset(p, 0, PAGE_SIZE);
+       pos = 0;
+       sz = xino_fwrite(sbinfo->si_xwrite, sbinfo->si_xib, p, PAGE_SIZE, &pos);
+       if (unlikely(sz != PAGE_SIZE)) {
+               err = sz;
+               AuIOErr("err %d\n", err);
+               if (sz >= 0)
+                       err = -EIO;
+               goto out;
+       }
+
+       if (au_opt_test_xino(mnt_flags)) {
+               mutex_lock(&sbinfo->si_xib_mtx);
+               /* mnt_want_write() is unnecessary here */
+               err = xib_restore(sb);
+               mutex_unlock(&sbinfo->si_xib_mtx);
+#if 0 /* reserved for future use */
+       } else {
+               /* is it really safe? */
+               /* dont trust BKL */
+               AuDebugOn(!kernel_locked());
+               ino = AUFS_FIRST_INO;
+               list_for_each_entry(inode, &sb->s_inodes, i_sb_list)
+                       if (ino < inode->i_ino)
+                               ino = inode->i_ino;
+
+               /* make iunique to return larger than active max inode number */
+               iunique(sb, ino);
+               err = 0;
+#endif
+       }
+
+out:
+       AuTraceErr(err);
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * xino mount option handlers
+ */
+static au_readf_t find_readf(struct file *h_file)
+{
+       const struct file_operations *fop = h_file->f_op;
+
+       if (fop) {
+               if (fop->read)
+                       return fop->read;
+               if (fop->aio_read)
+                       return do_sync_read;
+       }
+       return ERR_PTR(-ENOSYS);
+}
+
+static au_writef_t find_writef(struct file *h_file)
+{
+       const struct file_operations *fop = h_file->f_op;
+
+       if (fop) {
+               if (fop->write)
+                       return fop->write;
+               if (fop->aio_write)
+                       return do_sync_write;
+       }
+       return ERR_PTR(-ENOSYS);
+}
+
+/* xino bitmap */
+static void xino_clear_xib(struct super_block *sb)
+{
+       struct au_sbinfo *sbinfo;
+
+       AuTraceEnter();
+       SiMustWriteLock(sb);
+
+       sbinfo = au_sbi(sb);
+       sbinfo->si_xread = NULL;
+       sbinfo->si_xwrite = NULL;
+       if (sbinfo->si_xib)
+               fput(sbinfo->si_xib);
+       sbinfo->si_xib = NULL;
+       free_page((unsigned long)sbinfo->si_xib_buf);
+       sbinfo->si_xib_buf = NULL;
+}
+
+static int au_xino_set_xib(struct super_block *sb, struct file *base)
+{
+       int err;
+       struct au_sbinfo *sbinfo;
+       struct file *file;
+       loff_t pos;
+
+       LKTRTrace("%.*s\n", AuDLNPair(base->f_dentry));
+       SiMustWriteLock(sb);
+
+       sbinfo = au_sbi(sb);
+       file = au_xino_create2(sb, base, sbinfo->si_xib);
+       err = PTR_ERR(file);
+       if (IS_ERR(file))
+               goto out;
+       if (sbinfo->si_xib)
+               fput(sbinfo->si_xib);
+       sbinfo->si_xib = file;
+       sbinfo->si_xread = find_readf(file);
+       AuDebugOn(IS_ERR(sbinfo->si_xread));
+       sbinfo->si_xwrite = find_writef(file);
+       AuDebugOn(IS_ERR(sbinfo->si_xwrite));
+
+       err = -ENOMEM;
+       if (!sbinfo->si_xib_buf)
+               sbinfo->si_xib_buf = (void *)get_zeroed_page(GFP_NOFS);
+       if (unlikely(!sbinfo->si_xib_buf))
+               goto out_unset;
+
+       sbinfo->si_xib_last_pindex = 0;
+       sbinfo->si_xib_next_bit = 0;
+
+       /* no need to lock for i_size_read() */
+       if (i_size_read(file->f_dentry->d_inode) < PAGE_SIZE) {
+               pos = 0;
+               err = xino_fwrite(sbinfo->si_xwrite, file, sbinfo->si_xib_buf,
+                                 PAGE_SIZE, &pos);
+               if (unlikely(err != PAGE_SIZE))
+                       goto out_free;
+       }
+       err = 0;
+       goto out; /* success */
+
+ out_free:
+       free_page((unsigned long)sbinfo->si_xib_buf);
+       sbinfo->si_xib_buf = NULL;
+       if (err >= 0)
+               err = -EIO;
+ out_unset:
+       fput(sbinfo->si_xib);
+       sbinfo->si_xib = NULL;
+       sbinfo->si_xread = NULL;
+       sbinfo->si_xwrite = NULL;
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+/* xino for each branch */
+static void xino_clear_br(struct super_block *sb)
+{
+       aufs_bindex_t bindex, bend;
+       struct au_branch *br;
+
+       AuTraceEnter();
+       SiMustWriteLock(sb);
+
+       bend = au_sbend(sb);
+       for (bindex = 0; bindex <= bend; bindex++) {
+               br = au_sbr(sb, bindex);
+               if (!br || !br->br_xino.xi_file)
+                       continue;
+
+               fput(br->br_xino.xi_file);
+               br->br_xino.xi_file = NULL;
+       }
+}
+
+static int au_xino_set_br(struct super_block *sb, struct file *base)
+{
+       int err;
+       aufs_bindex_t bindex, bend, bshared;
+       struct {
+               struct file *old, *new;
+       } *fpair, *p;
+       struct au_branch *br;
+       struct au_xino_entry xinoe;
+       struct inode *inode;
+       au_writef_t writef;
+
+       LKTRTrace("%.*s\n", AuDLNPair(base->f_dentry));
+       SiMustWriteLock(sb);
+
+       err = -ENOMEM;
+       bend = au_sbend(sb);
+       fpair = kcalloc(bend + 1, sizeof(*fpair), GFP_NOFS);
+       if (unlikely(!fpair))
+               goto out;
+
+       inode = sb->s_root->d_inode;
+       xinoe.ino = AUFS_ROOT_INO;
+       writef = au_sbi(sb)->si_xwrite;
+       for (bindex = 0, p = fpair; bindex <= bend; bindex++, p++) {
+               br = au_sbr(sb, bindex);
+               bshared = is_sb_shared(sb, bindex, bindex - 1);
+               if (bshared >= 0) {
+                       /* shared xino */
+                       *p = fpair[bshared];
+                       get_file(p->new);
+               }
+
+               if (!p->new) {
+                       /* new xino */
+                       p->old = br->br_xino.xi_file;
+                       p->new = au_xino_create2(sb, base, br->br_xino.xi_file);
+                       err = PTR_ERR(p->new);
+                       if (IS_ERR(p->new)) {
+                               p->new = NULL;
+                               goto out_pair;
+                       }
+               }
+
+               err = au_xino_do_write(writef, p->new,
+                                      au_h_iptr(inode, bindex)->i_ino, &xinoe);
+               if (unlikely(err))
+                       goto out_pair;
+       }
+
+       for (bindex = 0, p = fpair; bindex <= bend; bindex++, p++) {
+               br = au_sbr(sb, bindex);
+               AuDebugOn(p->old != br->br_xino.xi_file);
+               if (br->br_xino.xi_file)
+                       fput(br->br_xino.xi_file);
+               get_file(p->new);
+               br->br_xino.xi_file = p->new;
+       }
+
+ out_pair:
+       for (bindex = 0, p = fpair; bindex <= bend; bindex++, p++)
+               if (p->new)
+                       fput(p->new);
+               else
+                       break;
+       kfree(fpair);
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+void au_xino_clr(struct super_block *sb)
+{
+       struct au_sbinfo *sbinfo;
+
+       AuTraceEnter();
+       SiMustWriteLock(sb);
+
+       au_xigen_clr(sb);
+       xino_clear_xib(sb);
+       xino_clear_br(sb);
+       sbinfo = au_sbi(sb);
+       /* lvalue, do not call au_mntflags() */
+       au_opt_clr(sbinfo->si_mntflags, XINO);
+       au_xino_def_br_set(NULL, sbinfo);
+}
+
+int au_xino_set(struct super_block *sb, struct au_opt_xino *xino, int remount)
+{
+       int err, skip;
+       struct dentry *parent, *cur_parent;
+       struct qstr *dname, *cur_name;
+       struct file *cur_xino;
+       struct inode *dir;
+       struct au_sbinfo *sbinfo;
+
+       LKTRTrace("remount %d\n", remount);
+       SiMustWriteLock(sb);
+
+       err = 0;
+       sbinfo = au_sbi(sb);
+       parent = dget_parent(xino->file->f_dentry);
+       if (remount) {
+               skip = 0;
+               dname = &xino->file->f_dentry->d_name;
+               cur_xino = sbinfo->si_xib;
+               if (cur_xino) {
+                       cur_parent = dget_parent(cur_xino->f_dentry);
+                       cur_name = &cur_xino->f_dentry->d_name;
+                       skip = (cur_parent == parent
+                               && dname->len == cur_name->len
+                               && !memcmp(dname->name, cur_name->name,
+                                          dname->len));
+                       dput(cur_parent);
+               }
+               if (skip)
+                       goto out;
+       }
+
+       au_opt_set(sbinfo->si_mntflags, XINO);
+       au_xino_def_br_set(NULL, sbinfo);
+       dir = parent->d_inode;
+       mutex_lock_nested(&dir->i_mutex, AuLsc_I_PARENT);
+       /* mnt_want_write() is unnecessary here */
+       err = au_xino_set_xib(sb, xino->file);
+       if (!err)
+               err = au_xigen_set(sb, xino->file);
+       if (!err)
+               err = au_xino_set_br(sb, xino->file);
+       mutex_unlock(&dir->i_mutex);
+       if (!err)
+               goto out; /* success */
+
+       /* reset all */
+       AuIOErr("failed creating xino(%d).\n", err);
+
+ out:
+       dput(parent);
+       AuTraceErr(err);
+       return err;
+}
+
+int au_xino_trunc(struct super_block *sb, aufs_bindex_t bindex)
+{
+       int err;
+       struct au_branch *br;
+       struct file *new_xino;
+       struct super_block *h_sb;
+       aufs_bindex_t bi, bend;
+       struct dentry *parent;
+       struct inode *dir;
+
+       LKTRTrace("b%d\n", bindex);
+       SiMustWriteLock(sb);
+
+       err = -EINVAL;
+       bend = au_sbend(sb);
+       if (unlikely(bindex < 0 || bend < bindex))
+               goto out;
+       br = au_sbr(sb, bindex);
+       if (!br->br_xino.xi_file)
+               goto out;
+
+       parent = dget_parent(br->br_xino.xi_file->f_dentry);
+       dir = parent->d_inode;
+       mutex_lock_nested(&dir->i_mutex, AuLsc_I_PARENT);
+       /* mnt_want_write() is unnecessary here */
+       new_xino = au_xino_create2(sb, br->br_xino.xi_file,
+                                  br->br_xino.xi_file);
+       mutex_unlock(&dir->i_mutex);
+       dput(parent);
+       err = PTR_ERR(new_xino);
+       if (IS_ERR(new_xino))
+               goto out;
+       err = 0;
+       fput(br->br_xino.xi_file);
+       br->br_xino.xi_file = new_xino;
+
+       h_sb = br->br_mnt->mnt_sb;
+       for (bi = 0; bi <= bend; bi++) {
+               if (unlikely(bi == bindex))
+                       continue;
+               br = au_sbr(sb, bi);
+               if (br->br_mnt->mnt_sb != h_sb)
+                       continue;
+
+               fput(br->br_xino.xi_file);
+               br->br_xino.xi_file = new_xino;
+               get_file(new_xino);
+       }
+
+ out:
+       AuTraceErr(err);
+       return err;
+}
+
+/* ---------------------------------------------------------------------- */
+
+/*
+ * create a xinofile at the default place/path.
+ */
+struct file *au_xino_def(struct super_block *sb)
+{
+       struct file *file;
+       aufs_bindex_t bend, bindex, bwr;
+       char *page, *p;
+       struct path path;
+       struct au_branch *br;
+
+       AuTraceEnter();
+
+       bend = au_sbend(sb);
+       bwr = -1;
+       for (bindex = 0; bindex <= bend; bindex++) {
+               br = au_sbr(sb, bindex);
+               if (au_br_writable(br->br_perm)
+                   && !au_test_nfs(br->br_mnt->mnt_sb)
+                   && !au_test_ecryptfs(br->br_mnt->mnt_sb)) {
+                       bwr = bindex;
+                       break;
+               }
+       }
+
+       if (bwr >= 0) {
+               file = ERR_PTR(-ENOMEM);
+               page = __getname();
+               if (unlikely(!page))
+                       goto out;
+               path.mnt = au_sbr_mnt(sb, bwr);
+               path.dentry = au_h_dptr(sb->s_root, bwr);
+               p = d_path(&path, page, PATH_MAX - sizeof(AUFS_XINO_FNAME));
+               file = (void *)p;
+               if (!IS_ERR(p)) {
+                       strcat(p, "/" AUFS_XINO_FNAME);
+                       LKTRTrace("%s\n", p);
+                       file = au_xino_create(sb, p, /*silent*/0);
+                       if (!IS_ERR(file))
+                               au_xino_def_br_set(au_sbr(sb, bwr), au_sbi(sb));
+               }
+               __putname(page);
+       } else {
+               file = au_xino_create(sb, AUFS_XINO_DEFPATH, /*silent*/0);
+               if (unlikely(au_test_nfs(file->f_dentry->d_sb)
+                            || au_test_ecryptfs(file->f_dentry->d_sb))) {
+                       AuErr("xino or noxino option is required "
+                             "since %s is NFS\n", AUFS_XINO_DEFPATH);
+                       fput(file);
+                       file = ERR_PTR(-EINVAL);
+               }
+               if (!IS_ERR(file))
+                       au_xino_def_br_set(NULL, au_sbi(sb));
+       }
+
+ out:
+       AuTraceErrPtr(file);
+       return file;
+}
diff -urN linux/fs/Kconfig linux-aufs/fs/Kconfig
--- linux/fs/Kconfig    2009-01-05 11:42:15.000000000 +0100
+++ linux-aufs/fs/Kconfig       2009-03-12 17:02:25.753047602 +0100
@@ -1022,6 +1022,350 @@
        help
          If you say Y here, you can turn on debugging output from Unionfs.
 
+config AUFS
+       tristate "Another unionfs"
+       help
+       Aufs is a stackable unification filesystem such as Unionfs,
+       which unifies several directories and provides a merged single
+       directory.
+       In the early days, aufs was entirely re-designed and
+       re-implemented Unionfs Version 1.x series. After many original
+       ideas, approaches and improvements, it becomes totally
+       different from Unionfs while keeping the basic features.
+       See Unionfs for the basic features.
+
+if AUFS
+comment "These options are for "#UTS_RELEASE
+
+choice
+       prompt "Maximum number of branches"
+       default AUFS_BRANCH_MAX_127
+       help
+       Specifies the maximum number of branches (or member directories) in a
+       single aufs. The larger value consumes more system resources and has
+       an impact to performance.
+config AUFS_BRANCH_MAX_127
+       bool "127"
+       help
+       Specifies the maximum number of branches (or member directories) in a
+       single aufs. The larger value consumes more system resources and has
+       an impact to performance.
+config AUFS_BRANCH_MAX_511
+       bool "511"
+       help
+       Specifies the maximum number of branches (or member directories) in a
+       single aufs. The larger value consumes more system resources and has
+       an impact to performance.
+config AUFS_BRANCH_MAX_1023
+       bool "1023"
+       help
+       Specifies the maximum number of branches (or member directories) in a
+       single aufs. The larger value consumes more system resources and has
+       an impact to performance.
+# 128kb is available for kmalloc?
+config AUFS_BRANCH_MAX_32767
+       bool "32767"
+       help
+       Specifies the maximum number of branches (or member directories) in a
+       single aufs. The larger value consumes more system resources and has
+       an impact to performance.
+endchoice
+
+config AUFS_STAT
+       bool "Use <sysfs>/fs/aufs/stat"
+       depends on SYSFS
+       help
+       Shows some statistic data via <sysfs>/fs/aufs/stat.
+       See detail in aufs.5.
+
+comment "SYSFS and AUFS_STAT are disabled"
+       depends on SYSFS = n
+
+config AUFS_HINOTIFY
+       bool "Use inotify to detect actions on a branch"
+       depends on INOTIFY
+       help
+       If you want to modify files on branches directly, eg. bypassing aufs,
+       and want aufs to detect the changes of them fully, then enable this
+       option and use 'udba=inotify' mount option.
+       It will have a negative impact to the performance.
+       See detail in aufs.5.
+
+comment "INOTIFY and AUFS_HINOTIFY are disabled"
+       depends on INOTIFY = n
+
+config AUFS_EXPORT
+       bool "NFS-exportable aufs"
+       depends on (AUFS = y && EXPORTFS = y) || (AUFS = m && EXPORTFS)
+       help
+       If you want to export your mounted aufs, then enable this
+       option. There are several requirements for this configuration.
+       See detail in aufs.5.
+
+comment "EXPORTFS and AUFS_EXPORT are disabled"
+       depends on EXPORTFS = n
+
+comment "AUFS_EXPORT is disabled since EXPORTFS is a module but AUFS"
+       depends on EXPORTFS = m && AUFS = y
+
+# automatic configuration for internal use
+config AUFS_INO_T_64
+       bool # never appear on the menu
+       # typedef unsigned long/int __kernel_ino_t
+       # alpha and s390x are int
+       depends on 64BIT && !(ALPHA || S390)
+       default y
+
+config AUFS_ROBR
+       bool "Aufs as an readonly branch of another aufs mount"
+       help
+       If you want make your aufs to be a part of another aufs, then
+       enable this option. In other words, you can specify your aufs
+       path in 'br:' mount option for another aufs, but cannot
+       specify 'rw' as the branch permission.
+       It will have a negative impact to the performance.
+       See detail in aufs.5.
+
+config AUFS_DLGT
+       bool "Delegate the internal branch access the kernel thread"
+       help
+       If you want aufs to delegate
+       the internal access to the branches which is made by aufs, to
+       the kernel thread, in order to hide the access issued by your
+       application from your LSM or something or make your
+       application to be traced strictly by the task I/O accounting,
+       then enable this option and use 'dlgt' mount option.
+       It will have a negative impact to the performance.
+       See detail in aufs.5.
+
+# automatic configuration for internal use
+config AUFS_HIN_OR_DLGT
+       bool # never appear on the menu
+       depends on AUFS_HINOTIFY || AUFS_DLGT
+       default y
+       help
+       Automatic configuration for internal use.
+
+config AUFS_SHWH
+       bool "Show whiteouts"
+       help
+       If you want to make the whiteouts in aufs visible, then enable
+       this option and specify 'shwh' mount option. Although it may
+       sounds like philosophy or something, but in technically it
+       simply shows the name of whiteout with keeping its behaviour.
+
+# this is not in mainstream kernel
+config AUFS_RR_SQUASHFS
+       bool "Make squashfs branch RR (real readonly) by default"
+       default y
+       help
+       If you use squashfs or LZMA patched squashfs as an aufs branch
+       and want to set '=rr' to it by default, then enable this
+       configuration.
+       'rr' stands for real readonly and it optimizes some aspects of
+       'ro.'
+       See detail in aufs.5.
+
+config AUFS_SEC_PERM_PATCH
+       bool "sec_perm-2.6.24.patch was applied or not"
+       depends on AUFS = m
+       depends on SECURITY
+       help
+       If you build aufs as a module and enabled CONFIG_SECURITY,
+       then you need to apply the patch
+       'CVS_TREE/aufs/patch/sec_perm-2.6.24.patch' to your kernel
+       source, and enable this configuration.
+       The sec_perm-2.6.24.patch exports a kernel function
+       security_inode_permission() to modules.
+
+comment "SECURITY and AUFS_SEC_PERM_PATCH are disabled"
+       depends on SECURITY = n
+
+config AUFS_SPLICE_PATCH
+       bool "splice.patch for sendfile(2) and splice(2)"
+       help
+       If you use 'loopback mount' on a fs-image file, or use
+       splice(2) or sendfile(2) systemcall in aufs, then you need to
+       apply the patch 'CVS_TREE/aufs/patch/splice.patch' to your
+       kernel source, and enable this configuration.
+       The splice.patch makes the kernel function do_splice_to/from()
+       global and exports them to modules.
+
+config AUFS_LHASH_PATCH
+       bool "lhash.patch for NFS branch"
+       depends on NFS_FS
+       help
+       If you use mounted NFS as an aufs branch filesystem, then you
+       need to apply the patch 'CVS_TREE/aufs/patch/lhash.patch' (or
+       lhash-2.6.22.patch for linux-2.6.22 and later) to your kernel
+       source, and enable this configuration.
+       The patch file makes the kernel function __lookup_hash() global
+       and exports it to modules.
+
+comment "NFS_FS and AUFS_LHASH_PATCH are disabled"
+       depends on NFS_FS = n
+
+config AUFS_PUT_FILP_PATCH
+       bool "put_filp.patch for 'atomic open'"
+       depends on AUFS = m && NFS_V4
+       help
+       If you build aufs as a module and use a filesystem which
+       operates 'atomic open' (for instance NFSv4) as an aufs branch
+       filesystem, then you need to apply the patch
+       'CVS_TREE/aufs/patch/put_filp.patch' to your kernel source,
+       and enable this configuration.
+       The put_filp.patch exports a kernel function put_filp() to
+       modules.
+
+comment "NFS_V4 and AUFS_PUT_FILP_PATCH are disabled"
+       depends on NFS_V4 = n
+
+# automatic configuration for internal use
+config AUFS_BR_NFS
+       bool # never appear on the menu
+       depends on NFS_FS
+       depends on AUFS_LHASH_PATCH
+       default y
+       help
+       Automatic configuration for internal use.
+       When aufs supports NFS branch, enabled automatically.
+
+config AUFS_BR_NFS_V4
+       bool # never appear on the menu
+       depends on NFS_V4 && AUFS_BR_NFS
+       depends on AUFS = y || (AUFS = m && AUFS_PUT_FILP_PATCH)
+       default y
+       help
+       Automatic configuration for internal use.
+       When aufs supports a branch filesystem which operates
+       'atomic_open', for instance NFSv4, this configuration is enabled
+       automatically.
+
+config AUFS_BR_XFS
+       bool # never appear on the menu
+       depends on XFS_FS
+       default y
+       help
+       Automatic configuration for internal use.
+       When aufs supports XFS branch, enabled automatically.
+
+config AUFS_FSYNC_SUPER_PATCH
+       bool "fsync_super-2.6.xx.patch was applied or not"
+       depends on AUFS = m
+       help
+       If you build aufs as a module and want to flush everything for
+       branch filesystems which are not marked as 'rr' nor 'rr+wh' at
+       umount or remount time, then you need to apply the patch
+       'CVS_TREE/aufs/patch/fsync_super-2.6.16.patch' or
+       '...-2.6.19.patch' to your kernel source, and enable this
+       configuration.
+       It may be helpful at shutdown time in case of your aufs is a
+       root filesystem. But this behaviour will not guarantee the
+       consistency of branch filesystems. To guarantee it, try the
+       approach described in the aufs manual, and do not forget
+       installing auplink script.
+       The fsync_super-2.6.xx.patch does nothing but exports a kernel
+       function fsync_super() to modules.
+
+config AUFS_DENY_WRITE_ACCESS_PATCH
+       bool "deny_write_access.patch was applied or not"
+       depends on AUFS = m
+       help
+       A security enhancement to deny writing to a running executable
+       which exists on an aufs branch filesystem and executed through
+       aufs. If you applied
+       'CVS_TREE/aufs/patch/deny_write_access.patch' to your kernel
+       and you are compiling aufs as a module, then enable this
+       option.
+       The write_deny_access.patch does nothing but export the
+       function.
+
+config AUFS_WORKAROUND_FUSE
+       bool "Special handling for FUSE-based filesystem"
+       depends on FUSE_FS
+       help
+       A FUSE-based filesystem may not initialize its inode
+       attributes and the FUSE developer thinks the inode attributes
+       in a positive dentry which is returned by VFS lookup operation
+       are not reliable.
+       If you use a FUSE-based filesystem as an aufs branch, and it
+       customizes the inode attribute on it without overriding
+       fuse_lowlevel_ops.lookup, probably you need to enable this
+       configuration.
+       If you enable this configuration, aufs calls getattr operation
+       in every lookup and revalidate operation for the FUSE-based
+       filesystem branch.
+       It will have a negative impact to the performance even if you do
+       not use a FUSE-based filesystem branch.
+
+# automatic configuration for internal use
+config AUFS_GETATTR
+       bool # never appear on the menu
+       depends on AUFS_HINOTIFY || AUFS_WORKAROUND_FUSE || AUFS_BR_NFS
+       default y
+       help
+       Automatic configuration for internal use.
+
+config AUFS_DEBUG
+       bool "Debug aufs"
+       default y
+       help
+       Enable this to compile aufs internal debug code.
+       It will have a negative impact to the performance.
+
+# automatic configuration for internal use
+config AUFS_MAGIC_SYSRQ
+       bool # never appear on the menu
+       depends on AUFS_DEBUG && MAGIC_SYSRQ
+       default y
+       help
+       Automatic configuration for internal use.
+       When aufs supports Magic SysRq, enabled automatically.
+
+config AUFS_DEBUG_LOCK
+       bool "Show lock status in Magic SysRq"
+       depends on AUFS_MAGIC_SYSRQ
+       help
+       For developers only. Sometimes it is useful when a deadlock
+       occurs in aufs. Trace every aufs lock acquire and release, and
+       print them when Magic SysRq-<AUFS> key is pressed.
+       It will have a huge negative impact to the performance.
+
+config AUFS_COMPAT
+       bool "Compatibility with Unionfs (obsolete)"
+       help
+       This makes aufs compatible with unionfs-style mount options and some
+       behaviours.
+       The dirs= mount option and =nfsro branch permission flag are always
+       interpreted as br: mount option and =ro flag respectively. The
+       'debug', 'delete' and 'imap' mount options are ignored.
+       If you disable this option, you will get,
+       - aufs issues a warning about the ignored mount options
+       - the default branch permission flag is set. RW for the first branch,
+         and RO for the rests.
+       - the name of a internal file which represents the directory is
+         'opaque', becomes '.wh..wh..opq'
+       - the 'diropq=w' mount option is set by default
+
+config AUFS_UNIONFS22_PATCH
+       bool "Unionfs-2.2 or later patch is applied or not (obsolete)"
+       help
+       Unionfs version 2.2 (and later) patch introduces some changes in VFS
+       layer which has an impact to aufs. If you have applied such
+       patch to your kernel, you need to enable this configuration even
+       if you disabled CONFIG_UNIONFS.
+
+config AUFS_UNIONFS23_PATCH
+       bool "Unionfs-2.3 or later patch is applied or not (obsolete)"
+       select AUFS_SPLICE_PATCH
+       select AUFS_UNIONFS22_PATCH
+       help
+       Unionfs version 2.3 (and later) patch introduces some changes in VFS
+       layer which has an impact to aufs. If you have applied such
+       patch to your kernel, you need to enable this configuration even
+       if you disabled CONFIG_UNIONFS.
+endif
+
 endmenu
 
 menu "Miscellaneous filesystems"
diff -urN linux/fs/Makefile linux-aufs/fs/Makefile
--- linux/fs/Makefile   2009-03-12 11:25:26.000000000 +0100
+++ linux-aufs/fs/Makefile      2009-03-12 17:03:22.897115295 +0100
@@ -89,6 +89,7 @@
 obj-$(CONFIG_HFS_FS)           += hfs/
 obj-$(CONFIG_ECRYPT_FS)                += ecryptfs/
 obj-$(CONFIG_UNION_FS)         += unionfs/
+obj-$(CONFIG_AUFS)             += aufs/
 obj-$(CONFIG_VXFS_FS)          += freevxfs/
 obj-$(CONFIG_NFS_FS)           += nfs/
 obj-$(CONFIG_EXPORTFS)         += exportfs/
diff -urN linux/include/linux/aufs_type.h linux-aufs/include/linux/aufs_type.h
--- linux/include/linux/aufs_type.h     1970-01-01 01:00:00.000000000 +0100
+++ linux-aufs/include/linux/aufs_type.h        2009-03-12 16:18:04.000000000 +0100
@@ -0,0 +1,127 @@
+/*
+ * Copyright (C) 2005-2009 Junjiro Okajima
+ *
+ * This program, aufs is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/* $Id$ */
+
+#include <linux/ioctl.h>
+
+#ifndef __AUFS_TYPE_H__
+#define __AUFS_TYPE_H__
+
+#define AUFS_VERSION   "20090126"
+
+/* move this to linux-2.6.19/include/magic.h */
+#define AUFS_SUPER_MAGIC       ('a' << 24 | 'u' << 16 | 'f' << 8 | 's')
+
+/* ---------------------------------------------------------------------- */
+
+#ifdef CONFIG_AUFS_BRANCH_MAX_127
+/* some environments treat 'char' as 'unsigned char' by default */
+typedef signed char aufs_bindex_t;
+#define AUFS_BRANCH_MAX 127
+#else
+typedef short aufs_bindex_t;
+#ifdef CONFIG_AUFS_BRANCH_MAX_511
+#define AUFS_BRANCH_MAX 511
+#elif defined(CONFIG_AUFS_BRANCH_MAX_1023)
+#define AUFS_BRANCH_MAX 1023
+#elif defined(CONFIG_AUFS_BRANCH_MAX_32767)
+#define AUFS_BRANCH_MAX 32767
+#else
+#error unknown CONFIG_AUFS_BRANCH_MAX value
+#endif
+#endif
+
+#define AUFS_NAME              "aufs"
+#define AUFS_FSTYPE            AUFS_NAME
+
+#define AUFS_ROOT_INO          2
+#define AUFS_FIRST_INO         11
+
+#define AUFS_WH_PFX            ".wh."
+#define AUFS_WH_PFX_LEN                ((int)sizeof(AUFS_WH_PFX) - 1)
+#define AUFS_XINO_FNAME                "." AUFS_NAME ".xino"
+#define AUFS_XINO_DEFPATH      "/tmp/" AUFS_XINO_FNAME
+#define AUFS_XINO_TRUNC_INIT   64 /* blocks */
+#define AUFS_XINO_TRUNC_STEP   4  /* blocks */
+#define AUFS_DIRWH_DEF         3
+#define AUFS_RDCACHE_DEF       10 /* seconds */
+#define AUFS_WKQ_NAME          AUFS_NAME "d"
+#define AUFS_NWKQ_DEF          4
+#define AUFS_MFS_SECOND_DEF    30 /* seconds */
+#define AUFS_PLINK_WARN                100 /* number of plinks */
+
+#ifdef CONFIG_AUFS_COMPAT
+#define AUFS_DIROPQ_NAME       "__dir_opaque"
+#else
+#define AUFS_DIROPQ_NAME       AUFS_WH_PFX ".opq" /* whiteouted doubly */
+#endif
+#define AUFS_WH_DIROPQ         AUFS_WH_PFX AUFS_DIROPQ_NAME
+
+#define AUFS_BASE_NAME         AUFS_WH_PFX AUFS_NAME
+#define AUFS_PLINKDIR_NAME     AUFS_WH_PFX "plnk"
+#define AUFS_TMPDIR_NAME       AUFS_WH_PFX ".tmp"
+
+/* doubly whiteouted */
+#define AUFS_WH_BASE           AUFS_WH_PFX AUFS_BASE_NAME
+#define AUFS_WH_PLINKDIR       AUFS_WH_PFX AUFS_PLINKDIR_NAME
+#define AUFS_WH_TMPDIR         AUFS_WH_PFX AUFS_TMPDIR_NAME
+
+/* ---------------------------------------------------------------------- */
+
+/* ioctl */
+#if 0 /* reserved for future use */
+enum {
+       AuCtlErr,
+       AuCtlErr_Last
+};
+enum {
+       AuCtl_DIROPQ_GET, AuCtl_DIROPQ_SET,
+       AuCtl_MOVE,
+       AuCtl_MVDOWN,
+
+       /* unimplmented */
+       AuCtl_REFRESH, AuCtl_REFRESHV,
+       AuCtl_FLUSH_PLINK,
+       AuCtl_CPUP,
+       AuCtl_CPDOWN
+};
+
+struct aufs_ctl {
+       int err;
+       aufs_bindex_t bsrc, bdst;
+       char *path;
+};
+
+#define AuCtlType              'A'
+#define AUFS_CTL_DIROPQ_GET    _IO(AuCtlType, AuCtl_DIROPQ_GET)
+#define AUFS_CTL_DIROPQ_SET    _IOW(AuCtlType, AuCtl_DIROPQ_SET, aufs_bindex_t)
+#define AUFS_CTL_MOVE \
+       _IOW(AuCtlType, AuCtl_MVDOWN, aufs_bindex_t)
+#define AUFS_CTL_MVDOWN \
+       _IOWR(AuCtlType, AuCtl_MVDOWN, struct aufs_ctl)
+
+#define AUFS_CTL_REFRESH       _IO(AuCtlType, AuCtl_REFRESH)
+#define AUFS_CTL_REFRESHV      _IO(AuCtlType, AuCtl_REFRESHV)
+#define AUFS_CTL_FLUSH_PLINK   _IOR(AuCtlType, AuCtl_FLUSH_PLINK)
+#define AUFS_CTL_CPUP          _IOWR(AuCtlType, AuCtl_CPUP, struct aufs_ctl)
+#define AUFS_CTL_CPDOWN \
+       _IOWR(AuCtlType, AuCtl_CPDOWN, struct aufs_ctl_cp)
+#endif
+
+#endif /* __AUFS_TYPE_H__ */