+++ /dev/null
-diff --git a/Documentation/filesystems/00-INDEX b/Documentation/filesystems/00-INDEX
-index 8c624a1..4aa288b 100644
---- a/Documentation/filesystems/00-INDEX
-+++ b/Documentation/filesystems/00-INDEX
-@@ -110,6 +110,8 @@ udf.txt
- - info and mount options for the UDF filesystem.
- ufs.txt
- - info on the ufs filesystem.
-+unionfs/
-+ - info on the unionfs filesystem
- vfat.txt
- - info on using the VFAT filesystem used in Windows NT and Windows 95
- vfs.txt
-diff --git a/Documentation/filesystems/unionfs/00-INDEX b/Documentation/filesystems/unionfs/00-INDEX
-new file mode 100644
-index 0000000..96fdf67
---- /dev/null
-+++ b/Documentation/filesystems/unionfs/00-INDEX
-@@ -0,0 +1,10 @@
-+00-INDEX
-+ - this file.
-+concepts.txt
-+ - A brief introduction of concepts.
-+issues.txt
-+ - A summary of known issues with unionfs.
-+rename.txt
-+ - Information regarding rename operations.
-+usage.txt
-+ - Usage information and examples.
-diff --git a/Documentation/filesystems/unionfs/concepts.txt b/Documentation/filesystems/unionfs/concepts.txt
-new file mode 100644
-index 0000000..b853788
---- /dev/null
-+++ b/Documentation/filesystems/unionfs/concepts.txt
-@@ -0,0 +1,287 @@
-+Unionfs 2.x CONCEPTS:
-+=====================
-+
-+This file describes the concepts needed by a namespace unification file
-+system.
-+
-+
-+Branch Priority:
-+================
-+
-+Each branch is assigned a unique priority - starting from 0 (highest
-+priority). No two branches can have the same priority.
-+
-+
-+Branch Mode:
-+============
-+
-+Each branch is assigned a mode - read-write or read-only. This allows
-+directories on media mounted read-write to be used in a read-only manner.
-+
-+
-+Whiteouts:
-+==========
-+
-+A whiteout removes a file name from the namespace. Whiteouts are needed when
-+one attempts to remove a file on a read-only branch.
-+
-+Suppose we have a two-branch union, where branch 0 is read-write and branch
-+1 is read-only. And a file 'foo' on branch 1:
-+
-+./b0/
-+./b1/
-+./b1/foo
-+
-+The unified view would simply be:
-+
-+./union/
-+./union/foo
-+
-+Since 'foo' is stored on a read-only branch, it cannot be removed. A
-+whiteout is used to remove the name 'foo' from the unified namespace. Again,
-+since branch 1 is read-only, the whiteout cannot be created there. So, we
-+try on a higher priority (lower numerically) branch and create the whiteout
-+there.
-+
-+./b0/
-+./b0/.wh.foo
-+./b1/
-+./b1/foo
-+
-+Later, when Unionfs traverses branches (due to lookup or readdir), it
-+eliminate 'foo' from the namespace (as well as the whiteout itself.)
-+
-+
-+Opaque Directories:
-+===================
-+
-+Assume we have a unionfs mount comprising of two branches. Branch 0 is
-+empty; branch 1 has the directory /a and file /a/f. Let's say we mount a
-+union of branch 0 as read-write and branch 1 as read-only. Now, let's say
-+we try to perform the following operation in the union:
-+
-+ rm -fr a
-+
-+Because branch 1 is not writable, we cannot physically remove the file /a/f
-+or the directory /a. So instead, we will create a whiteout in branch 0
-+named /.wh.a, masking out the name "a" from branch 1. Next, let's say we
-+try to create a directory named "a" as follows:
-+
-+ mkdir a
-+
-+Because we have a whiteout for "a" already, Unionfs behaves as if "a"
-+doesn't exist, and thus will delete the whiteout and replace it with an
-+actual directory named "a".
-+
-+The problem now is that if you try to "ls" in the union, Unionfs will
-+perform is normal directory name unification, for *all* directories named
-+"a" in all branches. This will cause the file /a/f from branch 1 to
-+re-appear in the union's namespace, which violates Unix semantics.
-+
-+To avoid this problem, we have a different form of whiteouts for
-+directories, called "opaque directories" (same as BSD Union Mount does).
-+Whenever we replace a whiteout with a directory, that directory is marked as
-+opaque. In Unionfs 2.x, it means that we create a file named
-+/a/.wh.__dir_opaque in branch 0, after having created directory /a there.
-+When unionfs notices that a directory is opaque, it stops all namespace
-+operations (including merging readdir contents) at that opaque directory.
-+This prevents re-exposing names from masked out directories.
-+
-+
-+Duplicate Elimination:
-+======================
-+
-+It is possible for files on different branches to have the same name.
-+Unionfs then has to select which instance of the file to show to the user.
-+Given the fact that each branch has a priority associated with it, the
-+simplest solution is to take the instance from the highest priority
-+(numerically lowest value) and "hide" the others.
-+
-+
-+Unlinking:
-+=========
-+
-+Unlink operation on non-directory instances is optimized to remove the
-+maximum possible objects in case multiple underlying branches have the same
-+file name. The unlink operation will first try to delete file instances
-+from highest priority branch and then move further to delete from remaining
-+branches in order of their decreasing priority. Consider a case (F..D..F),
-+where F is a file and D is a directory of the same name; here, some
-+intermediate branch could have an empty directory instance with the same
-+name, so this operation also tries to delete this directory instance and
-+proceed further to delete from next possible lower priority branch. The
-+unionfs unlink operation will smoothly delete the files with same name from
-+all possible underlying branches. In case if some error occurs, it creates
-+whiteout in highest priority branch that will hide file instance in rest of
-+the branches. An error could occur either if an unlink operations in any of
-+the underlying branch failed or if a branch has no write permission.
-+
-+This unlinking policy is known as "delete all" and it has the benefit of
-+overall reducing the number of inodes used by duplicate files, and further
-+reducing the total number of inodes consumed by whiteouts. The cost is of
-+extra processing, but testing shows this extra processing is well worth the
-+savings.
-+
-+
-+Copyup:
-+=======
-+
-+When a change is made to the contents of a file's data or meta-data, they
-+have to be stored somewhere. The best way is to create a copy of the
-+original file on a branch that is writable, and then redirect the write
-+though to this copy. The copy must be made on a higher priority branch so
-+that lookup and readdir return this newer "version" of the file rather than
-+the original (see duplicate elimination).
-+
-+An entire unionfs mount can be read-only or read-write. If it's read-only,
-+then none of the branches will be written to, even if some of the branches
-+are physically writeable. If the unionfs mount is read-write, then the
-+leftmost (highest priority) branch must be writeable (for copyup to take
-+place); the remaining branches can be any mix of read-write and read-only.
-+
-+In a writeable mount, unionfs will create new files/dir in the leftmost
-+branch. If one tries to modify a file in a read-only branch/media, unionfs
-+will copyup the file to the leftmost branch and modify it there. If you try
-+to modify a file from a writeable branch which is not the leftmost branch,
-+then unionfs will modify it in that branch; this is useful if you, say,
-+unify differnet packages (e.g., apache, sendmail, ftpd, etc.) and you want
-+changes to specific package files to remain logically in the directory where
-+they came from.
-+
-+Cache Coherency:
-+================
-+
-+Unionfs users often want to be able to modify files and directories directly
-+on the lower branches, and have those changes be visible at the Unionfs
-+level. This means that data (e.g., pages) and meta-data (dentries, inodes,
-+open files, etc.) have to be synchronized between the upper and lower
-+layers. In other words, the newest changes from a layer below have to be
-+propagated to the Unionfs layer above. If the two layers are not in sync, a
-+cache incoherency ensues, which could lead to application failures and even
-+oopses. The Linux kernel, however, has a rather limited set of mechanisms
-+to ensure this inter-layer cache coherency---so Unionfs has to do most of
-+the hard work on its own.
-+
-+Maintaining Invariants:
-+
-+The way Unionfs ensures cache coherency is as follows. At each entry point
-+to a Unionfs file system method, we call a utility function to validate the
-+primary objects of this method. Generally, we call unionfs_file_revalidate
-+on open files, and __unionfs_d_revalidate_chain on dentries (which also
-+validates inodes). These utility functions check to see whether the upper
-+Unionfs object is in sync with any of the lower objects that it represents.
-+The checks we perform include whether the Unionfs superblock has a newer
-+generation number, or if any of the lower objects mtime's or ctime's are
-+newer. (Note: generation numbers change when branch-management commands are
-+issued, so in a way, maintaining cache coherency is also very important for
-+branch-management.) If indeed we determine that any Unionfs object is no
-+longer in sync with its lower counterparts, then we rebuild that object
-+similarly to how we do so for branch-management.
-+
-+While rebuilding Unionfs's objects, we also purge any page mappings and
-+truncate inode pages (see fs/unionfs/dentry.c:purge_inode_data). This is to
-+ensure that Unionfs will re-get the newer data from the lower branches. We
-+perform this purging only if the Unionfs operation in question is a reading
-+operation; if Unionfs is performing a data writing operation (e.g., ->write,
-+->commit_write, etc.) then we do NOT flush the lower mappings/pages: this is
-+because (1) a self-deadlock could occur and (2) the upper Unionfs pages are
-+considered more authoritative anyway, as they are newer and will overwrite
-+any lower pages.
-+
-+Unionfs maintains the following important invariant regarding mtime's,
-+ctime's, and atime's: the upper inode object's times are the max() of all of
-+the lower ones. For non-directory objects, there's only one object below,
-+so the mapping is simple; for directory objects, there could me multiple
-+lower objects and we have to sync up with the newest one of all the lower
-+ones. This invariant is important to maintain, especially for directories
-+(besides, we need this to be POSIX compliant). A union could comprise
-+multiple writable branches, each of which could change. If we don't reflect
-+the newest possible mtime/ctime, some applications could fail. For example,
-+NFSv2/v3 exports check for newer directory mtimes on the server to determine
-+if the client-side attribute cache should be purged.
-+
-+To maintain these important invariants, of course, Unionfs carefully
-+synchronizes upper and lower times in various places. For example, if we
-+copy-up a file to a top-level branch, the parent directory where the file
-+was copied up to will now have a new mtime: so after a successful copy-up,
-+we sync up with the new top-level branch's parent directory mtime.
-+
-+Implementation:
-+
-+This cache-coherency implementation is efficient because it defers any
-+synchronizing between the upper and lower layers until absolutely needed.
-+Consider the example a common situation where users perform a lot of lower
-+changes, such as untarring a whole package. While these take place,
-+typically the user doesn't access the files via Unionfs; only after the
-+lower changes are done, does the user try to access the lower files. With
-+our cache-coherency implementation, the entirety of the changes to the lower
-+branches will not result in a single CPU cycle spent at the Unionfs level
-+until the user invokes a system call that goes through Unionfs.
-+
-+We have considered two alternate cache-coherency designs. (1) Using the
-+dentry/inode notify functionality to register interest in finding out about
-+any lower changes. This is a somewhat limited and also a heavy-handed
-+approach which could result in many notifications to the Unionfs layer upon
-+each small change at the lower layer (imagine a file being modified multiple
-+times in rapid succession). (2) Rewriting the VFS to support explicit
-+callbacks from lower objects to upper objects. We began exploring such an
-+implementation, but found it to be very complicated--it would have resulted
-+in massive VFS/MM changes which are unlikely to be accepted by the LKML
-+community. We therefore believe that our current cache-coherency design and
-+implementation represent the best approach at this time.
-+
-+Limitations:
-+
-+Our implementation works in that as long as a user process will have caused
-+Unionfs to be called, directly or indirectly, even to just do
-+->d_revalidate; then we will have purged the current Unionfs data and the
-+process will see the new data. For example, a process that continually
-+re-reads the same file's data will see the NEW data as soon as the lower
-+file had changed, upon the next read(2) syscall (even if the file is still
-+open!) However, this doesn't work when the process re-reads the open file's
-+data via mmap(2) (unless the user unmaps/closes the file and remaps/reopens
-+it). Once we respond to ->readpage(s), then the kernel maps the page into
-+the process's address space and there doesn't appear to be a way to force
-+the kernel to invalidate those pages/mappings, and force the process to
-+re-issue ->readpage. If there's a way to invalidate active mappings and
-+force a ->readpage, let us know please (invalidate_inode_pages2 doesn't do
-+the trick).
-+
-+Our current Unionfs code has to perform many file-revalidation calls. It
-+would be really nice if the VFS would export an optional file system hook
-+->file_revalidate (similarly to dentry->d_revalidate) that will be called
-+before each VFS op that has a "struct file" in it.
-+
-+Certain file systems have micro-second granularity (or better) for inode
-+times, and asynchronous actions could cause those times to change with some
-+small delay. In such cases, Unionfs may see a changed inode time that only
-+differs by a tiny fraction of a second: such a change may be a false
-+positive indication that the lower object has changed, whereas if unionfs
-+waits a little longer, that false indication will not be seen. (These false
-+positives are harmless, because they would at most cause unionfs to
-+re-validate an object that may need no revalidation, and print a debugging
-+message that clutters the console/logs.) Therefore, to minimize the chances
-+of these situations, we delay the detection of changed times by a small
-+factor of a few seconds, called UNIONFS_MIN_CC_TIME (which defaults to 3
-+seconds, as does NFS). This means that we will detect the change, only a
-+couple of seconds later, if indeed the time change persists in the lower
-+file object. This delayed detection has an added performance benefit: we
-+reduce the number of times that unionfs has to revalidate objects, in case
-+there's a lot of concurrent activity on both the upper and lower objects,
-+for the same file(s). Lastly, this delayed time attribute detection is
-+similar to how NFS clients operate (e.g., acregmin).
-+
-+Finally, there is no way currently in Linux to prevent lower directories
-+from being moved around (i.e., topology changes); there's no way to prevent
-+modifications to directory sub-trees of whole file systems which are mounted
-+read-write. It is therefore possible for in-flight operations in unionfs to
-+take place, while a lower directory is being moved around. Therefore, if
-+you try to, say, create a new file in a directory through unionfs, while the
-+directory is being moved around directly, then the new file may get created
-+in the new location where that directory was moved to. This is a somewhat
-+similar behaviour in NFS: an NFS client could be creating a new file while
-+th NFS server is moving th directory around; the file will get successfully
-+created in the new location. (The one exception in unionfs is that if the
-+branch is marked read-only by unionfs, then a copyup will take place.)
-+
-+For more information, see <http://unionfs.filesystems.org/>.
-diff --git a/Documentation/filesystems/unionfs/issues.txt b/Documentation/filesystems/unionfs/issues.txt
-new file mode 100644
-index 0000000..f4b7e7e
---- /dev/null
-+++ b/Documentation/filesystems/unionfs/issues.txt
-@@ -0,0 +1,28 @@
-+KNOWN Unionfs 2.x ISSUES:
-+=========================
-+
-+1. Unionfs should not use lookup_one_len() on the underlying f/s as it
-+ confuses NFSv4. Currently, unionfs_lookup() passes lookup intents to the
-+ lower file-system, this eliminates part of the problem. The remaining
-+ calls to lookup_one_len may need to be changed to pass an intent. We are
-+ currently introducing VFS changes to fs/namei.c's do_path_lookup() to
-+ allow proper file lookup and opening in stackable file systems.
-+
-+2. Lockdep (a debugging feature) isn't aware of stacking, and so it
-+ incorrectly complains about locking problems. The problem boils down to
-+ this: Lockdep considers all objects of a certain type to be in the same
-+ class, for example, all inodes. Lockdep doesn't like to see a lock held
-+ on two inodes within the same task, and warns that it could lead to a
-+ deadlock. However, stackable file systems do precisely that: they lock
-+ an upper object, and then a lower object, in a strict order to avoid
-+ locking problems; in addition, Unionfs, as a fan-out file system, may
-+ have to lock several lower inodes. We are currently looking into Lockdep
-+ to see how to make it aware of stackable file systems. For now, we
-+ temporarily disable lockdep when calling vfs methods on lower objects,
-+ but only for those places where lockdep complained. While this solution
-+ may seem unclean, it is not without precedent: other places in the kernel
-+ also do similar temporary disabling, of course after carefully having
-+ checked that it is the right thing to do. Anyway, you get any warnings
-+ from Lockdep, please report them to the Unionfs maintainers.
-+
-+For more information, see <http://unionfs.filesystems.org/>.
-diff --git a/Documentation/filesystems/unionfs/rename.txt b/Documentation/filesystems/unionfs/rename.txt
-new file mode 100644
-index 0000000..e20bb82
---- /dev/null
-+++ b/Documentation/filesystems/unionfs/rename.txt
-@@ -0,0 +1,31 @@
-+Rename is a complex beast. The following table shows which rename(2) operations
-+should succeed and which should fail.
-+
-+o: success
-+E: error (either unionfs or vfs)
-+X: EXDEV
-+
-+none = file does not exist
-+file = file is a file
-+dir = file is a empty directory
-+child= file is a non-empty directory
-+wh = file is a directory containing only whiteouts; this makes it logically
-+ empty
-+
-+ none file dir child wh
-+file o o E E E
-+dir o E o E o
-+child X E X E X
-+wh o E o E o
-+
-+
-+Renaming directories:
-+=====================
-+
-+Whenever a empty (either physically or logically) directory is being renamed,
-+the following sequence of events should take place:
-+
-+1) Remove whiteouts from both source and destination directory
-+2) Rename source to destination
-+3) Make destination opaque to prevent anything under it from showing up
-+
-diff --git a/Documentation/filesystems/unionfs/usage.txt b/Documentation/filesystems/unionfs/usage.txt
-new file mode 100644
-index 0000000..1adde69
---- /dev/null
-+++ b/Documentation/filesystems/unionfs/usage.txt
-@@ -0,0 +1,134 @@
-+Unionfs is a stackable unification file system, which can appear to merge
-+the contents of several directories (branches), while keeping their physical
-+content separate. Unionfs is useful for unified source tree management,
-+merged contents of split CD-ROM, merged separate software package
-+directories, data grids, and more. Unionfs allows any mix of read-only and
-+read-write branches, as well as insertion and deletion of branches anywhere
-+in the fan-out. To maintain Unix semantics, Unionfs handles elimination of
-+duplicates, partial-error conditions, and more.
-+
-+GENERAL SYNTAX
-+==============
-+
-+# mount -t unionfs -o <OPTIONS>,<BRANCH-OPTIONS> none MOUNTPOINT
-+
-+OPTIONS can be any legal combination of:
-+
-+- ro # mount file system read-only
-+- rw # mount file system read-write
-+- remount # remount the file system (see Branch Management below)
-+- incgen # increment generation no. (see Cache Consistency below)
-+
-+BRANCH-OPTIONS can be either (1) a list of branches given to the "dirs="
-+option, or (2) a list of individual branch manipulation commands, combined
-+with the "remount" option, and is further described in the "Branch
-+Management" section below.
-+
-+The syntax for the "dirs=" mount option is:
-+
-+ dirs=branch[=ro|=rw][:...]
-+
-+The "dirs=" option takes a colon-delimited list of directories to compose
-+the union, with an optional branch mode for each of those directories.
-+Directories that come earlier (specified first, on the left) in the list
-+have a higher precedence than those which come later. Additionally,
-+read-only or read-write permissions of the branch can be specified by
-+appending =ro or =rw (default) to each directory. See the Copyup section in
-+concepts.txt, for a description of Unionfs's behavior when mixing read-only
-+and read-write branches and mounts.
-+
-+Syntax:
-+
-+ dirs=/branch1[=ro|=rw]:/branch2[=ro|=rw]:...:/branchN[=ro|=rw]
-+
-+Example:
-+
-+ dirs=/writable_branch=rw:/read-only_branch=ro
-+
-+
-+BRANCH MANAGEMENT
-+=================
-+
-+Once you mount your union for the first time, using the "dirs=" option, you
-+can then change the union's overall mode or reconfigure the branches, using
-+the remount option, as follows.
-+
-+To downgrade a union from read-write to read-only:
-+
-+# mount -t unionfs -o remount,ro none MOUNTPOINT
-+
-+To upgrade a union from read-only to read-write:
-+
-+# mount -t unionfs -o remount,rw none MOUNTPOINT
-+
-+To delete a branch /foo, regardless where it is in the current union:
-+
-+# mount -t unionfs -o remount,del=/foo none MOUNTPOINT
-+
-+To insert (add) a branch /foo before /bar:
-+
-+# mount -t unionfs -o remount,add=/bar:/foo none MOUNTPOINT
-+
-+To insert (add) a branch /foo (with the "rw" mode flag) before /bar:
-+
-+# mount -t unionfs -o remount,add=/bar:/foo=rw none MOUNTPOINT
-+
-+To insert (add) a branch /foo (in "rw" mode) at the very beginning (i.e., a
-+new highest-priority branch), you can use the above syntax, or use a short
-+hand version as follows:
-+
-+# mount -t unionfs -o remount,add=/foo none MOUNTPOINT
-+
-+To append a branch to the very end (new lowest-priority branch):
-+
-+# mount -t unionfs -o remount,add=:/foo none MOUNTPOINT
-+
-+To append a branch to the very end (new lowest-priority branch), in
-+read-only mode:
-+
-+# mount -t unionfs -o remount,add=:/foo=ro none MOUNTPOINT
-+
-+Finally, to change the mode of one existing branch, say /foo, from read-only
-+to read-write, and change /bar from read-write to read-only:
-+
-+# mount -t unionfs -o remount,mode=/foo=rw,mode=/bar=ro none MOUNTPOINT
-+
-+Note: in Unionfs 2.x, you cannot set the leftmost branch to readonly because
-+then Unionfs won't have any writable place for copyups to take place.
-+Moreover, the VFS can get confused when it tries to modify something in a
-+file system mounted read-write, but isn't permitted to write to it.
-+Instead, you should set the whole union as readonly, as described above.
-+If, however, you must set the leftmost branch as readonly, perhaps so you
-+can get a snapshot of it at a point in time, then you should insert a new
-+writable top-level branch, and mark the one you want as readonly. This can
-+be accomplished as follows, assuming that /foo is your current leftmost
-+branch:
-+
-+# mount -t tmpfs -o size=NNN /new
-+# mount -t unionfs -o remount,add=/new,mode=/foo=ro none MOUNTPOINT
-+<do what you want safely in /foo>
-+# mount -t unionfs -o remount,del=/new,mode=/foo=rw none MOUNTPOINT
-+<check if there's anything in /new you want to preserve>
-+# umount /new
-+
-+CACHE CONSISTENCY
-+=================
-+
-+If you modify any file on any of the lower branches directly, while there is
-+a Unionfs 2.x mounted above any of those branches, you should tell Unionfs
-+to purge its caches and re-get the objects. To do that, you have to
-+increment the generation number of the superblock using the following
-+command:
-+
-+# mount -t unionfs -o remount,incgen none MOUNTPOINT
-+
-+Note that the older way of incrementing the generation number using an
-+ioctl, is no longer supported in Unionfs 2.0 and newer. Ioctls in general
-+are not encouraged. Plus, an ioctl is per-file concept, whereas the
-+generation number is a per-file-system concept. Worse, such an ioctl
-+requires an open file, which then has to be invalidated by the very nature
-+of the generation number increase (read: the old generation increase ioctl
-+was pretty racy).
-+
-+
-+For more information, see <http://unionfs.filesystems.org/>.
-diff --git a/MAINTAINERS b/MAINTAINERS
-index 9a648eb..81b24a8 100644
---- a/MAINTAINERS
-+++ b/MAINTAINERS
-@@ -6765,6 +6765,14 @@ F: Documentation/cdrom/
- F: drivers/cdrom/cdrom.c
- F: include/linux/cdrom.h
-
-+UNIONFS
-+P: Erez Zadok
-+M: ezk@cs.sunysb.edu
-+L: unionfs@filesystems.org
-+W: http://unionfs.filesystems.org/
-+T: git git.kernel.org/pub/scm/linux/kernel/git/ezk/unionfs.git
-+S: Maintained
-+
- UNSORTED BLOCK IMAGES (UBI)
- M: Artem Bityutskiy <dedekind1@gmail.com>
- W: http://www.linux-mtd.infradead.org/
-diff --git a/fs/Kconfig b/fs/Kconfig
-index d621f02..c12677d 100644
---- a/fs/Kconfig
-+++ b/fs/Kconfig
-@@ -194,6 +194,7 @@ if MISC_FILESYSTEMS
- source "fs/adfs/Kconfig"
- source "fs/affs/Kconfig"
- source "fs/ecryptfs/Kconfig"
-+source "fs/unionfs/Kconfig"
- source "fs/hfs/Kconfig"
- source "fs/hfsplus/Kconfig"
- source "fs/befs/Kconfig"
-diff --git a/fs/Makefile b/fs/Makefile
-index 93804d4..3ff10bb 100644
---- a/fs/Makefile
-+++ b/fs/Makefile
-@@ -83,6 +83,7 @@ obj-$(CONFIG_ISO9660_FS) += isofs/
- obj-$(CONFIG_HFSPLUS_FS) += hfsplus/ # Before hfs to find wrapped HFS+
- obj-$(CONFIG_HFS_FS) += hfs/
- obj-$(CONFIG_ECRYPT_FS) += ecryptfs/
-+obj-$(CONFIG_UNION_FS) += unionfs/
- obj-$(CONFIG_VXFS_FS) += freevxfs/
- obj-$(CONFIG_NFS_FS) += nfs/
- obj-$(CONFIG_EXPORTFS) += exportfs/
-diff --git a/fs/namei.c b/fs/namei.c
-index 208c6aa..050eded 100644
---- a/fs/namei.c
-+++ b/fs/namei.c
-@@ -491,6 +491,7 @@ void release_open_intent(struct nameidata *nd)
- fput(file);
- }
- }
-+EXPORT_SYMBOL_GPL(release_open_intent);
-
- static inline int d_revalidate(struct dentry *dentry, struct nameidata *nd)
- {
-@@ -1804,6 +1805,42 @@ struct dentry *lookup_one_len(const char *name, struct dentry *base, int len)
- return __lookup_hash(&this, base, NULL);
- }
-
-+/* pass nameidata from caller (useful for NFS) */
-+struct dentry *lookup_one_len_nd(const char *name, struct dentry *base,
-+ int len, struct nameidata *nd)
-+{
-+ struct qstr this;
-+ unsigned long hash;
-+ unsigned int c;
-+
-+ WARN_ON_ONCE(!mutex_is_locked(&base->d_inode->i_mutex));
-+
-+ this.name = name;
-+ this.len = len;
-+ if (!len)
-+ return ERR_PTR(-EACCES);
-+
-+ hash = init_name_hash();
-+ while (len--) {
-+ c = *(const unsigned char *)name++;
-+ if (c == '/' || c == '\0')
-+ return ERR_PTR(-EACCES);
-+ hash = partial_name_hash(c, hash);
-+ }
-+ this.hash = end_name_hash(hash);
-+ /*
-+ * See if the low-level filesystem might want
-+ * to use its own hash..
-+ */
-+ if (base->d_flags & DCACHE_OP_HASH) {
-+ int err = base->d_op->d_hash(base, base->d_inode, &this);
-+ if (err < 0)
-+ return ERR_PTR(err);
-+ }
-+
-+ return __lookup_hash(&this, base, nd);
-+}
-+
- int user_path_at_empty(int dfd, const char __user *name, unsigned flags,
- struct path *path, int *empty)
- {
-@@ -3384,6 +3421,7 @@ EXPORT_SYMBOL(get_write_access); /* binfmt_aout */
- EXPORT_SYMBOL(getname);
- EXPORT_SYMBOL(lock_rename);
- EXPORT_SYMBOL(lookup_one_len);
-+EXPORT_SYMBOL(lookup_one_len_nd);
- EXPORT_SYMBOL(page_follow_link_light);
- EXPORT_SYMBOL(page_put_link);
- EXPORT_SYMBOL(page_readlink);
-diff --git a/fs/splice.c b/fs/splice.c
-index 1ec0493..3215728 100644
---- a/fs/splice.c
-+++ b/fs/splice.c
-@@ -1084,8 +1084,8 @@ EXPORT_SYMBOL(generic_splice_sendpage);
- /*
- * Attempt to initiate a splice from pipe to file.
- */
--static long do_splice_from(struct pipe_inode_info *pipe, struct file *out,
-- loff_t *ppos, size_t len, unsigned int flags)
-+long vfs_splice_from(struct pipe_inode_info *pipe, struct file *out,
-+ loff_t *ppos, size_t len, unsigned int flags)
- {
- ssize_t (*splice_write)(struct pipe_inode_info *, struct file *,
- loff_t *, size_t, unsigned int);
-@@ -1108,13 +1108,14 @@ static long do_splice_from(struct pipe_inode_info *pipe, struct file *out,
-
- return splice_write(pipe, out, ppos, len, flags);
- }
-+EXPORT_SYMBOL_GPL(vfs_splice_from);
-
- /*
- * Attempt to initiate a splice from a file to a pipe.
- */
--static long do_splice_to(struct file *in, loff_t *ppos,
-- struct pipe_inode_info *pipe, size_t len,
-- unsigned int flags)
-+long vfs_splice_to(struct file *in, loff_t *ppos,
-+ struct pipe_inode_info *pipe, size_t len,
-+ unsigned int flags)
- {
- ssize_t (*splice_read)(struct file *, loff_t *,
- struct pipe_inode_info *, size_t, unsigned int);
-@@ -1134,6 +1135,7 @@ static long do_splice_to(struct file *in, loff_t *ppos,
-
- return splice_read(in, ppos, pipe, len, flags);
- }
-+EXPORT_SYMBOL_GPL(vfs_splice_to);
-
- /**
- * splice_direct_to_actor - splices data directly between two non-pipes
-@@ -1203,7 +1205,7 @@ ssize_t splice_direct_to_actor(struct file *in, struct splice_desc *sd,
- size_t read_len;
- loff_t pos = sd->pos, prev_pos = pos;
-
-- ret = do_splice_to(in, &pos, pipe, len, flags);
-+ ret = vfs_splice_to(in, &pos, pipe, len, flags);
- if (unlikely(ret <= 0))
- goto out_release;
-
-@@ -1262,8 +1264,8 @@ static int direct_splice_actor(struct pipe_inode_info *pipe,
- {
- struct file *file = sd->u.file;
-
-- return do_splice_from(pipe, file, &file->f_pos, sd->total_len,
-- sd->flags);
-+ return vfs_splice_from(pipe, file, &file->f_pos, sd->total_len,
-+ sd->flags);
- }
-
- /**
-@@ -1348,7 +1350,7 @@ static long do_splice(struct file *in, loff_t __user *off_in,
- } else
- off = &out->f_pos;
-
-- ret = do_splice_from(ipipe, out, off, len, flags);
-+ ret = vfs_splice_from(ipipe, out, off, len, flags);
-
- if (off_out && copy_to_user(off_out, off, sizeof(loff_t)))
- ret = -EFAULT;
-@@ -1368,7 +1370,7 @@ static long do_splice(struct file *in, loff_t __user *off_in,
- } else
- off = &in->f_pos;
-
-- ret = do_splice_to(in, off, opipe, len, flags);
-+ ret = vfs_splice_to(in, off, opipe, len, flags);
-
- if (off_in && copy_to_user(off_in, off, sizeof(loff_t)))
- ret = -EFAULT;
-diff --git a/fs/unionfs/Kconfig b/fs/unionfs/Kconfig
-new file mode 100644
-index 0000000..f3c1ac4
---- /dev/null
-+++ b/fs/unionfs/Kconfig
-@@ -0,0 +1,24 @@
-+config UNION_FS
-+ tristate "Union file system (EXPERIMENTAL)"
-+ depends on EXPERIMENTAL
-+ help
-+ Unionfs is a stackable unification file system, which appears to
-+ merge the contents of several directories (branches), while keeping
-+ their physical content separate.
-+
-+ See <http://unionfs.filesystems.org> for details
-+
-+config UNION_FS_XATTR
-+ bool "Unionfs extended attributes"
-+ depends on UNION_FS
-+ help
-+ Extended attributes are name:value pairs associated with inodes by
-+ the kernel or by users (see the attr(5) manual page).
-+
-+ If unsure, say N.
-+
-+config UNION_FS_DEBUG
-+ bool "Debug Unionfs"
-+ depends on UNION_FS
-+ help
-+ If you say Y here, you can turn on debugging output from Unionfs.
-diff --git a/fs/unionfs/Makefile b/fs/unionfs/Makefile
-new file mode 100644
-index 0000000..60b6060
---- /dev/null
-+++ b/fs/unionfs/Makefile
-@@ -0,0 +1,17 @@
-+UNIONFS_VERSION="2.5.11 (for 3.3.0-rc3)"
-+
-+EXTRA_CFLAGS += -DUNIONFS_VERSION=\"$(UNIONFS_VERSION)\"
-+
-+obj-$(CONFIG_UNION_FS) += unionfs.o
-+
-+unionfs-y := subr.o dentry.o file.o inode.o main.o super.o \
-+ rdstate.o copyup.o dirhelper.o rename.o unlink.o \
-+ lookup.o commonfops.o dirfops.o sioq.o mmap.o whiteout.o
-+
-+unionfs-$(CONFIG_UNION_FS_XATTR) += xattr.o
-+
-+unionfs-$(CONFIG_UNION_FS_DEBUG) += debug.o
-+
-+ifeq ($(CONFIG_UNION_FS_DEBUG),y)
-+EXTRA_CFLAGS += -DDEBUG
-+endif
-diff --git a/fs/unionfs/commonfops.c b/fs/unionfs/commonfops.c
-new file mode 100644
-index 0000000..71cacfe
---- /dev/null
-+++ b/fs/unionfs/commonfops.c
-@@ -0,0 +1,901 @@
-+/*
-+ * Copyright (c) 2003-2011 Erez Zadok
-+ * Copyright (c) 2003-2006 Charles P. Wright
-+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2005-2006 Junjiro Okajima
-+ * Copyright (c) 2005 Arun M. Krishnakumar
-+ * Copyright (c) 2004-2006 David P. Quigley
-+ * Copyright (c) 2003-2004 Mohammad Nayyer Zubair
-+ * Copyright (c) 2003 Puja Gupta
-+ * Copyright (c) 2003 Harikesavan Krishnan
-+ * Copyright (c) 2003-2011 Stony Brook University
-+ * Copyright (c) 2003-2011 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#include "union.h"
-+
-+/*
-+ * 1) Copyup the file
-+ * 2) Rename the file to '.unionfs<original inode#><counter>' - obviously
-+ * stolen from NFS's silly rename
-+ */
-+static int copyup_deleted_file(struct file *file, struct dentry *dentry,
-+ struct dentry *parent, int bstart, int bindex)
-+{
-+ static unsigned int counter;
-+ const int i_inosize = sizeof(dentry->d_inode->i_ino) * 2;
-+ const int countersize = sizeof(counter) * 2;
-+ const int nlen = sizeof(".unionfs") + i_inosize + countersize - 1;
-+ char name[nlen + 1];
-+ int err;
-+ struct dentry *tmp_dentry = NULL;
-+ struct dentry *lower_dentry;
-+ struct dentry *lower_dir_dentry = NULL;
-+
-+ lower_dentry = unionfs_lower_dentry_idx(dentry, bstart);
-+
-+ sprintf(name, ".unionfs%*.*lx",
-+ i_inosize, i_inosize, lower_dentry->d_inode->i_ino);
-+
-+ /*
-+ * Loop, looking for an unused temp name to copyup to.
-+ *
-+ * It's somewhat silly that we look for a free temp tmp name in the
-+ * source branch (bstart) instead of the dest branch (bindex), where
-+ * the final name will be created. We _will_ catch it if somehow
-+ * the name exists in the dest branch, but it'd be nice to catch it
-+ * sooner than later.
-+ */
-+retry:
-+ tmp_dentry = NULL;
-+ do {
-+ char *suffix = name + nlen - countersize;
-+
-+ dput(tmp_dentry);
-+ counter++;
-+ sprintf(suffix, "%*.*x", countersize, countersize, counter);
-+
-+ pr_debug("unionfs: trying to rename %s to %s\n",
-+ dentry->d_name.name, name);
-+
-+ tmp_dentry = lookup_lck_len(name, lower_dentry->d_parent,
-+ nlen);
-+ if (IS_ERR(tmp_dentry)) {
-+ err = PTR_ERR(tmp_dentry);
-+ goto out;
-+ }
-+ } while (tmp_dentry->d_inode != NULL); /* need negative dentry */
-+ dput(tmp_dentry);
-+
-+ err = copyup_named_file(parent->d_inode, file, name, bstart, bindex,
-+ i_size_read(file->f_path.dentry->d_inode));
-+ if (err) {
-+ if (unlikely(err == -EEXIST))
-+ goto retry;
-+ goto out;
-+ }
-+
-+ /* bring it to the same state as an unlinked file */
-+ lower_dentry = unionfs_lower_dentry_idx(dentry, dbstart(dentry));
-+ if (!unionfs_lower_inode_idx(dentry->d_inode, bindex)) {
-+ atomic_inc(&lower_dentry->d_inode->i_count);
-+ unionfs_set_lower_inode_idx(dentry->d_inode, bindex,
-+ lower_dentry->d_inode);
-+ }
-+ lower_dir_dentry = lock_parent(lower_dentry);
-+ err = vfs_unlink(lower_dir_dentry->d_inode, lower_dentry);
-+ unlock_dir(lower_dir_dentry);
-+
-+out:
-+ if (!err)
-+ unionfs_check_dentry(dentry);
-+ return err;
-+}
-+
-+/*
-+ * put all references held by upper struct file and free lower file pointer
-+ * array
-+ */
-+static void cleanup_file(struct file *file)
-+{
-+ int bindex, bstart, bend;
-+ struct file **lower_files;
-+ struct file *lower_file;
-+ struct super_block *sb = file->f_path.dentry->d_sb;
-+
-+ lower_files = UNIONFS_F(file)->lower_files;
-+ bstart = fbstart(file);
-+ bend = fbend(file);
-+
-+ for (bindex = bstart; bindex <= bend; bindex++) {
-+ int i; /* holds (possibly) updated branch index */
-+ int old_bid;
-+
-+ lower_file = unionfs_lower_file_idx(file, bindex);
-+ if (!lower_file)
-+ continue;
-+
-+ /*
-+ * Find new index of matching branch with an open
-+ * file, since branches could have been added or
-+ * deleted causing the one with open files to shift.
-+ */
-+ old_bid = UNIONFS_F(file)->saved_branch_ids[bindex];
-+ i = branch_id_to_idx(sb, old_bid);
-+ if (unlikely(i < 0)) {
-+ printk(KERN_ERR "unionfs: no superblock for "
-+ "file %p\n", file);
-+ continue;
-+ }
-+
-+ /* decrement count of open files */
-+ branchput(sb, i);
-+ /*
-+ * fput will perform an mntput for us on the correct branch.
-+ * Although we're using the file's old branch configuration,
-+ * bindex, which is the old index, correctly points to the
-+ * right branch in the file's branch list. In other words,
-+ * we're going to mntput the correct branch even if branches
-+ * have been added/removed.
-+ */
-+ fput(lower_file);
-+ UNIONFS_F(file)->lower_files[bindex] = NULL;
-+ UNIONFS_F(file)->saved_branch_ids[bindex] = -1;
-+ }
-+
-+ UNIONFS_F(file)->lower_files = NULL;
-+ kfree(lower_files);
-+ kfree(UNIONFS_F(file)->saved_branch_ids);
-+ /* set to NULL because caller needs to know if to kfree on error */
-+ UNIONFS_F(file)->saved_branch_ids = NULL;
-+}
-+
-+/* open all lower files for a given file */
-+static int open_all_files(struct file *file)
-+{
-+ int bindex, bstart, bend, err = 0;
-+ struct file *lower_file;
-+ struct dentry *lower_dentry;
-+ struct dentry *dentry = file->f_path.dentry;
-+ struct super_block *sb = dentry->d_sb;
-+
-+ bstart = dbstart(dentry);
-+ bend = dbend(dentry);
-+
-+ for (bindex = bstart; bindex <= bend; bindex++) {
-+ lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
-+ if (!lower_dentry)
-+ continue;
-+
-+ dget(lower_dentry);
-+ unionfs_mntget(dentry, bindex);
-+ branchget(sb, bindex);
-+
-+ lower_file =
-+ dentry_open(lower_dentry,
-+ unionfs_lower_mnt_idx(dentry, bindex),
-+ file->f_flags, current_cred());
-+ if (IS_ERR(lower_file)) {
-+ branchput(sb, bindex);
-+ err = PTR_ERR(lower_file);
-+ goto out;
-+ } else {
-+ unionfs_set_lower_file_idx(file, bindex, lower_file);
-+ }
-+ }
-+out:
-+ return err;
-+}
-+
-+/* open the highest priority file for a given upper file */
-+static int open_highest_file(struct file *file, bool willwrite)
-+{
-+ int bindex, bstart, bend, err = 0;
-+ struct file *lower_file;
-+ struct dentry *lower_dentry;
-+ struct dentry *dentry = file->f_path.dentry;
-+ struct dentry *parent = dget_parent(dentry);
-+ struct inode *parent_inode = parent->d_inode;
-+ struct super_block *sb = dentry->d_sb;
-+
-+ bstart = dbstart(dentry);
-+ bend = dbend(dentry);
-+
-+ lower_dentry = unionfs_lower_dentry(dentry);
-+ if (willwrite && IS_WRITE_FLAG(file->f_flags) && is_robranch(dentry)) {
-+ for (bindex = bstart - 1; bindex >= 0; bindex--) {
-+ err = copyup_file(parent_inode, file, bstart, bindex,
-+ i_size_read(dentry->d_inode));
-+ if (!err)
-+ break;
-+ }
-+ atomic_set(&UNIONFS_F(file)->generation,
-+ atomic_read(&UNIONFS_I(dentry->d_inode)->
-+ generation));
-+ goto out;
-+ }
-+
-+ dget(lower_dentry);
-+ unionfs_mntget(dentry, bstart);
-+ lower_file = dentry_open(lower_dentry,
-+ unionfs_lower_mnt_idx(dentry, bstart),
-+ file->f_flags, current_cred());
-+ if (IS_ERR(lower_file)) {
-+ err = PTR_ERR(lower_file);
-+ goto out;
-+ }
-+ branchget(sb, bstart);
-+ unionfs_set_lower_file(file, lower_file);
-+ /* Fix up the position. */
-+ lower_file->f_pos = file->f_pos;
-+
-+ memcpy(&lower_file->f_ra, &file->f_ra, sizeof(struct file_ra_state));
-+out:
-+ dput(parent);
-+ return err;
-+}
-+
-+/* perform a delayed copyup of a read-write file on a read-only branch */
-+static int do_delayed_copyup(struct file *file, struct dentry *parent)
-+{
-+ int bindex, bstart, bend, err = 0;
-+ struct dentry *dentry = file->f_path.dentry;
-+ struct inode *parent_inode = parent->d_inode;
-+
-+ bstart = fbstart(file);
-+ bend = fbend(file);
-+
-+ BUG_ON(!S_ISREG(dentry->d_inode->i_mode));
-+
-+ unionfs_check_file(file);
-+ for (bindex = bstart - 1; bindex >= 0; bindex--) {
-+ if (!d_deleted(dentry))
-+ err = copyup_file(parent_inode, file, bstart,
-+ bindex,
-+ i_size_read(dentry->d_inode));
-+ else
-+ err = copyup_deleted_file(file, dentry, parent,
-+ bstart, bindex);
-+ /* if succeeded, set lower open-file flags and break */
-+ if (!err) {
-+ struct file *lower_file;
-+ lower_file = unionfs_lower_file_idx(file, bindex);
-+ lower_file->f_flags = file->f_flags;
-+ break;
-+ }
-+ }
-+ if (err || (bstart <= fbstart(file)))
-+ goto out;
-+ bend = fbend(file);
-+ for (bindex = bstart; bindex <= bend; bindex++) {
-+ if (unionfs_lower_file_idx(file, bindex)) {
-+ branchput(dentry->d_sb, bindex);
-+ fput(unionfs_lower_file_idx(file, bindex));
-+ unionfs_set_lower_file_idx(file, bindex, NULL);
-+ }
-+ }
-+ path_put_lowers(dentry, bstart, bend, false);
-+ iput_lowers(dentry->d_inode, bstart, bend, false);
-+ /* for reg file, we only open it "once" */
-+ fbend(file) = fbstart(file);
-+ dbend(dentry) = dbstart(dentry);
-+ ibend(dentry->d_inode) = ibstart(dentry->d_inode);
-+
-+out:
-+ unionfs_check_file(file);
-+ return err;
-+}
-+
-+/*
-+ * Helper function for unionfs_file_revalidate/locked.
-+ * Expects dentry/parent to be locked already, and revalidated.
-+ */
-+static int __unionfs_file_revalidate(struct file *file, struct dentry *dentry,
-+ struct dentry *parent,
-+ struct super_block *sb, int sbgen,
-+ int dgen, bool willwrite)
-+{
-+ int fgen;
-+ int bstart, bend, orig_brid;
-+ int size;
-+ int err = 0;
-+
-+ fgen = atomic_read(&UNIONFS_F(file)->generation);
-+
-+ /*
-+ * There are two cases we are interested in. The first is if the
-+ * generation is lower than the super-block. The second is if
-+ * someone has copied up this file from underneath us, we also need
-+ * to refresh things.
-+ */
-+ if (d_deleted(dentry) ||
-+ (sbgen <= fgen &&
-+ dbstart(dentry) == fbstart(file) &&
-+ unionfs_lower_file(file)))
-+ goto out_may_copyup;
-+
-+ /* save orig branch ID */
-+ orig_brid = UNIONFS_F(file)->saved_branch_ids[fbstart(file)];
-+
-+ /* First we throw out the existing files. */
-+ cleanup_file(file);
-+
-+ /* Now we reopen the file(s) as in unionfs_open. */
-+ bstart = fbstart(file) = dbstart(dentry);
-+ bend = fbend(file) = dbend(dentry);
-+
-+ size = sizeof(struct file *) * sbmax(sb);
-+ UNIONFS_F(file)->lower_files = kzalloc(size, GFP_KERNEL);
-+ if (unlikely(!UNIONFS_F(file)->lower_files)) {
-+ err = -ENOMEM;
-+ goto out;
-+ }
-+ size = sizeof(int) * sbmax(sb);
-+ UNIONFS_F(file)->saved_branch_ids = kzalloc(size, GFP_KERNEL);
-+ if (unlikely(!UNIONFS_F(file)->saved_branch_ids)) {
-+ err = -ENOMEM;
-+ goto out;
-+ }
-+
-+ if (S_ISDIR(dentry->d_inode->i_mode)) {
-+ /* We need to open all the files. */
-+ err = open_all_files(file);
-+ if (err)
-+ goto out;
-+ } else {
-+ int new_brid;
-+ /* We only open the highest priority branch. */
-+ err = open_highest_file(file, willwrite);
-+ if (err)
-+ goto out;
-+ new_brid = UNIONFS_F(file)->saved_branch_ids[fbstart(file)];
-+ if (unlikely(new_brid != orig_brid && sbgen > fgen)) {
-+ /*
-+ * If we re-opened the file on a different branch
-+ * than the original one, and this was due to a new
-+ * branch inserted, then update the mnt counts of
-+ * the old and new branches accordingly.
-+ */
-+ unionfs_mntget(dentry, bstart);
-+ unionfs_mntput(sb->s_root,
-+ branch_id_to_idx(sb, orig_brid));
-+ }
-+ /* regular files have only one open lower file */
-+ fbend(file) = fbstart(file);
-+ }
-+ atomic_set(&UNIONFS_F(file)->generation,
-+ atomic_read(&UNIONFS_I(dentry->d_inode)->generation));
-+
-+out_may_copyup:
-+ /* Copyup on the first write to a file on a readonly branch. */
-+ if (willwrite && IS_WRITE_FLAG(file->f_flags) &&
-+ !IS_WRITE_FLAG(unionfs_lower_file(file)->f_flags) &&
-+ is_robranch(dentry)) {
-+ pr_debug("unionfs: do delay copyup of \"%s\"\n",
-+ dentry->d_name.name);
-+ err = do_delayed_copyup(file, parent);
-+ /* regular files have only one open lower file */
-+ if (!err && !S_ISDIR(dentry->d_inode->i_mode))
-+ fbend(file) = fbstart(file);
-+ }
-+
-+out:
-+ if (err) {
-+ kfree(UNIONFS_F(file)->lower_files);
-+ kfree(UNIONFS_F(file)->saved_branch_ids);
-+ }
-+ return err;
-+}
-+
-+/*
-+ * Revalidate the struct file
-+ * @file: file to revalidate
-+ * @parent: parent dentry (locked by caller)
-+ * @willwrite: true if caller may cause changes to the file; false otherwise.
-+ * Caller must lock/unlock dentry's branch configuration.
-+ */
-+int unionfs_file_revalidate(struct file *file, struct dentry *parent,
-+ bool willwrite)
-+{
-+ struct super_block *sb;
-+ struct dentry *dentry;
-+ int sbgen, dgen;
-+ int err = 0;
-+
-+ dentry = file->f_path.dentry;
-+ sb = dentry->d_sb;
-+ verify_locked(dentry);
-+ verify_locked(parent);
-+
-+ /*
-+ * First revalidate the dentry inside struct file,
-+ * but not unhashed dentries.
-+ */
-+ if (!d_deleted(dentry) &&
-+ !__unionfs_d_revalidate(dentry, parent, willwrite)) {
-+ err = -ESTALE;
-+ goto out;
-+ }
-+
-+ sbgen = atomic_read(&UNIONFS_SB(sb)->generation);
-+ dgen = atomic_read(&UNIONFS_D(dentry)->generation);
-+
-+ if (unlikely(sbgen > dgen)) { /* XXX: should never happen */
-+ pr_debug("unionfs: failed to revalidate dentry (%s)\n",
-+ dentry->d_name.name);
-+ err = -ESTALE;
-+ goto out;
-+ }
-+
-+ err = __unionfs_file_revalidate(file, dentry, parent, sb,
-+ sbgen, dgen, willwrite);
-+out:
-+ return err;
-+}
-+
-+/* unionfs_open helper function: open a directory */
-+static int __open_dir(struct inode *inode, struct file *file,
-+ struct dentry *parent)
-+{
-+ struct dentry *lower_dentry;
-+ struct file *lower_file;
-+ int bindex, bstart, bend;
-+ struct vfsmount *lower_mnt;
-+ struct dentry *dentry = file->f_path.dentry;
-+
-+ bstart = fbstart(file) = dbstart(dentry);
-+ bend = fbend(file) = dbend(dentry);
-+
-+ for (bindex = bstart; bindex <= bend; bindex++) {
-+ lower_dentry =
-+ unionfs_lower_dentry_idx(dentry, bindex);
-+ if (!lower_dentry)
-+ continue;
-+
-+ dget(lower_dentry);
-+ lower_mnt = unionfs_mntget(dentry, bindex);
-+ if (!lower_mnt)
-+ lower_mnt = unionfs_mntget(parent, bindex);
-+ lower_file = dentry_open(lower_dentry, lower_mnt, file->f_flags,
-+ current_cred());
-+ if (IS_ERR(lower_file))
-+ return PTR_ERR(lower_file);
-+
-+ unionfs_set_lower_file_idx(file, bindex, lower_file);
-+ if (!unionfs_lower_mnt_idx(dentry, bindex))
-+ unionfs_set_lower_mnt_idx(dentry, bindex, lower_mnt);
-+
-+ /*
-+ * The branchget goes after the open, because otherwise
-+ * we would miss the reference on release.
-+ */
-+ branchget(inode->i_sb, bindex);
-+ }
-+
-+ return 0;
-+}
-+
-+/* unionfs_open helper function: open a file */
-+static int __open_file(struct inode *inode, struct file *file,
-+ struct dentry *parent)
-+{
-+ struct dentry *lower_dentry;
-+ struct file *lower_file;
-+ int lower_flags;
-+ int bindex, bstart, bend;
-+ struct dentry *dentry = file->f_path.dentry;
-+ struct vfsmount *lower_mnt;
-+
-+ lower_dentry = unionfs_lower_dentry(dentry);
-+ lower_flags = file->f_flags;
-+
-+ bstart = fbstart(file) = dbstart(dentry);
-+ bend = fbend(file) = dbend(dentry);
-+
-+ /*
-+ * check for the permission for lower file. If the error is
-+ * COPYUP_ERR, copyup the file.
-+ */
-+ if (lower_dentry->d_inode && is_robranch(dentry)) {
-+ /*
-+ * if the open will change the file, copy it up otherwise
-+ * defer it.
-+ */
-+ if (lower_flags & O_TRUNC) {
-+ int size = 0;
-+ int err = -EROFS;
-+
-+ /* copyup the file */
-+ for (bindex = bstart - 1; bindex >= 0; bindex--) {
-+ err = copyup_file(parent->d_inode, file,
-+ bstart, bindex, size);
-+ if (!err) {
-+ /* only one regular file open */
-+ fbend(file) = fbstart(file);
-+ break;
-+ }
-+ }
-+ return err;
-+ } else {
-+ /*
-+ * turn off writeable flags, to force delayed copyup
-+ * by caller.
-+ */
-+ lower_flags &= ~(OPEN_WRITE_FLAGS);
-+ }
-+ }
-+
-+ dget(lower_dentry);
-+
-+ /*
-+ * dentry_open will decrement mnt refcnt if err.
-+ * otherwise fput() will do an mntput() for us upon file close.
-+ */
-+ lower_mnt = unionfs_mntget(dentry, bstart);
-+ lower_file = dentry_open(lower_dentry, lower_mnt, lower_flags,
-+ current_cred());
-+ if (IS_ERR(lower_file))
-+ return PTR_ERR(lower_file);
-+
-+ unionfs_set_lower_file(file, lower_file);
-+ branchget(inode->i_sb, bstart);
-+
-+ return 0;
-+}
-+
-+int unionfs_open(struct inode *inode, struct file *file)
-+{
-+ int err = 0;
-+ struct file *lower_file = NULL;
-+ struct dentry *dentry = file->f_path.dentry;
-+ struct dentry *parent;
-+ int bindex = 0, bstart = 0, bend = 0;
-+ int size;
-+ int valid = 0;
-+
-+ unionfs_read_lock(inode->i_sb, UNIONFS_SMUTEX_PARENT);
-+ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
-+ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+ /* don't open unhashed/deleted files */
-+ if (d_deleted(dentry)) {
-+ err = -ENOENT;
-+ goto out_nofree;
-+ }
-+
-+ /* XXX: should I change 'false' below to the 'willwrite' flag? */
-+ valid = __unionfs_d_revalidate(dentry, parent, false);
-+ if (unlikely(!valid)) {
-+ err = -ESTALE;
-+ goto out_nofree;
-+ }
-+
-+ file->private_data =
-+ kzalloc(sizeof(struct unionfs_file_info), GFP_KERNEL);
-+ if (unlikely(!UNIONFS_F(file))) {
-+ err = -ENOMEM;
-+ goto out_nofree;
-+ }
-+ fbstart(file) = -1;
-+ fbend(file) = -1;
-+ atomic_set(&UNIONFS_F(file)->generation,
-+ atomic_read(&UNIONFS_I(inode)->generation));
-+
-+ size = sizeof(struct file *) * sbmax(inode->i_sb);
-+ UNIONFS_F(file)->lower_files = kzalloc(size, GFP_KERNEL);
-+ if (unlikely(!UNIONFS_F(file)->lower_files)) {
-+ err = -ENOMEM;
-+ goto out;
-+ }
-+ size = sizeof(int) * sbmax(inode->i_sb);
-+ UNIONFS_F(file)->saved_branch_ids = kzalloc(size, GFP_KERNEL);
-+ if (unlikely(!UNIONFS_F(file)->saved_branch_ids)) {
-+ err = -ENOMEM;
-+ goto out;
-+ }
-+
-+ bstart = fbstart(file) = dbstart(dentry);
-+ bend = fbend(file) = dbend(dentry);
-+
-+ /*
-+ * open all directories and make the unionfs file struct point to
-+ * these lower file structs
-+ */
-+ if (S_ISDIR(inode->i_mode))
-+ err = __open_dir(inode, file, parent); /* open a dir */
-+ else
-+ err = __open_file(inode, file, parent); /* open a file */
-+
-+ /* freeing the allocated resources, and fput the opened files */
-+ if (err) {
-+ for (bindex = bstart; bindex <= bend; bindex++) {
-+ lower_file = unionfs_lower_file_idx(file, bindex);
-+ if (!lower_file)
-+ continue;
-+
-+ branchput(dentry->d_sb, bindex);
-+ /* fput calls dput for lower_dentry */
-+ fput(lower_file);
-+ }
-+ }
-+
-+out:
-+ if (err) {
-+ kfree(UNIONFS_F(file)->lower_files);
-+ kfree(UNIONFS_F(file)->saved_branch_ids);
-+ kfree(UNIONFS_F(file));
-+ }
-+out_nofree:
-+ if (!err) {
-+ unionfs_postcopyup_setmnt(dentry);
-+ unionfs_copy_attr_times(inode);
-+ unionfs_check_file(file);
-+ unionfs_check_inode(inode);
-+ }
-+ unionfs_unlock_dentry(dentry);
-+ unionfs_unlock_parent(dentry, parent);
-+ unionfs_read_unlock(inode->i_sb);
-+ return err;
-+}
-+
-+/*
-+ * release all lower object references & free the file info structure
-+ *
-+ * No need to grab sb info's rwsem.
-+ */
-+int unionfs_file_release(struct inode *inode, struct file *file)
-+{
-+ struct file *lower_file = NULL;
-+ struct unionfs_file_info *fileinfo;
-+ struct unionfs_inode_info *inodeinfo;
-+ struct super_block *sb = inode->i_sb;
-+ struct dentry *dentry = file->f_path.dentry;
-+ struct dentry *parent;
-+ int bindex, bstart, bend;
-+ int err = 0;
-+
-+ /*
-+ * Since mm/memory.c:might_fault() (under PROVE_LOCKING) was
-+ * modified in 2.6.29-rc1 to call might_lock_read on mmap_sem, this
-+ * has been causing false positives in file system stacking layers.
-+ * In particular, our ->mmap is called after sys_mmap2 already holds
-+ * mmap_sem, then we lock our own mutexes; but earlier, it's
-+ * possible for lockdep to have locked our mutexes first, and then
-+ * we call a lower ->readdir which could call might_fault. The
-+ * different ordering of the locks is what lockdep complains about
-+ * -- unnecessarily. Therefore, we have no choice but to tell
-+ * lockdep to temporarily turn off lockdep here. Note: the comments
-+ * inside might_sleep also suggest that it would have been
-+ * nicer to only annotate paths that needs that might_lock_read.
-+ */
-+ lockdep_off();
-+ unionfs_read_lock(sb, UNIONFS_SMUTEX_PARENT);
-+ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
-+ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+ /*
-+ * We try to revalidate, but the VFS ignores return return values
-+ * from file->release, so we must always try to succeed here,
-+ * including to do the kfree and dput below. So if revalidation
-+ * failed, all we can do is print some message and keep going.
-+ */
-+ err = unionfs_file_revalidate(file, parent,
-+ UNIONFS_F(file)->wrote_to_file);
-+ if (!err)
-+ unionfs_check_file(file);
-+ fileinfo = UNIONFS_F(file);
-+ BUG_ON(file->f_path.dentry->d_inode != inode);
-+ inodeinfo = UNIONFS_I(inode);
-+
-+ /* fput all the lower files */
-+ bstart = fbstart(file);
-+ bend = fbend(file);
-+
-+ for (bindex = bstart; bindex <= bend; bindex++) {
-+ lower_file = unionfs_lower_file_idx(file, bindex);
-+
-+ if (lower_file) {
-+ unionfs_set_lower_file_idx(file, bindex, NULL);
-+ fput(lower_file);
-+ branchput(sb, bindex);
-+ }
-+
-+ /* if there are no more refs to the dentry, dput it */
-+ if (d_deleted(dentry)) {
-+ dput(unionfs_lower_dentry_idx(dentry, bindex));
-+ unionfs_set_lower_dentry_idx(dentry, bindex, NULL);
-+ }
-+ }
-+
-+ kfree(fileinfo->lower_files);
-+ kfree(fileinfo->saved_branch_ids);
-+
-+ if (fileinfo->rdstate) {
-+ fileinfo->rdstate->access = jiffies;
-+ spin_lock(&inodeinfo->rdlock);
-+ inodeinfo->rdcount++;
-+ list_add_tail(&fileinfo->rdstate->cache,
-+ &inodeinfo->readdircache);
-+ mark_inode_dirty(inode);
-+ spin_unlock(&inodeinfo->rdlock);
-+ fileinfo->rdstate = NULL;
-+ }
-+ kfree(fileinfo);
-+
-+ unionfs_unlock_dentry(dentry);
-+ unionfs_unlock_parent(dentry, parent);
-+ unionfs_read_unlock(sb);
-+ lockdep_on();
-+ return err;
-+}
-+
-+/* pass the ioctl to the lower fs */
-+static long do_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
-+{
-+ struct file *lower_file;
-+ int err;
-+
-+ lower_file = unionfs_lower_file(file);
-+
-+ err = -ENOTTY;
-+ if (!lower_file || !lower_file->f_op)
-+ goto out;
-+ if (lower_file->f_op->unlocked_ioctl) {
-+ err = lower_file->f_op->unlocked_ioctl(lower_file, cmd, arg);
-+#ifdef CONFIG_COMPAT
-+ } else if (lower_file->f_op->compat_ioctl) {
-+ err = lower_file->f_op->compat_ioctl(lower_file, cmd, arg);
-+#endif
-+ }
-+
-+out:
-+ return err;
-+}
-+
-+/*
-+ * return to user-space the branch indices containing the file in question
-+ *
-+ * We use fd_set and therefore we are limited to the number of the branches
-+ * to FD_SETSIZE, which is currently 1024 - plenty for most people
-+ */
-+static int unionfs_ioctl_queryfile(struct file *file, struct dentry *parent,
-+ unsigned int cmd, unsigned long arg)
-+{
-+ int err = 0;
-+ fd_set branchlist;
-+ int bstart = 0, bend = 0, bindex = 0;
-+ int orig_bstart, orig_bend;
-+ struct dentry *dentry, *lower_dentry;
-+ struct vfsmount *mnt;
-+
-+ dentry = file->f_path.dentry;
-+ orig_bstart = dbstart(dentry);
-+ orig_bend = dbend(dentry);
-+ err = unionfs_partial_lookup(dentry, parent);
-+ if (err)
-+ goto out;
-+ bstart = dbstart(dentry);
-+ bend = dbend(dentry);
-+
-+ FD_ZERO(&branchlist);
-+
-+ for (bindex = bstart; bindex <= bend; bindex++) {
-+ lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
-+ if (!lower_dentry)
-+ continue;
-+ if (likely(lower_dentry->d_inode))
-+ FD_SET(bindex, &branchlist);
-+ /* purge any lower objects after partial_lookup */
-+ if (bindex < orig_bstart || bindex > orig_bend) {
-+ dput(lower_dentry);
-+ unionfs_set_lower_dentry_idx(dentry, bindex, NULL);
-+ iput(unionfs_lower_inode_idx(dentry->d_inode, bindex));
-+ unionfs_set_lower_inode_idx(dentry->d_inode, bindex,
-+ NULL);
-+ mnt = unionfs_lower_mnt_idx(dentry, bindex);
-+ if (!mnt)
-+ continue;
-+ unionfs_mntput(dentry, bindex);
-+ unionfs_set_lower_mnt_idx(dentry, bindex, NULL);
-+ }
-+ }
-+ /* restore original dentry's offsets */
-+ dbstart(dentry) = orig_bstart;
-+ dbend(dentry) = orig_bend;
-+ ibstart(dentry->d_inode) = orig_bstart;
-+ ibend(dentry->d_inode) = orig_bend;
-+
-+ err = copy_to_user((void __user *)arg, &branchlist, sizeof(fd_set));
-+ if (unlikely(err))
-+ err = -EFAULT;
-+
-+out:
-+ return err < 0 ? err : bend;
-+}
-+
-+long unionfs_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
-+{
-+ long err;
-+ struct dentry *dentry = file->f_path.dentry;
-+ struct dentry *parent;
-+
-+ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT);
-+ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
-+ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+ err = unionfs_file_revalidate(file, parent, true);
-+ if (unlikely(err))
-+ goto out;
-+
-+ /* check if asked for local commands */
-+ switch (cmd) {
-+ case UNIONFS_IOCTL_INCGEN:
-+ /* Increment the superblock generation count */
-+ pr_info("unionfs: incgen ioctl deprecated; "
-+ "use \"-o remount,incgen\"\n");
-+ err = -ENOSYS;
-+ break;
-+
-+ case UNIONFS_IOCTL_QUERYFILE:
-+ /* Return list of branches containing the given file */
-+ err = unionfs_ioctl_queryfile(file, parent, cmd, arg);
-+ break;
-+
-+ default:
-+ /* pass the ioctl down */
-+ err = do_ioctl(file, cmd, arg);
-+ break;
-+ }
-+
-+out:
-+ unionfs_check_file(file);
-+ unionfs_unlock_dentry(dentry);
-+ unionfs_unlock_parent(dentry, parent);
-+ unionfs_read_unlock(dentry->d_sb);
-+ return err;
-+}
-+
-+int unionfs_flush(struct file *file, fl_owner_t id)
-+{
-+ int err = 0;
-+ struct file *lower_file = NULL;
-+ struct dentry *dentry = file->f_path.dentry;
-+ struct dentry *parent;
-+ int bindex, bstart, bend;
-+
-+ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT);
-+ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
-+ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+ err = unionfs_file_revalidate(file, parent,
-+ UNIONFS_F(file)->wrote_to_file);
-+ if (unlikely(err))
-+ goto out;
-+ unionfs_check_file(file);
-+
-+ bstart = fbstart(file);
-+ bend = fbend(file);
-+ for (bindex = bstart; bindex <= bend; bindex++) {
-+ lower_file = unionfs_lower_file_idx(file, bindex);
-+
-+ if (lower_file && lower_file->f_op &&
-+ lower_file->f_op->flush) {
-+ err = lower_file->f_op->flush(lower_file, id);
-+ if (err)
-+ goto out;
-+ }
-+
-+ }
-+
-+out:
-+ if (!err)
-+ unionfs_check_file(file);
-+ unionfs_unlock_dentry(dentry);
-+ unionfs_unlock_parent(dentry, parent);
-+ unionfs_read_unlock(dentry->d_sb);
-+ return err;
-+}
-diff --git a/fs/unionfs/copyup.c b/fs/unionfs/copyup.c
-new file mode 100644
-index 0000000..078ca27
---- /dev/null
-+++ b/fs/unionfs/copyup.c
-@@ -0,0 +1,899 @@
-+/*
-+ * Copyright (c) 2003-2011 Erez Zadok
-+ * Copyright (c) 2003-2006 Charles P. Wright
-+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2005-2006 Junjiro Okajima
-+ * Copyright (c) 2005 Arun M. Krishnakumar
-+ * Copyright (c) 2004-2006 David P. Quigley
-+ * Copyright (c) 2003-2004 Mohammad Nayyer Zubair
-+ * Copyright (c) 2003 Puja Gupta
-+ * Copyright (c) 2003 Harikesavan Krishnan
-+ * Copyright (c) 2003-2011 Stony Brook University
-+ * Copyright (c) 2003-2011 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#include "union.h"
-+
-+/*
-+ * For detailed explanation of copyup see:
-+ * Documentation/filesystems/unionfs/concepts.txt
-+ */
-+
-+#ifdef CONFIG_UNION_FS_XATTR
-+/* copyup all extended attrs for a given dentry */
-+static int copyup_xattrs(struct dentry *old_lower_dentry,
-+ struct dentry *new_lower_dentry)
-+{
-+ int err = 0;
-+ ssize_t list_size = -1;
-+ char *name_list = NULL;
-+ char *attr_value = NULL;
-+ char *name_list_buf = NULL;
-+
-+ /* query the actual size of the xattr list */
-+ list_size = vfs_listxattr(old_lower_dentry, NULL, 0);
-+ if (list_size <= 0) {
-+ err = list_size;
-+ goto out;
-+ }
-+
-+ /* allocate space for the actual list */
-+ name_list = unionfs_xattr_alloc(list_size + 1, XATTR_LIST_MAX);
-+ if (unlikely(!name_list || IS_ERR(name_list))) {
-+ err = PTR_ERR(name_list);
-+ goto out;
-+ }
-+
-+ name_list_buf = name_list; /* save for kfree at end */
-+
-+ /* now get the actual xattr list of the source file */
-+ list_size = vfs_listxattr(old_lower_dentry, name_list, list_size);
-+ if (list_size <= 0) {
-+ err = list_size;
-+ goto out;
-+ }
-+
-+ /* allocate space to hold each xattr's value */
-+ attr_value = unionfs_xattr_alloc(XATTR_SIZE_MAX, XATTR_SIZE_MAX);
-+ if (unlikely(!attr_value || IS_ERR(attr_value))) {
-+ err = PTR_ERR(name_list);
-+ goto out;
-+ }
-+
-+ /* in a loop, get and set each xattr from src to dst file */
-+ while (*name_list) {
-+ ssize_t size;
-+
-+ /* Lock here since vfs_getxattr doesn't lock for us */
-+ mutex_lock(&old_lower_dentry->d_inode->i_mutex);
-+ size = vfs_getxattr(old_lower_dentry, name_list,
-+ attr_value, XATTR_SIZE_MAX);
-+ mutex_unlock(&old_lower_dentry->d_inode->i_mutex);
-+ if (size < 0) {
-+ err = size;
-+ goto out;
-+ }
-+ if (size > XATTR_SIZE_MAX) {
-+ err = -E2BIG;
-+ goto out;
-+ }
-+ /* Don't lock here since vfs_setxattr does it for us. */
-+ err = vfs_setxattr(new_lower_dentry, name_list, attr_value,
-+ size, 0);
-+ /*
-+ * Selinux depends on "security.*" xattrs, so to maintain
-+ * the security of copied-up files, if Selinux is active,
-+ * then we must copy these xattrs as well. So we need to
-+ * temporarily get FOWNER privileges.
-+ * XXX: move entire copyup code to SIOQ.
-+ */
-+ if (err == -EPERM && !capable(CAP_FOWNER)) {
-+ const struct cred *old_creds;
-+ struct cred *new_creds;
-+
-+ new_creds = prepare_creds();
-+ if (unlikely(!new_creds)) {
-+ err = -ENOMEM;
-+ goto out;
-+ }
-+ cap_raise(new_creds->cap_effective, CAP_FOWNER);
-+ old_creds = override_creds(new_creds);
-+ err = vfs_setxattr(new_lower_dentry, name_list,
-+ attr_value, size, 0);
-+ revert_creds(old_creds);
-+ }
-+ if (err < 0)
-+ goto out;
-+ name_list += strlen(name_list) + 1;
-+ }
-+out:
-+ unionfs_xattr_kfree(name_list_buf);
-+ unionfs_xattr_kfree(attr_value);
-+ /* Ignore if xattr isn't supported */
-+ if (err == -ENOTSUPP || err == -EOPNOTSUPP)
-+ err = 0;
-+ return err;
-+}
-+#endif /* CONFIG_UNION_FS_XATTR */
-+
-+/*
-+ * Determine the mode based on the copyup flags, and the existing dentry.
-+ *
-+ * Handle file systems which may not support certain options. For example
-+ * jffs2 doesn't allow one to chmod a symlink. So we ignore such harmless
-+ * errors, rather than propagating them up, which results in copyup errors
-+ * and errors returned back to users.
-+ */
-+static int copyup_permissions(struct super_block *sb,
-+ struct dentry *old_lower_dentry,
-+ struct dentry *new_lower_dentry)
-+{
-+ struct inode *i = old_lower_dentry->d_inode;
-+ struct iattr newattrs;
-+ int err;
-+
-+ newattrs.ia_atime = i->i_atime;
-+ newattrs.ia_mtime = i->i_mtime;
-+ newattrs.ia_ctime = i->i_ctime;
-+ newattrs.ia_gid = i->i_gid;
-+ newattrs.ia_uid = i->i_uid;
-+ newattrs.ia_valid = ATTR_CTIME | ATTR_ATIME | ATTR_MTIME |
-+ ATTR_ATIME_SET | ATTR_MTIME_SET | ATTR_FORCE |
-+ ATTR_GID | ATTR_UID;
-+ mutex_lock(&new_lower_dentry->d_inode->i_mutex);
-+ err = notify_change(new_lower_dentry, &newattrs);
-+ if (err)
-+ goto out;
-+
-+ /* now try to change the mode and ignore EOPNOTSUPP on symlinks */
-+ newattrs.ia_mode = i->i_mode;
-+ newattrs.ia_valid = ATTR_MODE | ATTR_FORCE;
-+ err = notify_change(new_lower_dentry, &newattrs);
-+ if (err == -EOPNOTSUPP &&
-+ S_ISLNK(new_lower_dentry->d_inode->i_mode)) {
-+ printk(KERN_WARNING
-+ "unionfs: changing \"%s\" symlink mode unsupported\n",
-+ new_lower_dentry->d_name.name);
-+ err = 0;
-+ }
-+
-+out:
-+ mutex_unlock(&new_lower_dentry->d_inode->i_mutex);
-+ return err;
-+}
-+
-+/*
-+ * create the new device/file/directory - use copyup_permission to copyup
-+ * times, and mode
-+ *
-+ * if the object being copied up is a regular file, the file is only created,
-+ * the contents have to be copied up separately
-+ */
-+static int __copyup_ndentry(struct dentry *old_lower_dentry,
-+ struct dentry *new_lower_dentry,
-+ struct dentry *new_lower_parent_dentry,
-+ char *symbuf)
-+{
-+ int err = 0;
-+ umode_t old_mode = old_lower_dentry->d_inode->i_mode;
-+ struct sioq_args args;
-+
-+ if (S_ISDIR(old_mode)) {
-+ args.mkdir.parent = new_lower_parent_dentry->d_inode;
-+ args.mkdir.dentry = new_lower_dentry;
-+ args.mkdir.mode = old_mode;
-+
-+ run_sioq(__unionfs_mkdir, &args);
-+ err = args.err;
-+ } else if (S_ISLNK(old_mode)) {
-+ args.symlink.parent = new_lower_parent_dentry->d_inode;
-+ args.symlink.dentry = new_lower_dentry;
-+ args.symlink.symbuf = symbuf;
-+
-+ run_sioq(__unionfs_symlink, &args);
-+ err = args.err;
-+ } else if (S_ISBLK(old_mode) || S_ISCHR(old_mode) ||
-+ S_ISFIFO(old_mode) || S_ISSOCK(old_mode)) {
-+ args.mknod.parent = new_lower_parent_dentry->d_inode;
-+ args.mknod.dentry = new_lower_dentry;
-+ args.mknod.mode = old_mode;
-+ args.mknod.dev = old_lower_dentry->d_inode->i_rdev;
-+
-+ run_sioq(__unionfs_mknod, &args);
-+ err = args.err;
-+ } else if (S_ISREG(old_mode)) {
-+ struct nameidata nd;
-+ err = init_lower_nd(&nd, LOOKUP_CREATE);
-+ if (unlikely(err < 0))
-+ goto out;
-+ args.create.nd = &nd;
-+ args.create.parent = new_lower_parent_dentry->d_inode;
-+ args.create.dentry = new_lower_dentry;
-+ args.create.mode = old_mode;
-+
-+ run_sioq(__unionfs_create, &args);
-+ err = args.err;
-+ release_lower_nd(&nd, err);
-+ } else {
-+ printk(KERN_CRIT "unionfs: unknown inode type %d\n",
-+ old_mode);
-+ BUG();
-+ }
-+
-+out:
-+ return err;
-+}
-+
-+static int __copyup_reg_data(struct dentry *dentry,
-+ struct dentry *new_lower_dentry, int new_bindex,
-+ struct dentry *old_lower_dentry, int old_bindex,
-+ struct file **copyup_file, loff_t len)
-+{
-+ struct super_block *sb = dentry->d_sb;
-+ struct file *input_file;
-+ struct file *output_file;
-+ struct vfsmount *output_mnt;
-+ mm_segment_t old_fs;
-+ char *buf = NULL;
-+ ssize_t read_bytes, write_bytes;
-+ loff_t size;
-+ int err = 0;
-+
-+ /* open old file */
-+ unionfs_mntget(dentry, old_bindex);
-+ branchget(sb, old_bindex);
-+ /* dentry_open calls dput and mntput if it returns an error */
-+ input_file = dentry_open(old_lower_dentry,
-+ unionfs_lower_mnt_idx(dentry, old_bindex),
-+ O_RDONLY | O_LARGEFILE, current_cred());
-+ if (IS_ERR(input_file)) {
-+ dput(old_lower_dentry);
-+ err = PTR_ERR(input_file);
-+ goto out;
-+ }
-+ if (unlikely(!input_file->f_op || !input_file->f_op->read)) {
-+ err = -EINVAL;
-+ goto out_close_in;
-+ }
-+
-+ /* open new file */
-+ dget(new_lower_dentry);
-+ output_mnt = unionfs_mntget(sb->s_root, new_bindex);
-+ branchget(sb, new_bindex);
-+ output_file = dentry_open(new_lower_dentry, output_mnt,
-+ O_RDWR | O_LARGEFILE, current_cred());
-+ if (IS_ERR(output_file)) {
-+ err = PTR_ERR(output_file);
-+ goto out_close_in2;
-+ }
-+ if (unlikely(!output_file->f_op || !output_file->f_op->write)) {
-+ err = -EINVAL;
-+ goto out_close_out;
-+ }
-+
-+ /* allocating a buffer */
-+ buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
-+ if (unlikely(!buf)) {
-+ err = -ENOMEM;
-+ goto out_close_out;
-+ }
-+
-+ input_file->f_pos = 0;
-+ output_file->f_pos = 0;
-+
-+ old_fs = get_fs();
-+ set_fs(KERNEL_DS);
-+
-+ size = len;
-+ err = 0;
-+ do {
-+ if (len >= PAGE_SIZE)
-+ size = PAGE_SIZE;
-+ else if ((len < PAGE_SIZE) && (len > 0))
-+ size = len;
-+
-+ len -= PAGE_SIZE;
-+
-+ read_bytes =
-+ input_file->f_op->read(input_file,
-+ (char __user *)buf, size,
-+ &input_file->f_pos);
-+ if (read_bytes <= 0) {
-+ err = read_bytes;
-+ break;
-+ }
-+
-+ /* see Documentation/filesystems/unionfs/issues.txt */
-+ lockdep_off();
-+ write_bytes =
-+ output_file->f_op->write(output_file,
-+ (char __user *)buf,
-+ read_bytes,
-+ &output_file->f_pos);
-+ lockdep_on();
-+ if ((write_bytes < 0) || (write_bytes < read_bytes)) {
-+ err = write_bytes;
-+ break;
-+ }
-+ } while ((read_bytes > 0) && (len > 0));
-+
-+ set_fs(old_fs);
-+
-+ kfree(buf);
-+
-+#if 0
-+ /* XXX: code no longer needed? */
-+ if (!err)
-+ err = output_file->f_op->fsync(output_file, 0);
-+#endif
-+
-+ if (err)
-+ goto out_close_out;
-+
-+ if (copyup_file) {
-+ *copyup_file = output_file;
-+ goto out_close_in;
-+ }
-+
-+out_close_out:
-+ fput(output_file);
-+
-+out_close_in2:
-+ branchput(sb, new_bindex);
-+
-+out_close_in:
-+ fput(input_file);
-+
-+out:
-+ branchput(sb, old_bindex);
-+
-+ return err;
-+}
-+
-+/*
-+ * dput the lower references for old and new dentry & clear a lower dentry
-+ * pointer
-+ */
-+static void __clear(struct dentry *dentry, struct dentry *old_lower_dentry,
-+ int old_bstart, int old_bend,
-+ struct dentry *new_lower_dentry, int new_bindex)
-+{
-+ /* get rid of the lower dentry and all its traces */
-+ unionfs_set_lower_dentry_idx(dentry, new_bindex, NULL);
-+ dbstart(dentry) = old_bstart;
-+ dbend(dentry) = old_bend;
-+
-+ dput(new_lower_dentry);
-+ dput(old_lower_dentry);
-+}
-+
-+/*
-+ * Copy up a dentry to a file of specified name.
-+ *
-+ * @dir: used to pull the ->i_sb to access other branches
-+ * @dentry: the non-negative dentry whose lower_inode we should copy
-+ * @bstart: the branch of the lower_inode to copy from
-+ * @new_bindex: the branch to create the new file in
-+ * @name: the name of the file to create
-+ * @namelen: length of @name
-+ * @copyup_file: the "struct file" to return (optional)
-+ * @len: how many bytes to copy-up?
-+ */
-+int copyup_dentry(struct inode *dir, struct dentry *dentry, int bstart,
-+ int new_bindex, const char *name, int namelen,
-+ struct file **copyup_file, loff_t len)
-+{
-+ struct dentry *new_lower_dentry;
-+ struct dentry *old_lower_dentry = NULL;
-+ struct super_block *sb;
-+ int err = 0;
-+ int old_bindex;
-+ int old_bstart;
-+ int old_bend;
-+ struct dentry *new_lower_parent_dentry = NULL;
-+ mm_segment_t oldfs;
-+ char *symbuf = NULL;
-+
-+ verify_locked(dentry);
-+
-+ old_bindex = bstart;
-+ old_bstart = dbstart(dentry);
-+ old_bend = dbend(dentry);
-+
-+ BUG_ON(new_bindex < 0);
-+ BUG_ON(new_bindex >= old_bindex);
-+
-+ sb = dir->i_sb;
-+
-+ err = is_robranch_super(sb, new_bindex);
-+ if (err)
-+ goto out;
-+
-+ /* Create the directory structure above this dentry. */
-+ new_lower_dentry = create_parents(dir, dentry, name, new_bindex);
-+ if (IS_ERR(new_lower_dentry)) {
-+ err = PTR_ERR(new_lower_dentry);
-+ goto out;
-+ }
-+
-+ old_lower_dentry = unionfs_lower_dentry_idx(dentry, old_bindex);
-+ /* we conditionally dput this old_lower_dentry at end of function */
-+ dget(old_lower_dentry);
-+
-+ /* For symlinks, we must read the link before we lock the directory. */
-+ if (S_ISLNK(old_lower_dentry->d_inode->i_mode)) {
-+
-+ symbuf = kmalloc(PATH_MAX, GFP_KERNEL);
-+ if (unlikely(!symbuf)) {
-+ __clear(dentry, old_lower_dentry,
-+ old_bstart, old_bend,
-+ new_lower_dentry, new_bindex);
-+ err = -ENOMEM;
-+ goto out_free;
-+ }
-+
-+ oldfs = get_fs();
-+ set_fs(KERNEL_DS);
-+ err = old_lower_dentry->d_inode->i_op->readlink(
-+ old_lower_dentry,
-+ (char __user *)symbuf,
-+ PATH_MAX);
-+ set_fs(oldfs);
-+ if (err < 0) {
-+ __clear(dentry, old_lower_dentry,
-+ old_bstart, old_bend,
-+ new_lower_dentry, new_bindex);
-+ goto out_free;
-+ }
-+ symbuf[err] = '\0';
-+ }
-+
-+ /* Now we lock the parent, and create the object in the new branch. */
-+ new_lower_parent_dentry = lock_parent(new_lower_dentry);
-+
-+ /* create the new inode */
-+ err = __copyup_ndentry(old_lower_dentry, new_lower_dentry,
-+ new_lower_parent_dentry, symbuf);
-+
-+ if (err) {
-+ __clear(dentry, old_lower_dentry,
-+ old_bstart, old_bend,
-+ new_lower_dentry, new_bindex);
-+ goto out_unlock;
-+ }
-+
-+ /* We actually copyup the file here. */
-+ if (S_ISREG(old_lower_dentry->d_inode->i_mode))
-+ err = __copyup_reg_data(dentry, new_lower_dentry, new_bindex,
-+ old_lower_dentry, old_bindex,
-+ copyup_file, len);
-+ if (err)
-+ goto out_unlink;
-+
-+ /* Set permissions. */
-+ err = copyup_permissions(sb, old_lower_dentry, new_lower_dentry);
-+ if (err)
-+ goto out_unlink;
-+
-+#ifdef CONFIG_UNION_FS_XATTR
-+ /* Selinux uses extended attributes for permissions. */
-+ err = copyup_xattrs(old_lower_dentry, new_lower_dentry);
-+ if (err)
-+ goto out_unlink;
-+#endif /* CONFIG_UNION_FS_XATTR */
-+
-+ /* do not allow files getting deleted to be re-interposed */
-+ if (!d_deleted(dentry))
-+ unionfs_reinterpose(dentry);
-+
-+ goto out_unlock;
-+
-+out_unlink:
-+ /*
-+ * copyup failed, because we possibly ran out of space or
-+ * quota, or something else happened so let's unlink; we don't
-+ * really care about the return value of vfs_unlink
-+ */
-+ vfs_unlink(new_lower_parent_dentry->d_inode, new_lower_dentry);
-+
-+ if (copyup_file) {
-+ /* need to close the file */
-+
-+ fput(*copyup_file);
-+ branchput(sb, new_bindex);
-+ }
-+
-+ /*
-+ * TODO: should we reset the error to something like -EIO?
-+ *
-+ * If we don't reset, the user may get some nonsensical errors, but
-+ * on the other hand, if we reset to EIO, we guarantee that the user
-+ * will get a "confusing" error message.
-+ */
-+
-+out_unlock:
-+ unlock_dir(new_lower_parent_dentry);
-+
-+out_free:
-+ /*
-+ * If old_lower_dentry was not a file, then we need to dput it. If
-+ * it was a file, then it was already dput indirectly by other
-+ * functions we call above which operate on regular files.
-+ */
-+ if (old_lower_dentry && old_lower_dentry->d_inode &&
-+ !S_ISREG(old_lower_dentry->d_inode->i_mode))
-+ dput(old_lower_dentry);
-+ kfree(symbuf);
-+
-+ if (err) {
-+ /*
-+ * if directory creation succeeded, but inode copyup failed,
-+ * then purge new dentries.
-+ */
-+ if (dbstart(dentry) < old_bstart &&
-+ ibstart(dentry->d_inode) > dbstart(dentry))
-+ __clear(dentry, NULL, old_bstart, old_bend,
-+ unionfs_lower_dentry(dentry), dbstart(dentry));
-+ goto out;
-+ }
-+ if (!S_ISDIR(dentry->d_inode->i_mode)) {
-+ unionfs_postcopyup_release(dentry);
-+ if (!unionfs_lower_inode(dentry->d_inode)) {
-+ /*
-+ * If we got here, then we copied up to an
-+ * unlinked-open file, whose name is .unionfsXXXXX.
-+ */
-+ struct inode *inode = new_lower_dentry->d_inode;
-+ atomic_inc(&inode->i_count);
-+ unionfs_set_lower_inode_idx(dentry->d_inode,
-+ ibstart(dentry->d_inode),
-+ inode);
-+ }
-+ }
-+ unionfs_postcopyup_setmnt(dentry);
-+ /* sync inode times from copied-up inode to our inode */
-+ unionfs_copy_attr_times(dentry->d_inode);
-+ unionfs_check_inode(dir);
-+ unionfs_check_dentry(dentry);
-+out:
-+ return err;
-+}
-+
-+/*
-+ * This function creates a copy of a file represented by 'file' which
-+ * currently resides in branch 'bstart' to branch 'new_bindex.' The copy
-+ * will be named "name".
-+ */
-+int copyup_named_file(struct inode *dir, struct file *file, char *name,
-+ int bstart, int new_bindex, loff_t len)
-+{
-+ int err = 0;
-+ struct file *output_file = NULL;
-+
-+ err = copyup_dentry(dir, file->f_path.dentry, bstart, new_bindex,
-+ name, strlen(name), &output_file, len);
-+ if (!err) {
-+ fbstart(file) = new_bindex;
-+ unionfs_set_lower_file_idx(file, new_bindex, output_file);
-+ }
-+
-+ return err;
-+}
-+
-+/*
-+ * This function creates a copy of a file represented by 'file' which
-+ * currently resides in branch 'bstart' to branch 'new_bindex'.
-+ */
-+int copyup_file(struct inode *dir, struct file *file, int bstart,
-+ int new_bindex, loff_t len)
-+{
-+ int err = 0;
-+ struct file *output_file = NULL;
-+ struct dentry *dentry = file->f_path.dentry;
-+
-+ err = copyup_dentry(dir, dentry, bstart, new_bindex,
-+ dentry->d_name.name, dentry->d_name.len,
-+ &output_file, len);
-+ if (!err) {
-+ fbstart(file) = new_bindex;
-+ unionfs_set_lower_file_idx(file, new_bindex, output_file);
-+ }
-+
-+ return err;
-+}
-+
-+/* purge a dentry's lower-branch states (dput/mntput, etc.) */
-+static void __cleanup_dentry(struct dentry *dentry, int bindex,
-+ int old_bstart, int old_bend)
-+{
-+ int loop_start;
-+ int loop_end;
-+ int new_bstart = -1;
-+ int new_bend = -1;
-+ int i;
-+
-+ loop_start = min(old_bstart, bindex);
-+ loop_end = max(old_bend, bindex);
-+
-+ /*
-+ * This loop sets the bstart and bend for the new dentry by
-+ * traversing from left to right. It also dputs all negative
-+ * dentries except bindex
-+ */
-+ for (i = loop_start; i <= loop_end; i++) {
-+ if (!unionfs_lower_dentry_idx(dentry, i))
-+ continue;
-+
-+ if (i == bindex) {
-+ new_bend = i;
-+ if (new_bstart < 0)
-+ new_bstart = i;
-+ continue;
-+ }
-+
-+ if (!unionfs_lower_dentry_idx(dentry, i)->d_inode) {
-+ dput(unionfs_lower_dentry_idx(dentry, i));
-+ unionfs_set_lower_dentry_idx(dentry, i, NULL);
-+
-+ unionfs_mntput(dentry, i);
-+ unionfs_set_lower_mnt_idx(dentry, i, NULL);
-+ } else {
-+ if (new_bstart < 0)
-+ new_bstart = i;
-+ new_bend = i;
-+ }
-+ }
-+
-+ if (new_bstart < 0)
-+ new_bstart = bindex;
-+ if (new_bend < 0)
-+ new_bend = bindex;
-+ dbstart(dentry) = new_bstart;
-+ dbend(dentry) = new_bend;
-+
-+}
-+
-+/* set lower inode ptr and update bstart & bend if necessary */
-+static void __set_inode(struct dentry *upper, struct dentry *lower,
-+ int bindex)
-+{
-+ unionfs_set_lower_inode_idx(upper->d_inode, bindex,
-+ igrab(lower->d_inode));
-+ if (likely(ibstart(upper->d_inode) > bindex))
-+ ibstart(upper->d_inode) = bindex;
-+ if (likely(ibend(upper->d_inode) < bindex))
-+ ibend(upper->d_inode) = bindex;
-+
-+}
-+
-+/* set lower dentry ptr and update bstart & bend if necessary */
-+static void __set_dentry(struct dentry *upper, struct dentry *lower,
-+ int bindex)
-+{
-+ unionfs_set_lower_dentry_idx(upper, bindex, lower);
-+ if (likely(dbstart(upper) > bindex))
-+ dbstart(upper) = bindex;
-+ if (likely(dbend(upper) < bindex))
-+ dbend(upper) = bindex;
-+}
-+
-+/*
-+ * This function replicates the directory structure up-to given dentry
-+ * in the bindex branch.
-+ */
-+struct dentry *create_parents(struct inode *dir, struct dentry *dentry,
-+ const char *name, int bindex)
-+{
-+ int err;
-+ struct dentry *child_dentry;
-+ struct dentry *parent_dentry;
-+ struct dentry *lower_parent_dentry = NULL;
-+ struct dentry *lower_dentry = NULL;
-+ const char *childname;
-+ unsigned int childnamelen;
-+ int nr_dentry;
-+ int count = 0;
-+ int old_bstart;
-+ int old_bend;
-+ struct dentry **path = NULL;
-+ struct super_block *sb;
-+
-+ verify_locked(dentry);
-+
-+ err = is_robranch_super(dir->i_sb, bindex);
-+ if (err) {
-+ lower_dentry = ERR_PTR(err);
-+ goto out;
-+ }
-+
-+ old_bstart = dbstart(dentry);
-+ old_bend = dbend(dentry);
-+
-+ lower_dentry = ERR_PTR(-ENOMEM);
-+
-+ /* There is no sense allocating any less than the minimum. */
-+ nr_dentry = 1;
-+ path = kmalloc(nr_dentry * sizeof(struct dentry *), GFP_KERNEL);
-+ if (unlikely(!path))
-+ goto out;
-+
-+ /* assume the negative dentry of unionfs as the parent dentry */
-+ parent_dentry = dentry;
-+
-+ /*
-+ * This loop finds the first parent that exists in the given branch.
-+ * We start building the directory structure from there. At the end
-+ * of the loop, the following should hold:
-+ * - child_dentry is the first nonexistent child
-+ * - parent_dentry is the first existent parent
-+ * - path[0] is the = deepest child
-+ * - path[count] is the first child to create
-+ */
-+ do {
-+ child_dentry = parent_dentry;
-+
-+ /* find the parent directory dentry in unionfs */
-+ parent_dentry = dget_parent(child_dentry);
-+
-+ /* find out the lower_parent_dentry in the given branch */
-+ lower_parent_dentry =
-+ unionfs_lower_dentry_idx(parent_dentry, bindex);
-+
-+ /* grow path table */
-+ if (count == nr_dentry) {
-+ void *p;
-+
-+ nr_dentry *= 2;
-+ p = krealloc(path, nr_dentry * sizeof(struct dentry *),
-+ GFP_KERNEL);
-+ if (unlikely(!p)) {
-+ lower_dentry = ERR_PTR(-ENOMEM);
-+ goto out;
-+ }
-+ path = p;
-+ }
-+
-+ /* store the child dentry */
-+ path[count++] = child_dentry;
-+ } while (!lower_parent_dentry);
-+ count--;
-+
-+ sb = dentry->d_sb;
-+
-+ /*
-+ * This code goes between the begin/end labels and basically
-+ * emulates a while(child_dentry != dentry), only cleaner and
-+ * shorter than what would be a much longer while loop.
-+ */
-+begin:
-+ /* get lower parent dir in the current branch */
-+ lower_parent_dentry = unionfs_lower_dentry_idx(parent_dentry, bindex);
-+ dput(parent_dentry);
-+
-+ /* init the values to lookup */
-+ childname = child_dentry->d_name.name;
-+ childnamelen = child_dentry->d_name.len;
-+
-+ if (child_dentry != dentry) {
-+ /* lookup child in the underlying file system */
-+ lower_dentry = lookup_lck_len(childname, lower_parent_dentry,
-+ childnamelen);
-+ if (IS_ERR(lower_dentry))
-+ goto out;
-+ } else {
-+ /*
-+ * Is the name a whiteout of the child name ? lookup the
-+ * whiteout child in the underlying file system
-+ */
-+ lower_dentry = lookup_lck_len(name, lower_parent_dentry,
-+ strlen(name));
-+ if (IS_ERR(lower_dentry))
-+ goto out;
-+
-+ /* Replace the current dentry (if any) with the new one */
-+ dput(unionfs_lower_dentry_idx(dentry, bindex));
-+ unionfs_set_lower_dentry_idx(dentry, bindex,
-+ lower_dentry);
-+
-+ __cleanup_dentry(dentry, bindex, old_bstart, old_bend);
-+ goto out;
-+ }
-+
-+ if (lower_dentry->d_inode) {
-+ /*
-+ * since this already exists we dput to avoid
-+ * multiple references on the same dentry
-+ */
-+ dput(lower_dentry);
-+ } else {
-+ struct sioq_args args;
-+
-+ /* it's a negative dentry, create a new dir */
-+ lower_parent_dentry = lock_parent(lower_dentry);
-+
-+ args.mkdir.parent = lower_parent_dentry->d_inode;
-+ args.mkdir.dentry = lower_dentry;
-+ args.mkdir.mode = child_dentry->d_inode->i_mode;
-+
-+ run_sioq(__unionfs_mkdir, &args);
-+ err = args.err;
-+
-+ if (!err)
-+ err = copyup_permissions(dir->i_sb, child_dentry,
-+ lower_dentry);
-+ unlock_dir(lower_parent_dentry);
-+ if (err) {
-+ dput(lower_dentry);
-+ lower_dentry = ERR_PTR(err);
-+ goto out;
-+ }
-+
-+ }
-+
-+ __set_inode(child_dentry, lower_dentry, bindex);
-+ __set_dentry(child_dentry, lower_dentry, bindex);
-+ /*
-+ * update times of this dentry, but also the parent, because if
-+ * we changed, the parent may have changed too.
-+ */
-+ fsstack_copy_attr_times(parent_dentry->d_inode,
-+ lower_parent_dentry->d_inode);
-+ unionfs_copy_attr_times(child_dentry->d_inode);
-+
-+ parent_dentry = child_dentry;
-+ child_dentry = path[--count];
-+ goto begin;
-+out:
-+ /* cleanup any leftover locks from the do/while loop above */
-+ if (IS_ERR(lower_dentry))
-+ while (count)
-+ dput(path[count--]);
-+ kfree(path);
-+ return lower_dentry;
-+}
-+
-+/*
-+ * Post-copyup helper to ensure we have valid mnts: set lower mnt of
-+ * dentry+parents to the first parent node that has an mnt.
-+ */
-+void unionfs_postcopyup_setmnt(struct dentry *dentry)
-+{
-+ struct dentry *parent, *hasone;
-+ int bindex = dbstart(dentry);
-+
-+ if (unionfs_lower_mnt_idx(dentry, bindex))
-+ return;
-+ hasone = dentry->d_parent;
-+ /* this loop should stop at root dentry */
-+ while (!unionfs_lower_mnt_idx(hasone, bindex))
-+ hasone = hasone->d_parent;
-+ parent = dentry;
-+ while (!unionfs_lower_mnt_idx(parent, bindex)) {
-+ unionfs_set_lower_mnt_idx(parent, bindex,
-+ unionfs_mntget(hasone, bindex));
-+ parent = parent->d_parent;
-+ }
-+}
-+
-+/*
-+ * Post-copyup helper to release all non-directory source objects of a
-+ * copied-up file. Regular files should have only one lower object.
-+ */
-+void unionfs_postcopyup_release(struct dentry *dentry)
-+{
-+ int bstart, bend;
-+
-+ BUG_ON(S_ISDIR(dentry->d_inode->i_mode));
-+ bstart = dbstart(dentry);
-+ bend = dbend(dentry);
-+
-+ path_put_lowers(dentry, bstart + 1, bend, false);
-+ iput_lowers(dentry->d_inode, bstart + 1, bend, false);
-+
-+ dbend(dentry) = bstart;
-+ ibend(dentry->d_inode) = ibstart(dentry->d_inode) = bstart;
-+}
-diff --git a/fs/unionfs/debug.c b/fs/unionfs/debug.c
-new file mode 100644
-index 0000000..21ce90c
---- /dev/null
-+++ b/fs/unionfs/debug.c
-@@ -0,0 +1,551 @@
-+/*
-+ * Copyright (c) 2003-2011 Erez Zadok
-+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2003-2011 Stony Brook University
-+ * Copyright (c) 2003-2011 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#include "union.h"
-+#include "../mount.h"
-+
-+/*
-+ * Helper debugging functions for maintainers (and for users to report back
-+ * useful information back to maintainers)
-+ */
-+
-+/* it's always useful to know what part of the code called us */
-+#define PRINT_CALLER(fname, fxn, line) \
-+ do { \
-+ if (!printed_caller) { \
-+ pr_debug("PC:%s:%s:%d\n", (fname), (fxn), (line)); \
-+ printed_caller = 1; \
-+ } \
-+ } while (0)
-+
-+/*
-+ * __unionfs_check_{inode,dentry,file} perform exhaustive sanity checking on
-+ * the fan-out of various Unionfs objects. We check that no lower objects
-+ * exist outside the start/end branch range; that all objects within are
-+ * non-NULL (with some allowed exceptions); that for every lower file
-+ * there's a lower dentry+inode; that the start/end ranges match for all
-+ * corresponding lower objects; that open files/symlinks have only one lower
-+ * objects, but directories can have several; and more.
-+ */
-+void __unionfs_check_inode(const struct inode *inode,
-+ const char *fname, const char *fxn, int line)
-+{
-+ int bindex;
-+ int istart, iend;
-+ struct inode *lower_inode;
-+ struct super_block *sb;
-+ int printed_caller = 0;
-+ void *poison_ptr;
-+
-+ /* for inodes now */
-+ BUG_ON(!inode);
-+ sb = inode->i_sb;
-+ istart = ibstart(inode);
-+ iend = ibend(inode);
-+ /* don't check inode if no lower branches */
-+ if (istart < 0 && iend < 0)
-+ return;
-+ if (unlikely(istart > iend)) {
-+ PRINT_CALLER(fname, fxn, line);
-+ pr_debug(" Ci0: inode=%p istart/end=%d:%d\n",
-+ inode, istart, iend);
-+ }
-+ if (unlikely((istart == -1 && iend != -1) ||
-+ (istart != -1 && iend == -1))) {
-+ PRINT_CALLER(fname, fxn, line);
-+ pr_debug(" Ci1: inode=%p istart/end=%d:%d\n",
-+ inode, istart, iend);
-+ }
-+ if (!S_ISDIR(inode->i_mode)) {
-+ if (unlikely(iend != istart)) {
-+ PRINT_CALLER(fname, fxn, line);
-+ pr_debug(" Ci2: inode=%p istart=%d iend=%d\n",
-+ inode, istart, iend);
-+ }
-+ }
-+
-+ for (bindex = sbstart(sb); bindex < sbmax(sb); bindex++) {
-+ if (unlikely(!UNIONFS_I(inode))) {
-+ PRINT_CALLER(fname, fxn, line);
-+ pr_debug(" Ci3: no inode_info %p\n", inode);
-+ return;
-+ }
-+ if (unlikely(!UNIONFS_I(inode)->lower_inodes)) {
-+ PRINT_CALLER(fname, fxn, line);
-+ pr_debug(" Ci4: no lower_inodes %p\n", inode);
-+ return;
-+ }
-+ lower_inode = unionfs_lower_inode_idx(inode, bindex);
-+ if (lower_inode) {
-+ memset(&poison_ptr, POISON_INUSE, sizeof(void *));
-+ if (unlikely(bindex < istart || bindex > iend)) {
-+ PRINT_CALLER(fname, fxn, line);
-+ pr_debug(" Ci5: inode/linode=%p:%p bindex=%d "
-+ "istart/end=%d:%d\n", inode,
-+ lower_inode, bindex, istart, iend);
-+ } else if (unlikely(lower_inode == poison_ptr)) {
-+ /* freed inode! */
-+ PRINT_CALLER(fname, fxn, line);
-+ pr_debug(" Ci6: inode/linode=%p:%p bindex=%d "
-+ "istart/end=%d:%d\n", inode,
-+ lower_inode, bindex, istart, iend);
-+ }
-+ continue;
-+ }
-+ /* if we get here, then lower_inode == NULL */
-+ if (bindex < istart || bindex > iend)
-+ continue;
-+ /*
-+ * directories can have NULL lower inodes in b/t start/end,
-+ * but NOT if at the start/end range.
-+ */
-+ if (unlikely(S_ISDIR(inode->i_mode) &&
-+ bindex > istart && bindex < iend))
-+ continue;
-+ PRINT_CALLER(fname, fxn, line);
-+ pr_debug(" Ci7: inode/linode=%p:%p "
-+ "bindex=%d istart/end=%d:%d\n",
-+ inode, lower_inode, bindex, istart, iend);
-+ }
-+}
-+
-+void __unionfs_check_dentry(const struct dentry *dentry,
-+ const char *fname, const char *fxn, int line)
-+{
-+ int bindex;
-+ int dstart, dend, istart, iend;
-+ struct dentry *lower_dentry;
-+ struct inode *inode, *lower_inode;
-+ struct super_block *sb;
-+ struct vfsmount *lower_mnt;
-+ int printed_caller = 0;
-+ void *poison_ptr;
-+
-+ BUG_ON(!dentry);
-+ sb = dentry->d_sb;
-+ inode = dentry->d_inode;
-+ dstart = dbstart(dentry);
-+ dend = dbend(dentry);
-+ /* don't check dentry/mnt if no lower branches */
-+ if (dstart < 0 && dend < 0)
-+ goto check_inode;
-+ BUG_ON(dstart > dend);
-+
-+ if (unlikely((dstart == -1 && dend != -1) ||
-+ (dstart != -1 && dend == -1))) {
-+ PRINT_CALLER(fname, fxn, line);
-+ pr_debug(" CD0: dentry=%p dstart/end=%d:%d\n",
-+ dentry, dstart, dend);
-+ }
-+ /*
-+ * check for NULL dentries inside the start/end range, or
-+ * non-NULL dentries outside the start/end range.
-+ */
-+ for (bindex = sbstart(sb); bindex < sbmax(sb); bindex++) {
-+ lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
-+ if (lower_dentry) {
-+ if (unlikely(bindex < dstart || bindex > dend)) {
-+ PRINT_CALLER(fname, fxn, line);
-+ pr_debug(" CD1: dentry/lower=%p:%p(%p) "
-+ "bindex=%d dstart/end=%d:%d\n",
-+ dentry, lower_dentry,
-+ (lower_dentry ? lower_dentry->d_inode :
-+ (void *) -1L),
-+ bindex, dstart, dend);
-+ }
-+ } else { /* lower_dentry == NULL */
-+ if (bindex < dstart || bindex > dend)
-+ continue;
-+ /*
-+ * Directories can have NULL lower inodes in b/t
-+ * start/end, but NOT if at the start/end range.
-+ * Ignore this rule, however, if this is a NULL
-+ * dentry or a deleted dentry.
-+ */
-+ if (unlikely(!d_deleted((struct dentry *) dentry) &&
-+ inode &&
-+ !(inode && S_ISDIR(inode->i_mode) &&
-+ bindex > dstart && bindex < dend))) {
-+ PRINT_CALLER(fname, fxn, line);
-+ pr_debug(" CD2: dentry/lower=%p:%p(%p) "
-+ "bindex=%d dstart/end=%d:%d\n",
-+ dentry, lower_dentry,
-+ (lower_dentry ?
-+ lower_dentry->d_inode :
-+ (void *) -1L),
-+ bindex, dstart, dend);
-+ }
-+ }
-+ }
-+
-+ /* check for vfsmounts same as for dentries */
-+ for (bindex = sbstart(sb); bindex < sbmax(sb); bindex++) {
-+ lower_mnt = unionfs_lower_mnt_idx(dentry, bindex);
-+ if (lower_mnt) {
-+ if (unlikely(bindex < dstart || bindex > dend)) {
-+ PRINT_CALLER(fname, fxn, line);
-+ pr_debug(" CM0: dentry/lmnt=%p:%p bindex=%d "
-+ "dstart/end=%d:%d\n", dentry,
-+ lower_mnt, bindex, dstart, dend);
-+ }
-+ } else { /* lower_mnt == NULL */
-+ if (bindex < dstart || bindex > dend)
-+ continue;
-+ /*
-+ * Directories can have NULL lower inodes in b/t
-+ * start/end, but NOT if at the start/end range.
-+ * Ignore this rule, however, if this is a NULL
-+ * dentry.
-+ */
-+ if (unlikely(inode &&
-+ !(inode && S_ISDIR(inode->i_mode) &&
-+ bindex > dstart && bindex < dend))) {
-+ PRINT_CALLER(fname, fxn, line);
-+ pr_debug(" CM1: dentry/lmnt=%p:%p "
-+ "bindex=%d dstart/end=%d:%d\n",
-+ dentry, lower_mnt, bindex,
-+ dstart, dend);
-+ }
-+ }
-+ }
-+
-+check_inode:
-+ /* for inodes now */
-+ if (!inode)
-+ return;
-+ istart = ibstart(inode);
-+ iend = ibend(inode);
-+ /* don't check inode if no lower branches */
-+ if (istart < 0 && iend < 0)
-+ return;
-+ BUG_ON(istart > iend);
-+ if (unlikely((istart == -1 && iend != -1) ||
-+ (istart != -1 && iend == -1))) {
-+ PRINT_CALLER(fname, fxn, line);
-+ pr_debug(" CI0: dentry/inode=%p:%p istart/end=%d:%d\n",
-+ dentry, inode, istart, iend);
-+ }
-+ if (unlikely(istart != dstart)) {
-+ PRINT_CALLER(fname, fxn, line);
-+ pr_debug(" CI1: dentry/inode=%p:%p istart=%d dstart=%d\n",
-+ dentry, inode, istart, dstart);
-+ }
-+ if (unlikely(iend != dend)) {
-+ PRINT_CALLER(fname, fxn, line);
-+ pr_debug(" CI2: dentry/inode=%p:%p iend=%d dend=%d\n",
-+ dentry, inode, iend, dend);
-+ }
-+
-+ if (!S_ISDIR(inode->i_mode)) {
-+ if (unlikely(dend != dstart)) {
-+ PRINT_CALLER(fname, fxn, line);
-+ pr_debug(" CI3: dentry/inode=%p:%p dstart=%d dend=%d\n",
-+ dentry, inode, dstart, dend);
-+ }
-+ if (unlikely(iend != istart)) {
-+ PRINT_CALLER(fname, fxn, line);
-+ pr_debug(" CI4: dentry/inode=%p:%p istart=%d iend=%d\n",
-+ dentry, inode, istart, iend);
-+ }
-+ }
-+
-+ for (bindex = sbstart(sb); bindex < sbmax(sb); bindex++) {
-+ lower_inode = unionfs_lower_inode_idx(inode, bindex);
-+ if (lower_inode) {
-+ memset(&poison_ptr, POISON_INUSE, sizeof(void *));
-+ if (unlikely(bindex < istart || bindex > iend)) {
-+ PRINT_CALLER(fname, fxn, line);
-+ pr_debug(" CI5: dentry/linode=%p:%p bindex=%d "
-+ "istart/end=%d:%d\n", dentry,
-+ lower_inode, bindex, istart, iend);
-+ } else if (unlikely(lower_inode == poison_ptr)) {
-+ /* freed inode! */
-+ PRINT_CALLER(fname, fxn, line);
-+ pr_debug(" CI6: dentry/linode=%p:%p bindex=%d "
-+ "istart/end=%d:%d\n", dentry,
-+ lower_inode, bindex, istart, iend);
-+ }
-+ continue;
-+ }
-+ /* if we get here, then lower_inode == NULL */
-+ if (bindex < istart || bindex > iend)
-+ continue;
-+ /*
-+ * directories can have NULL lower inodes in b/t start/end,
-+ * but NOT if at the start/end range.
-+ */
-+ if (unlikely(S_ISDIR(inode->i_mode) &&
-+ bindex > istart && bindex < iend))
-+ continue;
-+ PRINT_CALLER(fname, fxn, line);
-+ pr_debug(" CI7: dentry/linode=%p:%p "
-+ "bindex=%d istart/end=%d:%d\n",
-+ dentry, lower_inode, bindex, istart, iend);
-+ }
-+
-+ /*
-+ * If it's a directory, then intermediate objects b/t start/end can
-+ * be NULL. But, check that all three are NULL: lower dentry, mnt,
-+ * and inode.
-+ */
-+ if (dstart >= 0 && dend >= 0 && S_ISDIR(inode->i_mode))
-+ for (bindex = dstart+1; bindex < dend; bindex++) {
-+ lower_inode = unionfs_lower_inode_idx(inode, bindex);
-+ lower_dentry = unionfs_lower_dentry_idx(dentry,
-+ bindex);
-+ lower_mnt = unionfs_lower_mnt_idx(dentry, bindex);
-+ if (unlikely(!((lower_inode && lower_dentry &&
-+ lower_mnt) ||
-+ (!lower_inode &&
-+ !lower_dentry && !lower_mnt)))) {
-+ PRINT_CALLER(fname, fxn, line);
-+ pr_debug(" Cx: lmnt/ldentry/linode=%p:%p:%p "
-+ "bindex=%d dstart/end=%d:%d\n",
-+ lower_mnt, lower_dentry, lower_inode,
-+ bindex, dstart, dend);
-+ }
-+ }
-+ /* check if lower inode is newer than upper one (it shouldn't) */
-+ if (unlikely(is_newer_lower(dentry) && !is_negative_lower(dentry))) {
-+ PRINT_CALLER(fname, fxn, line);
-+ for (bindex = ibstart(inode); bindex <= ibend(inode);
-+ bindex++) {
-+ lower_inode = unionfs_lower_inode_idx(inode, bindex);
-+ if (unlikely(!lower_inode))
-+ continue;
-+ pr_debug(" CI8: bindex=%d mtime/lmtime=%lu.%lu/%lu.%lu "
-+ "ctime/lctime=%lu.%lu/%lu.%lu\n",
-+ bindex,
-+ inode->i_mtime.tv_sec,
-+ inode->i_mtime.tv_nsec,
-+ lower_inode->i_mtime.tv_sec,
-+ lower_inode->i_mtime.tv_nsec,
-+ inode->i_ctime.tv_sec,
-+ inode->i_ctime.tv_nsec,
-+ lower_inode->i_ctime.tv_sec,
-+ lower_inode->i_ctime.tv_nsec);
-+ }
-+ }
-+}
-+
-+void __unionfs_check_file(const struct file *file,
-+ const char *fname, const char *fxn, int line)
-+{
-+ int bindex;
-+ int dstart, dend, fstart, fend;
-+ struct dentry *dentry;
-+ struct file *lower_file;
-+ struct inode *inode;
-+ struct super_block *sb;
-+ int printed_caller = 0;
-+
-+ BUG_ON(!file);
-+ dentry = file->f_path.dentry;
-+ sb = dentry->d_sb;
-+ dstart = dbstart(dentry);
-+ dend = dbend(dentry);
-+ BUG_ON(dstart > dend);
-+ fstart = fbstart(file);
-+ fend = fbend(file);
-+ BUG_ON(fstart > fend);
-+
-+ if (unlikely((fstart == -1 && fend != -1) ||
-+ (fstart != -1 && fend == -1))) {
-+ PRINT_CALLER(fname, fxn, line);
-+ pr_debug(" CF0: file/dentry=%p:%p fstart/end=%d:%d\n",
-+ file, dentry, fstart, fend);
-+ }
-+ /* d_deleted dentries can be ignored for this test */
-+ if (unlikely(fstart != dstart) && !d_deleted(dentry)) {
-+ PRINT_CALLER(fname, fxn, line);
-+ pr_debug(" CF1: file/dentry=%p:%p fstart=%d dstart=%d\n",
-+ file, dentry, fstart, dstart);
-+ }
-+ if (unlikely(fend != dend) && !d_deleted(dentry)) {
-+ PRINT_CALLER(fname, fxn, line);
-+ pr_debug(" CF2: file/dentry=%p:%p fend=%d dend=%d\n",
-+ file, dentry, fend, dend);
-+ }
-+ inode = dentry->d_inode;
-+ if (!S_ISDIR(inode->i_mode)) {
-+ if (unlikely(fend != fstart)) {
-+ PRINT_CALLER(fname, fxn, line);
-+ pr_debug(" CF3: file/inode=%p:%p fstart=%d fend=%d\n",
-+ file, inode, fstart, fend);
-+ }
-+ if (unlikely(dend != dstart)) {
-+ PRINT_CALLER(fname, fxn, line);
-+ pr_debug(" CF4: file/dentry=%p:%p dstart=%d dend=%d\n",
-+ file, dentry, dstart, dend);
-+ }
-+ }
-+
-+ /*
-+ * check for NULL dentries inside the start/end range, or
-+ * non-NULL dentries outside the start/end range.
-+ */
-+ for (bindex = sbstart(sb); bindex < sbmax(sb); bindex++) {
-+ lower_file = unionfs_lower_file_idx(file, bindex);
-+ if (lower_file) {
-+ if (unlikely(bindex < fstart || bindex > fend)) {
-+ PRINT_CALLER(fname, fxn, line);
-+ pr_debug(" CF5: file/lower=%p:%p bindex=%d "
-+ "fstart/end=%d:%d\n", file,
-+ lower_file, bindex, fstart, fend);
-+ }
-+ } else { /* lower_file == NULL */
-+ if (bindex >= fstart && bindex <= fend) {
-+ /*
-+ * directories can have NULL lower inodes in
-+ * b/t start/end, but NOT if at the
-+ * start/end range.
-+ */
-+ if (unlikely(!(S_ISDIR(inode->i_mode) &&
-+ bindex > fstart &&
-+ bindex < fend))) {
-+ PRINT_CALLER(fname, fxn, line);
-+ pr_debug(" CF6: file/lower=%p:%p "
-+ "bindex=%d fstart/end=%d:%d\n",
-+ file, lower_file, bindex,
-+ fstart, fend);
-+ }
-+ }
-+ }
-+ }
-+
-+ __unionfs_check_dentry(dentry, fname, fxn, line);
-+}
-+
-+void __unionfs_check_nd(const struct nameidata *nd,
-+ const char *fname, const char *fxn, int line)
-+{
-+ struct file *file;
-+ int printed_caller = 0;
-+
-+ if (unlikely(!nd))
-+ return;
-+ if (nd->flags & LOOKUP_OPEN) {
-+ file = nd->intent.open.file;
-+ if (unlikely(file->f_path.dentry &&
-+ strcmp(file->f_path.dentry->d_sb->s_type->name,
-+ UNIONFS_NAME))) {
-+ PRINT_CALLER(fname, fxn, line);
-+ pr_debug(" CND1: lower_file of type %s\n",
-+ file->f_path.dentry->d_sb->s_type->name);
-+ }
-+ }
-+}
-+
-+static unsigned int __mnt_get_count(struct vfsmount *mnt)
-+{
-+ struct mount *m = real_mount(mnt);
-+#ifdef CONFIG_SMP
-+ unsigned int count = 0;
-+ int cpu;
-+
-+ for_each_possible_cpu(cpu) {
-+ count += per_cpu_ptr(m->mnt_pcp, cpu)->mnt_count;
-+ }
-+
-+ return count;
-+#else
-+ return m->mnt_count;
-+#endif
-+}
-+
-+/* useful to track vfsmount leaks that could cause EBUSY on unmount */
-+void __show_branch_counts(const struct super_block *sb,
-+ const char *file, const char *fxn, int line)
-+{
-+ int i;
-+ struct vfsmount *mnt;
-+
-+ pr_debug("BC:");
-+ for (i = 0; i < sbmax(sb); i++) {
-+ if (likely(sb->s_root))
-+ mnt = UNIONFS_D(sb->s_root)->lower_paths[i].mnt;
-+ else
-+ mnt = NULL;
-+ printk(KERN_CONT "%d:",
-+ (mnt ? __mnt_get_count(mnt) : -99));
-+ }
-+ printk(KERN_CONT "%s:%s:%d\n", file, fxn, line);
-+}
-+
-+void __show_inode_times(const struct inode *inode,
-+ const char *file, const char *fxn, int line)
-+{
-+ struct inode *lower_inode;
-+ int bindex;
-+
-+ for (bindex = ibstart(inode); bindex <= ibend(inode); bindex++) {
-+ lower_inode = unionfs_lower_inode_idx(inode, bindex);
-+ if (unlikely(!lower_inode))
-+ continue;
-+ pr_debug("IT(%lu:%d): %s:%s:%d "
-+ "um=%lu/%lu lm=%lu/%lu uc=%lu/%lu lc=%lu/%lu\n",
-+ inode->i_ino, bindex,
-+ file, fxn, line,
-+ inode->i_mtime.tv_sec, inode->i_mtime.tv_nsec,
-+ lower_inode->i_mtime.tv_sec,
-+ lower_inode->i_mtime.tv_nsec,
-+ inode->i_ctime.tv_sec, inode->i_ctime.tv_nsec,
-+ lower_inode->i_ctime.tv_sec,
-+ lower_inode->i_ctime.tv_nsec);
-+ }
-+}
-+
-+void __show_dinode_times(const struct dentry *dentry,
-+ const char *file, const char *fxn, int line)
-+{
-+ struct inode *inode = dentry->d_inode;
-+ struct inode *lower_inode;
-+ int bindex;
-+
-+ for (bindex = ibstart(inode); bindex <= ibend(inode); bindex++) {
-+ lower_inode = unionfs_lower_inode_idx(inode, bindex);
-+ if (!lower_inode)
-+ continue;
-+ pr_debug("DT(%s:%lu:%d): %s:%s:%d "
-+ "um=%lu/%lu lm=%lu/%lu uc=%lu/%lu lc=%lu/%lu\n",
-+ dentry->d_name.name, inode->i_ino, bindex,
-+ file, fxn, line,
-+ inode->i_mtime.tv_sec, inode->i_mtime.tv_nsec,
-+ lower_inode->i_mtime.tv_sec,
-+ lower_inode->i_mtime.tv_nsec,
-+ inode->i_ctime.tv_sec, inode->i_ctime.tv_nsec,
-+ lower_inode->i_ctime.tv_sec,
-+ lower_inode->i_ctime.tv_nsec);
-+ }
-+}
-+
-+void __show_inode_counts(const struct inode *inode,
-+ const char *file, const char *fxn, int line)
-+{
-+ struct inode *lower_inode;
-+ int bindex;
-+
-+ if (unlikely(!inode)) {
-+ pr_debug("SiC: Null inode\n");
-+ return;
-+ }
-+ for (bindex = sbstart(inode->i_sb); bindex <= sbend(inode->i_sb);
-+ bindex++) {
-+ lower_inode = unionfs_lower_inode_idx(inode, bindex);
-+ if (unlikely(!lower_inode))
-+ continue;
-+ pr_debug("SIC(%lu:%d:%d): lc=%d %s:%s:%d\n",
-+ inode->i_ino, bindex,
-+ atomic_read(&(inode)->i_count),
-+ atomic_read(&(lower_inode)->i_count),
-+ file, fxn, line);
-+ }
-+}
-diff --git a/fs/unionfs/dentry.c b/fs/unionfs/dentry.c
-new file mode 100644
-index 0000000..1628dad
---- /dev/null
-+++ b/fs/unionfs/dentry.c
-@@ -0,0 +1,409 @@
-+/*
-+ * Copyright (c) 2003-2011 Erez Zadok
-+ * Copyright (c) 2003-2006 Charles P. Wright
-+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2005-2006 Junjiro Okajima
-+ * Copyright (c) 2005 Arun M. Krishnakumar
-+ * Copyright (c) 2004-2006 David P. Quigley
-+ * Copyright (c) 2003-2004 Mohammad Nayyer Zubair
-+ * Copyright (c) 2003 Puja Gupta
-+ * Copyright (c) 2003 Harikesavan Krishnan
-+ * Copyright (c) 2003-2011 Stony Brook University
-+ * Copyright (c) 2003-2011 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#include "union.h"
-+
-+bool is_negative_lower(const struct dentry *dentry)
-+{
-+ int bindex;
-+ struct dentry *lower_dentry;
-+
-+ BUG_ON(!dentry);
-+ /* cache coherency: check if file was deleted on lower branch */
-+ if (dbstart(dentry) < 0)
-+ return true;
-+ for (bindex = dbstart(dentry); bindex <= dbend(dentry); bindex++) {
-+ lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
-+ /* unhashed (i.e., unlinked) lower dentries don't count */
-+ if (lower_dentry && lower_dentry->d_inode &&
-+ !d_deleted(lower_dentry) &&
-+ !(lower_dentry->d_flags & DCACHE_NFSFS_RENAMED))
-+ return false;
-+ }
-+ return true;
-+}
-+
-+static inline void __dput_lowers(struct dentry *dentry, int start, int end)
-+{
-+ struct dentry *lower_dentry;
-+ int bindex;
-+
-+ if (start < 0)
-+ return;
-+ for (bindex = start; bindex <= end; bindex++) {
-+ lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
-+ if (!lower_dentry)
-+ continue;
-+ unionfs_set_lower_dentry_idx(dentry, bindex, NULL);
-+ dput(lower_dentry);
-+ }
-+}
-+
-+/*
-+ * Purge and invalidate as many data pages of a unionfs inode. This is
-+ * called when the lower inode has changed, and we want to force processes
-+ * to re-get the new data.
-+ */
-+static inline void purge_inode_data(struct inode *inode)
-+{
-+ /* remove all non-private mappings */
-+ unmap_mapping_range(inode->i_mapping, 0, 0, 0);
-+ /* invalidate as many pages as possible */
-+ invalidate_mapping_pages(inode->i_mapping, 0, -1);
-+ /*
-+ * Don't try to truncate_inode_pages here, because this could lead
-+ * to a deadlock between some of address_space ops and dentry
-+ * revalidation: the address space op is invoked with a lock on our
-+ * own page, and truncate_inode_pages will block on locked pages.
-+ */
-+}
-+
-+/*
-+ * Revalidate a single file/symlink/special dentry. Assume that info nodes
-+ * of the @dentry and its @parent are locked. Assume parent is valid,
-+ * otherwise return false (and let's hope the VFS will try to re-lookup this
-+ * dentry). Returns true if valid, false otherwise.
-+ */
-+bool __unionfs_d_revalidate(struct dentry *dentry, struct dentry *parent,
-+ bool willwrite)
-+{
-+ bool valid = true; /* default is valid */
-+ struct dentry *lower_dentry;
-+ struct dentry *result;
-+ int bindex, bstart, bend;
-+ int sbgen, dgen, pdgen;
-+ int positive = 0;
-+ int interpose_flag;
-+
-+ verify_locked(dentry);
-+ verify_locked(parent);
-+
-+ /* if the dentry is unhashed, do NOT revalidate */
-+ if (d_deleted(dentry))
-+ goto out;
-+
-+ dgen = atomic_read(&UNIONFS_D(dentry)->generation);
-+
-+ if (is_newer_lower(dentry)) {
-+ /* root dentry is always valid */
-+ if (IS_ROOT(dentry)) {
-+ unionfs_copy_attr_times(dentry->d_inode);
-+ } else {
-+ /*
-+ * reset generation number to zero, guaranteed to be
-+ * "old"
-+ */
-+ dgen = 0;
-+ atomic_set(&UNIONFS_D(dentry)->generation, dgen);
-+ }
-+ if (!willwrite)
-+ purge_inode_data(dentry->d_inode);
-+ }
-+
-+ sbgen = atomic_read(&UNIONFS_SB(dentry->d_sb)->generation);
-+
-+ BUG_ON(dbstart(dentry) == -1);
-+ if (dentry->d_inode)
-+ positive = 1;
-+
-+ /* if our dentry is valid, then validate all lower ones */
-+ if (sbgen == dgen)
-+ goto validate_lowers;
-+
-+ /* The root entry should always be valid */
-+ BUG_ON(IS_ROOT(dentry));
-+
-+ /* We can't work correctly if our parent isn't valid. */
-+ pdgen = atomic_read(&UNIONFS_D(parent)->generation);
-+
-+ /* Free the pointers for our inodes and this dentry. */
-+ path_put_lowers_all(dentry, false);
-+
-+ interpose_flag = INTERPOSE_REVAL_NEG;
-+ if (positive) {
-+ interpose_flag = INTERPOSE_REVAL;
-+ iput_lowers_all(dentry->d_inode, true);
-+ }
-+
-+ if (realloc_dentry_private_data(dentry) != 0) {
-+ valid = false;
-+ goto out;
-+ }
-+
-+ result = unionfs_lookup_full(dentry, parent, interpose_flag);
-+ if (result) {
-+ if (IS_ERR(result)) {
-+ valid = false;
-+ goto out;
-+ }
-+ /*
-+ * current unionfs_lookup_backend() doesn't return
-+ * a valid dentry
-+ */
-+ dput(dentry);
-+ dentry = result;
-+ }
-+
-+ if (unlikely(positive && is_negative_lower(dentry))) {
-+ /* call make_bad_inode here ? */
-+ d_drop(dentry);
-+ valid = false;
-+ goto out;
-+ }
-+
-+ /*
-+ * if we got here then we have revalidated our dentry and all lower
-+ * ones, so we can return safely.
-+ */
-+ if (!valid) /* lower dentry revalidation failed */
-+ goto out;
-+
-+ /*
-+ * If the parent's gen no. matches the superblock's gen no., then
-+ * we can update our denty's gen no. If they didn't match, then it
-+ * was OK to revalidate this dentry with a stale parent, but we'll
-+ * purposely not update our dentry's gen no. (so it can be redone);
-+ * and, we'll mark our parent dentry as invalid so it'll force it
-+ * (and our dentry) to be revalidated.
-+ */
-+ if (pdgen == sbgen)
-+ atomic_set(&UNIONFS_D(dentry)->generation, sbgen);
-+ goto out;
-+
-+validate_lowers:
-+
-+ /* The revalidation must occur across all branches */
-+ bstart = dbstart(dentry);
-+ bend = dbend(dentry);
-+ BUG_ON(bstart == -1);
-+ for (bindex = bstart; bindex <= bend; bindex++) {
-+ int err;
-+ struct nameidata lower_nd;
-+
-+ lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
-+ if (!lower_dentry || !lower_dentry->d_op
-+ || !lower_dentry->d_op->d_revalidate)
-+ continue;
-+ /*
-+ * Don't pass nameidata to lower file system, because we
-+ * don't want an arbitrary lower file being opened or
-+ * returned to us: it may be useless to us because of the
-+ * fanout nature of unionfs (cf. file/directory open-file
-+ * invariants). We will open lower files as and when needed
-+ * later on.
-+ */
-+ err = init_lower_nd(&lower_nd, LOOKUP_OPEN);
-+ if (unlikely(err < 0)) {
-+ valid = false;
-+ break;
-+ }
-+ if (!lower_dentry->d_op->d_revalidate(lower_dentry, &lower_nd))
-+ valid = false;
-+ release_lower_nd(&lower_nd, err);
-+ }
-+
-+ if (!dentry->d_inode ||
-+ ibstart(dentry->d_inode) < 0 ||
-+ ibend(dentry->d_inode) < 0) {
-+ valid = false;
-+ goto out;
-+ }
-+
-+ if (valid) {
-+ /*
-+ * If we get here, and we copy the meta-data from the lower
-+ * inode to our inode, then it is vital that we have already
-+ * purged all unionfs-level file data. We do that in the
-+ * caller (__unionfs_d_revalidate) by calling
-+ * purge_inode_data.
-+ */
-+ unionfs_copy_attr_all(dentry->d_inode,
-+ unionfs_lower_inode(dentry->d_inode));
-+ fsstack_copy_inode_size(dentry->d_inode,
-+ unionfs_lower_inode(dentry->d_inode));
-+ }
-+
-+out:
-+ return valid;
-+}
-+
-+/*
-+ * Determine if the lower inode objects have changed from below the unionfs
-+ * inode. Return true if changed, false otherwise.
-+ *
-+ * We check if the mtime or ctime have changed. However, the inode times
-+ * can be changed by anyone without much protection, including
-+ * asynchronously. This can sometimes cause unionfs to find that the lower
-+ * file system doesn't change its inode times quick enough, resulting in a
-+ * false positive indication (which is harmless, it just makes unionfs do
-+ * extra work in re-validating the objects). To minimize the chances of
-+ * these situations, we still consider such small time changes valid, but we
-+ * don't print debugging messages unless the time changes are greater than
-+ * UNIONFS_MIN_CC_TIME (which defaults to 3 seconds, as with NFS's acregmin)
-+ * because significant changes are more likely due to users manually
-+ * touching lower files.
-+ */
-+bool is_newer_lower(const struct dentry *dentry)
-+{
-+ int bindex;
-+ struct inode *inode;
-+ struct inode *lower_inode;
-+
-+ /* ignore if we're called on semi-initialized dentries/inodes */
-+ if (!dentry || !UNIONFS_D(dentry))
-+ return false;
-+ inode = dentry->d_inode;
-+ if (!inode || !UNIONFS_I(inode)->lower_inodes ||
-+ ibstart(inode) < 0 || ibend(inode) < 0)
-+ return false;
-+
-+ for (bindex = ibstart(inode); bindex <= ibend(inode); bindex++) {
-+ lower_inode = unionfs_lower_inode_idx(inode, bindex);
-+ if (!lower_inode)
-+ continue;
-+
-+ /* check if mtime/ctime have changed */
-+ if (unlikely(timespec_compare(&inode->i_mtime,
-+ &lower_inode->i_mtime) < 0)) {
-+ if ((lower_inode->i_mtime.tv_sec -
-+ inode->i_mtime.tv_sec) > UNIONFS_MIN_CC_TIME) {
-+ pr_info("unionfs: new lower inode mtime "
-+ "(bindex=%d, name=%s)\n", bindex,
-+ dentry->d_name.name);
-+ show_dinode_times(dentry);
-+ }
-+ return true;
-+ }
-+ if (unlikely(timespec_compare(&inode->i_ctime,
-+ &lower_inode->i_ctime) < 0)) {
-+ if ((lower_inode->i_ctime.tv_sec -
-+ inode->i_ctime.tv_sec) > UNIONFS_MIN_CC_TIME) {
-+ pr_info("unionfs: new lower inode ctime "
-+ "(bindex=%d, name=%s)\n", bindex,
-+ dentry->d_name.name);
-+ show_dinode_times(dentry);
-+ }
-+ return true;
-+ }
-+ }
-+
-+ /*
-+ * Last check: if this is a positive dentry, but somehow all lower
-+ * dentries are negative or unhashed, then this dentry needs to be
-+ * revalidated, because someone probably deleted the objects from
-+ * the lower branches directly.
-+ */
-+ if (is_negative_lower(dentry))
-+ return true;
-+
-+ return false; /* default: lower is not newer */
-+}
-+
-+static int unionfs_d_revalidate(struct dentry *dentry,
-+ struct nameidata *nd)
-+{
-+ bool valid = true;
-+ int err = 1; /* 1 means valid for the VFS */
-+ struct dentry *parent;
-+
-+ if (nd && nd->flags & LOOKUP_RCU)
-+ return -ECHILD;
-+
-+ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
-+ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
-+ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+ valid = __unionfs_d_revalidate(dentry, parent, false);
-+ if (valid) {
-+ unionfs_postcopyup_setmnt(dentry);
-+ unionfs_check_dentry(dentry);
-+ } else {
-+ d_drop(dentry);
-+ err = valid;
-+ }
-+ unionfs_unlock_dentry(dentry);
-+ unionfs_unlock_parent(dentry, parent);
-+ unionfs_read_unlock(dentry->d_sb);
-+
-+ return err;
-+}
-+
-+static void unionfs_d_release(struct dentry *dentry)
-+{
-+ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
-+ if (unlikely(!UNIONFS_D(dentry)))
-+ goto out; /* skip if no lower branches */
-+ /* must lock our branch configuration here */
-+ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+ unionfs_check_dentry(dentry);
-+ /* this could be a negative dentry, so check first */
-+ if (dbstart(dentry) < 0) {
-+ unionfs_unlock_dentry(dentry);
-+ goto out; /* due to a (normal) failed lookup */
-+ }
-+
-+ /* Release all the lower dentries */
-+ path_put_lowers_all(dentry, true);
-+
-+ unionfs_unlock_dentry(dentry);
-+
-+out:
-+ free_dentry_private_data(dentry);
-+ unionfs_read_unlock(dentry->d_sb);
-+ return;
-+}
-+
-+/*
-+ * Called when we're removing the last reference to our dentry. So we
-+ * should drop all lower references too.
-+ */
-+static void unionfs_d_iput(struct dentry *dentry, struct inode *inode)
-+{
-+ int rc;
-+
-+ BUG_ON(!dentry);
-+ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
-+ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+ if (!UNIONFS_D(dentry) || dbstart(dentry) < 0)
-+ goto drop_lower_inodes;
-+ path_put_lowers_all(dentry, false);
-+
-+drop_lower_inodes:
-+ rc = atomic_read(&inode->i_count);
-+ if (rc == 1 && inode->i_nlink == 1 && ibstart(inode) >= 0) {
-+ /* see Documentation/filesystems/unionfs/issues.txt */
-+ lockdep_off();
-+ iput(unionfs_lower_inode(inode));
-+ lockdep_on();
-+ unionfs_set_lower_inode(inode, NULL);
-+ /* XXX: may need to set start/end to -1? */
-+ }
-+
-+ iput(inode);
-+
-+ unionfs_unlock_dentry(dentry);
-+ unionfs_read_unlock(dentry->d_sb);
-+}
-+
-+struct dentry_operations unionfs_dops = {
-+ .d_revalidate = unionfs_d_revalidate,
-+ .d_release = unionfs_d_release,
-+ .d_iput = unionfs_d_iput,
-+};
-diff --git a/fs/unionfs/dirfops.c b/fs/unionfs/dirfops.c
-new file mode 100644
-index 0000000..72a9c1a
---- /dev/null
-+++ b/fs/unionfs/dirfops.c
-@@ -0,0 +1,302 @@
-+/*
-+ * Copyright (c) 2003-2011 Erez Zadok
-+ * Copyright (c) 2003-2006 Charles P. Wright
-+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2005-2006 Junjiro Okajima
-+ * Copyright (c) 2005 Arun M. Krishnakumar
-+ * Copyright (c) 2004-2006 David P. Quigley
-+ * Copyright (c) 2003-2004 Mohammad Nayyer Zubair
-+ * Copyright (c) 2003 Puja Gupta
-+ * Copyright (c) 2003 Harikesavan Krishnan
-+ * Copyright (c) 2003-2011 Stony Brook University
-+ * Copyright (c) 2003-2011 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#include "union.h"
-+
-+/* Make sure our rdstate is playing by the rules. */
-+static void verify_rdstate_offset(struct unionfs_dir_state *rdstate)
-+{
-+ BUG_ON(rdstate->offset >= DIREOF);
-+ BUG_ON(rdstate->cookie >= MAXRDCOOKIE);
-+}
-+
-+struct unionfs_getdents_callback {
-+ struct unionfs_dir_state *rdstate;
-+ void *dirent;
-+ int entries_written;
-+ int filldir_called;
-+ int filldir_error;
-+ filldir_t filldir;
-+ struct super_block *sb;
-+};
-+
-+/* based on generic filldir in fs/readir.c */
-+static int unionfs_filldir(void *dirent, const char *oname, int namelen,
-+ loff_t offset, u64 ino, unsigned int d_type)
-+{
-+ struct unionfs_getdents_callback *buf = dirent;
-+ struct filldir_node *found = NULL;
-+ int err = 0;
-+ int is_whiteout;
-+ char *name = (char *) oname;
-+
-+ buf->filldir_called++;
-+
-+ is_whiteout = is_whiteout_name(&name, &namelen);
-+
-+ found = find_filldir_node(buf->rdstate, name, namelen, is_whiteout);
-+
-+ if (found) {
-+ /*
-+ * If we had non-whiteout entry in dir cache, then mark it
-+ * as a whiteout and but leave it in the dir cache.
-+ */
-+ if (is_whiteout && !found->whiteout)
-+ found->whiteout = is_whiteout;
-+ goto out;
-+ }
-+
-+ /* if 'name' isn't a whiteout, filldir it. */
-+ if (!is_whiteout) {
-+ off_t pos = rdstate2offset(buf->rdstate);
-+ u64 unionfs_ino = ino;
-+
-+ err = buf->filldir(buf->dirent, name, namelen, pos,
-+ unionfs_ino, d_type);
-+ buf->rdstate->offset++;
-+ verify_rdstate_offset(buf->rdstate);
-+ }
-+ /*
-+ * If we did fill it, stuff it in our hash, otherwise return an
-+ * error.
-+ */
-+ if (err) {
-+ buf->filldir_error = err;
-+ goto out;
-+ }
-+ buf->entries_written++;
-+ err = add_filldir_node(buf->rdstate, name, namelen,
-+ buf->rdstate->bindex, is_whiteout);
-+ if (err)
-+ buf->filldir_error = err;
-+
-+out:
-+ return err;
-+}
-+
-+static int unionfs_readdir(struct file *file, void *dirent, filldir_t filldir)
-+{
-+ int err = 0;
-+ struct file *lower_file = NULL;
-+ struct dentry *dentry = file->f_path.dentry;
-+ struct dentry *parent;
-+ struct inode *inode = NULL;
-+ struct unionfs_getdents_callback buf;
-+ struct unionfs_dir_state *uds;
-+ int bend;
-+ loff_t offset;
-+
-+ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT);
-+ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
-+ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+ err = unionfs_file_revalidate(file, parent, false);
-+ if (unlikely(err))
-+ goto out;
-+
-+ inode = dentry->d_inode;
-+
-+ uds = UNIONFS_F(file)->rdstate;
-+ if (!uds) {
-+ if (file->f_pos == DIREOF) {
-+ goto out;
-+ } else if (file->f_pos > 0) {
-+ uds = find_rdstate(inode, file->f_pos);
-+ if (unlikely(!uds)) {
-+ err = -ESTALE;
-+ goto out;
-+ }
-+ UNIONFS_F(file)->rdstate = uds;
-+ } else {
-+ init_rdstate(file);
-+ uds = UNIONFS_F(file)->rdstate;
-+ }
-+ }
-+ bend = fbend(file);
-+
-+ while (uds->bindex <= bend) {
-+ lower_file = unionfs_lower_file_idx(file, uds->bindex);
-+ if (!lower_file) {
-+ uds->bindex++;
-+ uds->dirpos = 0;
-+ continue;
-+ }
-+
-+ /* prepare callback buffer */
-+ buf.filldir_called = 0;
-+ buf.filldir_error = 0;
-+ buf.entries_written = 0;
-+ buf.dirent = dirent;
-+ buf.filldir = filldir;
-+ buf.rdstate = uds;
-+ buf.sb = inode->i_sb;
-+
-+ /* Read starting from where we last left off. */
-+ offset = vfs_llseek(lower_file, uds->dirpos, SEEK_SET);
-+ if (offset < 0) {
-+ err = offset;
-+ goto out;
-+ }
-+ err = vfs_readdir(lower_file, unionfs_filldir, &buf);
-+
-+ /* Save the position for when we continue. */
-+ offset = vfs_llseek(lower_file, 0, SEEK_CUR);
-+ if (offset < 0) {
-+ err = offset;
-+ goto out;
-+ }
-+ uds->dirpos = offset;
-+
-+ /* Copy the atime. */
-+ fsstack_copy_attr_atime(inode,
-+ lower_file->f_path.dentry->d_inode);
-+
-+ if (err < 0)
-+ goto out;
-+
-+ if (buf.filldir_error)
-+ break;
-+
-+ if (!buf.entries_written) {
-+ uds->bindex++;
-+ uds->dirpos = 0;
-+ }
-+ }
-+
-+ if (!buf.filldir_error && uds->bindex >= bend) {
-+ /* Save the number of hash entries for next time. */
-+ UNIONFS_I(inode)->hashsize = uds->hashentries;
-+ free_rdstate(uds);
-+ UNIONFS_F(file)->rdstate = NULL;
-+ file->f_pos = DIREOF;
-+ } else {
-+ file->f_pos = rdstate2offset(uds);
-+ }
-+
-+out:
-+ if (!err)
-+ unionfs_check_file(file);
-+ unionfs_unlock_dentry(dentry);
-+ unionfs_unlock_parent(dentry, parent);
-+ unionfs_read_unlock(dentry->d_sb);
-+ return err;
-+}
-+
-+/*
-+ * This is not meant to be a generic repositioning function. If you do
-+ * things that aren't supported, then we return EINVAL.
-+ *
-+ * What is allowed:
-+ * (1) seeking to the same position that you are currently at
-+ * This really has no effect, but returns where you are.
-+ * (2) seeking to the beginning of the file
-+ * This throws out all state, and lets you begin again.
-+ */
-+static loff_t unionfs_dir_llseek(struct file *file, loff_t offset, int origin)
-+{
-+ struct unionfs_dir_state *rdstate;
-+ struct dentry *dentry = file->f_path.dentry;
-+ struct dentry *parent;
-+ loff_t err;
-+
-+ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT);
-+ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
-+ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+ err = unionfs_file_revalidate(file, parent, false);
-+ if (unlikely(err))
-+ goto out;
-+
-+ rdstate = UNIONFS_F(file)->rdstate;
-+
-+ /*
-+ * we let users seek to their current position, but not anywhere
-+ * else.
-+ */
-+ if (!offset) {
-+ switch (origin) {
-+ case SEEK_SET:
-+ if (rdstate) {
-+ free_rdstate(rdstate);
-+ UNIONFS_F(file)->rdstate = NULL;
-+ }
-+ init_rdstate(file);
-+ err = 0;
-+ break;
-+ case SEEK_CUR:
-+ err = file->f_pos;
-+ break;
-+ case SEEK_END:
-+ /* Unsupported, because we would break everything. */
-+ err = -EINVAL;
-+ break;
-+ }
-+ } else {
-+ switch (origin) {
-+ case SEEK_SET:
-+ if (rdstate) {
-+ if (offset == rdstate2offset(rdstate))
-+ err = offset;
-+ else if (file->f_pos == DIREOF)
-+ err = DIREOF;
-+ else
-+ err = -EINVAL;
-+ } else {
-+ struct inode *inode;
-+ inode = dentry->d_inode;
-+ rdstate = find_rdstate(inode, offset);
-+ if (rdstate) {
-+ UNIONFS_F(file)->rdstate = rdstate;
-+ err = rdstate->offset;
-+ } else {
-+ err = -EINVAL;
-+ }
-+ }
-+ break;
-+ case SEEK_CUR:
-+ case SEEK_END:
-+ /* Unsupported, because we would break everything. */
-+ err = -EINVAL;
-+ break;
-+ }
-+ }
-+
-+out:
-+ if (!err)
-+ unionfs_check_file(file);
-+ unionfs_unlock_dentry(dentry);
-+ unionfs_unlock_parent(dentry, parent);
-+ unionfs_read_unlock(dentry->d_sb);
-+ return err;
-+}
-+
-+/*
-+ * Trimmed directory options, we shouldn't pass everything down since
-+ * we don't want to operate on partial directories.
-+ */
-+struct file_operations unionfs_dir_fops = {
-+ .llseek = unionfs_dir_llseek,
-+ .read = generic_read_dir,
-+ .readdir = unionfs_readdir,
-+ .unlocked_ioctl = unionfs_ioctl,
-+ .open = unionfs_open,
-+ .release = unionfs_file_release,
-+ .flush = unionfs_flush,
-+ .fsync = unionfs_fsync,
-+ .fasync = unionfs_fasync,
-+};
-diff --git a/fs/unionfs/dirhelper.c b/fs/unionfs/dirhelper.c
-new file mode 100644
-index 0000000..62ec9af
---- /dev/null
-+++ b/fs/unionfs/dirhelper.c
-@@ -0,0 +1,158 @@
-+/*
-+ * Copyright (c) 2003-2011 Erez Zadok
-+ * Copyright (c) 2003-2006 Charles P. Wright
-+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2005-2006 Junjiro Okajima
-+ * Copyright (c) 2005 Arun M. Krishnakumar
-+ * Copyright (c) 2004-2006 David P. Quigley
-+ * Copyright (c) 2003-2004 Mohammad Nayyer Zubair
-+ * Copyright (c) 2003 Puja Gupta
-+ * Copyright (c) 2003 Harikesavan Krishnan
-+ * Copyright (c) 2003-2011 Stony Brook University
-+ * Copyright (c) 2003-2011 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#include "union.h"
-+
-+#define RD_NONE 0
-+#define RD_CHECK_EMPTY 1
-+/* The callback structure for check_empty. */
-+struct unionfs_rdutil_callback {
-+ int err;
-+ int filldir_called;
-+ struct unionfs_dir_state *rdstate;
-+ int mode;
-+};
-+
-+/* This filldir function makes sure only whiteouts exist within a directory. */
-+static int readdir_util_callback(void *dirent, const char *oname, int namelen,
-+ loff_t offset, u64 ino, unsigned int d_type)
-+{
-+ int err = 0;
-+ struct unionfs_rdutil_callback *buf = dirent;
-+ int is_whiteout;
-+ struct filldir_node *found;
-+ char *name = (char *) oname;
-+
-+ buf->filldir_called = 1;
-+
-+ if (name[0] == '.' && (namelen == 1 ||
-+ (name[1] == '.' && namelen == 2)))
-+ goto out;
-+
-+ is_whiteout = is_whiteout_name(&name, &namelen);
-+
-+ found = find_filldir_node(buf->rdstate, name, namelen, is_whiteout);
-+ /* If it was found in the table there was a previous whiteout. */
-+ if (found)
-+ goto out;
-+
-+ /*
-+ * if it wasn't found and isn't a whiteout, the directory isn't
-+ * empty.
-+ */
-+ err = -ENOTEMPTY;
-+ if ((buf->mode == RD_CHECK_EMPTY) && !is_whiteout)
-+ goto out;
-+
-+ err = add_filldir_node(buf->rdstate, name, namelen,
-+ buf->rdstate->bindex, is_whiteout);
-+
-+out:
-+ buf->err = err;
-+ return err;
-+}
-+
-+/* Is a directory logically empty? */
-+int check_empty(struct dentry *dentry, struct dentry *parent,
-+ struct unionfs_dir_state **namelist)
-+{
-+ int err = 0;
-+ struct dentry *lower_dentry = NULL;
-+ struct vfsmount *mnt;
-+ struct super_block *sb;
-+ struct file *lower_file;
-+ struct unionfs_rdutil_callback *buf = NULL;
-+ int bindex, bstart, bend, bopaque;
-+
-+ sb = dentry->d_sb;
-+
-+
-+ BUG_ON(!S_ISDIR(dentry->d_inode->i_mode));
-+
-+ err = unionfs_partial_lookup(dentry, parent);
-+ if (err)
-+ goto out;
-+
-+ bstart = dbstart(dentry);
-+ bend = dbend(dentry);
-+ bopaque = dbopaque(dentry);
-+ if (0 <= bopaque && bopaque < bend)
-+ bend = bopaque;
-+
-+ buf = kmalloc(sizeof(struct unionfs_rdutil_callback), GFP_KERNEL);
-+ if (unlikely(!buf)) {
-+ err = -ENOMEM;
-+ goto out;
-+ }
-+ buf->err = 0;
-+ buf->mode = RD_CHECK_EMPTY;
-+ buf->rdstate = alloc_rdstate(dentry->d_inode, bstart);
-+ if (unlikely(!buf->rdstate)) {
-+ err = -ENOMEM;
-+ goto out;
-+ }
-+
-+ /* Process the lower directories with rdutil_callback as a filldir. */
-+ for (bindex = bstart; bindex <= bend; bindex++) {
-+ lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
-+ if (!lower_dentry)
-+ continue;
-+ if (!lower_dentry->d_inode)
-+ continue;
-+ if (!S_ISDIR(lower_dentry->d_inode->i_mode))
-+ continue;
-+
-+ dget(lower_dentry);
-+ mnt = unionfs_mntget(dentry, bindex);
-+ branchget(sb, bindex);
-+ lower_file = dentry_open(lower_dentry, mnt, O_RDONLY, current_cred());
-+ if (IS_ERR(lower_file)) {
-+ err = PTR_ERR(lower_file);
-+ branchput(sb, bindex);
-+ goto out;
-+ }
-+
-+ do {
-+ buf->filldir_called = 0;
-+ buf->rdstate->bindex = bindex;
-+ err = vfs_readdir(lower_file,
-+ readdir_util_callback, buf);
-+ if (buf->err)
-+ err = buf->err;
-+ } while ((err >= 0) && buf->filldir_called);
-+
-+ /* fput calls dput for lower_dentry */
-+ fput(lower_file);
-+ branchput(sb, bindex);
-+
-+ if (err < 0)
-+ goto out;
-+ }
-+
-+out:
-+ if (buf) {
-+ if (namelist && !err)
-+ *namelist = buf->rdstate;
-+ else if (buf->rdstate)
-+ free_rdstate(buf->rdstate);
-+ kfree(buf);
-+ }
-+
-+
-+ return err;
-+}
-diff --git a/fs/unionfs/fanout.h b/fs/unionfs/fanout.h
-new file mode 100644
-index 0000000..ae1b86a
---- /dev/null
-+++ b/fs/unionfs/fanout.h
-@@ -0,0 +1,407 @@
-+/*
-+ * Copyright (c) 2003-2011 Erez Zadok
-+ * Copyright (c) 2003-2006 Charles P. Wright
-+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2005 Arun M. Krishnakumar
-+ * Copyright (c) 2004-2006 David P. Quigley
-+ * Copyright (c) 2003-2004 Mohammad Nayyer Zubair
-+ * Copyright (c) 2003 Puja Gupta
-+ * Copyright (c) 2003 Harikesavan Krishnan
-+ * Copyright (c) 2003-2011 Stony Brook University
-+ * Copyright (c) 2003-2011 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#ifndef _FANOUT_H_
-+#define _FANOUT_H_
-+
-+/*
-+ * Inode to private data
-+ *
-+ * Since we use containers and the struct inode is _inside_ the
-+ * unionfs_inode_info structure, UNIONFS_I will always (given a non-NULL
-+ * inode pointer), return a valid non-NULL pointer.
-+ */
-+static inline struct unionfs_inode_info *UNIONFS_I(const struct inode *inode)
-+{
-+ return container_of(inode, struct unionfs_inode_info, vfs_inode);
-+}
-+
-+#define ibstart(ino) (UNIONFS_I(ino)->bstart)
-+#define ibend(ino) (UNIONFS_I(ino)->bend)
-+
-+/* Dentry to private data */
-+#define UNIONFS_D(dent) ((struct unionfs_dentry_info *)(dent)->d_fsdata)
-+#define dbstart(dent) (UNIONFS_D(dent)->bstart)
-+#define dbend(dent) (UNIONFS_D(dent)->bend)
-+#define dbopaque(dent) (UNIONFS_D(dent)->bopaque)
-+
-+/* Superblock to private data */
-+#define UNIONFS_SB(super) ((struct unionfs_sb_info *)(super)->s_fs_info)
-+#define sbstart(sb) 0
-+#define sbend(sb) (UNIONFS_SB(sb)->bend)
-+#define sbmax(sb) (UNIONFS_SB(sb)->bend + 1)
-+#define sbhbid(sb) (UNIONFS_SB(sb)->high_branch_id)
-+
-+/* File to private Data */
-+#define UNIONFS_F(file) ((struct unionfs_file_info *)((file)->private_data))
-+#define fbstart(file) (UNIONFS_F(file)->bstart)
-+#define fbend(file) (UNIONFS_F(file)->bend)
-+
-+/* macros to manipulate branch IDs in stored in our superblock */
-+static inline int branch_id(struct super_block *sb, int index)
-+{
-+ BUG_ON(!sb || index < 0);
-+ return UNIONFS_SB(sb)->data[index].branch_id;
-+}
-+
-+static inline void set_branch_id(struct super_block *sb, int index, int val)
-+{
-+ BUG_ON(!sb || index < 0);
-+ UNIONFS_SB(sb)->data[index].branch_id = val;
-+}
-+
-+static inline void new_branch_id(struct super_block *sb, int index)
-+{
-+ BUG_ON(!sb || index < 0);
-+ set_branch_id(sb, index, ++UNIONFS_SB(sb)->high_branch_id);
-+}
-+
-+/*
-+ * Find new index of matching branch with an existing superblock of a known
-+ * (possibly old) id. This is needed because branches could have been
-+ * added/deleted causing the branches of any open files to shift.
-+ *
-+ * @sb: the new superblock which may have new/different branch IDs
-+ * @id: the old/existing id we're looking for
-+ * Returns index of newly found branch (0 or greater), -1 otherwise.
-+ */
-+static inline int branch_id_to_idx(struct super_block *sb, int id)
-+{
-+ int i;
-+ for (i = 0; i < sbmax(sb); i++) {
-+ if (branch_id(sb, i) == id)
-+ return i;
-+ }
-+ /* in the non-ODF code, this should really never happen */
-+ printk(KERN_WARNING "unionfs: cannot find branch with id %d\n", id);
-+ return -1;
-+}
-+
-+/* File to lower file. */
-+static inline struct file *unionfs_lower_file(const struct file *f)
-+{
-+ BUG_ON(!f);
-+ return UNIONFS_F(f)->lower_files[fbstart(f)];
-+}
-+
-+static inline struct file *unionfs_lower_file_idx(const struct file *f,
-+ int index)
-+{
-+ BUG_ON(!f || index < 0);
-+ return UNIONFS_F(f)->lower_files[index];
-+}
-+
-+static inline void unionfs_set_lower_file_idx(struct file *f, int index,
-+ struct file *val)
-+{
-+ BUG_ON(!f || index < 0);
-+ UNIONFS_F(f)->lower_files[index] = val;
-+ /* save branch ID (may be redundant?) */
-+ UNIONFS_F(f)->saved_branch_ids[index] =
-+ branch_id((f)->f_path.dentry->d_sb, index);
-+}
-+
-+static inline void unionfs_set_lower_file(struct file *f, struct file *val)
-+{
-+ BUG_ON(!f);
-+ unionfs_set_lower_file_idx((f), fbstart(f), (val));
-+}
-+
-+/* Inode to lower inode. */
-+static inline struct inode *unionfs_lower_inode(const struct inode *i)
-+{
-+ BUG_ON(!i);
-+ return UNIONFS_I(i)->lower_inodes[ibstart(i)];
-+}
-+
-+static inline struct inode *unionfs_lower_inode_idx(const struct inode *i,
-+ int index)
-+{
-+ BUG_ON(!i || index < 0);
-+ return UNIONFS_I(i)->lower_inodes[index];
-+}
-+
-+static inline void unionfs_set_lower_inode_idx(struct inode *i, int index,
-+ struct inode *val)
-+{
-+ BUG_ON(!i || index < 0);
-+ UNIONFS_I(i)->lower_inodes[index] = val;
-+}
-+
-+static inline void unionfs_set_lower_inode(struct inode *i, struct inode *val)
-+{
-+ BUG_ON(!i);
-+ UNIONFS_I(i)->lower_inodes[ibstart(i)] = val;
-+}
-+
-+/* Superblock to lower superblock. */
-+static inline struct super_block *unionfs_lower_super(
-+ const struct super_block *sb)
-+{
-+ BUG_ON(!sb);
-+ return UNIONFS_SB(sb)->data[sbstart(sb)].sb;
-+}
-+
-+static inline struct super_block *unionfs_lower_super_idx(
-+ const struct super_block *sb,
-+ int index)
-+{
-+ BUG_ON(!sb || index < 0);
-+ return UNIONFS_SB(sb)->data[index].sb;
-+}
-+
-+static inline void unionfs_set_lower_super_idx(struct super_block *sb,
-+ int index,
-+ struct super_block *val)
-+{
-+ BUG_ON(!sb || index < 0);
-+ UNIONFS_SB(sb)->data[index].sb = val;
-+}
-+
-+static inline void unionfs_set_lower_super(struct super_block *sb,
-+ struct super_block *val)
-+{
-+ BUG_ON(!sb);
-+ UNIONFS_SB(sb)->data[sbstart(sb)].sb = val;
-+}
-+
-+/* Branch count macros. */
-+static inline int branch_count(const struct super_block *sb, int index)
-+{
-+ BUG_ON(!sb || index < 0);
-+ return atomic_read(&UNIONFS_SB(sb)->data[index].open_files);
-+}
-+
-+static inline void set_branch_count(struct super_block *sb, int index, int val)
-+{
-+ BUG_ON(!sb || index < 0);
-+ atomic_set(&UNIONFS_SB(sb)->data[index].open_files, val);
-+}
-+
-+static inline void branchget(struct super_block *sb, int index)
-+{
-+ BUG_ON(!sb || index < 0);
-+ atomic_inc(&UNIONFS_SB(sb)->data[index].open_files);
-+}
-+
-+static inline void branchput(struct super_block *sb, int index)
-+{
-+ BUG_ON(!sb || index < 0);
-+ atomic_dec(&UNIONFS_SB(sb)->data[index].open_files);
-+}
-+
-+/* Dentry macros */
-+static inline void unionfs_set_lower_dentry_idx(struct dentry *dent, int index,
-+ struct dentry *val)
-+{
-+ BUG_ON(!dent || index < 0);
-+ UNIONFS_D(dent)->lower_paths[index].dentry = val;
-+}
-+
-+static inline struct dentry *unionfs_lower_dentry_idx(
-+ const struct dentry *dent,
-+ int index)
-+{
-+ BUG_ON(!dent || index < 0);
-+ return UNIONFS_D(dent)->lower_paths[index].dentry;
-+}
-+
-+static inline struct dentry *unionfs_lower_dentry(const struct dentry *dent)
-+{
-+ BUG_ON(!dent);
-+ return unionfs_lower_dentry_idx(dent, dbstart(dent));
-+}
-+
-+static inline void unionfs_set_lower_mnt_idx(struct dentry *dent, int index,
-+ struct vfsmount *mnt)
-+{
-+ BUG_ON(!dent || index < 0);
-+ UNIONFS_D(dent)->lower_paths[index].mnt = mnt;
-+}
-+
-+static inline struct vfsmount *unionfs_lower_mnt_idx(
-+ const struct dentry *dent,
-+ int index)
-+{
-+ BUG_ON(!dent || index < 0);
-+ return UNIONFS_D(dent)->lower_paths[index].mnt;
-+}
-+
-+static inline struct vfsmount *unionfs_lower_mnt(const struct dentry *dent)
-+{
-+ BUG_ON(!dent);
-+ return unionfs_lower_mnt_idx(dent, dbstart(dent));
-+}
-+
-+/* Macros for locking a dentry. */
-+enum unionfs_dentry_lock_class {
-+ UNIONFS_DMUTEX_NORMAL,
-+ UNIONFS_DMUTEX_ROOT,
-+ UNIONFS_DMUTEX_PARENT,
-+ UNIONFS_DMUTEX_CHILD,
-+ UNIONFS_DMUTEX_WHITEOUT,
-+ UNIONFS_DMUTEX_REVAL_PARENT, /* for file/dentry revalidate */
-+ UNIONFS_DMUTEX_REVAL_CHILD, /* for file/dentry revalidate */
-+};
-+
-+static inline void unionfs_lock_dentry(struct dentry *d,
-+ unsigned int subclass)
-+{
-+ BUG_ON(!d);
-+ mutex_lock_nested(&UNIONFS_D(d)->lock, subclass);
-+}
-+
-+static inline void unionfs_unlock_dentry(struct dentry *d)
-+{
-+ BUG_ON(!d);
-+ mutex_unlock(&UNIONFS_D(d)->lock);
-+}
-+
-+static inline struct dentry *unionfs_lock_parent(struct dentry *d,
-+ unsigned int subclass)
-+{
-+ struct dentry *p;
-+
-+ BUG_ON(!d);
-+ p = dget_parent(d);
-+ if (p != d)
-+ mutex_lock_nested(&UNIONFS_D(p)->lock, subclass);
-+ return p;
-+}
-+
-+static inline void unionfs_unlock_parent(struct dentry *d, struct dentry *p)
-+{
-+ BUG_ON(!d);
-+ BUG_ON(!p);
-+ if (p != d) {
-+ BUG_ON(!mutex_is_locked(&UNIONFS_D(p)->lock));
-+ mutex_unlock(&UNIONFS_D(p)->lock);
-+ }
-+ dput(p);
-+}
-+
-+static inline void verify_locked(struct dentry *d)
-+{
-+ BUG_ON(!d);
-+ BUG_ON(!mutex_is_locked(&UNIONFS_D(d)->lock));
-+}
-+
-+/* macros to put lower objects */
-+
-+/*
-+ * iput lower inodes of an unionfs dentry, from bstart to bend. If
-+ * @free_lower is true, then also kfree the memory used to hold the lower
-+ * object pointers.
-+ */
-+static inline void iput_lowers(struct inode *inode,
-+ int bstart, int bend, bool free_lower)
-+{
-+ struct inode *lower_inode;
-+ int bindex;
-+
-+ BUG_ON(!inode);
-+ BUG_ON(!UNIONFS_I(inode));
-+ BUG_ON(bstart < 0);
-+
-+ for (bindex = bstart; bindex <= bend; bindex++) {
-+ lower_inode = unionfs_lower_inode_idx(inode, bindex);
-+ if (lower_inode) {
-+ unionfs_set_lower_inode_idx(inode, bindex, NULL);
-+ /* see Documentation/filesystems/unionfs/issues.txt */
-+ lockdep_off();
-+ iput(lower_inode);
-+ lockdep_on();
-+ }
-+ }
-+
-+ if (free_lower) {
-+ kfree(UNIONFS_I(inode)->lower_inodes);
-+ UNIONFS_I(inode)->lower_inodes = NULL;
-+ }
-+}
-+
-+/* iput all lower inodes, and reset start/end branch indices to -1 */
-+static inline void iput_lowers_all(struct inode *inode, bool free_lower)
-+{
-+ int bstart, bend;
-+
-+ BUG_ON(!inode);
-+ BUG_ON(!UNIONFS_I(inode));
-+ bstart = ibstart(inode);
-+ bend = ibend(inode);
-+ BUG_ON(bstart < 0);
-+
-+ iput_lowers(inode, bstart, bend, free_lower);
-+ ibstart(inode) = ibend(inode) = -1;
-+}
-+
-+/*
-+ * dput/mntput all lower dentries and vfsmounts of an unionfs dentry, from
-+ * bstart to bend. If @free_lower is true, then also kfree the memory used
-+ * to hold the lower object pointers.
-+ *
-+ * XXX: implement using path_put VFS macros
-+ */
-+static inline void path_put_lowers(struct dentry *dentry,
-+ int bstart, int bend, bool free_lower)
-+{
-+ struct dentry *lower_dentry;
-+ struct vfsmount *lower_mnt;
-+ int bindex;
-+
-+ BUG_ON(!dentry);
-+ BUG_ON(!UNIONFS_D(dentry));
-+ BUG_ON(bstart < 0);
-+
-+ for (bindex = bstart; bindex <= bend; bindex++) {
-+ lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
-+ if (lower_dentry) {
-+ unionfs_set_lower_dentry_idx(dentry, bindex, NULL);
-+ dput(lower_dentry);
-+ }
-+ lower_mnt = unionfs_lower_mnt_idx(dentry, bindex);
-+ if (lower_mnt) {
-+ unionfs_set_lower_mnt_idx(dentry, bindex, NULL);
-+ mntput(lower_mnt);
-+ }
-+ }
-+
-+ if (free_lower) {
-+ kfree(UNIONFS_D(dentry)->lower_paths);
-+ UNIONFS_D(dentry)->lower_paths = NULL;
-+ }
-+}
-+
-+/*
-+ * dput/mntput all lower dentries and vfsmounts, and reset start/end branch
-+ * indices to -1.
-+ */
-+static inline void path_put_lowers_all(struct dentry *dentry, bool free_lower)
-+{
-+ int bstart, bend;
-+
-+ BUG_ON(!dentry);
-+ BUG_ON(!UNIONFS_D(dentry));
-+ bstart = dbstart(dentry);
-+ bend = dbend(dentry);
-+ BUG_ON(bstart < 0);
-+
-+ path_put_lowers(dentry, bstart, bend, free_lower);
-+ dbstart(dentry) = dbend(dentry) = -1;
-+}
-+
-+#endif /* not _FANOUT_H */
-diff --git a/fs/unionfs/file.c b/fs/unionfs/file.c
-new file mode 100644
-index 0000000..f583c8f
---- /dev/null
-+++ b/fs/unionfs/file.c
-@@ -0,0 +1,386 @@
-+/*
-+ * Copyright (c) 2003-2011 Erez Zadok
-+ * Copyright (c) 2003-2006 Charles P. Wright
-+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2005-2006 Junjiro Okajima
-+ * Copyright (c) 2005 Arun M. Krishnakumar
-+ * Copyright (c) 2004-2006 David P. Quigley
-+ * Copyright (c) 2003-2004 Mohammad Nayyer Zubair
-+ * Copyright (c) 2003 Puja Gupta
-+ * Copyright (c) 2003 Harikesavan Krishnan
-+ * Copyright (c) 2003-2011 Stony Brook University
-+ * Copyright (c) 2003-2011 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#include "union.h"
-+
-+static ssize_t unionfs_read(struct file *file, char __user *buf,
-+ size_t count, loff_t *ppos)
-+{
-+ int err;
-+ struct file *lower_file;
-+ struct dentry *dentry = file->f_path.dentry;
-+ struct dentry *parent;
-+
-+ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT);
-+ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
-+ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+ err = unionfs_file_revalidate(file, parent, false);
-+ if (unlikely(err))
-+ goto out;
-+
-+ lower_file = unionfs_lower_file(file);
-+ err = vfs_read(lower_file, buf, count, ppos);
-+ /* update our inode atime upon a successful lower read */
-+ if (err >= 0) {
-+ fsstack_copy_attr_atime(dentry->d_inode,
-+ lower_file->f_path.dentry->d_inode);
-+ unionfs_check_file(file);
-+ }
-+
-+out:
-+ unionfs_unlock_dentry(dentry);
-+ unionfs_unlock_parent(dentry, parent);
-+ unionfs_read_unlock(dentry->d_sb);
-+ return err;
-+}
-+
-+static ssize_t unionfs_write(struct file *file, const char __user *buf,
-+ size_t count, loff_t *ppos)
-+{
-+ int err = 0;
-+ struct file *lower_file;
-+ struct dentry *dentry = file->f_path.dentry;
-+ struct dentry *parent;
-+
-+ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT);
-+ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
-+ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+ err = unionfs_file_revalidate(file, parent, true);
-+ if (unlikely(err))
-+ goto out;
-+
-+ lower_file = unionfs_lower_file(file);
-+ err = vfs_write(lower_file, buf, count, ppos);
-+ /* update our inode times+sizes upon a successful lower write */
-+ if (err >= 0) {
-+ fsstack_copy_inode_size(dentry->d_inode,
-+ lower_file->f_path.dentry->d_inode);
-+ fsstack_copy_attr_times(dentry->d_inode,
-+ lower_file->f_path.dentry->d_inode);
-+ UNIONFS_F(file)->wrote_to_file = true; /* for delayed copyup */
-+ unionfs_check_file(file);
-+ }
-+
-+out:
-+ unionfs_unlock_dentry(dentry);
-+ unionfs_unlock_parent(dentry, parent);
-+ unionfs_read_unlock(dentry->d_sb);
-+ return err;
-+}
-+
-+static int unionfs_file_readdir(struct file *file, void *dirent,
-+ filldir_t filldir)
-+{
-+ return -ENOTDIR;
-+}
-+
-+static int unionfs_mmap(struct file *file, struct vm_area_struct *vma)
-+{
-+ int err = 0;
-+ bool willwrite;
-+ struct file *lower_file;
-+ struct dentry *dentry = file->f_path.dentry;
-+ struct dentry *parent;
-+ const struct vm_operations_struct *saved_vm_ops = NULL;
-+
-+ /*
-+ * Since mm/memory.c:might_fault() (under PROVE_LOCKING) was
-+ * modified in 2.6.29-rc1 to call might_lock_read on mmap_sem, this
-+ * has been causing false positives in file system stacking layers.
-+ * In particular, our ->mmap is called after sys_mmap2 already holds
-+ * mmap_sem, then we lock our own mutexes; but earlier, it's
-+ * possible for lockdep to have locked our mutexes first, and then
-+ * we call a lower ->readdir which could call might_fault. The
-+ * different ordering of the locks is what lockdep complains about
-+ * -- unnecessarily. Therefore, we have no choice but to tell
-+ * lockdep to temporarily turn off lockdep here. Note: the comments
-+ * inside might_sleep also suggest that it would have been
-+ * nicer to only annotate paths that needs that might_lock_read.
-+ */
-+ lockdep_off();
-+ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT);
-+ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
-+ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+ /* This might be deferred to mmap's writepage */
-+ willwrite = ((vma->vm_flags | VM_SHARED | VM_WRITE) == vma->vm_flags);
-+ err = unionfs_file_revalidate(file, parent, willwrite);
-+ if (unlikely(err))
-+ goto out;
-+ unionfs_check_file(file);
-+
-+ /*
-+ * File systems which do not implement ->writepage may use
-+ * generic_file_readonly_mmap as their ->mmap op. If you call
-+ * generic_file_readonly_mmap with VM_WRITE, you'd get an -EINVAL.
-+ * But we cannot call the lower ->mmap op, so we can't tell that
-+ * writeable mappings won't work. Therefore, our only choice is to
-+ * check if the lower file system supports the ->writepage, and if
-+ * not, return EINVAL (the same error that
-+ * generic_file_readonly_mmap returns in that case).
-+ */
-+ lower_file = unionfs_lower_file(file);
-+ if (willwrite && !lower_file->f_mapping->a_ops->writepage) {
-+ err = -EINVAL;
-+ printk(KERN_ERR "unionfs: branch %d file system does not "
-+ "support writeable mmap\n", fbstart(file));
-+ goto out;
-+ }
-+
-+ /*
-+ * find and save lower vm_ops.
-+ *
-+ * XXX: the VFS should have a cleaner way of finding the lower vm_ops
-+ */
-+ if (!UNIONFS_F(file)->lower_vm_ops) {
-+ err = lower_file->f_op->mmap(lower_file, vma);
-+ if (err) {
-+ printk(KERN_ERR "unionfs: lower mmap failed %d\n", err);
-+ goto out;
-+ }
-+ saved_vm_ops = vma->vm_ops;
-+ err = vm_munmap(vma->vm_start,
-+ vma->vm_end - vma->vm_start);
-+ if (err) {
-+ printk(KERN_ERR "unionfs: vm_munmap failed %d\n", err);
-+ goto out;
-+ }
-+ }
-+
-+ file->f_mapping->a_ops = &unionfs_dummy_aops;
-+ err = generic_file_mmap(file, vma);
-+ file->f_mapping->a_ops = &unionfs_aops;
-+ if (err) {
-+ printk(KERN_ERR "unionfs: generic_file_mmap failed %d\n", err);
-+ goto out;
-+ }
-+ vma->vm_ops = &unionfs_vm_ops;
-+ if (!UNIONFS_F(file)->lower_vm_ops)
-+ UNIONFS_F(file)->lower_vm_ops = saved_vm_ops;
-+
-+out:
-+ if (!err) {
-+ /* copyup could cause parent dir times to change */
-+ unionfs_copy_attr_times(parent->d_inode);
-+ unionfs_check_file(file);
-+ }
-+ unionfs_unlock_dentry(dentry);
-+ unionfs_unlock_parent(dentry, parent);
-+ unionfs_read_unlock(dentry->d_sb);
-+ lockdep_on();
-+ return err;
-+}
-+
-+int unionfs_fsync(struct file *file, loff_t start, loff_t end, int datasync)
-+{
-+ int bindex, bstart, bend;
-+ struct file *lower_file;
-+ struct dentry *dentry = file->f_path.dentry;
-+ struct dentry *lower_dentry;
-+ struct dentry *parent;
-+ struct inode *lower_inode, *inode;
-+ int err = -EINVAL;
-+
-+ lockdep_off();
-+ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT);
-+ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
-+ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+ err = unionfs_file_revalidate(file, parent, true);
-+ if (unlikely(err))
-+ goto out;
-+ unionfs_check_file(file);
-+
-+ err = generic_file_fsync(file, start, end, datasync);
-+ if (err)
-+ goto out;
-+
-+ bstart = fbstart(file);
-+ bend = fbend(file);
-+ if (bstart < 0 || bend < 0)
-+ goto out;
-+
-+ inode = dentry->d_inode;
-+ if (unlikely(!inode)) {
-+ printk(KERN_ERR
-+ "unionfs: null lower inode in unionfs_fsync\n");
-+ goto out;
-+ }
-+ for (bindex = bstart; bindex <= bend; bindex++) {
-+ lower_inode = unionfs_lower_inode_idx(inode, bindex);
-+ if (!lower_inode || !lower_inode->i_fop->fsync)
-+ continue;
-+ lower_file = unionfs_lower_file_idx(file, bindex);
-+ lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
-+ err = vfs_fsync_range(lower_file, start, end, datasync);
-+ if (!err && bindex == bstart)
-+ fsstack_copy_attr_times(inode, lower_inode);
-+ if (err)
-+ goto out;
-+ }
-+
-+out:
-+ if (!err)
-+ unionfs_check_file(file);
-+ unionfs_unlock_dentry(dentry);
-+ unionfs_unlock_parent(dentry, parent);
-+ unionfs_read_unlock(dentry->d_sb);
-+ lockdep_on();
-+ return err;
-+}
-+
-+int unionfs_fasync(int fd, struct file *file, int flag)
-+{
-+ int bindex, bstart, bend;
-+ struct file *lower_file;
-+ struct dentry *dentry = file->f_path.dentry;
-+ struct dentry *parent;
-+ struct inode *lower_inode, *inode;
-+ int err = 0;
-+
-+ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT);
-+ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
-+ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+ err = unionfs_file_revalidate(file, parent, true);
-+ if (unlikely(err))
-+ goto out;
-+ unionfs_check_file(file);
-+
-+ bstart = fbstart(file);
-+ bend = fbend(file);
-+ if (bstart < 0 || bend < 0)
-+ goto out;
-+
-+ inode = dentry->d_inode;
-+ if (unlikely(!inode)) {
-+ printk(KERN_ERR
-+ "unionfs: null lower inode in unionfs_fasync\n");
-+ goto out;
-+ }
-+ for (bindex = bstart; bindex <= bend; bindex++) {
-+ lower_inode = unionfs_lower_inode_idx(inode, bindex);
-+ if (!lower_inode || !lower_inode->i_fop->fasync)
-+ continue;
-+ lower_file = unionfs_lower_file_idx(file, bindex);
-+ mutex_lock(&lower_inode->i_mutex);
-+ err = lower_inode->i_fop->fasync(fd, lower_file, flag);
-+ if (!err && bindex == bstart)
-+ fsstack_copy_attr_times(inode, lower_inode);
-+ mutex_unlock(&lower_inode->i_mutex);
-+ if (err)
-+ goto out;
-+ }
-+
-+out:
-+ if (!err)
-+ unionfs_check_file(file);
-+ unionfs_unlock_dentry(dentry);
-+ unionfs_unlock_parent(dentry, parent);
-+ unionfs_read_unlock(dentry->d_sb);
-+ return err;
-+}
-+
-+static ssize_t unionfs_splice_read(struct file *file, loff_t *ppos,
-+ struct pipe_inode_info *pipe, size_t len,
-+ unsigned int flags)
-+{
-+ ssize_t err;
-+ struct file *lower_file;
-+ struct dentry *dentry = file->f_path.dentry;
-+ struct dentry *parent;
-+
-+ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT);
-+ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
-+ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+ err = unionfs_file_revalidate(file, parent, false);
-+ if (unlikely(err))
-+ goto out;
-+
-+ lower_file = unionfs_lower_file(file);
-+ err = vfs_splice_to(lower_file, ppos, pipe, len, flags);
-+ /* update our inode atime upon a successful lower splice-read */
-+ if (err >= 0) {
-+ fsstack_copy_attr_atime(dentry->d_inode,
-+ lower_file->f_path.dentry->d_inode);
-+ unionfs_check_file(file);
-+ }
-+
-+out:
-+ unionfs_unlock_dentry(dentry);
-+ unionfs_unlock_parent(dentry, parent);
-+ unionfs_read_unlock(dentry->d_sb);
-+ return err;
-+}
-+
-+static ssize_t unionfs_splice_write(struct pipe_inode_info *pipe,
-+ struct file *file, loff_t *ppos,
-+ size_t len, unsigned int flags)
-+{
-+ ssize_t err = 0;
-+ struct file *lower_file;
-+ struct dentry *dentry = file->f_path.dentry;
-+ struct dentry *parent;
-+
-+ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_PARENT);
-+ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
-+ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+ err = unionfs_file_revalidate(file, parent, true);
-+ if (unlikely(err))
-+ goto out;
-+
-+ lower_file = unionfs_lower_file(file);
-+ err = vfs_splice_from(pipe, lower_file, ppos, len, flags);
-+ /* update our inode times+sizes upon a successful lower write */
-+ if (err >= 0) {
-+ fsstack_copy_inode_size(dentry->d_inode,
-+ lower_file->f_path.dentry->d_inode);
-+ fsstack_copy_attr_times(dentry->d_inode,
-+ lower_file->f_path.dentry->d_inode);
-+ unionfs_check_file(file);
-+ }
-+
-+out:
-+ unionfs_unlock_dentry(dentry);
-+ unionfs_unlock_parent(dentry, parent);
-+ unionfs_read_unlock(dentry->d_sb);
-+ return err;
-+}
-+
-+struct file_operations unionfs_main_fops = {
-+ .llseek = generic_file_llseek,
-+ .read = unionfs_read,
-+ .write = unionfs_write,
-+ .readdir = unionfs_file_readdir,
-+ .unlocked_ioctl = unionfs_ioctl,
-+#ifdef CONFIG_COMPAT
-+ .compat_ioctl = unionfs_ioctl,
-+#endif
-+ .mmap = unionfs_mmap,
-+ .open = unionfs_open,
-+ .flush = unionfs_flush,
-+ .release = unionfs_file_release,
-+ .fsync = unionfs_fsync,
-+ .fasync = unionfs_fasync,
-+ .splice_read = unionfs_splice_read,
-+ .splice_write = unionfs_splice_write,
-+};
-diff --git a/fs/unionfs/inode.c b/fs/unionfs/inode.c
-new file mode 100644
-index 0000000..dd522c2
---- /dev/null
-+++ b/fs/unionfs/inode.c
-@@ -0,0 +1,1085 @@
-+/*
-+ * Copyright (c) 2003-2011 Erez Zadok
-+ * Copyright (c) 2003-2006 Charles P. Wright
-+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2005-2006 Junjiro Okajima
-+ * Copyright (c) 2005 Arun M. Krishnakumar
-+ * Copyright (c) 2004-2006 David P. Quigley
-+ * Copyright (c) 2003-2004 Mohammad Nayyer Zubair
-+ * Copyright (c) 2003 Puja Gupta
-+ * Copyright (c) 2003 Harikesavan Krishnan
-+ * Copyright (c) 2003-2011 Stony Brook University
-+ * Copyright (c) 2003-2011 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#include "union.h"
-+
-+/*
-+ * Find a writeable branch to create new object in. Checks all writeble
-+ * branches of the parent inode, from istart to iend order; if none are
-+ * suitable, also tries branch 0 (which may require a copyup).
-+ *
-+ * Return a lower_dentry we can use to create object in, or ERR_PTR.
-+ */
-+static struct dentry *find_writeable_branch(struct inode *parent,
-+ struct dentry *dentry)
-+{
-+ int err = -EINVAL;
-+ int bindex, istart, iend;
-+ struct dentry *lower_dentry = NULL;
-+
-+ istart = ibstart(parent);
-+ iend = ibend(parent);
-+ if (istart < 0)
-+ goto out;
-+
-+begin:
-+ for (bindex = istart; bindex <= iend; bindex++) {
-+ /* skip non-writeable branches */
-+ err = is_robranch_super(dentry->d_sb, bindex);
-+ if (err) {
-+ err = -EROFS;
-+ continue;
-+ }
-+ lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
-+ if (!lower_dentry)
-+ continue;
-+ /*
-+ * check for whiteouts in writeable branch, and remove them
-+ * if necessary.
-+ */
-+ err = check_unlink_whiteout(dentry, lower_dentry, bindex);
-+ if (err > 0) /* ignore if whiteout found and removed */
-+ err = 0;
-+ if (err)
-+ continue;
-+ /* if get here, we can write to the branch */
-+ break;
-+ }
-+ /*
-+ * If istart wasn't already branch 0, and we got any error, then try
-+ * branch 0 (which may require copyup)
-+ */
-+ if (err && istart > 0) {
-+ istart = iend = 0;
-+ goto begin;
-+ }
-+
-+ /*
-+ * If we tried even branch 0, and still got an error, abort. But if
-+ * the error was an EROFS, then we should try to copyup.
-+ */
-+ if (err && err != -EROFS)
-+ goto out;
-+
-+ /*
-+ * If we get here, then check if copyup needed. If lower_dentry is
-+ * NULL, create the entire dentry directory structure in branch 0.
-+ */
-+ if (!lower_dentry) {
-+ bindex = 0;
-+ lower_dentry = create_parents(parent, dentry,
-+ dentry->d_name.name, bindex);
-+ if (IS_ERR(lower_dentry)) {
-+ err = PTR_ERR(lower_dentry);
-+ goto out;
-+ }
-+ }
-+ err = 0; /* all's well */
-+out:
-+ if (err)
-+ return ERR_PTR(err);
-+ return lower_dentry;
-+}
-+
-+static int unionfs_create(struct inode *dir, struct dentry *dentry,
-+ umode_t mode, struct nameidata *nd_unused)
-+{
-+ int err = 0;
-+ struct dentry *lower_dentry = NULL;
-+ struct dentry *lower_parent_dentry = NULL;
-+ struct dentry *parent;
-+ int valid = 0;
-+ struct nameidata lower_nd;
-+
-+ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
-+ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
-+ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+ valid = __unionfs_d_revalidate(dentry, parent, false);
-+ if (unlikely(!valid)) {
-+ err = -ESTALE; /* same as what real_lookup does */
-+ goto out;
-+ }
-+
-+ lower_dentry = find_writeable_branch(dir, dentry);
-+ if (IS_ERR(lower_dentry)) {
-+ err = PTR_ERR(lower_dentry);
-+ goto out;
-+ }
-+
-+ lower_parent_dentry = lock_parent(lower_dentry);
-+ if (IS_ERR(lower_parent_dentry)) {
-+ err = PTR_ERR(lower_parent_dentry);
-+ goto out_unlock;
-+ }
-+
-+ err = init_lower_nd(&lower_nd, LOOKUP_CREATE);
-+ if (unlikely(err < 0))
-+ goto out_unlock;
-+ err = vfs_create(lower_parent_dentry->d_inode, lower_dentry, mode,
-+ &lower_nd);
-+ release_lower_nd(&lower_nd, err);
-+
-+ if (!err) {
-+ err = PTR_ERR(unionfs_interpose(dentry, dir->i_sb, 0));
-+ if (!err) {
-+ unionfs_copy_attr_times(dir);
-+ fsstack_copy_inode_size(dir,
-+ lower_parent_dentry->d_inode);
-+ /* update no. of links on parent directory */
-+ set_nlink(dir, unionfs_get_nlinks(dir));
-+ }
-+ }
-+
-+out_unlock:
-+ unlock_dir(lower_parent_dentry);
-+out:
-+ if (!err) {
-+ unionfs_postcopyup_setmnt(dentry);
-+ unionfs_check_inode(dir);
-+ unionfs_check_dentry(dentry);
-+ }
-+ unionfs_unlock_dentry(dentry);
-+ unionfs_unlock_parent(dentry, parent);
-+ unionfs_read_unlock(dentry->d_sb);
-+ return err;
-+}
-+
-+/*
-+ * unionfs_lookup is the only special function which takes a dentry, yet we
-+ * do NOT want to call __unionfs_d_revalidate_chain because by definition,
-+ * we don't have a valid dentry here yet.
-+ */
-+static struct dentry *unionfs_lookup(struct inode *dir,
-+ struct dentry *dentry,
-+ struct nameidata *nd_unused)
-+{
-+ struct dentry *ret, *parent;
-+ int err = 0;
-+
-+ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
-+ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
-+
-+ /*
-+ * As long as we lock/dget the parent, then can skip validating the
-+ * parent now; we may have to rebuild this dentry on the next
-+ * ->d_revalidate, however.
-+ */
-+
-+ /* allocate dentry private data. We free it in ->d_release */
-+ err = new_dentry_private_data(dentry, UNIONFS_DMUTEX_CHILD);
-+ if (unlikely(err)) {
-+ ret = ERR_PTR(err);
-+ goto out;
-+ }
-+
-+ ret = unionfs_lookup_full(dentry, parent, INTERPOSE_LOOKUP);
-+
-+ if (!IS_ERR(ret)) {
-+ if (ret)
-+ dentry = ret;
-+ /* lookup_full can return multiple positive dentries */
-+ if (dentry->d_inode && !S_ISDIR(dentry->d_inode->i_mode)) {
-+ BUG_ON(dbstart(dentry) < 0);
-+ unionfs_postcopyup_release(dentry);
-+ }
-+ unionfs_copy_attr_times(dentry->d_inode);
-+ }
-+
-+ unionfs_check_inode(dir);
-+ if (!IS_ERR(ret))
-+ unionfs_check_dentry(dentry);
-+ unionfs_check_dentry(parent);
-+ unionfs_unlock_dentry(dentry); /* locked in new_dentry_private data */
-+
-+out:
-+ unionfs_unlock_parent(dentry, parent);
-+ unionfs_read_unlock(dentry->d_sb);
-+
-+ return ret;
-+}
-+
-+static int unionfs_link(struct dentry *old_dentry, struct inode *dir,
-+ struct dentry *new_dentry)
-+{
-+ int err = 0;
-+ struct dentry *lower_old_dentry = NULL;
-+ struct dentry *lower_new_dentry = NULL;
-+ struct dentry *lower_dir_dentry = NULL;
-+ struct dentry *old_parent, *new_parent;
-+ char *name = NULL;
-+ bool valid;
-+
-+ unionfs_read_lock(old_dentry->d_sb, UNIONFS_SMUTEX_CHILD);
-+ old_parent = dget_parent(old_dentry);
-+ new_parent = dget_parent(new_dentry);
-+ unionfs_double_lock_parents(old_parent, new_parent);
-+ unionfs_double_lock_dentry(old_dentry, new_dentry);
-+
-+ valid = __unionfs_d_revalidate(old_dentry, old_parent, false);
-+ if (unlikely(!valid)) {
-+ err = -ESTALE;
-+ goto out;
-+ }
-+ if (new_dentry->d_inode) {
-+ valid = __unionfs_d_revalidate(new_dentry, new_parent, false);
-+ if (unlikely(!valid)) {
-+ err = -ESTALE;
-+ goto out;
-+ }
-+ }
-+
-+ lower_new_dentry = unionfs_lower_dentry(new_dentry);
-+
-+ /* check for a whiteout in new dentry branch, and delete it */
-+ err = check_unlink_whiteout(new_dentry, lower_new_dentry,
-+ dbstart(new_dentry));
-+ if (err > 0) { /* whiteout found and removed successfully */
-+ lower_dir_dentry = dget_parent(lower_new_dentry);
-+ fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
-+ dput(lower_dir_dentry);
-+ set_nlink(dir, unionfs_get_nlinks(dir));
-+ err = 0;
-+ }
-+ if (err)
-+ goto out;
-+
-+ /* check if parent hierachy is needed, then link in same branch */
-+ if (dbstart(old_dentry) != dbstart(new_dentry)) {
-+ lower_new_dentry = create_parents(dir, new_dentry,
-+ new_dentry->d_name.name,
-+ dbstart(old_dentry));
-+ err = PTR_ERR(lower_new_dentry);
-+ if (IS_COPYUP_ERR(err))
-+ goto docopyup;
-+ if (!lower_new_dentry || IS_ERR(lower_new_dentry))
-+ goto out;
-+ }
-+ lower_new_dentry = unionfs_lower_dentry(new_dentry);
-+ lower_old_dentry = unionfs_lower_dentry(old_dentry);
-+
-+ BUG_ON(dbstart(old_dentry) != dbstart(new_dentry));
-+ lower_dir_dentry = lock_parent(lower_new_dentry);
-+ err = is_robranch(old_dentry);
-+ if (!err) {
-+ /* see Documentation/filesystems/unionfs/issues.txt */
-+ lockdep_off();
-+ err = vfs_link(lower_old_dentry, lower_dir_dentry->d_inode,
-+ lower_new_dentry);
-+ lockdep_on();
-+ }
-+ unlock_dir(lower_dir_dentry);
-+
-+docopyup:
-+ if (IS_COPYUP_ERR(err)) {
-+ int old_bstart = dbstart(old_dentry);
-+ int bindex;
-+
-+ for (bindex = old_bstart - 1; bindex >= 0; bindex--) {
-+ err = copyup_dentry(old_parent->d_inode,
-+ old_dentry, old_bstart,
-+ bindex, old_dentry->d_name.name,
-+ old_dentry->d_name.len, NULL,
-+ i_size_read(old_dentry->d_inode));
-+ if (err)
-+ continue;
-+ lower_new_dentry =
-+ create_parents(dir, new_dentry,
-+ new_dentry->d_name.name,
-+ bindex);
-+ lower_old_dentry = unionfs_lower_dentry(old_dentry);
-+ lower_dir_dentry = lock_parent(lower_new_dentry);
-+ /* see Documentation/filesystems/unionfs/issues.txt */
-+ lockdep_off();
-+ /* do vfs_link */
-+ err = vfs_link(lower_old_dentry,
-+ lower_dir_dentry->d_inode,
-+ lower_new_dentry);
-+ lockdep_on();
-+ unlock_dir(lower_dir_dentry);
-+ goto check_link;
-+ }
-+ goto out;
-+ }
-+
-+check_link:
-+ if (err || !lower_new_dentry->d_inode)
-+ goto out;
-+
-+ /* Its a hard link, so use the same inode */
-+ new_dentry->d_inode = igrab(old_dentry->d_inode);
-+ d_add(new_dentry, new_dentry->d_inode);
-+ unionfs_copy_attr_all(dir, lower_new_dentry->d_parent->d_inode);
-+ fsstack_copy_inode_size(dir, lower_new_dentry->d_parent->d_inode);
-+
-+ /* propagate number of hard-links */
-+ set_nlink(old_dentry->d_inode,
-+ unionfs_get_nlinks(old_dentry->d_inode));
-+ /* new dentry's ctime may have changed due to hard-link counts */
-+ unionfs_copy_attr_times(new_dentry->d_inode);
-+
-+out:
-+ if (!new_dentry->d_inode)
-+ d_drop(new_dentry);
-+
-+ kfree(name);
-+ if (!err)
-+ unionfs_postcopyup_setmnt(new_dentry);
-+
-+ unionfs_check_inode(dir);
-+ unionfs_check_dentry(new_dentry);
-+ unionfs_check_dentry(old_dentry);
-+
-+ unionfs_double_unlock_dentry(old_dentry, new_dentry);
-+ unionfs_double_unlock_parents(old_parent, new_parent);
-+ dput(new_parent);
-+ dput(old_parent);
-+ unionfs_read_unlock(old_dentry->d_sb);
-+
-+ return err;
-+}
-+
-+static int unionfs_symlink(struct inode *dir, struct dentry *dentry,
-+ const char *symname)
-+{
-+ int err = 0;
-+ struct dentry *lower_dentry = NULL;
-+ struct dentry *wh_dentry = NULL;
-+ struct dentry *lower_parent_dentry = NULL;
-+ struct dentry *parent;
-+ char *name = NULL;
-+ int valid = 0;
-+ umode_t mode;
-+
-+ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
-+ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
-+ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+ valid = __unionfs_d_revalidate(dentry, parent, false);
-+ if (unlikely(!valid)) {
-+ err = -ESTALE;
-+ goto out;
-+ }
-+
-+ /*
-+ * It's only a bug if this dentry was not negative and couldn't be
-+ * revalidated (shouldn't happen).
-+ */
-+ BUG_ON(!valid && dentry->d_inode);
-+
-+ lower_dentry = find_writeable_branch(dir, dentry);
-+ if (IS_ERR(lower_dentry)) {
-+ err = PTR_ERR(lower_dentry);
-+ goto out;
-+ }
-+
-+ lower_parent_dentry = lock_parent(lower_dentry);
-+ if (IS_ERR(lower_parent_dentry)) {
-+ err = PTR_ERR(lower_parent_dentry);
-+ goto out_unlock;
-+ }
-+
-+ mode = S_IALLUGO;
-+ err = vfs_symlink(lower_parent_dentry->d_inode, lower_dentry, symname);
-+ if (!err) {
-+ err = PTR_ERR(unionfs_interpose(dentry, dir->i_sb, 0));
-+ if (!err) {
-+ unionfs_copy_attr_times(dir);
-+ fsstack_copy_inode_size(dir,
-+ lower_parent_dentry->d_inode);
-+ /* update no. of links on parent directory */
-+ set_nlink(dir, unionfs_get_nlinks(dir));
-+ }
-+ }
-+
-+out_unlock:
-+ unlock_dir(lower_parent_dentry);
-+out:
-+ dput(wh_dentry);
-+ kfree(name);
-+
-+ if (!err) {
-+ unionfs_postcopyup_setmnt(dentry);
-+ unionfs_check_inode(dir);
-+ unionfs_check_dentry(dentry);
-+ }
-+ unionfs_unlock_dentry(dentry);
-+ unionfs_unlock_parent(dentry, parent);
-+ unionfs_read_unlock(dentry->d_sb);
-+ return err;
-+}
-+
-+static int unionfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
-+{
-+ int err = 0;
-+ struct dentry *lower_dentry = NULL;
-+ struct dentry *lower_parent_dentry = NULL;
-+ struct dentry *parent;
-+ int bindex = 0, bstart;
-+ char *name = NULL;
-+ int valid;
-+
-+ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
-+ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
-+ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+ valid = __unionfs_d_revalidate(dentry, parent, false);
-+ if (unlikely(!valid)) {
-+ err = -ESTALE; /* same as what real_lookup does */
-+ goto out;
-+ }
-+
-+ bstart = dbstart(dentry);
-+
-+ lower_dentry = unionfs_lower_dentry(dentry);
-+
-+ /* check for a whiteout in new dentry branch, and delete it */
-+ err = check_unlink_whiteout(dentry, lower_dentry, bstart);
-+ if (err > 0) /* whiteout found and removed successfully */
-+ err = 0;
-+ if (err) {
-+ /* exit if the error returned was NOT -EROFS */
-+ if (!IS_COPYUP_ERR(err))
-+ goto out;
-+ bstart--;
-+ }
-+
-+ /* check if copyup's needed, and mkdir */
-+ for (bindex = bstart; bindex >= 0; bindex--) {
-+ int i;
-+ int bend = dbend(dentry);
-+
-+ if (is_robranch_super(dentry->d_sb, bindex))
-+ continue;
-+
-+ lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
-+ if (!lower_dentry) {
-+ lower_dentry = create_parents(dir, dentry,
-+ dentry->d_name.name,
-+ bindex);
-+ if (!lower_dentry || IS_ERR(lower_dentry)) {
-+ printk(KERN_ERR "unionfs: lower dentry "
-+ " NULL for bindex = %d\n", bindex);
-+ continue;
-+ }
-+ }
-+
-+ lower_parent_dentry = lock_parent(lower_dentry);
-+
-+ if (IS_ERR(lower_parent_dentry)) {
-+ err = PTR_ERR(lower_parent_dentry);
-+ goto out;
-+ }
-+
-+ err = vfs_mkdir(lower_parent_dentry->d_inode, lower_dentry,
-+ mode);
-+
-+ unlock_dir(lower_parent_dentry);
-+
-+ /* did the mkdir succeed? */
-+ if (err)
-+ break;
-+
-+ for (i = bindex + 1; i <= bend; i++) {
-+ /* XXX: use path_put_lowers? */
-+ if (unionfs_lower_dentry_idx(dentry, i)) {
-+ dput(unionfs_lower_dentry_idx(dentry, i));
-+ unionfs_set_lower_dentry_idx(dentry, i, NULL);
-+ }
-+ }
-+ dbend(dentry) = bindex;
-+
-+ /*
-+ * Only INTERPOSE_LOOKUP can return a value other than 0 on
-+ * err.
-+ */
-+ err = PTR_ERR(unionfs_interpose(dentry, dir->i_sb, 0));
-+ if (!err) {
-+ unionfs_copy_attr_times(dir);
-+ fsstack_copy_inode_size(dir,
-+ lower_parent_dentry->d_inode);
-+
-+ /* update number of links on parent directory */
-+ set_nlink(dir, unionfs_get_nlinks(dir));
-+ }
-+
-+ err = make_dir_opaque(dentry, dbstart(dentry));
-+ if (err) {
-+ printk(KERN_ERR "unionfs: mkdir: error creating "
-+ ".wh.__dir_opaque: %d\n", err);
-+ goto out;
-+ }
-+
-+ /* we are done! */
-+ break;
-+ }
-+
-+out:
-+ if (!dentry->d_inode)
-+ d_drop(dentry);
-+
-+ kfree(name);
-+
-+ if (!err) {
-+ unionfs_copy_attr_times(dentry->d_inode);
-+ unionfs_postcopyup_setmnt(dentry);
-+ }
-+ unionfs_check_inode(dir);
-+ unionfs_check_dentry(dentry);
-+ unionfs_unlock_dentry(dentry);
-+ unionfs_unlock_parent(dentry, parent);
-+ unionfs_read_unlock(dentry->d_sb);
-+
-+ return err;
-+}
-+
-+static int unionfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode,
-+ dev_t dev)
-+{
-+ int err = 0;
-+ struct dentry *lower_dentry = NULL;
-+ struct dentry *wh_dentry = NULL;
-+ struct dentry *lower_parent_dentry = NULL;
-+ struct dentry *parent;
-+ char *name = NULL;
-+ int valid = 0;
-+
-+ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
-+ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
-+ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+ valid = __unionfs_d_revalidate(dentry, parent, false);
-+ if (unlikely(!valid)) {
-+ err = -ESTALE;
-+ goto out;
-+ }
-+
-+ /*
-+ * It's only a bug if this dentry was not negative and couldn't be
-+ * revalidated (shouldn't happen).
-+ */
-+ BUG_ON(!valid && dentry->d_inode);
-+
-+ lower_dentry = find_writeable_branch(dir, dentry);
-+ if (IS_ERR(lower_dentry)) {
-+ err = PTR_ERR(lower_dentry);
-+ goto out;
-+ }
-+
-+ lower_parent_dentry = lock_parent(lower_dentry);
-+ if (IS_ERR(lower_parent_dentry)) {
-+ err = PTR_ERR(lower_parent_dentry);
-+ goto out_unlock;
-+ }
-+
-+ err = vfs_mknod(lower_parent_dentry->d_inode, lower_dentry, mode, dev);
-+ if (!err) {
-+ err = PTR_ERR(unionfs_interpose(dentry, dir->i_sb, 0));
-+ if (!err) {
-+ unionfs_copy_attr_times(dir);
-+ fsstack_copy_inode_size(dir,
-+ lower_parent_dentry->d_inode);
-+ /* update no. of links on parent directory */
-+ set_nlink(dir, unionfs_get_nlinks(dir));
-+ }
-+ }
-+
-+out_unlock:
-+ unlock_dir(lower_parent_dentry);
-+out:
-+ dput(wh_dentry);
-+ kfree(name);
-+
-+ if (!err) {
-+ unionfs_postcopyup_setmnt(dentry);
-+ unionfs_check_inode(dir);
-+ unionfs_check_dentry(dentry);
-+ }
-+ unionfs_unlock_dentry(dentry);
-+ unionfs_unlock_parent(dentry, parent);
-+ unionfs_read_unlock(dentry->d_sb);
-+ return err;
-+}
-+
-+/* requires sb, dentry, and parent to already be locked */
-+static int __unionfs_readlink(struct dentry *dentry, char __user *buf,
-+ int bufsiz)
-+{
-+ int err;
-+ struct dentry *lower_dentry;
-+
-+ lower_dentry = unionfs_lower_dentry(dentry);
-+
-+ if (!lower_dentry->d_inode->i_op ||
-+ !lower_dentry->d_inode->i_op->readlink) {
-+ err = -EINVAL;
-+ goto out;
-+ }
-+
-+ err = lower_dentry->d_inode->i_op->readlink(lower_dentry,
-+ buf, bufsiz);
-+ if (err >= 0)
-+ fsstack_copy_attr_atime(dentry->d_inode,
-+ lower_dentry->d_inode);
-+
-+out:
-+ return err;
-+}
-+
-+static int unionfs_readlink(struct dentry *dentry, char __user *buf,
-+ int bufsiz)
-+{
-+ int err;
-+ struct dentry *parent;
-+
-+ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
-+ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
-+ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+ if (unlikely(!__unionfs_d_revalidate(dentry, parent, false))) {
-+ err = -ESTALE;
-+ goto out;
-+ }
-+
-+ err = __unionfs_readlink(dentry, buf, bufsiz);
-+
-+out:
-+ unionfs_check_dentry(dentry);
-+ unionfs_unlock_dentry(dentry);
-+ unionfs_unlock_parent(dentry, parent);
-+ unionfs_read_unlock(dentry->d_sb);
-+
-+ return err;
-+}
-+
-+static void *unionfs_follow_link(struct dentry *dentry, struct nameidata *nd)
-+{
-+ char *buf;
-+ int len = PAGE_SIZE, err;
-+ mm_segment_t old_fs;
-+ struct dentry *parent;
-+
-+ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
-+ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
-+ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+ /* This is freed by the put_link method assuming a successful call. */
-+ buf = kmalloc(len, GFP_KERNEL);
-+ if (unlikely(!buf)) {
-+ err = -ENOMEM;
-+ goto out;
-+ }
-+
-+ /* read the symlink, and then we will follow it */
-+ old_fs = get_fs();
-+ set_fs(KERNEL_DS);
-+ err = __unionfs_readlink(dentry, buf, len);
-+ set_fs(old_fs);
-+ if (err < 0) {
-+ kfree(buf);
-+ buf = NULL;
-+ goto out;
-+ }
-+ buf[err] = 0;
-+ nd_set_link(nd, buf);
-+ err = 0;
-+
-+out:
-+ if (err >= 0) {
-+ unionfs_check_nd(nd);
-+ unionfs_check_dentry(dentry);
-+ }
-+
-+ unionfs_unlock_dentry(dentry);
-+ unionfs_unlock_parent(dentry, parent);
-+ unionfs_read_unlock(dentry->d_sb);
-+
-+ return ERR_PTR(err);
-+}
-+
-+/* this @nd *IS* still used */
-+static void unionfs_put_link(struct dentry *dentry, struct nameidata *nd,
-+ void *cookie)
-+{
-+ struct dentry *parent;
-+ char *buf;
-+
-+ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
-+ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
-+ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+ if (unlikely(!__unionfs_d_revalidate(dentry, parent, false)))
-+ printk(KERN_ERR
-+ "unionfs: put_link failed to revalidate dentry\n");
-+
-+ unionfs_check_dentry(dentry);
-+#if 0
-+ /* XXX: can't run this check b/c this fxn can receive a poisoned 'nd' PTR */
-+ unionfs_check_nd(nd);
-+#endif
-+ buf = nd_get_link(nd);
-+ if (!IS_ERR(buf))
-+ kfree(buf);
-+ unionfs_unlock_dentry(dentry);
-+ unionfs_unlock_parent(dentry, parent);
-+ unionfs_read_unlock(dentry->d_sb);
-+}
-+
-+/*
-+ * This is a variant of fs/namei.c:permission() or inode_permission() which
-+ * skips over EROFS tests (because we perform copyup on EROFS).
-+ */
-+static int __inode_permission(struct inode *inode, int mask)
-+{
-+ int retval;
-+
-+ /* nobody gets write access to an immutable file */
-+ if ((mask & MAY_WRITE) && IS_IMMUTABLE(inode))
-+ return -EACCES;
-+
-+ /* Ordinary permission routines do not understand MAY_APPEND. */
-+ if (inode->i_op && inode->i_op->permission) {
-+ retval = inode->i_op->permission(inode, mask);
-+ if (!retval) {
-+ /*
-+ * Exec permission on a regular file is denied if none
-+ * of the execute bits are set.
-+ *
-+ * This check should be done by the ->permission()
-+ * method.
-+ */
-+ if ((mask & MAY_EXEC) && S_ISREG(inode->i_mode) &&
-+ !(inode->i_mode & S_IXUGO))
-+ return -EACCES;
-+ }
-+ } else {
-+ retval = generic_permission(inode, mask);
-+ }
-+ if (retval)
-+ return retval;
-+
-+ return security_inode_permission(inode,
-+ mask & (MAY_READ|MAY_WRITE|MAY_EXEC|MAY_APPEND));
-+}
-+
-+/*
-+ * Don't grab the superblock read-lock in unionfs_permission, which prevents
-+ * a deadlock with the branch-management "add branch" code (which grabbed
-+ * the write lock). It is safe to not grab the read lock here, because even
-+ * with branch management taking place, there is no chance that
-+ * unionfs_permission, or anything it calls, will use stale branch
-+ * information.
-+ */
-+static int unionfs_permission(struct inode *inode, int mask)
-+{
-+ struct inode *lower_inode = NULL;
-+ int err = 0;
-+ int bindex, bstart, bend;
-+ int is_file;
-+ const int write_mask = (mask & MAY_WRITE) && !(mask & MAY_READ);
-+ struct inode *inode_grabbed;
-+
-+ inode_grabbed = igrab(inode);
-+ is_file = !S_ISDIR(inode->i_mode);
-+
-+ if (!UNIONFS_I(inode)->lower_inodes) {
-+ if (is_file) /* dirs can be unlinked but chdir'ed to */
-+ err = -ESTALE; /* force revalidate */
-+ goto out;
-+ }
-+ bstart = ibstart(inode);
-+ bend = ibend(inode);
-+ if (unlikely(bstart < 0 || bend < 0)) {
-+ /*
-+ * With branch-management, we can get a stale inode here.
-+ * If so, we return ESTALE back to link_path_walk, which
-+ * would discard the dcache entry and re-lookup the
-+ * dentry+inode. This should be equivalent to issuing
-+ * __unionfs_d_revalidate_chain on nd.dentry here.
-+ */
-+ if (is_file) /* dirs can be unlinked but chdir'ed to */
-+ err = -ESTALE; /* force revalidate */
-+ goto out;
-+ }
-+
-+ for (bindex = bstart; bindex <= bend; bindex++) {
-+ lower_inode = unionfs_lower_inode_idx(inode, bindex);
-+ if (!lower_inode)
-+ continue;
-+
-+ /*
-+ * check the condition for D-F-D underlying files/directories,
-+ * we don't have to check for files, if we are checking for
-+ * directories.
-+ */
-+ if (!is_file && !S_ISDIR(lower_inode->i_mode))
-+ continue;
-+
-+ /*
-+ * We check basic permissions, but we ignore any conditions
-+ * such as readonly file systems or branches marked as
-+ * readonly, because those conditions should lead to a
-+ * copyup taking place later on. However, if user never had
-+ * access to the file, then no copyup could ever take place.
-+ */
-+ err = __inode_permission(lower_inode, mask);
-+ if (err && err != -EACCES && err != EPERM && bindex > 0) {
-+ umode_t mode = lower_inode->i_mode;
-+ if ((is_robranch_super(inode->i_sb, bindex) ||
-+ __is_rdonly(lower_inode)) &&
-+ (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode)))
-+ err = 0;
-+ if (IS_COPYUP_ERR(err))
-+ err = 0;
-+ }
-+
-+ /*
-+ * NFS HACK: NFSv2/3 return EACCES on readonly-exported,
-+ * locally readonly-mounted file systems, instead of EROFS
-+ * like other file systems do. So we have no choice here
-+ * but to intercept this and ignore it for NFS branches
-+ * marked readonly. Specifically, we avoid using NFS's own
-+ * "broken" ->permission method, and rely on
-+ * generic_permission() to do basic checking for us.
-+ */
-+ if (err && err == -EACCES &&
-+ is_robranch_super(inode->i_sb, bindex) &&
-+ lower_inode->i_sb->s_magic == NFS_SUPER_MAGIC)
-+ err = generic_permission(lower_inode, mask);
-+
-+ /*
-+ * The permissions are an intersection of the overall directory
-+ * permissions, so we fail if one fails.
-+ */
-+ if (err)
-+ goto out;
-+
-+ /* only the leftmost file matters. */
-+ if (is_file || write_mask) {
-+ if (is_file && write_mask) {
-+ err = get_write_access(lower_inode);
-+ if (!err)
-+ put_write_access(lower_inode);
-+ }
-+ break;
-+ }
-+ }
-+ /* sync times which may have changed (asynchronously) below */
-+ unionfs_copy_attr_times(inode);
-+
-+out:
-+ unionfs_check_inode(inode);
-+ iput(inode_grabbed);
-+ return err;
-+}
-+
-+static int unionfs_setattr(struct dentry *dentry, struct iattr *ia)
-+{
-+ int err = 0;
-+ struct dentry *lower_dentry;
-+ struct dentry *parent;
-+ struct inode *inode;
-+ struct inode *lower_inode;
-+ int bstart, bend, bindex;
-+ loff_t size;
-+ struct iattr lower_ia;
-+
-+ /* check if user has permission to change inode */
-+ err = inode_change_ok(dentry->d_inode, ia);
-+ if (err)
-+ goto out_err;
-+
-+ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
-+ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
-+ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+ if (unlikely(!__unionfs_d_revalidate(dentry, parent, false))) {
-+ err = -ESTALE;
-+ goto out;
-+ }
-+
-+ bstart = dbstart(dentry);
-+ bend = dbend(dentry);
-+ inode = dentry->d_inode;
-+
-+ /*
-+ * mode change is for clearing setuid/setgid. Allow lower filesystem
-+ * to reinterpret it in its own way.
-+ */
-+ if (ia->ia_valid & (ATTR_KILL_SUID | ATTR_KILL_SGID))
-+ ia->ia_valid &= ~ATTR_MODE;
-+
-+ lower_dentry = unionfs_lower_dentry(dentry);
-+ if (!lower_dentry) { /* should never happen after above revalidate */
-+ err = -EINVAL;
-+ goto out;
-+ }
-+
-+ /*
-+ * Get the lower inode directly from lower dentry, in case ibstart
-+ * is -1 (which happens when the file is open but unlinked.
-+ */
-+ lower_inode = lower_dentry->d_inode;
-+
-+ /* check if user has permission to change lower inode */
-+ err = inode_change_ok(lower_inode, ia);
-+ if (err)
-+ goto out;
-+
-+ /* copyup if the file is on a read only branch */
-+ if (is_robranch_super(dentry->d_sb, bstart)
-+ || __is_rdonly(lower_inode)) {
-+ /* check if we have a branch to copy up to */
-+ if (bstart <= 0) {
-+ err = -EACCES;
-+ goto out;
-+ }
-+
-+ if (ia->ia_valid & ATTR_SIZE)
-+ size = ia->ia_size;
-+ else
-+ size = i_size_read(inode);
-+ /* copyup to next available branch */
-+ for (bindex = bstart - 1; bindex >= 0; bindex--) {
-+ err = copyup_dentry(parent->d_inode,
-+ dentry, bstart, bindex,
-+ dentry->d_name.name,
-+ dentry->d_name.len,
-+ NULL, size);
-+ if (!err)
-+ break;
-+ }
-+ if (err)
-+ goto out;
-+ /* get updated lower_dentry/inode after copyup */
-+ lower_dentry = unionfs_lower_dentry(dentry);
-+ lower_inode = unionfs_lower_inode(inode);
-+ /*
-+ * check for whiteouts in writeable branch, and remove them
-+ * if necessary.
-+ */
-+ if (lower_dentry) {
-+ err = check_unlink_whiteout(dentry, lower_dentry,
-+ bindex);
-+ if (err > 0) /* ignore if whiteout found and removed */
-+ err = 0;
-+ }
-+ }
-+
-+ /*
-+ * If shrinking, first truncate upper level to cancel writing dirty
-+ * pages beyond the new eof; and also if its' maxbytes is more
-+ * limiting (fail with -EFBIG before making any change to the lower
-+ * level). There is no need to vmtruncate the upper level
-+ * afterwards in the other cases: we fsstack_copy_inode_size from
-+ * the lower level.
-+ */
-+ if (ia->ia_valid & ATTR_SIZE) {
-+ size = i_size_read(inode);
-+ if (ia->ia_size < size || (ia->ia_size > size &&
-+ inode->i_sb->s_maxbytes < lower_inode->i_sb->s_maxbytes)) {
-+ err = vmtruncate(inode, ia->ia_size);
-+ if (err)
-+ goto out;
-+ }
-+ }
-+
-+ /* notify the (possibly copied-up) lower inode */
-+ /*
-+ * Note: we use lower_dentry->d_inode, because lower_inode may be
-+ * unlinked (no inode->i_sb and i_ino==0. This happens if someone
-+ * tries to open(), unlink(), then ftruncate() a file.
-+ */
-+ /* prepare our own lower struct iattr (with our own lower file) */
-+ memcpy(&lower_ia, ia, sizeof(lower_ia));
-+ if (ia->ia_valid & ATTR_FILE) {
-+ lower_ia.ia_file = unionfs_lower_file(ia->ia_file);
-+ BUG_ON(!lower_ia.ia_file); // XXX?
-+ }
-+
-+ mutex_lock(&lower_dentry->d_inode->i_mutex);
-+ err = notify_change(lower_dentry, &lower_ia);
-+ mutex_unlock(&lower_dentry->d_inode->i_mutex);
-+ if (err)
-+ goto out;
-+
-+ /* get attributes from the first lower inode */
-+ if (ibstart(inode) >= 0)
-+ unionfs_copy_attr_all(inode, lower_inode);
-+ /*
-+ * unionfs_copy_attr_all will copy the lower times to our inode if
-+ * the lower ones are newer (useful for cache coherency). However,
-+ * ->setattr is the only place in which we may have to copy the
-+ * lower inode times absolutely, to support utimes(2).
-+ */
-+ if (ia->ia_valid & ATTR_MTIME_SET)
-+ inode->i_mtime = lower_inode->i_mtime;
-+ if (ia->ia_valid & ATTR_CTIME)
-+ inode->i_ctime = lower_inode->i_ctime;
-+ if (ia->ia_valid & ATTR_ATIME_SET)
-+ inode->i_atime = lower_inode->i_atime;
-+ fsstack_copy_inode_size(inode, lower_inode);
-+
-+out:
-+ if (!err)
-+ unionfs_check_dentry(dentry);
-+ unionfs_unlock_dentry(dentry);
-+ unionfs_unlock_parent(dentry, parent);
-+ unionfs_read_unlock(dentry->d_sb);
-+out_err:
-+ return err;
-+}
-+
-+struct inode_operations unionfs_symlink_iops = {
-+ .readlink = unionfs_readlink,
-+ .permission = unionfs_permission,
-+ .follow_link = unionfs_follow_link,
-+ .setattr = unionfs_setattr,
-+ .put_link = unionfs_put_link,
-+};
-+
-+struct inode_operations unionfs_dir_iops = {
-+ .create = unionfs_create,
-+ .lookup = unionfs_lookup,
-+ .link = unionfs_link,
-+ .unlink = unionfs_unlink,
-+ .symlink = unionfs_symlink,
-+ .mkdir = unionfs_mkdir,
-+ .rmdir = unionfs_rmdir,
-+ .mknod = unionfs_mknod,
-+ .rename = unionfs_rename,
-+ .permission = unionfs_permission,
-+ .setattr = unionfs_setattr,
-+#ifdef CONFIG_UNION_FS_XATTR
-+ .setxattr = unionfs_setxattr,
-+ .getxattr = unionfs_getxattr,
-+ .removexattr = unionfs_removexattr,
-+ .listxattr = unionfs_listxattr,
-+#endif /* CONFIG_UNION_FS_XATTR */
-+};
-+
-+struct inode_operations unionfs_main_iops = {
-+ .permission = unionfs_permission,
-+ .setattr = unionfs_setattr,
-+#ifdef CONFIG_UNION_FS_XATTR
-+ .setxattr = unionfs_setxattr,
-+ .getxattr = unionfs_getxattr,
-+ .removexattr = unionfs_removexattr,
-+ .listxattr = unionfs_listxattr,
-+#endif /* CONFIG_UNION_FS_XATTR */
-+};
-diff --git a/fs/unionfs/lookup.c b/fs/unionfs/lookup.c
-new file mode 100644
-index 0000000..041d674
---- /dev/null
-+++ b/fs/unionfs/lookup.c
-@@ -0,0 +1,570 @@
-+/*
-+ * Copyright (c) 2003-2011 Erez Zadok
-+ * Copyright (c) 2003-2006 Charles P. Wright
-+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2005-2006 Junjiro Okajima
-+ * Copyright (c) 2005 Arun M. Krishnakumar
-+ * Copyright (c) 2004-2006 David P. Quigley
-+ * Copyright (c) 2003-2004 Mohammad Nayyer Zubair
-+ * Copyright (c) 2003 Puja Gupta
-+ * Copyright (c) 2003 Harikesavan Krishnan
-+ * Copyright (c) 2003-2011 Stony Brook University
-+ * Copyright (c) 2003-2011 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#include "union.h"
-+
-+/*
-+ * Lookup one path component @name relative to a <base,mnt> path pair.
-+ * Behaves nearly the same as lookup_one_len (i.e., return negative dentry
-+ * on ENOENT), but uses the @mnt passed, so it can cross bind mounts and
-+ * other lower mounts properly. If @new_mnt is non-null, will fill in the
-+ * new mnt there. Caller is responsible to dput/mntput/path_put returned
-+ * @dentry and @new_mnt.
-+ */
-+struct dentry *__lookup_one(struct dentry *base, struct vfsmount *mnt,
-+ const char *name, struct vfsmount **new_mnt)
-+{
-+ struct dentry *dentry = NULL;
-+ struct path lower_path = {NULL, NULL};
-+ int err;
-+
-+ /* we use flags=0 to get basic lookup */
-+ err = vfs_path_lookup(base, mnt, name, 0, &lower_path);
-+
-+ switch (err) {
-+ case 0: /* no error */
-+ dentry = lower_path.dentry;
-+ if (new_mnt)
-+ *new_mnt = lower_path.mnt; /* rc already inc'ed */
-+ break;
-+ case -ENOENT:
-+ /*
-+ * We don't consider ENOENT an error, and we want to return
-+ * a negative dentry (ala lookup_one_len). As we know
-+ * there was no inode for this name before (-ENOENT), then
-+ * it's safe to call lookup_one_len (which doesn't take a
-+ * vfsmount).
-+ */
-+ dentry = lookup_lck_len(name, base, strlen(name));
-+ if (new_mnt)
-+ *new_mnt = mntget(lower_path.mnt);
-+ break;
-+ default: /* all other real errors */
-+ dentry = ERR_PTR(err);
-+ break;
-+ }
-+
-+ return dentry;
-+}
-+
-+/*
-+ * This is a utility function that fills in a unionfs dentry.
-+ * Caller must lock this dentry with unionfs_lock_dentry.
-+ *
-+ * Returns: 0 (ok), or -ERRNO if an error occurred.
-+ * XXX: get rid of _partial_lookup and make callers call _lookup_full directly
-+ */
-+int unionfs_partial_lookup(struct dentry *dentry, struct dentry *parent)
-+{
-+ struct dentry *tmp;
-+ int err = -ENOSYS;
-+
-+ tmp = unionfs_lookup_full(dentry, parent, INTERPOSE_PARTIAL);
-+
-+ if (!tmp) {
-+ err = 0;
-+ goto out;
-+ }
-+ if (IS_ERR(tmp)) {
-+ err = PTR_ERR(tmp);
-+ goto out;
-+ }
-+ /* XXX: need to change the interface */
-+ BUG_ON(tmp != dentry);
-+out:
-+ return err;
-+}
-+
-+/* The dentry cache is just so we have properly sized dentries. */
-+static struct kmem_cache *unionfs_dentry_cachep;
-+int unionfs_init_dentry_cache(void)
-+{
-+ unionfs_dentry_cachep =
-+ kmem_cache_create("unionfs_dentry",
-+ sizeof(struct unionfs_dentry_info),
-+ 0, SLAB_RECLAIM_ACCOUNT, NULL);
-+
-+ return (unionfs_dentry_cachep ? 0 : -ENOMEM);
-+}
-+
-+void unionfs_destroy_dentry_cache(void)
-+{
-+ if (unionfs_dentry_cachep)
-+ kmem_cache_destroy(unionfs_dentry_cachep);
-+}
-+
-+void free_dentry_private_data(struct dentry *dentry)
-+{
-+ if (!dentry || !dentry->d_fsdata)
-+ return;
-+ kfree(UNIONFS_D(dentry)->lower_paths);
-+ UNIONFS_D(dentry)->lower_paths = NULL;
-+ kmem_cache_free(unionfs_dentry_cachep, dentry->d_fsdata);
-+ dentry->d_fsdata = NULL;
-+}
-+
-+static inline int __realloc_dentry_private_data(struct dentry *dentry)
-+{
-+ struct unionfs_dentry_info *info = UNIONFS_D(dentry);
-+ void *p;
-+ int size;
-+
-+ BUG_ON(!info);
-+
-+ size = sizeof(struct path) * sbmax(dentry->d_sb);
-+ p = krealloc(info->lower_paths, size, GFP_ATOMIC);
-+ if (unlikely(!p))
-+ return -ENOMEM;
-+
-+ info->lower_paths = p;
-+
-+ info->bstart = -1;
-+ info->bend = -1;
-+ info->bopaque = -1;
-+ info->bcount = sbmax(dentry->d_sb);
-+ atomic_set(&info->generation,
-+ atomic_read(&UNIONFS_SB(dentry->d_sb)->generation));
-+
-+ memset(info->lower_paths, 0, size);
-+
-+ return 0;
-+}
-+
-+/* UNIONFS_D(dentry)->lock must be locked */
-+int realloc_dentry_private_data(struct dentry *dentry)
-+{
-+ if (!__realloc_dentry_private_data(dentry))
-+ return 0;
-+
-+ kfree(UNIONFS_D(dentry)->lower_paths);
-+ free_dentry_private_data(dentry);
-+ return -ENOMEM;
-+}
-+
-+/* allocate new dentry private data */
-+int new_dentry_private_data(struct dentry *dentry, int subclass)
-+{
-+ struct unionfs_dentry_info *info = UNIONFS_D(dentry);
-+
-+ BUG_ON(info);
-+
-+ info = kmem_cache_alloc(unionfs_dentry_cachep, GFP_ATOMIC);
-+ if (unlikely(!info))
-+ return -ENOMEM;
-+
-+ mutex_init(&info->lock);
-+ mutex_lock_nested(&info->lock, subclass);
-+
-+ info->lower_paths = NULL;
-+
-+ dentry->d_fsdata = info;
-+
-+ if (!__realloc_dentry_private_data(dentry))
-+ return 0;
-+
-+ mutex_unlock(&info->lock);
-+ free_dentry_private_data(dentry);
-+ return -ENOMEM;
-+}
-+
-+/*
-+ * scan through the lower dentry objects, and set bstart to reflect the
-+ * starting branch
-+ */
-+void update_bstart(struct dentry *dentry)
-+{
-+ int bindex;
-+ int bstart = dbstart(dentry);
-+ int bend = dbend(dentry);
-+ struct dentry *lower_dentry;
-+
-+ for (bindex = bstart; bindex <= bend; bindex++) {
-+ lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
-+ if (!lower_dentry)
-+ continue;
-+ if (lower_dentry->d_inode) {
-+ dbstart(dentry) = bindex;
-+ break;
-+ }
-+ dput(lower_dentry);
-+ unionfs_set_lower_dentry_idx(dentry, bindex, NULL);
-+ }
-+}
-+
-+
-+/*
-+ * Initialize a nameidata structure (the intent part) we can pass to a lower
-+ * file system. Returns 0 on success or -error (only -ENOMEM possible).
-+ * Inside that nd structure, this function may also return an allocated
-+ * struct file (for open intents). The caller, when done with this nd, must
-+ * kfree the intent file (using release_lower_nd).
-+ *
-+ * XXX: this code, and the callers of this code, should be redone using
-+ * vfs_path_lookup() when (1) the nameidata structure is refactored into a
-+ * separate intent-structure, and (2) open_namei() is broken into a VFS-only
-+ * function and a method that other file systems can call.
-+ */
-+int init_lower_nd(struct nameidata *nd, unsigned int flags)
-+{
-+ int err = 0;
-+#ifdef ALLOC_LOWER_ND_FILE
-+ /*
-+ * XXX: one day we may need to have the lower return an open file
-+ * for us. It is not needed in 2.6.23-rc1 for nfs2/nfs3, but may
-+ * very well be needed for nfs4.
-+ */
-+ struct file *file;
-+#endif /* ALLOC_LOWER_ND_FILE */
-+
-+ memset(nd, 0, sizeof(struct nameidata));
-+ if (!flags)
-+ return err;
-+
-+ switch (flags) {
-+ case LOOKUP_CREATE:
-+ nd->intent.open.flags |= O_CREAT;
-+ /* fall through: shared code for create/open cases */
-+ case LOOKUP_OPEN:
-+ nd->flags = flags;
-+ nd->intent.open.flags |= (FMODE_READ | FMODE_WRITE);
-+#ifdef ALLOC_LOWER_ND_FILE
-+ file = kzalloc(sizeof(struct file), GFP_KERNEL);
-+ if (unlikely(!file)) {
-+ err = -ENOMEM;
-+ break; /* exit switch statement and thus return */
-+ }
-+ nd->intent.open.file = file;
-+#endif /* ALLOC_LOWER_ND_FILE */
-+ break;
-+ default:
-+ /*
-+ * We should never get here, for now.
-+ * We can add new cases here later on.
-+ */
-+ pr_debug("unionfs: unknown nameidata flag 0x%x\n", flags);
-+ BUG();
-+ break;
-+ }
-+
-+ return err;
-+}
-+
-+void release_lower_nd(struct nameidata *nd, int err)
-+{
-+ if (!nd->intent.open.file)
-+ return;
-+ else if (!err)
-+ release_open_intent(nd);
-+#ifdef ALLOC_LOWER_ND_FILE
-+ kfree(nd->intent.open.file);
-+#endif /* ALLOC_LOWER_ND_FILE */
-+}
-+
-+/*
-+ * Main (and complex) driver function for Unionfs's lookup
-+ *
-+ * Returns: NULL (ok), ERR_PTR if an error occurred, or a non-null non-error
-+ * PTR if d_splice returned a different dentry.
-+ *
-+ * If lookupmode is INTERPOSE_PARTIAL/REVAL/REVAL_NEG, the passed dentry's
-+ * inode info must be locked. If lookupmode is INTERPOSE_LOOKUP (i.e., a
-+ * newly looked-up dentry), then unionfs_lookup_backend will return a locked
-+ * dentry's info, which the caller must unlock.
-+ */
-+struct dentry *unionfs_lookup_full(struct dentry *dentry,
-+ struct dentry *parent, int lookupmode)
-+{
-+ int err = 0;
-+ struct dentry *lower_dentry = NULL;
-+ struct vfsmount *lower_mnt;
-+ struct vfsmount *lower_dir_mnt;
-+ struct dentry *wh_lower_dentry = NULL;
-+ struct dentry *lower_dir_dentry = NULL;
-+ struct dentry *d_interposed = NULL;
-+ int bindex, bstart, bend, bopaque;
-+ int opaque, num_positive = 0;
-+ const char *name;
-+ int namelen;
-+ int pos_start, pos_end;
-+
-+ /*
-+ * We should already have a lock on this dentry in the case of a
-+ * partial lookup, or a revalidation. Otherwise it is returned from
-+ * new_dentry_private_data already locked.
-+ */
-+ verify_locked(dentry);
-+ verify_locked(parent);
-+
-+ /* must initialize dentry operations */
-+ if (lookupmode == INTERPOSE_LOOKUP)
-+ d_set_d_op(dentry, &unionfs_dops);
-+
-+ /* We never partial lookup the root directory. */
-+ if (IS_ROOT(dentry))
-+ goto out;
-+
-+ name = dentry->d_name.name;
-+ namelen = dentry->d_name.len;
-+
-+ /* No dentries should get created for possible whiteout names. */
-+ if (!is_validname(name)) {
-+ err = -EPERM;
-+ goto out_free;
-+ }
-+
-+ /* Now start the actual lookup procedure. */
-+ bstart = dbstart(parent);
-+ bend = dbend(parent);
-+ bopaque = dbopaque(parent);
-+ BUG_ON(bstart < 0);
-+
-+ /* adjust bend to bopaque if needed */
-+ if ((bopaque >= 0) && (bopaque < bend))
-+ bend = bopaque;
-+
-+ /* lookup all possible dentries */
-+ for (bindex = bstart; bindex <= bend; bindex++) {
-+
-+ lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
-+ lower_mnt = unionfs_lower_mnt_idx(dentry, bindex);
-+
-+ /* skip if we already have a positive lower dentry */
-+ if (lower_dentry) {
-+ if (dbstart(dentry) < 0)
-+ dbstart(dentry) = bindex;
-+ if (bindex > dbend(dentry))
-+ dbend(dentry) = bindex;
-+ if (lower_dentry->d_inode)
-+ num_positive++;
-+ continue;
-+ }
-+
-+ lower_dir_dentry =
-+ unionfs_lower_dentry_idx(parent, bindex);
-+ /* if the lower dentry's parent does not exist, skip this */
-+ if (!lower_dir_dentry || !lower_dir_dentry->d_inode)
-+ continue;
-+
-+ /* also skip it if the parent isn't a directory. */
-+ if (!S_ISDIR(lower_dir_dentry->d_inode->i_mode))
-+ continue; /* XXX: should be BUG_ON */
-+
-+ /* check for whiteouts: stop lookup if found */
-+ wh_lower_dentry = lookup_whiteout(name, lower_dir_dentry);
-+ if (IS_ERR(wh_lower_dentry)) {
-+ err = PTR_ERR(wh_lower_dentry);
-+ goto out_free;
-+ }
-+ if (wh_lower_dentry->d_inode) {
-+ dbend(dentry) = dbopaque(dentry) = bindex;
-+ if (dbstart(dentry) < 0)
-+ dbstart(dentry) = bindex;
-+ dput(wh_lower_dentry);
-+ break;
-+ }
-+ dput(wh_lower_dentry);
-+
-+ /* Now do regular lookup; lookup @name */
-+ lower_dir_mnt = unionfs_lower_mnt_idx(parent, bindex);
-+ lower_mnt = NULL; /* XXX: needed? */
-+
-+ lower_dentry = __lookup_one(lower_dir_dentry, lower_dir_mnt,
-+ name, &lower_mnt);
-+
-+ if (IS_ERR(lower_dentry)) {
-+ err = PTR_ERR(lower_dentry);
-+ goto out_free;
-+ }
-+ unionfs_set_lower_dentry_idx(dentry, bindex, lower_dentry);
-+ if (!lower_mnt)
-+ lower_mnt = unionfs_mntget(dentry->d_sb->s_root,
-+ bindex);
-+ unionfs_set_lower_mnt_idx(dentry, bindex, lower_mnt);
-+
-+ /* adjust dbstart/end */
-+ if (dbstart(dentry) < 0)
-+ dbstart(dentry) = bindex;
-+ if (bindex > dbend(dentry))
-+ dbend(dentry) = bindex;
-+ /*
-+ * We always store the lower dentries above, and update
-+ * dbstart/dbend, even if the whole unionfs dentry is
-+ * negative (i.e., no lower inodes).
-+ */
-+ if (!lower_dentry->d_inode)
-+ continue;
-+ num_positive++;
-+
-+ /*
-+ * check if we just found an opaque directory, if so, stop
-+ * lookups here.
-+ */
-+ if (!S_ISDIR(lower_dentry->d_inode->i_mode))
-+ continue;
-+ opaque = is_opaque_dir(dentry, bindex);
-+ if (opaque < 0) {
-+ err = opaque;
-+ goto out_free;
-+ } else if (opaque) {
-+ dbend(dentry) = dbopaque(dentry) = bindex;
-+ break;
-+ }
-+ dbend(dentry) = bindex;
-+
-+ /* update parent directory's atime with the bindex */
-+ fsstack_copy_attr_atime(parent->d_inode,
-+ lower_dir_dentry->d_inode);
-+ }
-+
-+ /* sanity checks, then decide if to process a negative dentry */
-+ BUG_ON(dbstart(dentry) < 0 && dbend(dentry) >= 0);
-+ BUG_ON(dbstart(dentry) >= 0 && dbend(dentry) < 0);
-+
-+ if (num_positive > 0)
-+ goto out_positive;
-+
-+ /*** handle NEGATIVE dentries ***/
-+
-+ /*
-+ * If negative, keep only first lower negative dentry, to save on
-+ * memory.
-+ */
-+ if (dbstart(dentry) < dbend(dentry)) {
-+ path_put_lowers(dentry, dbstart(dentry) + 1,
-+ dbend(dentry), false);
-+ dbend(dentry) = dbstart(dentry);
-+ }
-+ if (lookupmode == INTERPOSE_PARTIAL)
-+ goto out;
-+ if (lookupmode == INTERPOSE_LOOKUP) {
-+ /*
-+ * If all we found was a whiteout in the first available
-+ * branch, then create a negative dentry for a possibly new
-+ * file to be created.
-+ */
-+ if (dbopaque(dentry) < 0)
-+ goto out;
-+ /* XXX: need to get mnt here */
-+ bindex = dbstart(dentry);
-+ if (unionfs_lower_dentry_idx(dentry, bindex))
-+ goto out;
-+ lower_dir_dentry =
-+ unionfs_lower_dentry_idx(parent, bindex);
-+ if (!lower_dir_dentry || !lower_dir_dentry->d_inode)
-+ goto out;
-+ if (!S_ISDIR(lower_dir_dentry->d_inode->i_mode))
-+ goto out; /* XXX: should be BUG_ON */
-+ /* XXX: do we need to cross bind mounts here? */
-+ lower_dentry = lookup_lck_len(name, lower_dir_dentry, namelen);
-+ if (IS_ERR(lower_dentry)) {
-+ err = PTR_ERR(lower_dentry);
-+ goto out;
-+ }
-+ /* XXX: need to mntget/mntput as needed too! */
-+ unionfs_set_lower_dentry_idx(dentry, bindex, lower_dentry);
-+ /* XXX: wrong mnt for crossing bind mounts! */
-+ lower_mnt = unionfs_mntget(dentry->d_sb->s_root, bindex);
-+ unionfs_set_lower_mnt_idx(dentry, bindex, lower_mnt);
-+
-+ goto out;
-+ }
-+
-+ /* if we're revalidating a positive dentry, don't make it negative */
-+ if (lookupmode != INTERPOSE_REVAL)
-+ d_add(dentry, NULL);
-+
-+ goto out;
-+
-+out_positive:
-+ /*** handle POSITIVE dentries ***/
-+
-+ /*
-+ * This unionfs dentry is positive (at least one lower inode
-+ * exists), so scan entire dentry from beginning to end, and remove
-+ * any negative lower dentries, if any. Then, update dbstart/dbend
-+ * to reflect the start/end of positive dentries.
-+ */
-+ pos_start = pos_end = -1;
-+ for (bindex = bstart; bindex <= bend; bindex++) {
-+ lower_dentry = unionfs_lower_dentry_idx(dentry,
-+ bindex);
-+ if (lower_dentry && lower_dentry->d_inode) {
-+ if (pos_start < 0)
-+ pos_start = bindex;
-+ if (bindex > pos_end)
-+ pos_end = bindex;
-+ continue;
-+ }
-+ path_put_lowers(dentry, bindex, bindex, false);
-+ }
-+ if (pos_start >= 0)
-+ dbstart(dentry) = pos_start;
-+ if (pos_end >= 0)
-+ dbend(dentry) = pos_end;
-+
-+ /* Partial lookups need to re-interpose, or throw away older negs. */
-+ if (lookupmode == INTERPOSE_PARTIAL) {
-+ if (dentry->d_inode) {
-+ unionfs_reinterpose(dentry);
-+ goto out;
-+ }
-+
-+ /*
-+ * This dentry was positive, so it is as if we had a
-+ * negative revalidation.
-+ */
-+ lookupmode = INTERPOSE_REVAL_NEG;
-+ update_bstart(dentry);
-+ }
-+
-+ /*
-+ * Interpose can return a dentry if d_splice returned a different
-+ * dentry.
-+ */
-+ d_interposed = unionfs_interpose(dentry, dentry->d_sb, lookupmode);
-+ if (IS_ERR(d_interposed))
-+ err = PTR_ERR(d_interposed);
-+ else if (d_interposed)
-+ dentry = d_interposed;
-+
-+ if (!err)
-+ goto out;
-+ d_drop(dentry);
-+
-+out_free:
-+ /* should dput/mntput all the underlying dentries on error condition */
-+ if (dbstart(dentry) >= 0)
-+ path_put_lowers_all(dentry, false);
-+ /* free lower_paths unconditionally */
-+ kfree(UNIONFS_D(dentry)->lower_paths);
-+ UNIONFS_D(dentry)->lower_paths = NULL;
-+
-+out:
-+ if (dentry && UNIONFS_D(dentry)) {
-+ BUG_ON(dbstart(dentry) < 0 && dbend(dentry) >= 0);
-+ BUG_ON(dbstart(dentry) >= 0 && dbend(dentry) < 0);
-+ }
-+ if (d_interposed && UNIONFS_D(d_interposed)) {
-+ BUG_ON(dbstart(d_interposed) < 0 && dbend(d_interposed) >= 0);
-+ BUG_ON(dbstart(d_interposed) >= 0 && dbend(d_interposed) < 0);
-+ }
-+
-+ if (!err && d_interposed)
-+ return d_interposed;
-+ return ERR_PTR(err);
-+}
-diff --git a/fs/unionfs/main.c b/fs/unionfs/main.c
-new file mode 100644
-index 0000000..ee78f1d
---- /dev/null
-+++ b/fs/unionfs/main.c
-@@ -0,0 +1,752 @@
-+/*
-+ * Copyright (c) 2003-2011 Erez Zadok
-+ * Copyright (c) 2003-2006 Charles P. Wright
-+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2005-2006 Junjiro Okajima
-+ * Copyright (c) 2005 Arun M. Krishnakumar
-+ * Copyright (c) 2004-2006 David P. Quigley
-+ * Copyright (c) 2003-2004 Mohammad Nayyer Zubair
-+ * Copyright (c) 2003 Puja Gupta
-+ * Copyright (c) 2003 Harikesavan Krishnan
-+ * Copyright (c) 2003-2011 Stony Brook University
-+ * Copyright (c) 2003-2011 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#include "union.h"
-+#include <linux/module.h>
-+#include <linux/moduleparam.h>
-+
-+static void unionfs_fill_inode(struct dentry *dentry,
-+ struct inode *inode)
-+{
-+ struct inode *lower_inode;
-+ struct dentry *lower_dentry;
-+ int bindex, bstart, bend;
-+
-+ bstart = dbstart(dentry);
-+ bend = dbend(dentry);
-+
-+ for (bindex = bstart; bindex <= bend; bindex++) {
-+ lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
-+ if (!lower_dentry) {
-+ unionfs_set_lower_inode_idx(inode, bindex, NULL);
-+ continue;
-+ }
-+
-+ /* Initialize the lower inode to the new lower inode. */
-+ if (!lower_dentry->d_inode)
-+ continue;
-+
-+ unionfs_set_lower_inode_idx(inode, bindex,
-+ igrab(lower_dentry->d_inode));
-+ }
-+
-+ ibstart(inode) = dbstart(dentry);
-+ ibend(inode) = dbend(dentry);
-+
-+ /* Use attributes from the first branch. */
-+ lower_inode = unionfs_lower_inode(inode);
-+
-+ /* Use different set of inode ops for symlinks & directories */
-+ if (S_ISLNK(lower_inode->i_mode))
-+ inode->i_op = &unionfs_symlink_iops;
-+ else if (S_ISDIR(lower_inode->i_mode))
-+ inode->i_op = &unionfs_dir_iops;
-+
-+ /* Use different set of file ops for directories */
-+ if (S_ISDIR(lower_inode->i_mode))
-+ inode->i_fop = &unionfs_dir_fops;
-+
-+ /* properly initialize special inodes */
-+ if (S_ISBLK(lower_inode->i_mode) || S_ISCHR(lower_inode->i_mode) ||
-+ S_ISFIFO(lower_inode->i_mode) || S_ISSOCK(lower_inode->i_mode))
-+ init_special_inode(inode, lower_inode->i_mode,
-+ lower_inode->i_rdev);
-+
-+ /* all well, copy inode attributes */
-+ unionfs_copy_attr_all(inode, lower_inode);
-+ fsstack_copy_inode_size(inode, lower_inode);
-+}
-+
-+/*
-+ * Connect a unionfs inode dentry/inode with several lower ones. This is
-+ * the classic stackable file system "vnode interposition" action.
-+ *
-+ * @sb: unionfs's super_block
-+ */
-+struct dentry *unionfs_interpose(struct dentry *dentry, struct super_block *sb,
-+ int flag)
-+{
-+ int err = 0;
-+ struct inode *inode;
-+ int need_fill_inode = 1;
-+ struct dentry *spliced = NULL;
-+
-+ verify_locked(dentry);
-+
-+ /*
-+ * We allocate our new inode below by calling unionfs_iget,
-+ * which will initialize some of the new inode's fields
-+ */
-+
-+ /*
-+ * On revalidate we've already got our own inode and just need
-+ * to fix it up.
-+ */
-+ if (flag == INTERPOSE_REVAL) {
-+ inode = dentry->d_inode;
-+ UNIONFS_I(inode)->bstart = -1;
-+ UNIONFS_I(inode)->bend = -1;
-+ atomic_set(&UNIONFS_I(inode)->generation,
-+ atomic_read(&UNIONFS_SB(sb)->generation));
-+
-+ UNIONFS_I(inode)->lower_inodes =
-+ kcalloc(sbmax(sb), sizeof(struct inode *), GFP_KERNEL);
-+ if (unlikely(!UNIONFS_I(inode)->lower_inodes)) {
-+ err = -ENOMEM;
-+ goto out;
-+ }
-+ } else {
-+ /* get unique inode number for unionfs */
-+ inode = unionfs_iget(sb, iunique(sb, UNIONFS_ROOT_INO));
-+ if (IS_ERR(inode)) {
-+ err = PTR_ERR(inode);
-+ goto out;
-+ }
-+ if (atomic_read(&inode->i_count) > 1)
-+ goto skip;
-+ }
-+
-+ need_fill_inode = 0;
-+ unionfs_fill_inode(dentry, inode);
-+
-+skip:
-+ /* only (our) lookup wants to do a d_add */
-+ switch (flag) {
-+ case INTERPOSE_DEFAULT:
-+ /* for operations which create new inodes */
-+ d_add(dentry, inode);
-+ break;
-+ case INTERPOSE_REVAL_NEG:
-+ d_instantiate(dentry, inode);
-+ break;
-+ case INTERPOSE_LOOKUP:
-+ spliced = d_splice_alias(inode, dentry);
-+ if (spliced && spliced != dentry) {
-+ /*
-+ * d_splice can return a dentry if it was
-+ * disconnected and had to be moved. We must ensure
-+ * that the private data of the new dentry is
-+ * correct and that the inode info was filled
-+ * properly. Finally we must return this new
-+ * dentry.
-+ */
-+ d_set_d_op(spliced, &unionfs_dops);
-+ spliced->d_fsdata = dentry->d_fsdata;
-+ dentry->d_fsdata = NULL;
-+ dentry = spliced;
-+ if (need_fill_inode) {
-+ need_fill_inode = 0;
-+ unionfs_fill_inode(dentry, inode);
-+ }
-+ goto out_spliced;
-+ } else if (!spliced) {
-+ if (need_fill_inode) {
-+ need_fill_inode = 0;
-+ unionfs_fill_inode(dentry, inode);
-+ goto out_spliced;
-+ }
-+ }
-+ break;
-+ case INTERPOSE_REVAL:
-+ /* Do nothing. */
-+ break;
-+ default:
-+ printk(KERN_CRIT "unionfs: invalid interpose flag passed!\n");
-+ BUG();
-+ }
-+ goto out;
-+
-+out_spliced:
-+ if (!err)
-+ return spliced;
-+out:
-+ return ERR_PTR(err);
-+}
-+
-+/* like interpose above, but for an already existing dentry */
-+void unionfs_reinterpose(struct dentry *dentry)
-+{
-+ struct dentry *lower_dentry;
-+ struct inode *inode;
-+ int bindex, bstart, bend;
-+
-+ verify_locked(dentry);
-+
-+ /* This is pre-allocated inode */
-+ inode = dentry->d_inode;
-+
-+ bstart = dbstart(dentry);
-+ bend = dbend(dentry);
-+ for (bindex = bstart; bindex <= bend; bindex++) {
-+ lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
-+ if (!lower_dentry)
-+ continue;
-+
-+ if (!lower_dentry->d_inode)
-+ continue;
-+ if (unionfs_lower_inode_idx(inode, bindex))
-+ continue;
-+ unionfs_set_lower_inode_idx(inode, bindex,
-+ igrab(lower_dentry->d_inode));
-+ }
-+ ibstart(inode) = dbstart(dentry);
-+ ibend(inode) = dbend(dentry);
-+}
-+
-+/*
-+ * make sure the branch we just looked up (nd) makes sense:
-+ *
-+ * 1) we're not trying to stack unionfs on top of unionfs
-+ * 2) it exists
-+ * 3) is a directory
-+ */
-+int check_branch(const struct path *path)
-+{
-+ /* XXX: remove in ODF code -- stacking unions allowed there */
-+ if (!strcmp(path->dentry->d_sb->s_type->name, UNIONFS_NAME))
-+ return -EINVAL;
-+ if (!path->dentry->d_inode)
-+ return -ENOENT;
-+ if (!S_ISDIR(path->dentry->d_inode->i_mode))
-+ return -ENOTDIR;
-+ return 0;
-+}
-+
-+/* checks if two lower_dentries have overlapping branches */
-+static int is_branch_overlap(struct dentry *dent1, struct dentry *dent2)
-+{
-+ struct dentry *dent = NULL;
-+
-+ dent = dent1;
-+ while ((dent != dent2) && (dent->d_parent != dent))
-+ dent = dent->d_parent;
-+
-+ if (dent == dent2)
-+ return 1;
-+
-+ dent = dent2;
-+ while ((dent != dent1) && (dent->d_parent != dent))
-+ dent = dent->d_parent;
-+
-+ return (dent == dent1);
-+}
-+
-+/*
-+ * Parse "ro" or "rw" options, but default to "rw" if no mode options was
-+ * specified. Fill the mode bits in @perms. If encounter an unknown
-+ * string, return -EINVAL. Otherwise return 0.
-+ */
-+int parse_branch_mode(const char *name, int *perms)
-+{
-+ if (!name || !strcmp(name, "rw")) {
-+ *perms = MAY_READ | MAY_WRITE;
-+ return 0;
-+ }
-+ if (!strcmp(name, "ro")) {
-+ *perms = MAY_READ;
-+ return 0;
-+ }
-+ return -EINVAL;
-+}
-+
-+/*
-+ * parse the dirs= mount argument
-+ *
-+ * We don't need to lock the superblock private data's rwsem, as we get
-+ * called only by unionfs_read_super - it is still a long time before anyone
-+ * can even get a reference to us.
-+ */
-+static int parse_dirs_option(struct super_block *sb, struct unionfs_dentry_info
-+ *lower_root_info, char *options)
-+{
-+ struct path path;
-+ char *name;
-+ int err = 0;
-+ int branches = 1;
-+ int bindex = 0;
-+ int i = 0;
-+ int j = 0;
-+ struct dentry *dent1;
-+ struct dentry *dent2;
-+
-+ if (options[0] == '\0') {
-+ printk(KERN_ERR "unionfs: no branches specified\n");
-+ err = -EINVAL;
-+ goto out_return;
-+ }
-+
-+ /*
-+ * Each colon means we have a separator, this is really just a rough
-+ * guess, since strsep will handle empty fields for us.
-+ */
-+ for (i = 0; options[i]; i++)
-+ if (options[i] == ':')
-+ branches++;
-+
-+ /* allocate space for underlying pointers to lower dentry */
-+ UNIONFS_SB(sb)->data =
-+ kcalloc(branches, sizeof(struct unionfs_data), GFP_KERNEL);
-+ if (unlikely(!UNIONFS_SB(sb)->data)) {
-+ err = -ENOMEM;
-+ goto out_return;
-+ }
-+
-+ lower_root_info->lower_paths =
-+ kcalloc(branches, sizeof(struct path), GFP_KERNEL);
-+ if (unlikely(!lower_root_info->lower_paths)) {
-+ err = -ENOMEM;
-+ /* free the underlying pointer array */
-+ kfree(UNIONFS_SB(sb)->data);
-+ UNIONFS_SB(sb)->data = NULL;
-+ goto out_return;
-+ }
-+
-+ /* now parsing a string such as "b1:b2=rw:b3=ro:b4" */
-+ branches = 0;
-+ while ((name = strsep(&options, ":")) != NULL) {
-+ int perms;
-+ char *mode = strchr(name, '=');
-+
-+ if (!name)
-+ continue;
-+ if (!*name) { /* bad use of ':' (extra colons) */
-+ err = -EINVAL;
-+ goto out;
-+ }
-+
-+ branches++;
-+
-+ /* strip off '=' if any */
-+ if (mode)
-+ *mode++ = '\0';
-+
-+ err = parse_branch_mode(mode, &perms);
-+ if (err) {
-+ printk(KERN_ERR "unionfs: invalid mode \"%s\" for "
-+ "branch %d\n", mode, bindex);
-+ goto out;
-+ }
-+ /* ensure that leftmost branch is writeable */
-+ if (!bindex && !(perms & MAY_WRITE)) {
-+ printk(KERN_ERR "unionfs: leftmost branch cannot be "
-+ "read-only (use \"-o ro\" to create a "
-+ "read-only union)\n");
-+ err = -EINVAL;
-+ goto out;
-+ }
-+
-+ err = kern_path(name, LOOKUP_FOLLOW, &path);
-+ if (err) {
-+ printk(KERN_ERR "unionfs: error accessing "
-+ "lower directory '%s' (error %d)\n",
-+ name, err);
-+ goto out;
-+ }
-+
-+ err = check_branch(&path);
-+ if (err) {
-+ printk(KERN_ERR "unionfs: lower directory "
-+ "'%s' is not a valid branch\n", name);
-+ path_put(&path);
-+ goto out;
-+ }
-+
-+ lower_root_info->lower_paths[bindex].dentry = path.dentry;
-+ lower_root_info->lower_paths[bindex].mnt = path.mnt;
-+
-+ set_branchperms(sb, bindex, perms);
-+ set_branch_count(sb, bindex, 0);
-+ new_branch_id(sb, bindex);
-+
-+ if (lower_root_info->bstart < 0)
-+ lower_root_info->bstart = bindex;
-+ lower_root_info->bend = bindex;
-+ bindex++;
-+ }
-+
-+ if (branches == 0) {
-+ printk(KERN_ERR "unionfs: no branches specified\n");
-+ err = -EINVAL;
-+ goto out;
-+ }
-+
-+ BUG_ON(branches != (lower_root_info->bend + 1));
-+
-+ /*
-+ * Ensure that no overlaps exist in the branches.
-+ *
-+ * This test is required because the Linux kernel has no support
-+ * currently for ensuring coherency between stackable layers and
-+ * branches. If we were to allow overlapping branches, it would be
-+ * possible, for example, to delete a file via one branch, which
-+ * would not be reflected in another branch. Such incoherency could
-+ * lead to inconsistencies and even kernel oopses. Rather than
-+ * implement hacks to work around some of these cache-coherency
-+ * problems, we prevent branch overlapping, for now. A complete
-+ * solution will involve proper kernel/VFS support for cache
-+ * coherency, at which time we could safely remove this
-+ * branch-overlapping test.
-+ */
-+ for (i = 0; i < branches; i++) {
-+ dent1 = lower_root_info->lower_paths[i].dentry;
-+ for (j = i + 1; j < branches; j++) {
-+ dent2 = lower_root_info->lower_paths[j].dentry;
-+ if (is_branch_overlap(dent1, dent2)) {
-+ printk(KERN_ERR "unionfs: branches %d and "
-+ "%d overlap\n", i, j);
-+ err = -EINVAL;
-+ goto out;
-+ }
-+ }
-+ }
-+
-+out:
-+ if (err) {
-+ for (i = 0; i < branches; i++)
-+ path_put(&lower_root_info->lower_paths[i]);
-+
-+ kfree(lower_root_info->lower_paths);
-+ kfree(UNIONFS_SB(sb)->data);
-+
-+ /*
-+ * MUST clear the pointers to prevent potential double free if
-+ * the caller dies later on
-+ */
-+ lower_root_info->lower_paths = NULL;
-+ UNIONFS_SB(sb)->data = NULL;
-+ }
-+out_return:
-+ return err;
-+}
-+
-+/*
-+ * Parse mount options. See the manual page for usage instructions.
-+ *
-+ * Returns the dentry object of the lower-level (lower) directory;
-+ * We want to mount our stackable file system on top of that lower directory.
-+ */
-+static struct unionfs_dentry_info *unionfs_parse_options(
-+ struct super_block *sb,
-+ char *options)
-+{
-+ struct unionfs_dentry_info *lower_root_info;
-+ char *optname;
-+ int err = 0;
-+ int bindex;
-+ int dirsfound = 0;
-+
-+ /* allocate private data area */
-+ err = -ENOMEM;
-+ lower_root_info =
-+ kzalloc(sizeof(struct unionfs_dentry_info), GFP_KERNEL);
-+ if (unlikely(!lower_root_info))
-+ goto out_error;
-+ lower_root_info->bstart = -1;
-+ lower_root_info->bend = -1;
-+ lower_root_info->bopaque = -1;
-+
-+ while ((optname = strsep(&options, ",")) != NULL) {
-+ char *optarg;
-+
-+ if (!optname || !*optname)
-+ continue;
-+
-+ optarg = strchr(optname, '=');
-+ if (optarg)
-+ *optarg++ = '\0';
-+
-+ /*
-+ * All of our options take an argument now. Insert ones that
-+ * don't, above this check.
-+ */
-+ if (!optarg) {
-+ printk(KERN_ERR "unionfs: %s requires an argument\n",
-+ optname);
-+ err = -EINVAL;
-+ goto out_error;
-+ }
-+
-+ if (!strcmp("dirs", optname)) {
-+ if (++dirsfound > 1) {
-+ printk(KERN_ERR
-+ "unionfs: multiple dirs specified\n");
-+ err = -EINVAL;
-+ goto out_error;
-+ }
-+ err = parse_dirs_option(sb, lower_root_info, optarg);
-+ if (err)
-+ goto out_error;
-+ continue;
-+ }
-+
-+ err = -EINVAL;
-+ printk(KERN_ERR
-+ "unionfs: unrecognized option '%s'\n", optname);
-+ goto out_error;
-+ }
-+ if (dirsfound != 1) {
-+ printk(KERN_ERR "unionfs: dirs option required\n");
-+ err = -EINVAL;
-+ goto out_error;
-+ }
-+ goto out;
-+
-+out_error:
-+ if (lower_root_info && lower_root_info->lower_paths) {
-+ for (bindex = lower_root_info->bstart;
-+ bindex >= 0 && bindex <= lower_root_info->bend;
-+ bindex++)
-+ path_put(&lower_root_info->lower_paths[bindex]);
-+ }
-+
-+ kfree(lower_root_info->lower_paths);
-+ kfree(lower_root_info);
-+
-+ kfree(UNIONFS_SB(sb)->data);
-+ UNIONFS_SB(sb)->data = NULL;
-+
-+ lower_root_info = ERR_PTR(err);
-+out:
-+ return lower_root_info;
-+}
-+
-+/*
-+ * There is no need to lock the unionfs_super_info's rwsem as there is no
-+ * way anyone can have a reference to the superblock at this point in time.
-+ */
-+static int unionfs_read_super(struct super_block *sb, void *raw_data,
-+ int silent)
-+{
-+ int err = 0;
-+ struct unionfs_dentry_info *lower_root_info = NULL;
-+ int bindex, bstart, bend;
-+ struct inode *inode = NULL;
-+
-+ if (!raw_data) {
-+ printk(KERN_ERR
-+ "unionfs: read_super: missing data argument\n");
-+ err = -EINVAL;
-+ goto out;
-+ }
-+
-+ /* Allocate superblock private data */
-+ sb->s_fs_info = kzalloc(sizeof(struct unionfs_sb_info), GFP_KERNEL);
-+ if (unlikely(!UNIONFS_SB(sb))) {
-+ printk(KERN_CRIT "unionfs: read_super: out of memory\n");
-+ err = -ENOMEM;
-+ goto out;
-+ }
-+
-+ UNIONFS_SB(sb)->bend = -1;
-+ atomic_set(&UNIONFS_SB(sb)->generation, 1);
-+ init_rwsem(&UNIONFS_SB(sb)->rwsem);
-+ UNIONFS_SB(sb)->high_branch_id = -1; /* -1 == invalid branch ID */
-+
-+ lower_root_info = unionfs_parse_options(sb, raw_data);
-+ if (IS_ERR(lower_root_info)) {
-+ printk(KERN_ERR
-+ "unionfs: read_super: error while parsing options "
-+ "(err = %ld)\n", PTR_ERR(lower_root_info));
-+ err = PTR_ERR(lower_root_info);
-+ lower_root_info = NULL;
-+ goto out_free;
-+ }
-+ if (lower_root_info->bstart == -1) {
-+ err = -ENOENT;
-+ goto out_free;
-+ }
-+
-+ /* set the lower superblock field of upper superblock */
-+ bstart = lower_root_info->bstart;
-+ BUG_ON(bstart != 0);
-+ sbend(sb) = bend = lower_root_info->bend;
-+ for (bindex = bstart; bindex <= bend; bindex++) {
-+ struct dentry *d = lower_root_info->lower_paths[bindex].dentry;
-+ atomic_inc(&d->d_sb->s_active);
-+ unionfs_set_lower_super_idx(sb, bindex, d->d_sb);
-+ }
-+
-+ /* max Bytes is the maximum bytes from highest priority branch */
-+ sb->s_maxbytes = unionfs_lower_super_idx(sb, 0)->s_maxbytes;
-+
-+ /*
-+ * Our c/m/atime granularity is 1 ns because we may stack on file
-+ * systems whose granularity is as good. This is important for our
-+ * time-based cache coherency.
-+ */
-+ sb->s_time_gran = 1;
-+
-+ sb->s_op = &unionfs_sops;
-+
-+ /* get a new inode and allocate our root dentry */
-+ inode = unionfs_iget(sb, iunique(sb, UNIONFS_ROOT_INO));
-+ if (IS_ERR(inode)) {
-+ err = PTR_ERR(inode);
-+ goto out_dput;
-+ }
-+ sb->s_root = d_make_root(inode);
-+ if (unlikely(!sb->s_root)) {
-+ err = -ENOMEM;
-+ goto out_dput;
-+ }
-+ d_set_d_op(sb->s_root, &unionfs_dops);
-+
-+ /* link the upper and lower dentries */
-+ sb->s_root->d_fsdata = NULL;
-+ err = new_dentry_private_data(sb->s_root, UNIONFS_DMUTEX_ROOT);
-+ if (unlikely(err))
-+ goto out_freedpd;
-+
-+ /* if get here: cannot have error */
-+
-+ /* Set the lower dentries for s_root */
-+ for (bindex = bstart; bindex <= bend; bindex++) {
-+ struct dentry *d;
-+ struct vfsmount *m;
-+
-+ d = lower_root_info->lower_paths[bindex].dentry;
-+ m = lower_root_info->lower_paths[bindex].mnt;
-+
-+ unionfs_set_lower_dentry_idx(sb->s_root, bindex, d);
-+ unionfs_set_lower_mnt_idx(sb->s_root, bindex, m);
-+ }
-+ dbstart(sb->s_root) = bstart;
-+ dbend(sb->s_root) = bend;
-+
-+ /* Set the generation number to one, since this is for the mount. */
-+ atomic_set(&UNIONFS_D(sb->s_root)->generation, 1);
-+
-+ if (atomic_read(&inode->i_count) <= 1)
-+ unionfs_fill_inode(sb->s_root, inode);
-+
-+ /*
-+ * No need to call interpose because we already have a positive
-+ * dentry, which was instantiated by d_alloc_root. Just need to
-+ * d_rehash it.
-+ */
-+ d_rehash(sb->s_root);
-+
-+ unionfs_unlock_dentry(sb->s_root);
-+ goto out; /* all is well */
-+
-+out_freedpd:
-+ if (UNIONFS_D(sb->s_root)) {
-+ kfree(UNIONFS_D(sb->s_root)->lower_paths);
-+ free_dentry_private_data(sb->s_root);
-+ }
-+ dput(sb->s_root);
-+
-+out_iput:
-+ iput(inode);
-+
-+out_dput:
-+ if (lower_root_info && !IS_ERR(lower_root_info)) {
-+ for (bindex = lower_root_info->bstart;
-+ bindex <= lower_root_info->bend; bindex++) {
-+ struct dentry *d;
-+ d = lower_root_info->lower_paths[bindex].dentry;
-+ /* drop refs we took earlier */
-+ atomic_dec(&d->d_sb->s_active);
-+ path_put(&lower_root_info->lower_paths[bindex]);
-+ }
-+ kfree(lower_root_info->lower_paths);
-+ kfree(lower_root_info);
-+ lower_root_info = NULL;
-+ }
-+
-+out_free:
-+ kfree(UNIONFS_SB(sb)->data);
-+ kfree(UNIONFS_SB(sb));
-+ sb->s_fs_info = NULL;
-+
-+out:
-+ if (lower_root_info && !IS_ERR(lower_root_info)) {
-+ kfree(lower_root_info->lower_paths);
-+ kfree(lower_root_info);
-+ }
-+ return err;
-+}
-+
-+static struct dentry *unionfs_mount(struct file_system_type *fs_type,
-+ int flags, const char *dev_name,
-+ void *raw_data)
-+{
-+ struct dentry *dentry;
-+
-+ dentry = mount_nodev(fs_type, flags, raw_data, unionfs_read_super);
-+ if (!IS_ERR(dentry))
-+ UNIONFS_SB(dentry->d_sb)->dev_name =
-+ kstrdup(dev_name, GFP_KERNEL);
-+ return dentry;
-+}
-+
-+static struct file_system_type unionfs_fs_type = {
-+ .owner = THIS_MODULE,
-+ .name = UNIONFS_NAME,
-+ .mount = unionfs_mount,
-+ .kill_sb = generic_shutdown_super,
-+ .fs_flags = FS_REVAL_DOT,
-+};
-+
-+static int __init init_unionfs_fs(void)
-+{
-+ int err;
-+
-+ pr_info("Registering unionfs " UNIONFS_VERSION "\n");
-+
-+ err = unionfs_init_filldir_cache();
-+ if (unlikely(err))
-+ goto out;
-+ err = unionfs_init_inode_cache();
-+ if (unlikely(err))
-+ goto out;
-+ err = unionfs_init_dentry_cache();
-+ if (unlikely(err))
-+ goto out;
-+ err = init_sioq();
-+ if (unlikely(err))
-+ goto out;
-+ err = register_filesystem(&unionfs_fs_type);
-+out:
-+ if (unlikely(err)) {
-+ stop_sioq();
-+ unionfs_destroy_filldir_cache();
-+ unionfs_destroy_inode_cache();
-+ unionfs_destroy_dentry_cache();
-+ }
-+ return err;
-+}
-+
-+static void __exit exit_unionfs_fs(void)
-+{
-+ stop_sioq();
-+ unionfs_destroy_filldir_cache();
-+ unionfs_destroy_inode_cache();
-+ unionfs_destroy_dentry_cache();
-+ unregister_filesystem(&unionfs_fs_type);
-+ pr_info("Completed unionfs module unload\n");
-+}
-+
-+MODULE_AUTHOR("Erez Zadok, Filesystems and Storage Lab, Stony Brook University"
-+ " (http://www.fsl.cs.sunysb.edu)");
-+MODULE_DESCRIPTION("Unionfs " UNIONFS_VERSION
-+ " (http://unionfs.filesystems.org)");
-+MODULE_LICENSE("GPL");
-+
-+module_init(init_unionfs_fs);
-+module_exit(exit_unionfs_fs);
-diff --git a/fs/unionfs/mmap.c b/fs/unionfs/mmap.c
-new file mode 100644
-index 0000000..bcc5652
---- /dev/null
-+++ b/fs/unionfs/mmap.c
-@@ -0,0 +1,89 @@
-+/*
-+ * Copyright (c) 2003-2011 Erez Zadok
-+ * Copyright (c) 2003-2006 Charles P. Wright
-+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2005-2006 Junjiro Okajima
-+ * Copyright (c) 2006 Shaya Potter
-+ * Copyright (c) 2005 Arun M. Krishnakumar
-+ * Copyright (c) 2004-2006 David P. Quigley
-+ * Copyright (c) 2003-2004 Mohammad Nayyer Zubair
-+ * Copyright (c) 2003 Puja Gupta
-+ * Copyright (c) 2003 Harikesavan Krishnan
-+ * Copyright (c) 2003-2011 Stony Brook University
-+ * Copyright (c) 2003-2011 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#include "union.h"
-+
-+
-+/*
-+ * XXX: we need a dummy readpage handler because generic_file_mmap (which we
-+ * use in unionfs_mmap) checks for the existence of
-+ * mapping->a_ops->readpage, else it returns -ENOEXEC. The VFS will need to
-+ * be fixed to allow a file system to define vm_ops->fault without any
-+ * address_space_ops whatsoever.
-+ *
-+ * Otherwise, we don't want to use our readpage method at all.
-+ */
-+static int unionfs_readpage(struct file *file, struct page *page)
-+{
-+ BUG();
-+ return -EINVAL;
-+}
-+
-+static int unionfs_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
-+{
-+ int err;
-+ struct file *file, *lower_file;
-+ const struct vm_operations_struct *lower_vm_ops;
-+ struct vm_area_struct lower_vma;
-+
-+ BUG_ON(!vma);
-+ memcpy(&lower_vma, vma, sizeof(struct vm_area_struct));
-+ file = lower_vma.vm_file;
-+ lower_vm_ops = UNIONFS_F(file)->lower_vm_ops;
-+ BUG_ON(!lower_vm_ops);
-+
-+ lower_file = unionfs_lower_file(file);
-+ BUG_ON(!lower_file);
-+ /*
-+ * XXX: vm_ops->fault may be called in parallel. Because we have to
-+ * resort to temporarily changing the vma->vm_file to point to the
-+ * lower file, a concurrent invocation of unionfs_fault could see a
-+ * different value. In this workaround, we keep a different copy of
-+ * the vma structure in our stack, so we never expose a different
-+ * value of the vma->vm_file called to us, even temporarily. A
-+ * better fix would be to change the calling semantics of ->fault to
-+ * take an explicit file pointer.
-+ */
-+ lower_vma.vm_file = lower_file;
-+ err = lower_vm_ops->fault(&lower_vma, vmf);
-+ return err;
-+}
-+
-+/*
-+ * XXX: the default address_space_ops for unionfs is empty. We cannot set
-+ * our inode->i_mapping->a_ops to NULL because too many code paths expect
-+ * the a_ops vector to be non-NULL.
-+ */
-+struct address_space_operations unionfs_aops = {
-+ /* empty on purpose */
-+};
-+
-+/*
-+ * XXX: we need a second, dummy address_space_ops vector, to be used
-+ * temporarily during unionfs_mmap, because the latter calls
-+ * generic_file_mmap, which checks if ->readpage exists, else returns
-+ * -ENOEXEC.
-+ */
-+struct address_space_operations unionfs_dummy_aops = {
-+ .readpage = unionfs_readpage,
-+};
-+
-+struct vm_operations_struct unionfs_vm_ops = {
-+ .fault = unionfs_fault,
-+};
-diff --git a/fs/unionfs/rdstate.c b/fs/unionfs/rdstate.c
-new file mode 100644
-index 0000000..59b7333
---- /dev/null
-+++ b/fs/unionfs/rdstate.c
-@@ -0,0 +1,285 @@
-+/*
-+ * Copyright (c) 2003-2011 Erez Zadok
-+ * Copyright (c) 2003-2006 Charles P. Wright
-+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2005-2006 Junjiro Okajima
-+ * Copyright (c) 2005 Arun M. Krishnakumar
-+ * Copyright (c) 2004-2006 David P. Quigley
-+ * Copyright (c) 2003-2004 Mohammad Nayyer Zubair
-+ * Copyright (c) 2003 Puja Gupta
-+ * Copyright (c) 2003 Harikesavan Krishnan
-+ * Copyright (c) 2003-2011 Stony Brook University
-+ * Copyright (c) 2003-2011 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#include "union.h"
-+
-+/* This file contains the routines for maintaining readdir state. */
-+
-+/*
-+ * There are two structures here, rdstate which is a hash table
-+ * of the second structure which is a filldir_node.
-+ */
-+
-+/*
-+ * This is a struct kmem_cache for filldir nodes, because we allocate a lot
-+ * of them and they shouldn't waste memory. If the node has a small name
-+ * (as defined by the dentry structure), then we use an inline name to
-+ * preserve kmalloc space.
-+ */
-+static struct kmem_cache *unionfs_filldir_cachep;
-+
-+int unionfs_init_filldir_cache(void)
-+{
-+ unionfs_filldir_cachep =
-+ kmem_cache_create("unionfs_filldir",
-+ sizeof(struct filldir_node), 0,
-+ SLAB_RECLAIM_ACCOUNT, NULL);
-+
-+ return (unionfs_filldir_cachep ? 0 : -ENOMEM);
-+}
-+
-+void unionfs_destroy_filldir_cache(void)
-+{
-+ if (unionfs_filldir_cachep)
-+ kmem_cache_destroy(unionfs_filldir_cachep);
-+}
-+
-+/*
-+ * This is a tuning parameter that tells us roughly how big to make the
-+ * hash table in directory entries per page. This isn't perfect, but
-+ * at least we get a hash table size that shouldn't be too overloaded.
-+ * The following averages are based on my home directory.
-+ * 14.44693 Overall
-+ * 12.29 Single Page Directories
-+ * 117.93 Multi-page directories
-+ */
-+#define DENTPAGE 4096
-+#define DENTPERONEPAGE 12
-+#define DENTPERPAGE 118
-+#define MINHASHSIZE 1
-+static int guesstimate_hash_size(struct inode *inode)
-+{
-+ struct inode *lower_inode;
-+ int bindex;
-+ int hashsize = MINHASHSIZE;
-+
-+ if (UNIONFS_I(inode)->hashsize > 0)
-+ return UNIONFS_I(inode)->hashsize;
-+
-+ for (bindex = ibstart(inode); bindex <= ibend(inode); bindex++) {
-+ lower_inode = unionfs_lower_inode_idx(inode, bindex);
-+ if (!lower_inode)
-+ continue;
-+
-+ if (i_size_read(lower_inode) == DENTPAGE)
-+ hashsize += DENTPERONEPAGE;
-+ else
-+ hashsize += (i_size_read(lower_inode) / DENTPAGE) *
-+ DENTPERPAGE;
-+ }
-+
-+ return hashsize;
-+}
-+
-+int init_rdstate(struct file *file)
-+{
-+ BUG_ON(sizeof(loff_t) !=
-+ (sizeof(unsigned int) + sizeof(unsigned int)));
-+ BUG_ON(UNIONFS_F(file)->rdstate != NULL);
-+
-+ UNIONFS_F(file)->rdstate = alloc_rdstate(file->f_path.dentry->d_inode,
-+ fbstart(file));
-+
-+ return (UNIONFS_F(file)->rdstate ? 0 : -ENOMEM);
-+}
-+
-+struct unionfs_dir_state *find_rdstate(struct inode *inode, loff_t fpos)
-+{
-+ struct unionfs_dir_state *rdstate = NULL;
-+ struct list_head *pos;
-+
-+ spin_lock(&UNIONFS_I(inode)->rdlock);
-+ list_for_each(pos, &UNIONFS_I(inode)->readdircache) {
-+ struct unionfs_dir_state *r =
-+ list_entry(pos, struct unionfs_dir_state, cache);
-+ if (fpos == rdstate2offset(r)) {
-+ UNIONFS_I(inode)->rdcount--;
-+ list_del(&r->cache);
-+ rdstate = r;
-+ break;
-+ }
-+ }
-+ spin_unlock(&UNIONFS_I(inode)->rdlock);
-+ return rdstate;
-+}
-+
-+struct unionfs_dir_state *alloc_rdstate(struct inode *inode, int bindex)
-+{
-+ int i = 0;
-+ int hashsize;
-+ unsigned long mallocsize = sizeof(struct unionfs_dir_state);
-+ struct unionfs_dir_state *rdstate;
-+
-+ hashsize = guesstimate_hash_size(inode);
-+ mallocsize += hashsize * sizeof(struct list_head);
-+ mallocsize = __roundup_pow_of_two(mallocsize);
-+
-+ /* This should give us about 500 entries anyway. */
-+ if (mallocsize > PAGE_SIZE)
-+ mallocsize = PAGE_SIZE;
-+
-+ hashsize = (mallocsize - sizeof(struct unionfs_dir_state)) /
-+ sizeof(struct list_head);
-+
-+ rdstate = kmalloc(mallocsize, GFP_KERNEL);
-+ if (unlikely(!rdstate))
-+ return NULL;
-+
-+ spin_lock(&UNIONFS_I(inode)->rdlock);
-+ if (UNIONFS_I(inode)->cookie >= (MAXRDCOOKIE - 1))
-+ UNIONFS_I(inode)->cookie = 1;
-+ else
-+ UNIONFS_I(inode)->cookie++;
-+
-+ rdstate->cookie = UNIONFS_I(inode)->cookie;
-+ spin_unlock(&UNIONFS_I(inode)->rdlock);
-+ rdstate->offset = 1;
-+ rdstate->access = jiffies;
-+ rdstate->bindex = bindex;
-+ rdstate->dirpos = 0;
-+ rdstate->hashentries = 0;
-+ rdstate->size = hashsize;
-+ for (i = 0; i < rdstate->size; i++)
-+ INIT_LIST_HEAD(&rdstate->list[i]);
-+
-+ return rdstate;
-+}
-+
-+static void free_filldir_node(struct filldir_node *node)
-+{
-+ if (node->namelen >= DNAME_INLINE_LEN)
-+ kfree(node->name);
-+ kmem_cache_free(unionfs_filldir_cachep, node);
-+}
-+
-+void free_rdstate(struct unionfs_dir_state *state)
-+{
-+ struct filldir_node *tmp;
-+ int i;
-+
-+ for (i = 0; i < state->size; i++) {
-+ struct list_head *head = &(state->list[i]);
-+ struct list_head *pos, *n;
-+
-+ /* traverse the list and deallocate space */
-+ list_for_each_safe(pos, n, head) {
-+ tmp = list_entry(pos, struct filldir_node, file_list);
-+ list_del(&tmp->file_list);
-+ free_filldir_node(tmp);
-+ }
-+ }
-+
-+ kfree(state);
-+}
-+
-+struct filldir_node *find_filldir_node(struct unionfs_dir_state *rdstate,
-+ const char *name, int namelen,
-+ int is_whiteout)
-+{
-+ int index;
-+ unsigned int hash;
-+ struct list_head *head;
-+ struct list_head *pos;
-+ struct filldir_node *cursor = NULL;
-+ int found = 0;
-+
-+ BUG_ON(namelen <= 0);
-+
-+ hash = full_name_hash(name, namelen);
-+ index = hash % rdstate->size;
-+
-+ head = &(rdstate->list[index]);
-+ list_for_each(pos, head) {
-+ cursor = list_entry(pos, struct filldir_node, file_list);
-+
-+ if (cursor->namelen == namelen && cursor->hash == hash &&
-+ !strncmp(cursor->name, name, namelen)) {
-+ /*
-+ * a duplicate exists, and hence no need to create
-+ * entry to the list
-+ */
-+ found = 1;
-+
-+ /*
-+ * if a duplicate is found in this branch, and is
-+ * not due to the caller looking for an entry to
-+ * whiteout, then the file system may be corrupted.
-+ */
-+ if (unlikely(!is_whiteout &&
-+ cursor->bindex == rdstate->bindex))
-+ printk(KERN_ERR "unionfs: filldir: possible "
-+ "I/O error: a file is duplicated "
-+ "in the same branch %d: %s\n",
-+ rdstate->bindex, cursor->name);
-+ break;
-+ }
-+ }
-+
-+ if (!found)
-+ cursor = NULL;
-+
-+ return cursor;
-+}
-+
-+int add_filldir_node(struct unionfs_dir_state *rdstate, const char *name,
-+ int namelen, int bindex, int whiteout)
-+{
-+ struct filldir_node *new;
-+ unsigned int hash;
-+ int index;
-+ int err = 0;
-+ struct list_head *head;
-+
-+ BUG_ON(namelen <= 0);
-+
-+ hash = full_name_hash(name, namelen);
-+ index = hash % rdstate->size;
-+ head = &(rdstate->list[index]);
-+
-+ new = kmem_cache_alloc(unionfs_filldir_cachep, GFP_KERNEL);
-+ if (unlikely(!new)) {
-+ err = -ENOMEM;
-+ goto out;
-+ }
-+
-+ INIT_LIST_HEAD(&new->file_list);
-+ new->namelen = namelen;
-+ new->hash = hash;
-+ new->bindex = bindex;
-+ new->whiteout = whiteout;
-+
-+ if (namelen < DNAME_INLINE_LEN) {
-+ new->name = new->iname;
-+ } else {
-+ new->name = kmalloc(namelen + 1, GFP_KERNEL);
-+ if (unlikely(!new->name)) {
-+ kmem_cache_free(unionfs_filldir_cachep, new);
-+ new = NULL;
-+ goto out;
-+ }
-+ }
-+
-+ memcpy(new->name, name, namelen);
-+ new->name[namelen] = '\0';
-+
-+ rdstate->hashentries++;
-+
-+ list_add(&(new->file_list), head);
-+out:
-+ return err;
-+}
-diff --git a/fs/unionfs/rename.c b/fs/unionfs/rename.c
-new file mode 100644
-index 0000000..ce85b84
---- /dev/null
-+++ b/fs/unionfs/rename.c
-@@ -0,0 +1,522 @@
-+/*
-+ * Copyright (c) 2003-2011 Erez Zadok
-+ * Copyright (c) 2003-2006 Charles P. Wright
-+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2005-2006 Junjiro Okajima
-+ * Copyright (c) 2005 Arun M. Krishnakumar
-+ * Copyright (c) 2004-2006 David P. Quigley
-+ * Copyright (c) 2003-2004 Mohammad Nayyer Zubair
-+ * Copyright (c) 2003 Puja Gupta
-+ * Copyright (c) 2003 Harikesavan Krishnan
-+ * Copyright (c) 2003-2011 Stony Brook University
-+ * Copyright (c) 2003-2011 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#include "union.h"
-+
-+/*
-+ * This is a helper function for rename, used when rename ends up with hosed
-+ * over dentries and we need to revert.
-+ */
-+static int unionfs_refresh_lower_dentry(struct dentry *dentry,
-+ struct dentry *parent, int bindex)
-+{
-+ struct dentry *lower_dentry;
-+ struct dentry *lower_parent;
-+ int err = 0;
-+ struct nameidata lower_nd;
-+
-+ verify_locked(dentry);
-+
-+ lower_parent = unionfs_lower_dentry_idx(parent, bindex);
-+
-+ BUG_ON(!S_ISDIR(lower_parent->d_inode->i_mode));
-+
-+ err = init_lower_nd(&lower_nd, LOOKUP_OPEN);
-+ if (unlikely(err < 0))
-+ goto out;
-+ lower_dentry = lookup_one_len_nd(dentry->d_name.name, lower_parent,
-+ dentry->d_name.len, &lower_nd);
-+ release_lower_nd(&lower_nd, err);
-+ if (IS_ERR(lower_dentry)) {
-+ err = PTR_ERR(lower_dentry);
-+ goto out;
-+ }
-+
-+ dput(unionfs_lower_dentry_idx(dentry, bindex));
-+ iput(unionfs_lower_inode_idx(dentry->d_inode, bindex));
-+ unionfs_set_lower_inode_idx(dentry->d_inode, bindex, NULL);
-+
-+ if (!lower_dentry->d_inode) {
-+ dput(lower_dentry);
-+ unionfs_set_lower_dentry_idx(dentry, bindex, NULL);
-+ } else {
-+ unionfs_set_lower_dentry_idx(dentry, bindex, lower_dentry);
-+ unionfs_set_lower_inode_idx(dentry->d_inode, bindex,
-+ igrab(lower_dentry->d_inode));
-+ }
-+
-+out:
-+ return err;
-+}
-+
-+static int __unionfs_rename(struct inode *old_dir, struct dentry *old_dentry,
-+ struct dentry *old_parent,
-+ struct inode *new_dir, struct dentry *new_dentry,
-+ struct dentry *new_parent,
-+ int bindex)
-+{
-+ int err = 0;
-+ struct dentry *lower_old_dentry;
-+ struct dentry *lower_new_dentry;
-+ struct dentry *lower_old_dir_dentry;
-+ struct dentry *lower_new_dir_dentry;
-+ struct dentry *trap;
-+
-+ lower_new_dentry = unionfs_lower_dentry_idx(new_dentry, bindex);
-+ lower_old_dentry = unionfs_lower_dentry_idx(old_dentry, bindex);
-+
-+ if (!lower_new_dentry) {
-+ lower_new_dentry =
-+ create_parents(new_parent->d_inode,
-+ new_dentry, new_dentry->d_name.name,
-+ bindex);
-+ if (IS_ERR(lower_new_dentry)) {
-+ err = PTR_ERR(lower_new_dentry);
-+ if (IS_COPYUP_ERR(err))
-+ goto out;
-+ printk(KERN_ERR "unionfs: error creating directory "
-+ "tree for rename, bindex=%d err=%d\n",
-+ bindex, err);
-+ goto out;
-+ }
-+ }
-+
-+ /* check for and remove whiteout, if any */
-+ err = check_unlink_whiteout(new_dentry, lower_new_dentry, bindex);
-+ if (err > 0) /* ignore if whiteout found and successfully removed */
-+ err = 0;
-+ if (err)
-+ goto out;
-+
-+ /* check of old_dentry branch is writable */
-+ err = is_robranch_super(old_dentry->d_sb, bindex);
-+ if (err)
-+ goto out;
-+
-+ dget(lower_old_dentry);
-+ dget(lower_new_dentry);
-+ lower_old_dir_dentry = dget_parent(lower_old_dentry);
-+ lower_new_dir_dentry = dget_parent(lower_new_dentry);
-+
-+ trap = lock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
-+ /* source should not be ancenstor of target */
-+ if (trap == lower_old_dentry) {
-+ err = -EINVAL;
-+ goto out_err_unlock;
-+ }
-+ /* target should not be ancenstor of source */
-+ if (trap == lower_new_dentry) {
-+ err = -ENOTEMPTY;
-+ goto out_err_unlock;
-+ }
-+ err = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry,
-+ lower_new_dir_dentry->d_inode, lower_new_dentry);
-+out_err_unlock:
-+ if (!err) {
-+ /* update parent dir times */
-+ fsstack_copy_attr_times(old_dir, lower_old_dir_dentry->d_inode);
-+ fsstack_copy_attr_times(new_dir, lower_new_dir_dentry->d_inode);
-+ }
-+ unlock_rename(lower_old_dir_dentry, lower_new_dir_dentry);
-+
-+ dput(lower_old_dir_dentry);
-+ dput(lower_new_dir_dentry);
-+ dput(lower_old_dentry);
-+ dput(lower_new_dentry);
-+
-+out:
-+ if (!err) {
-+ /* Fixup the new_dentry. */
-+ if (bindex < dbstart(new_dentry))
-+ dbstart(new_dentry) = bindex;
-+ else if (bindex > dbend(new_dentry))
-+ dbend(new_dentry) = bindex;
-+ }
-+
-+ return err;
-+}
-+
-+/*
-+ * Main rename code. This is sufficiently complex, that it's documented in
-+ * Documentation/filesystems/unionfs/rename.txt. This routine calls
-+ * __unionfs_rename() above to perform some of the work.
-+ */
-+static int do_unionfs_rename(struct inode *old_dir,
-+ struct dentry *old_dentry,
-+ struct dentry *old_parent,
-+ struct inode *new_dir,
-+ struct dentry *new_dentry,
-+ struct dentry *new_parent)
-+{
-+ int err = 0;
-+ int bindex;
-+ int old_bstart, old_bend;
-+ int new_bstart, new_bend;
-+ int do_copyup = -1;
-+ int local_err = 0;
-+ int eio = 0;
-+ int revert = 0;
-+
-+ old_bstart = dbstart(old_dentry);
-+ old_bend = dbend(old_dentry);
-+
-+ new_bstart = dbstart(new_dentry);
-+ new_bend = dbend(new_dentry);
-+
-+ /* Rename source to destination. */
-+ err = __unionfs_rename(old_dir, old_dentry, old_parent,
-+ new_dir, new_dentry, new_parent,
-+ old_bstart);
-+ if (err) {
-+ if (!IS_COPYUP_ERR(err))
-+ goto out;
-+ do_copyup = old_bstart - 1;
-+ } else {
-+ revert = 1;
-+ }
-+
-+ /*
-+ * Unlink all instances of destination that exist to the left of
-+ * bstart of source. On error, revert back, goto out.
-+ */
-+ for (bindex = old_bstart - 1; bindex >= new_bstart; bindex--) {
-+ struct dentry *unlink_dentry;
-+ struct dentry *unlink_dir_dentry;
-+
-+ BUG_ON(bindex < 0);
-+ unlink_dentry = unionfs_lower_dentry_idx(new_dentry, bindex);
-+ if (!unlink_dentry)
-+ continue;
-+
-+ unlink_dir_dentry = lock_parent(unlink_dentry);
-+ err = is_robranch_super(old_dir->i_sb, bindex);
-+ if (!err)
-+ err = vfs_unlink(unlink_dir_dentry->d_inode,
-+ unlink_dentry);
-+
-+ fsstack_copy_attr_times(new_parent->d_inode,
-+ unlink_dir_dentry->d_inode);
-+ /* propagate number of hard-links */
-+ set_nlink(new_parent->d_inode,
-+ unionfs_get_nlinks(new_parent->d_inode));
-+
-+ unlock_dir(unlink_dir_dentry);
-+ if (!err) {
-+ if (bindex != new_bstart) {
-+ dput(unlink_dentry);
-+ unionfs_set_lower_dentry_idx(new_dentry,
-+ bindex, NULL);
-+ }
-+ } else if (IS_COPYUP_ERR(err)) {
-+ do_copyup = bindex - 1;
-+ } else if (revert) {
-+ goto revert;
-+ }
-+ }
-+
-+ if (do_copyup != -1) {
-+ for (bindex = do_copyup; bindex >= 0; bindex--) {
-+ /*
-+ * copyup the file into some left directory, so that
-+ * you can rename it
-+ */
-+ err = copyup_dentry(old_parent->d_inode,
-+ old_dentry, old_bstart, bindex,
-+ old_dentry->d_name.name,
-+ old_dentry->d_name.len, NULL,
-+ i_size_read(old_dentry->d_inode));
-+ /* if copyup failed, try next branch to the left */
-+ if (err)
-+ continue;
-+ /*
-+ * create whiteout before calling __unionfs_rename
-+ * because the latter will change the old_dentry's
-+ * lower name and parent dir, resulting in the
-+ * whiteout getting created in the wrong dir.
-+ */
-+ err = create_whiteout(old_dentry, bindex);
-+ if (err) {
-+ printk(KERN_ERR "unionfs: can't create a "
-+ "whiteout for %s in rename (err=%d)\n",
-+ old_dentry->d_name.name, err);
-+ continue;
-+ }
-+ err = __unionfs_rename(old_dir, old_dentry, old_parent,
-+ new_dir, new_dentry, new_parent,
-+ bindex);
-+ break;
-+ }
-+ }
-+
-+ /* make it opaque */
-+ if (S_ISDIR(old_dentry->d_inode->i_mode)) {
-+ err = make_dir_opaque(old_dentry, dbstart(old_dentry));
-+ if (err)
-+ goto revert;
-+ }
-+
-+ /*
-+ * Create whiteout for source, only if:
-+ * (1) There is more than one underlying instance of source.
-+ * (We did a copy_up is taken care of above).
-+ */
-+ if ((old_bstart != old_bend) && (do_copyup == -1)) {
-+ err = create_whiteout(old_dentry, old_bstart);
-+ if (err) {
-+ /* can't fix anything now, so we exit with -EIO */
-+ printk(KERN_ERR "unionfs: can't create a whiteout for "
-+ "%s in rename!\n", old_dentry->d_name.name);
-+ err = -EIO;
-+ }
-+ }
-+
-+out:
-+ return err;
-+
-+revert:
-+ /* Do revert here. */
-+ local_err = unionfs_refresh_lower_dentry(new_dentry, new_parent,
-+ old_bstart);
-+ if (local_err) {
-+ printk(KERN_ERR "unionfs: revert failed in rename: "
-+ "the new refresh failed\n");
-+ eio = -EIO;
-+ }
-+
-+ local_err = unionfs_refresh_lower_dentry(old_dentry, old_parent,
-+ old_bstart);
-+ if (local_err) {
-+ printk(KERN_ERR "unionfs: revert failed in rename: "
-+ "the old refresh failed\n");
-+ eio = -EIO;
-+ goto revert_out;
-+ }
-+
-+ if (!unionfs_lower_dentry_idx(new_dentry, bindex) ||
-+ !unionfs_lower_dentry_idx(new_dentry, bindex)->d_inode) {
-+ printk(KERN_ERR "unionfs: revert failed in rename: "
-+ "the object disappeared from under us!\n");
-+ eio = -EIO;
-+ goto revert_out;
-+ }
-+
-+ if (unionfs_lower_dentry_idx(old_dentry, bindex) &&
-+ unionfs_lower_dentry_idx(old_dentry, bindex)->d_inode) {
-+ printk(KERN_ERR "unionfs: revert failed in rename: "
-+ "the object was created underneath us!\n");
-+ eio = -EIO;
-+ goto revert_out;
-+ }
-+
-+ local_err = __unionfs_rename(new_dir, new_dentry, new_parent,
-+ old_dir, old_dentry, old_parent,
-+ old_bstart);
-+
-+ /* If we can't fix it, then we cop-out with -EIO. */
-+ if (local_err) {
-+ printk(KERN_ERR "unionfs: revert failed in rename!\n");
-+ eio = -EIO;
-+ }
-+
-+ local_err = unionfs_refresh_lower_dentry(new_dentry, new_parent,
-+ bindex);
-+ if (local_err)
-+ eio = -EIO;
-+ local_err = unionfs_refresh_lower_dentry(old_dentry, old_parent,
-+ bindex);
-+ if (local_err)
-+ eio = -EIO;
-+
-+revert_out:
-+ if (eio)
-+ err = eio;
-+ return err;
-+}
-+
-+/*
-+ * We can't copyup a directory, because it may involve huge numbers of
-+ * children, etc. Doing that in the kernel would be bad, so instead we
-+ * return EXDEV to the user-space utility that caused this, and let the
-+ * user-space recurse and ask us to copy up each file separately.
-+ */
-+static int may_rename_dir(struct dentry *dentry, struct dentry *parent)
-+{
-+ int err, bstart;
-+
-+ err = check_empty(dentry, parent, NULL);
-+ if (err == -ENOTEMPTY) {
-+ if (is_robranch(dentry))
-+ return -EXDEV;
-+ } else if (err) {
-+ return err;
-+ }
-+
-+ bstart = dbstart(dentry);
-+ if (dbend(dentry) == bstart || dbopaque(dentry) == bstart)
-+ return 0;
-+
-+ dbstart(dentry) = bstart + 1;
-+ err = check_empty(dentry, parent, NULL);
-+ dbstart(dentry) = bstart;
-+ if (err == -ENOTEMPTY)
-+ err = -EXDEV;
-+ return err;
-+}
-+
-+/*
-+ * The locking rules in unionfs_rename are complex. We could use a simpler
-+ * superblock-level name-space lock for renames and copy-ups.
-+ */
-+int unionfs_rename(struct inode *old_dir, struct dentry *old_dentry,
-+ struct inode *new_dir, struct dentry *new_dentry)
-+{
-+ int err = 0;
-+ struct dentry *wh_dentry;
-+ struct dentry *old_parent, *new_parent;
-+ int valid = true;
-+
-+ unionfs_read_lock(old_dentry->d_sb, UNIONFS_SMUTEX_CHILD);
-+ old_parent = dget_parent(old_dentry);
-+ new_parent = dget_parent(new_dentry);
-+ /* un/lock parent dentries only if they differ from old/new_dentry */
-+ if (old_parent != old_dentry &&
-+ old_parent != new_dentry)
-+ unionfs_lock_dentry(old_parent, UNIONFS_DMUTEX_REVAL_PARENT);
-+ if (new_parent != old_dentry &&
-+ new_parent != new_dentry &&
-+ new_parent != old_parent)
-+ unionfs_lock_dentry(new_parent, UNIONFS_DMUTEX_REVAL_CHILD);
-+ unionfs_double_lock_dentry(old_dentry, new_dentry);
-+
-+ valid = __unionfs_d_revalidate(old_dentry, old_parent, false);
-+ if (!valid) {
-+ err = -ESTALE;
-+ goto out;
-+ }
-+ if (!d_deleted(new_dentry) && new_dentry->d_inode) {
-+ valid = __unionfs_d_revalidate(new_dentry, new_parent, false);
-+ if (!valid) {
-+ err = -ESTALE;
-+ goto out;
-+ }
-+ }
-+
-+ if (!S_ISDIR(old_dentry->d_inode->i_mode))
-+ err = unionfs_partial_lookup(old_dentry, old_parent);
-+ else
-+ err = may_rename_dir(old_dentry, old_parent);
-+
-+ if (err)
-+ goto out;
-+
-+ err = unionfs_partial_lookup(new_dentry, new_parent);
-+ if (err)
-+ goto out;
-+
-+ /*
-+ * if new_dentry is already lower because of whiteout,
-+ * simply override it even if the whited-out dir is not empty.
-+ */
-+ wh_dentry = find_first_whiteout(new_dentry);
-+ if (!IS_ERR(wh_dentry)) {
-+ dput(wh_dentry);
-+ } else if (new_dentry->d_inode) {
-+ if (S_ISDIR(old_dentry->d_inode->i_mode) !=
-+ S_ISDIR(new_dentry->d_inode->i_mode)) {
-+ err = S_ISDIR(old_dentry->d_inode->i_mode) ?
-+ -ENOTDIR : -EISDIR;
-+ goto out;
-+ }
-+
-+ if (S_ISDIR(new_dentry->d_inode->i_mode)) {
-+ struct unionfs_dir_state *namelist = NULL;
-+ /* check if this unionfs directory is empty or not */
-+ err = check_empty(new_dentry, new_parent, &namelist);
-+ if (err)
-+ goto out;
-+
-+ if (!is_robranch(new_dentry))
-+ err = delete_whiteouts(new_dentry,
-+ dbstart(new_dentry),
-+ namelist);
-+
-+ free_rdstate(namelist);
-+
-+ if (err)
-+ goto out;
-+ }
-+ }
-+
-+ err = do_unionfs_rename(old_dir, old_dentry, old_parent,
-+ new_dir, new_dentry, new_parent);
-+ if (err)
-+ goto out;
-+
-+ /*
-+ * force re-lookup since the dir on ro branch is not renamed, and
-+ * lower dentries still indicate the un-renamed ones.
-+ */
-+ if (S_ISDIR(old_dentry->d_inode->i_mode))
-+ atomic_dec(&UNIONFS_D(old_dentry)->generation);
-+ else
-+ unionfs_postcopyup_release(old_dentry);
-+ if (new_dentry->d_inode && !S_ISDIR(new_dentry->d_inode->i_mode)) {
-+ unionfs_postcopyup_release(new_dentry);
-+ unionfs_postcopyup_setmnt(new_dentry);
-+ if (!unionfs_lower_inode(new_dentry->d_inode)) {
-+ /*
-+ * If we get here, it means that no copyup was
-+ * needed, and that a file by the old name already
-+ * existing on the destination branch; that file got
-+ * renamed earlier in this function, so all we need
-+ * to do here is set the lower inode.
-+ */
-+ struct inode *inode;
-+ inode = unionfs_lower_inode(old_dentry->d_inode);
-+ igrab(inode);
-+ unionfs_set_lower_inode_idx(new_dentry->d_inode,
-+ dbstart(new_dentry),
-+ inode);
-+ }
-+ }
-+ /* if all of this renaming succeeded, update our times */
-+ unionfs_copy_attr_times(old_dentry->d_inode);
-+ unionfs_copy_attr_times(new_dentry->d_inode);
-+ unionfs_check_inode(old_dir);
-+ unionfs_check_inode(new_dir);
-+ unionfs_check_dentry(old_dentry);
-+ unionfs_check_dentry(new_dentry);
-+
-+out:
-+ if (err) /* clear the new_dentry stuff created */
-+ d_drop(new_dentry);
-+
-+ unionfs_double_unlock_dentry(old_dentry, new_dentry);
-+ if (new_parent != old_dentry &&
-+ new_parent != new_dentry &&
-+ new_parent != old_parent)
-+ unionfs_unlock_dentry(new_parent);
-+ if (old_parent != old_dentry &&
-+ old_parent != new_dentry)
-+ unionfs_unlock_dentry(old_parent);
-+ dput(new_parent);
-+ dput(old_parent);
-+ unionfs_read_unlock(old_dentry->d_sb);
-+
-+ return err;
-+}
-diff --git a/fs/unionfs/sioq.c b/fs/unionfs/sioq.c
-new file mode 100644
-index 0000000..b923742
---- /dev/null
-+++ b/fs/unionfs/sioq.c
-@@ -0,0 +1,101 @@
-+/*
-+ * Copyright (c) 2006-2011 Erez Zadok
-+ * Copyright (c) 2006 Charles P. Wright
-+ * Copyright (c) 2006-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2006 Junjiro Okajima
-+ * Copyright (c) 2006 David P. Quigley
-+ * Copyright (c) 2006-2011 Stony Brook University
-+ * Copyright (c) 2006-2011 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#include "union.h"
-+
-+/*
-+ * Super-user IO work Queue - sometimes we need to perform actions which
-+ * would fail due to the unix permissions on the parent directory (e.g.,
-+ * rmdir a directory which appears empty, but in reality contains
-+ * whiteouts).
-+ */
-+
-+static struct workqueue_struct *superio_workqueue;
-+
-+int __init init_sioq(void)
-+{
-+ int err;
-+
-+ superio_workqueue = create_workqueue("unionfs_siod");
-+ if (!IS_ERR(superio_workqueue))
-+ return 0;
-+
-+ err = PTR_ERR(superio_workqueue);
-+ printk(KERN_ERR "unionfs: create_workqueue failed %d\n", err);
-+ superio_workqueue = NULL;
-+ return err;
-+}
-+
-+void stop_sioq(void)
-+{
-+ if (superio_workqueue)
-+ destroy_workqueue(superio_workqueue);
-+}
-+
-+void run_sioq(work_func_t func, struct sioq_args *args)
-+{
-+ INIT_WORK(&args->work, func);
-+
-+ init_completion(&args->comp);
-+ while (!queue_work(superio_workqueue, &args->work)) {
-+ /* TODO: do accounting if needed */
-+ schedule();
-+ }
-+ wait_for_completion(&args->comp);
-+}
-+
-+void __unionfs_create(struct work_struct *work)
-+{
-+ struct sioq_args *args = container_of(work, struct sioq_args, work);
-+ struct create_args *c = &args->create;
-+
-+ args->err = vfs_create(c->parent, c->dentry, c->mode, c->nd);
-+ complete(&args->comp);
-+}
-+
-+void __unionfs_mkdir(struct work_struct *work)
-+{
-+ struct sioq_args *args = container_of(work, struct sioq_args, work);
-+ struct mkdir_args *m = &args->mkdir;
-+
-+ args->err = vfs_mkdir(m->parent, m->dentry, m->mode);
-+ complete(&args->comp);
-+}
-+
-+void __unionfs_mknod(struct work_struct *work)
-+{
-+ struct sioq_args *args = container_of(work, struct sioq_args, work);
-+ struct mknod_args *m = &args->mknod;
-+
-+ args->err = vfs_mknod(m->parent, m->dentry, m->mode, m->dev);
-+ complete(&args->comp);
-+}
-+
-+void __unionfs_symlink(struct work_struct *work)
-+{
-+ struct sioq_args *args = container_of(work, struct sioq_args, work);
-+ struct symlink_args *s = &args->symlink;
-+
-+ args->err = vfs_symlink(s->parent, s->dentry, s->symbuf);
-+ complete(&args->comp);
-+}
-+
-+void __unionfs_unlink(struct work_struct *work)
-+{
-+ struct sioq_args *args = container_of(work, struct sioq_args, work);
-+ struct unlink_args *u = &args->unlink;
-+
-+ args->err = vfs_unlink(u->parent, u->dentry);
-+ complete(&args->comp);
-+}
-diff --git a/fs/unionfs/sioq.h b/fs/unionfs/sioq.h
-new file mode 100644
-index 0000000..c2dfb94
---- /dev/null
-+++ b/fs/unionfs/sioq.h
-@@ -0,0 +1,91 @@
-+/*
-+ * Copyright (c) 2006-2011 Erez Zadok
-+ * Copyright (c) 2006 Charles P. Wright
-+ * Copyright (c) 2006-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2006 Junjiro Okajima
-+ * Copyright (c) 2006 David P. Quigley
-+ * Copyright (c) 2006-2011 Stony Brook University
-+ * Copyright (c) 2006-2011 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#ifndef _SIOQ_H
-+#define _SIOQ_H
-+
-+struct deletewh_args {
-+ struct unionfs_dir_state *namelist;
-+ struct dentry *dentry;
-+ int bindex;
-+};
-+
-+struct is_opaque_args {
-+ struct dentry *dentry;
-+};
-+
-+struct create_args {
-+ struct inode *parent;
-+ struct dentry *dentry;
-+ umode_t mode;
-+ struct nameidata *nd;
-+};
-+
-+struct mkdir_args {
-+ struct inode *parent;
-+ struct dentry *dentry;
-+ umode_t mode;
-+};
-+
-+struct mknod_args {
-+ struct inode *parent;
-+ struct dentry *dentry;
-+ umode_t mode;
-+ dev_t dev;
-+};
-+
-+struct symlink_args {
-+ struct inode *parent;
-+ struct dentry *dentry;
-+ char *symbuf;
-+};
-+
-+struct unlink_args {
-+ struct inode *parent;
-+ struct dentry *dentry;
-+};
-+
-+
-+struct sioq_args {
-+ struct completion comp;
-+ struct work_struct work;
-+ int err;
-+ void *ret;
-+
-+ union {
-+ struct deletewh_args deletewh;
-+ struct is_opaque_args is_opaque;
-+ struct create_args create;
-+ struct mkdir_args mkdir;
-+ struct mknod_args mknod;
-+ struct symlink_args symlink;
-+ struct unlink_args unlink;
-+ };
-+};
-+
-+/* Extern definitions for SIOQ functions */
-+extern int __init init_sioq(void);
-+extern void stop_sioq(void);
-+extern void run_sioq(work_func_t func, struct sioq_args *args);
-+
-+/* Extern definitions for our privilege escalation helpers */
-+extern void __unionfs_create(struct work_struct *work);
-+extern void __unionfs_mkdir(struct work_struct *work);
-+extern void __unionfs_mknod(struct work_struct *work);
-+extern void __unionfs_symlink(struct work_struct *work);
-+extern void __unionfs_unlink(struct work_struct *work);
-+extern void __delete_whiteouts(struct work_struct *work);
-+extern void __is_opaque_dir(struct work_struct *work);
-+
-+#endif /* not _SIOQ_H */
-diff --git a/fs/unionfs/subr.c b/fs/unionfs/subr.c
-new file mode 100644
-index 0000000..e7fc5a5
---- /dev/null
-+++ b/fs/unionfs/subr.c
-@@ -0,0 +1,95 @@
-+/*
-+ * Copyright (c) 2003-2011 Erez Zadok
-+ * Copyright (c) 2003-2006 Charles P. Wright
-+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2005-2006 Junjiro Okajima
-+ * Copyright (c) 2005 Arun M. Krishnakumar
-+ * Copyright (c) 2004-2006 David P. Quigley
-+ * Copyright (c) 2003-2004 Mohammad Nayyer Zubair
-+ * Copyright (c) 2003 Puja Gupta
-+ * Copyright (c) 2003 Harikesavan Krishnan
-+ * Copyright (c) 2003-2011 Stony Brook University
-+ * Copyright (c) 2003-2011 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#include "union.h"
-+
-+/*
-+ * returns the right n_link value based on the inode type
-+ */
-+int unionfs_get_nlinks(const struct inode *inode)
-+{
-+ /* don't bother to do all the work since we're unlinked */
-+ if (inode->i_nlink == 0)
-+ return 0;
-+
-+ if (!S_ISDIR(inode->i_mode))
-+ return unionfs_lower_inode(inode)->i_nlink;
-+
-+ /*
-+ * For directories, we return 1. The only place that could cares
-+ * about links is readdir, and there's d_type there so even that
-+ * doesn't matter.
-+ */
-+ return 1;
-+}
-+
-+/* copy a/m/ctime from the lower branch with the newest times */
-+void unionfs_copy_attr_times(struct inode *upper)
-+{
-+ int bindex;
-+ struct inode *lower;
-+
-+ if (!upper)
-+ return;
-+ if (ibstart(upper) < 0) {
-+#ifdef CONFIG_UNION_FS_DEBUG
-+ WARN_ON(ibstart(upper) < 0);
-+#endif /* CONFIG_UNION_FS_DEBUG */
-+ return;
-+ }
-+ for (bindex = ibstart(upper); bindex <= ibend(upper); bindex++) {
-+ lower = unionfs_lower_inode_idx(upper, bindex);
-+ if (!lower)
-+ continue; /* not all lower dir objects may exist */
-+ if (unlikely(timespec_compare(&upper->i_mtime,
-+ &lower->i_mtime) < 0))
-+ upper->i_mtime = lower->i_mtime;
-+ if (unlikely(timespec_compare(&upper->i_ctime,
-+ &lower->i_ctime) < 0))
-+ upper->i_ctime = lower->i_ctime;
-+ if (unlikely(timespec_compare(&upper->i_atime,
-+ &lower->i_atime) < 0))
-+ upper->i_atime = lower->i_atime;
-+ }
-+}
-+
-+/*
-+ * A unionfs/fanout version of fsstack_copy_attr_all. Uses a
-+ * unionfs_get_nlinks to properly calcluate the number of links to a file.
-+ * Also, copies the max() of all a/m/ctimes for all lower inodes (which is
-+ * important if the lower inode is a directory type)
-+ */
-+void unionfs_copy_attr_all(struct inode *dest,
-+ const struct inode *src)
-+{
-+ dest->i_mode = src->i_mode;
-+ dest->i_uid = src->i_uid;
-+ dest->i_gid = src->i_gid;
-+ dest->i_rdev = src->i_rdev;
-+
-+ unionfs_copy_attr_times(dest);
-+
-+ dest->i_blkbits = src->i_blkbits;
-+ dest->i_flags = src->i_flags;
-+
-+ /*
-+ * Update the nlinks AFTER updating the above fields, because the
-+ * get_links callback may depend on them.
-+ */
-+ set_nlink(dest, unionfs_get_nlinks(dest));
-+}
-diff --git a/fs/unionfs/super.c b/fs/unionfs/super.c
-new file mode 100644
-index 0000000..b99f14d
---- /dev/null
-+++ b/fs/unionfs/super.c
-@@ -0,0 +1,1030 @@
-+/*
-+ * Copyright (c) 2003-2011 Erez Zadok
-+ * Copyright (c) 2003-2006 Charles P. Wright
-+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2005-2006 Junjiro Okajima
-+ * Copyright (c) 2005 Arun M. Krishnakumar
-+ * Copyright (c) 2004-2006 David P. Quigley
-+ * Copyright (c) 2003-2004 Mohammad Nayyer Zubair
-+ * Copyright (c) 2003 Puja Gupta
-+ * Copyright (c) 2003 Harikesavan Krishnan
-+ * Copyright (c) 2003-2011 Stony Brook University
-+ * Copyright (c) 2003-2011 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#include "union.h"
-+
-+/*
-+ * The inode cache is used with alloc_inode for both our inode info and the
-+ * vfs inode.
-+ */
-+static struct kmem_cache *unionfs_inode_cachep;
-+
-+struct inode *unionfs_iget(struct super_block *sb, unsigned long ino)
-+{
-+ int size;
-+ struct unionfs_inode_info *info;
-+ struct inode *inode;
-+
-+ inode = iget_locked(sb, ino);
-+ if (!inode)
-+ return ERR_PTR(-ENOMEM);
-+ if (!(inode->i_state & I_NEW))
-+ return inode;
-+
-+ info = UNIONFS_I(inode);
-+ memset(info, 0, offsetof(struct unionfs_inode_info, vfs_inode));
-+ info->bstart = -1;
-+ info->bend = -1;
-+ atomic_set(&info->generation,
-+ atomic_read(&UNIONFS_SB(inode->i_sb)->generation));
-+ spin_lock_init(&info->rdlock);
-+ info->rdcount = 1;
-+ info->hashsize = -1;
-+ INIT_LIST_HEAD(&info->readdircache);
-+
-+ size = sbmax(inode->i_sb) * sizeof(struct inode *);
-+ info->lower_inodes = kzalloc(size, GFP_KERNEL);
-+ if (unlikely(!info->lower_inodes)) {
-+ printk(KERN_CRIT "unionfs: no kernel memory when allocating "
-+ "lower-pointer array!\n");
-+ iget_failed(inode);
-+ return ERR_PTR(-ENOMEM);
-+ }
-+
-+ inode->i_version++;
-+ inode->i_op = &unionfs_main_iops;
-+ inode->i_fop = &unionfs_main_fops;
-+
-+ inode->i_mapping->a_ops = &unionfs_aops;
-+
-+ /*
-+ * reset times so unionfs_copy_attr_all can keep out time invariants
-+ * right (upper inode time being the max of all lower ones).
-+ */
-+ inode->i_atime.tv_sec = inode->i_atime.tv_nsec = 0;
-+ inode->i_mtime.tv_sec = inode->i_mtime.tv_nsec = 0;
-+ inode->i_ctime.tv_sec = inode->i_ctime.tv_nsec = 0;
-+ unlock_new_inode(inode);
-+ return inode;
-+}
-+
-+/*
-+ * final actions when unmounting a file system
-+ *
-+ * No need to lock rwsem.
-+ */
-+static void unionfs_put_super(struct super_block *sb)
-+{
-+ int bindex, bstart, bend;
-+ struct unionfs_sb_info *spd;
-+ int leaks = 0;
-+
-+ spd = UNIONFS_SB(sb);
-+ if (!spd)
-+ return;
-+
-+ bstart = sbstart(sb);
-+ bend = sbend(sb);
-+
-+ /* Make sure we have no leaks of branchget/branchput. */
-+ for (bindex = bstart; bindex <= bend; bindex++)
-+ if (unlikely(branch_count(sb, bindex) != 0)) {
-+ printk(KERN_CRIT
-+ "unionfs: branch %d has %d references left!\n",
-+ bindex, branch_count(sb, bindex));
-+ leaks = 1;
-+ }
-+ WARN_ON(leaks != 0);
-+
-+ /* decrement lower super references */
-+ for (bindex = bstart; bindex <= bend; bindex++) {
-+ struct super_block *s;
-+ s = unionfs_lower_super_idx(sb, bindex);
-+ unionfs_set_lower_super_idx(sb, bindex, NULL);
-+ atomic_dec(&s->s_active);
-+ }
-+
-+ kfree(spd->dev_name);
-+ kfree(spd->data);
-+ kfree(spd);
-+ sb->s_fs_info = NULL;
-+}
-+
-+/*
-+ * Since people use this to answer the "How big of a file can I write?"
-+ * question, we report the size of the highest priority branch as the size of
-+ * the union.
-+ */
-+static int unionfs_statfs(struct dentry *dentry, struct kstatfs *buf)
-+{
-+ int err = 0;
-+ struct super_block *sb;
-+ struct dentry *lower_dentry;
-+ struct dentry *parent;
-+ struct path lower_path;
-+ bool valid;
-+
-+ sb = dentry->d_sb;
-+
-+ unionfs_read_lock(sb, UNIONFS_SMUTEX_CHILD);
-+ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
-+ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+ valid = __unionfs_d_revalidate(dentry, parent, false);
-+ if (unlikely(!valid)) {
-+ err = -ESTALE;
-+ goto out;
-+ }
-+ unionfs_check_dentry(dentry);
-+
-+ lower_dentry = unionfs_lower_dentry(sb->s_root);
-+ lower_path.dentry = lower_dentry;
-+ lower_path.mnt = unionfs_mntget(sb->s_root, 0);
-+ err = vfs_statfs(&lower_path, buf);
-+ mntput(lower_path.mnt);
-+
-+ /* set return buf to our f/s to avoid confusing user-level utils */
-+ buf->f_type = UNIONFS_SUPER_MAGIC;
-+ /*
-+ * Our maximum file name can is shorter by a few bytes because every
-+ * file name could potentially be whited-out.
-+ *
-+ * XXX: this restriction goes away with ODF.
-+ */
-+ unionfs_set_max_namelen(&buf->f_namelen);
-+
-+ /*
-+ * reset two fields to avoid confusing user-land.
-+ * XXX: is this still necessary?
-+ */
-+ memset(&buf->f_fsid, 0, sizeof(__kernel_fsid_t));
-+ memset(&buf->f_spare, 0, sizeof(buf->f_spare));
-+
-+out:
-+ unionfs_check_dentry(dentry);
-+ unionfs_unlock_dentry(dentry);
-+ unionfs_unlock_parent(dentry, parent);
-+ unionfs_read_unlock(sb);
-+ return err;
-+}
-+
-+/* handle mode changing during remount */
-+static noinline_for_stack int do_remount_mode_option(
-+ char *optarg,
-+ int cur_branches,
-+ struct unionfs_data *new_data,
-+ struct path *new_lower_paths)
-+{
-+ int err = -EINVAL;
-+ int perms, idx;
-+ char *modename = strchr(optarg, '=');
-+ struct path path;
-+
-+ /* by now, optarg contains the branch name */
-+ if (!*optarg) {
-+ printk(KERN_ERR
-+ "unionfs: no branch specified for mode change\n");
-+ goto out;
-+ }
-+ if (!modename) {
-+ printk(KERN_ERR "unionfs: branch \"%s\" requires a mode\n",
-+ optarg);
-+ goto out;
-+ }
-+ *modename++ = '\0';
-+ err = parse_branch_mode(modename, &perms);
-+ if (err) {
-+ printk(KERN_ERR "unionfs: invalid mode \"%s\" for \"%s\"\n",
-+ modename, optarg);
-+ goto out;
-+ }
-+
-+ /*
-+ * Find matching branch index. For now, this assumes that nothing
-+ * has been mounted on top of this Unionfs stack. Once we have /odf
-+ * and cache-coherency resolved, we'll address the branch-path
-+ * uniqueness.
-+ */
-+ err = kern_path(optarg, LOOKUP_FOLLOW, &path);
-+ if (err) {
-+ printk(KERN_ERR "unionfs: error accessing "
-+ "lower directory \"%s\" (error %d)\n",
-+ optarg, err);
-+ goto out;
-+ }
-+ for (idx = 0; idx < cur_branches; idx++)
-+ if (path.mnt == new_lower_paths[idx].mnt &&
-+ path.dentry == new_lower_paths[idx].dentry)
-+ break;
-+ path_put(&path); /* no longer needed */
-+ if (idx == cur_branches) {
-+ err = -ENOENT; /* err may have been reset above */
-+ printk(KERN_ERR "unionfs: branch \"%s\" "
-+ "not found\n", optarg);
-+ goto out;
-+ }
-+ /* check/change mode for existing branch */
-+ /* we don't warn if perms==branchperms */
-+ new_data[idx].branchperms = perms;
-+ err = 0;
-+out:
-+ return err;
-+}
-+
-+/* handle branch deletion during remount */
-+static noinline_for_stack int do_remount_del_option(
-+ char *optarg, int cur_branches,
-+ struct unionfs_data *new_data,
-+ struct path *new_lower_paths)
-+{
-+ int err = -EINVAL;
-+ int idx;
-+ struct path path;
-+
-+ /* optarg contains the branch name to delete */
-+
-+ /*
-+ * Find matching branch index. For now, this assumes that nothing
-+ * has been mounted on top of this Unionfs stack. Once we have /odf
-+ * and cache-coherency resolved, we'll address the branch-path
-+ * uniqueness.
-+ */
-+ err = kern_path(optarg, LOOKUP_FOLLOW, &path);
-+ if (err) {
-+ printk(KERN_ERR "unionfs: error accessing "
-+ "lower directory \"%s\" (error %d)\n",
-+ optarg, err);
-+ goto out;
-+ }
-+ for (idx = 0; idx < cur_branches; idx++)
-+ if (path.mnt == new_lower_paths[idx].mnt &&
-+ path.dentry == new_lower_paths[idx].dentry)
-+ break;
-+ path_put(&path); /* no longer needed */
-+ if (idx == cur_branches) {
-+ printk(KERN_ERR "unionfs: branch \"%s\" "
-+ "not found\n", optarg);
-+ err = -ENOENT;
-+ goto out;
-+ }
-+ /* check if there are any open files on the branch to be deleted */
-+ if (atomic_read(&new_data[idx].open_files) > 0) {
-+ err = -EBUSY;
-+ goto out;
-+ }
-+
-+ /*
-+ * Now we have to delete the branch. First, release any handles it
-+ * has. Then, move the remaining array indexes past "idx" in
-+ * new_data and new_lower_paths one to the left. Finally, adjust
-+ * cur_branches.
-+ */
-+ path_put(&new_lower_paths[idx]);
-+
-+ if (idx < cur_branches - 1) {
-+ /* if idx==cur_branches-1, we delete last branch: easy */
-+ memmove(&new_data[idx], &new_data[idx+1],
-+ (cur_branches - 1 - idx) *
-+ sizeof(struct unionfs_data));
-+ memmove(&new_lower_paths[idx], &new_lower_paths[idx+1],
-+ (cur_branches - 1 - idx) * sizeof(struct path));
-+ }
-+
-+ err = 0;
-+out:
-+ return err;
-+}
-+
-+/* handle branch insertion during remount */
-+static noinline_for_stack int do_remount_add_option(
-+ char *optarg, int cur_branches,
-+ struct unionfs_data *new_data,
-+ struct path *new_lower_paths,
-+ int *high_branch_id)
-+{
-+ int err = -EINVAL;
-+ int perms;
-+ int idx = 0; /* default: insert at beginning */
-+ char *new_branch , *modename = NULL;
-+ struct path path;
-+
-+ /*
-+ * optarg can be of several forms:
-+ *
-+ * /bar:/foo insert /foo before /bar
-+ * /bar:/foo=ro insert /foo in ro mode before /bar
-+ * /foo insert /foo in the beginning (prepend)
-+ * :/foo insert /foo at the end (append)
-+ */
-+ if (*optarg == ':') { /* append? */
-+ new_branch = optarg + 1; /* skip ':' */
-+ idx = cur_branches;
-+ goto found_insertion_point;
-+ }
-+ new_branch = strchr(optarg, ':');
-+ if (!new_branch) { /* prepend? */
-+ new_branch = optarg;
-+ goto found_insertion_point;
-+ }
-+ *new_branch++ = '\0'; /* holds path+mode of new branch */
-+
-+ /*
-+ * Find matching branch index. For now, this assumes that nothing
-+ * has been mounted on top of this Unionfs stack. Once we have /odf
-+ * and cache-coherency resolved, we'll address the branch-path
-+ * uniqueness.
-+ */
-+ err = kern_path(optarg, LOOKUP_FOLLOW, &path);
-+ if (err) {
-+ printk(KERN_ERR "unionfs: error accessing "
-+ "lower directory \"%s\" (error %d)\n",
-+ optarg, err);
-+ goto out;
-+ }
-+ for (idx = 0; idx < cur_branches; idx++)
-+ if (path.mnt == new_lower_paths[idx].mnt &&
-+ path.dentry == new_lower_paths[idx].dentry)
-+ break;
-+ path_put(&path); /* no longer needed */
-+ if (idx == cur_branches) {
-+ printk(KERN_ERR "unionfs: branch \"%s\" "
-+ "not found\n", optarg);
-+ err = -ENOENT;
-+ goto out;
-+ }
-+
-+ /*
-+ * At this point idx will hold the index where the new branch should
-+ * be inserted before.
-+ */
-+found_insertion_point:
-+ /* find the mode for the new branch */
-+ if (new_branch)
-+ modename = strchr(new_branch, '=');
-+ if (modename)
-+ *modename++ = '\0';
-+ if (!new_branch || !*new_branch) {
-+ printk(KERN_ERR "unionfs: null new branch\n");
-+ err = -EINVAL;
-+ goto out;
-+ }
-+ err = parse_branch_mode(modename, &perms);
-+ if (err) {
-+ printk(KERN_ERR "unionfs: invalid mode \"%s\" for "
-+ "branch \"%s\"\n", modename, new_branch);
-+ goto out;
-+ }
-+ err = kern_path(new_branch, LOOKUP_FOLLOW, &path);
-+ if (err) {
-+ printk(KERN_ERR "unionfs: error accessing "
-+ "lower directory \"%s\" (error %d)\n",
-+ new_branch, err);
-+ goto out;
-+ }
-+ /*
-+ * It's probably safe to check_mode the new branch to insert. Note:
-+ * we don't allow inserting branches which are unionfs's by
-+ * themselves (check_branch returns EINVAL in that case). This is
-+ * because this code base doesn't support stacking unionfs: the ODF
-+ * code base supports that correctly.
-+ */
-+ err = check_branch(&path);
-+ if (err) {
-+ printk(KERN_ERR "unionfs: lower directory "
-+ "\"%s\" is not a valid branch\n", optarg);
-+ path_put(&path);
-+ goto out;
-+ }
-+
-+ /*
-+ * Now we have to insert the new branch. But first, move the bits
-+ * to make space for the new branch, if needed. Finally, adjust
-+ * cur_branches.
-+ * We don't release nd here; it's kept until umount/remount.
-+ */
-+ if (idx < cur_branches) {
-+ /* if idx==cur_branches, we append: easy */
-+ memmove(&new_data[idx+1], &new_data[idx],
-+ (cur_branches - idx) * sizeof(struct unionfs_data));
-+ memmove(&new_lower_paths[idx+1], &new_lower_paths[idx],
-+ (cur_branches - idx) * sizeof(struct path));
-+ }
-+ new_lower_paths[idx].dentry = path.dentry;
-+ new_lower_paths[idx].mnt = path.mnt;
-+
-+ new_data[idx].sb = path.dentry->d_sb;
-+ atomic_set(&new_data[idx].open_files, 0);
-+ new_data[idx].branchperms = perms;
-+ new_data[idx].branch_id = ++*high_branch_id; /* assign new branch ID */
-+
-+ err = 0;
-+out:
-+ return err;
-+}
-+
-+
-+/*
-+ * Support branch management options on remount.
-+ *
-+ * See Documentation/filesystems/unionfs/ for details.
-+ *
-+ * @flags: numeric mount options
-+ * @options: mount options string
-+ *
-+ * This function can rearrange a mounted union dynamically, adding and
-+ * removing branches, including changing branch modes. Clearly this has to
-+ * be done safely and atomically. Luckily, the VFS already calls this
-+ * function with lock_super(sb) and lock_kernel() held, preventing
-+ * concurrent mixing of new mounts, remounts, and unmounts. Moreover,
-+ * do_remount_sb(), our caller function, already called shrink_dcache_sb(sb)
-+ * to purge dentries/inodes from our superblock, and also called
-+ * fsync_super(sb) to purge any dirty pages. So we're good.
-+ *
-+ * XXX: however, our remount code may also need to invalidate mapped pages
-+ * so as to force them to be re-gotten from the (newly reconfigured) lower
-+ * branches. This has to wait for proper mmap and cache coherency support
-+ * in the VFS.
-+ *
-+ */
-+static int unionfs_remount_fs(struct super_block *sb, int *flags,
-+ char *options)
-+{
-+ int err = 0;
-+ int i;
-+ char *optionstmp, *tmp_to_free; /* kstrdup'ed of "options" */
-+ char *optname;
-+ int cur_branches = 0; /* no. of current branches */
-+ int new_branches = 0; /* no. of branches actually left in the end */
-+ int add_branches; /* est. no. of branches to add */
-+ int del_branches; /* est. no. of branches to del */
-+ int max_branches; /* max possible no. of branches */
-+ struct unionfs_data *new_data = NULL, *tmp_data = NULL;
-+ struct path *new_lower_paths = NULL, *tmp_lower_paths = NULL;
-+ struct inode **new_lower_inodes = NULL;
-+ int new_high_branch_id; /* new high branch ID */
-+ int size; /* memory allocation size, temp var */
-+ int old_ibstart, old_ibend;
-+
-+ unionfs_write_lock(sb);
-+
-+ /*
-+ * The VFS will take care of "ro" and "rw" flags, and we can safely
-+ * ignore MS_SILENT, but anything else left over is an error. So we
-+ * need to check if any other flags may have been passed (none are
-+ * allowed/supported as of now).
-+ */
-+ if ((*flags & ~(MS_RDONLY | MS_SILENT)) != 0) {
-+ printk(KERN_ERR
-+ "unionfs: remount flags 0x%x unsupported\n", *flags);
-+ err = -EINVAL;
-+ goto out_error;
-+ }
-+
-+ /*
-+ * If 'options' is NULL, it's probably because the user just changed
-+ * the union to a "ro" or "rw" and the VFS took care of it. So
-+ * nothing to do and we're done.
-+ */
-+ if (!options || options[0] == '\0')
-+ goto out_error;
-+
-+ /*
-+ * Find out how many branches we will have in the end, counting
-+ * "add" and "del" commands. Copy the "options" string because
-+ * strsep modifies the string and we need it later.
-+ */
-+ tmp_to_free = kstrdup(options, GFP_KERNEL);
-+ optionstmp = tmp_to_free;
-+ if (unlikely(!optionstmp)) {
-+ err = -ENOMEM;
-+ goto out_free;
-+ }
-+ cur_branches = sbmax(sb); /* current no. branches */
-+ new_branches = sbmax(sb);
-+ del_branches = 0;
-+ add_branches = 0;
-+ new_high_branch_id = sbhbid(sb); /* save current high_branch_id */
-+ while ((optname = strsep(&optionstmp, ",")) != NULL) {
-+ char *optarg;
-+
-+ if (!optname || !*optname)
-+ continue;
-+
-+ optarg = strchr(optname, '=');
-+ if (optarg)
-+ *optarg++ = '\0';
-+
-+ if (!strcmp("add", optname))
-+ add_branches++;
-+ else if (!strcmp("del", optname))
-+ del_branches++;
-+ }
-+ kfree(tmp_to_free);
-+ /* after all changes, will we have at least one branch left? */
-+ if ((new_branches + add_branches - del_branches) < 1) {
-+ printk(KERN_ERR
-+ "unionfs: no branches left after remount\n");
-+ err = -EINVAL;
-+ goto out_free;
-+ }
-+
-+ /*
-+ * Since we haven't actually parsed all the add/del options, nor
-+ * have we checked them for errors, we don't know for sure how many
-+ * branches we will have after all changes have taken place. In
-+ * fact, the total number of branches left could be less than what
-+ * we have now. So we need to allocate space for a temporary
-+ * placeholder that is at least as large as the maximum number of
-+ * branches we *could* have, which is the current number plus all
-+ * the additions. Once we're done with these temp placeholders, we
-+ * may have to re-allocate the final size, copy over from the temp,
-+ * and then free the temps (done near the end of this function).
-+ */
-+ max_branches = cur_branches + add_branches;
-+ /* allocate space for new pointers to lower dentry */
-+ tmp_data = kcalloc(max_branches,
-+ sizeof(struct unionfs_data), GFP_KERNEL);
-+ if (unlikely(!tmp_data)) {
-+ err = -ENOMEM;
-+ goto out_free;
-+ }
-+ /* allocate space for new pointers to lower paths */
-+ tmp_lower_paths = kcalloc(max_branches,
-+ sizeof(struct path), GFP_KERNEL);
-+ if (unlikely(!tmp_lower_paths)) {
-+ err = -ENOMEM;
-+ goto out_free;
-+ }
-+ /* copy current info into new placeholders, incrementing refcnts */
-+ memcpy(tmp_data, UNIONFS_SB(sb)->data,
-+ cur_branches * sizeof(struct unionfs_data));
-+ memcpy(tmp_lower_paths, UNIONFS_D(sb->s_root)->lower_paths,
-+ cur_branches * sizeof(struct path));
-+ for (i = 0; i < cur_branches; i++)
-+ path_get(&tmp_lower_paths[i]); /* drop refs at end of fxn */
-+
-+ /*******************************************************************
-+ * For each branch command, do kern_path on the requested branch,
-+ * and apply the change to a temp branch list. To handle errors, we
-+ * already dup'ed the old arrays (above), and increased the refcnts
-+ * on various f/s objects. So now we can do all the kern_path'ss
-+ * and branch-management commands on the new arrays. If it fail mid
-+ * way, we free the tmp arrays and *put all objects. If we succeed,
-+ * then we free old arrays and *put its objects, and then replace
-+ * the arrays with the new tmp list (we may have to re-allocate the
-+ * memory because the temp lists could have been larger than what we
-+ * actually needed).
-+ *******************************************************************/
-+
-+ while ((optname = strsep(&options, ",")) != NULL) {
-+ char *optarg;
-+
-+ if (!optname || !*optname)
-+ continue;
-+ /*
-+ * At this stage optname holds a comma-delimited option, but
-+ * without the commas. Next, we need to break the string on
-+ * the '=' symbol to separate CMD=ARG, where ARG itself can
-+ * be KEY=VAL. For example, in mode=/foo=rw, CMD is "mode",
-+ * KEY is "/foo", and VAL is "rw".
-+ */
-+ optarg = strchr(optname, '=');
-+ if (optarg)
-+ *optarg++ = '\0';
-+ /* incgen remount option (instead of old ioctl) */
-+ if (!strcmp("incgen", optname)) {
-+ err = 0;
-+ goto out_no_change;
-+ }
-+
-+ /*
-+ * All of our options take an argument now. (Insert ones
-+ * that don't above this check.) So at this stage optname
-+ * contains the CMD part and optarg contains the ARG part.
-+ */
-+ if (!optarg || !*optarg) {
-+ printk(KERN_ERR "unionfs: all remount options require "
-+ "an argument (%s)\n", optname);
-+ err = -EINVAL;
-+ goto out_release;
-+ }
-+
-+ if (!strcmp("add", optname)) {
-+ err = do_remount_add_option(optarg, new_branches,
-+ tmp_data,
-+ tmp_lower_paths,
-+ &new_high_branch_id);
-+ if (err)
-+ goto out_release;
-+ new_branches++;
-+ if (new_branches > UNIONFS_MAX_BRANCHES) {
-+ printk(KERN_ERR "unionfs: command exceeds "
-+ "%d branches\n", UNIONFS_MAX_BRANCHES);
-+ err = -E2BIG;
-+ goto out_release;
-+ }
-+ continue;
-+ }
-+ if (!strcmp("del", optname)) {
-+ err = do_remount_del_option(optarg, new_branches,
-+ tmp_data,
-+ tmp_lower_paths);
-+ if (err)
-+ goto out_release;
-+ new_branches--;
-+ continue;
-+ }
-+ if (!strcmp("mode", optname)) {
-+ err = do_remount_mode_option(optarg, new_branches,
-+ tmp_data,
-+ tmp_lower_paths);
-+ if (err)
-+ goto out_release;
-+ continue;
-+ }
-+
-+ /*
-+ * When you use "mount -o remount,ro", mount(8) will
-+ * reportedly pass the original dirs= string from
-+ * /proc/mounts. So for now, we have to ignore dirs= and
-+ * not consider it an error, unless we want to allow users
-+ * to pass dirs= in remount. Note that to allow the VFS to
-+ * actually process the ro/rw remount options, we have to
-+ * return 0 from this function.
-+ */
-+ if (!strcmp("dirs", optname)) {
-+ printk(KERN_WARNING
-+ "unionfs: remount ignoring option \"%s\"\n",
-+ optname);
-+ continue;
-+ }
-+
-+ err = -EINVAL;
-+ printk(KERN_ERR
-+ "unionfs: unrecognized option \"%s\"\n", optname);
-+ goto out_release;
-+ }
-+
-+out_no_change:
-+
-+ /******************************************************************
-+ * WE'RE ALMOST DONE: check if leftmost branch might be read-only,
-+ * see if we need to allocate a small-sized new vector, copy the
-+ * vectors to their correct place, release the refcnt of the older
-+ * ones, and return. Also handle invalidating any pages that will
-+ * have to be re-read.
-+ *******************************************************************/
-+
-+ if (!(tmp_data[0].branchperms & MAY_WRITE)) {
-+ printk(KERN_ERR "unionfs: leftmost branch cannot be read-only "
-+ "(use \"remount,ro\" to create a read-only union)\n");
-+ err = -EINVAL;
-+ goto out_release;
-+ }
-+
-+ /* (re)allocate space for new pointers to lower dentry */
-+ size = new_branches * sizeof(struct unionfs_data);
-+ new_data = krealloc(tmp_data, size, GFP_KERNEL);
-+ if (unlikely(!new_data)) {
-+ err = -ENOMEM;
-+ goto out_release;
-+ }
-+
-+ /* allocate space for new pointers to lower paths */
-+ size = new_branches * sizeof(struct path);
-+ new_lower_paths = krealloc(tmp_lower_paths, size, GFP_KERNEL);
-+ if (unlikely(!new_lower_paths)) {
-+ err = -ENOMEM;
-+ goto out_release;
-+ }
-+
-+ /* allocate space for new pointers to lower inodes */
-+ new_lower_inodes = kcalloc(new_branches,
-+ sizeof(struct inode *), GFP_KERNEL);
-+ if (unlikely(!new_lower_inodes)) {
-+ err = -ENOMEM;
-+ goto out_release;
-+ }
-+
-+ /*
-+ * OK, just before we actually put the new set of branches in place,
-+ * we need to ensure that our own f/s has no dirty objects left.
-+ * Luckily, do_remount_sb() already calls shrink_dcache_sb(sb) and
-+ * fsync_super(sb), taking care of dentries, inodes, and dirty
-+ * pages. So all that's left is for us to invalidate any leftover
-+ * (non-dirty) pages to ensure that they will be re-read from the
-+ * new lower branches (and to support mmap).
-+ */
-+
-+ /*
-+ * Once we finish the remounting successfully, our superblock
-+ * generation number will have increased. This will be detected by
-+ * our dentry-revalidation code upon subsequent f/s operations
-+ * through unionfs. The revalidation code will rebuild the union of
-+ * lower inodes for a given unionfs inode and invalidate any pages
-+ * of such "stale" inodes (by calling our purge_inode_data
-+ * function). This revalidation will happen lazily and
-+ * incrementally, as users perform operations on cached inodes. We
-+ * would like to encourage this revalidation to happen sooner if
-+ * possible, so we like to try to invalidate as many other pages in
-+ * our superblock as we can. We used to call drop_pagecache_sb() or
-+ * a variant thereof, but either method was racy (drop_caches alone
-+ * is known to be racy). So now we let the revalidation happen on a
-+ * per file basis in ->d_revalidate.
-+ */
-+
-+ /* grab new lower super references; release old ones */
-+ for (i = 0; i < new_branches; i++)
-+ atomic_inc(&new_data[i].sb->s_active);
-+ for (i = 0; i < sbmax(sb); i++)
-+ atomic_dec(&UNIONFS_SB(sb)->data[i].sb->s_active);
-+
-+ /* copy new vectors into their correct place */
-+ tmp_data = UNIONFS_SB(sb)->data;
-+ UNIONFS_SB(sb)->data = new_data;
-+ new_data = NULL; /* so don't free good pointers below */
-+ tmp_lower_paths = UNIONFS_D(sb->s_root)->lower_paths;
-+ UNIONFS_D(sb->s_root)->lower_paths = new_lower_paths;
-+ new_lower_paths = NULL; /* so don't free good pointers below */
-+
-+ /* update our unionfs_sb_info and root dentry index of last branch */
-+ i = sbmax(sb); /* save no. of branches to release at end */
-+ sbend(sb) = new_branches - 1;
-+ dbend(sb->s_root) = new_branches - 1;
-+ old_ibstart = ibstart(sb->s_root->d_inode);
-+ old_ibend = ibend(sb->s_root->d_inode);
-+ ibend(sb->s_root->d_inode) = new_branches - 1;
-+ UNIONFS_D(sb->s_root)->bcount = new_branches;
-+ new_branches = i; /* no. of branches to release below */
-+
-+ /*
-+ * Update lower inodes: 3 steps
-+ * 1. grab ref on all new lower inodes
-+ */
-+ for (i = dbstart(sb->s_root); i <= dbend(sb->s_root); i++) {
-+ struct dentry *lower_dentry =
-+ unionfs_lower_dentry_idx(sb->s_root, i);
-+ igrab(lower_dentry->d_inode);
-+ new_lower_inodes[i] = lower_dentry->d_inode;
-+ }
-+ /* 2. release reference on all older lower inodes */
-+ iput_lowers(sb->s_root->d_inode, old_ibstart, old_ibend, true);
-+ /* 3. update root dentry's inode to new lower_inodes array */
-+ UNIONFS_I(sb->s_root->d_inode)->lower_inodes = new_lower_inodes;
-+ new_lower_inodes = NULL;
-+
-+ /* maxbytes may have changed */
-+ sb->s_maxbytes = unionfs_lower_super_idx(sb, 0)->s_maxbytes;
-+ /* update high branch ID */
-+ sbhbid(sb) = new_high_branch_id;
-+
-+ /* update our sb->generation for revalidating objects */
-+ i = atomic_inc_return(&UNIONFS_SB(sb)->generation);
-+ atomic_set(&UNIONFS_D(sb->s_root)->generation, i);
-+ atomic_set(&UNIONFS_I(sb->s_root->d_inode)->generation, i);
-+ if (!(*flags & MS_SILENT))
-+ pr_info("unionfs: %s: new generation number %d\n",
-+ UNIONFS_SB(sb)->dev_name, i);
-+ /* finally, update the root dentry's times */
-+ unionfs_copy_attr_times(sb->s_root->d_inode);
-+ err = 0; /* reset to success */
-+
-+ /*
-+ * The code above falls through to the next label, and releases the
-+ * refcnts of the older ones (stored in tmp_*): if we fell through
-+ * here, it means success. However, if we jump directly to this
-+ * label from any error above, then an error occurred after we
-+ * grabbed various refcnts, and so we have to release the
-+ * temporarily constructed structures.
-+ */
-+out_release:
-+ /* no need to cleanup/release anything in tmp_data */
-+ if (tmp_lower_paths)
-+ for (i = 0; i < new_branches; i++)
-+ path_put(&tmp_lower_paths[i]);
-+out_free:
-+ kfree(tmp_lower_paths);
-+ kfree(tmp_data);
-+ kfree(new_lower_paths);
-+ kfree(new_data);
-+ kfree(new_lower_inodes);
-+out_error:
-+ unionfs_check_dentry(sb->s_root);
-+ unionfs_write_unlock(sb);
-+ return err;
-+}
-+
-+/*
-+ * Called by iput() when the inode reference count reached zero
-+ * and the inode is not hashed anywhere. Used to clear anything
-+ * that needs to be, before the inode is completely destroyed and put
-+ * on the inode free list.
-+ *
-+ * No need to lock sb info's rwsem.
-+ */
-+static void unionfs_evict_inode(struct inode *inode)
-+{
-+ int bindex, bstart, bend;
-+ struct inode *lower_inode;
-+ struct list_head *pos, *n;
-+ struct unionfs_dir_state *rdstate;
-+
-+ truncate_inode_pages(&inode->i_data, 0);
-+ clear_inode(inode);
-+
-+ list_for_each_safe(pos, n, &UNIONFS_I(inode)->readdircache) {
-+ rdstate = list_entry(pos, struct unionfs_dir_state, cache);
-+ list_del(&rdstate->cache);
-+ free_rdstate(rdstate);
-+ }
-+
-+ /*
-+ * Decrement a reference to a lower_inode, which was incremented
-+ * by our read_inode when it was created initially.
-+ */
-+ bstart = ibstart(inode);
-+ bend = ibend(inode);
-+ if (bstart >= 0) {
-+ for (bindex = bstart; bindex <= bend; bindex++) {
-+ lower_inode = unionfs_lower_inode_idx(inode, bindex);
-+ if (!lower_inode)
-+ continue;
-+ unionfs_set_lower_inode_idx(inode, bindex, NULL);
-+ /* see Documentation/filesystems/unionfs/issues.txt */
-+ lockdep_off();
-+ iput(lower_inode);
-+ lockdep_on();
-+ }
-+ }
-+
-+ kfree(UNIONFS_I(inode)->lower_inodes);
-+ UNIONFS_I(inode)->lower_inodes = NULL;
-+}
-+
-+static struct inode *unionfs_alloc_inode(struct super_block *sb)
-+{
-+ struct unionfs_inode_info *i;
-+
-+ i = kmem_cache_alloc(unionfs_inode_cachep, GFP_KERNEL);
-+ if (unlikely(!i))
-+ return NULL;
-+
-+ /* memset everything up to the inode to 0 */
-+ memset(i, 0, offsetof(struct unionfs_inode_info, vfs_inode));
-+
-+ i->vfs_inode.i_version = 1;
-+ return &i->vfs_inode;
-+}
-+
-+static void unionfs_destroy_inode(struct inode *inode)
-+{
-+ kmem_cache_free(unionfs_inode_cachep, UNIONFS_I(inode));
-+}
-+
-+/* unionfs inode cache constructor */
-+static void init_once(void *obj)
-+{
-+ struct unionfs_inode_info *i = obj;
-+
-+ inode_init_once(&i->vfs_inode);
-+}
-+
-+int unionfs_init_inode_cache(void)
-+{
-+ int err = 0;
-+
-+ unionfs_inode_cachep =
-+ kmem_cache_create("unionfs_inode_cache",
-+ sizeof(struct unionfs_inode_info), 0,
-+ SLAB_RECLAIM_ACCOUNT, init_once);
-+ if (unlikely(!unionfs_inode_cachep))
-+ err = -ENOMEM;
-+ return err;
-+}
-+
-+/* unionfs inode cache destructor */
-+void unionfs_destroy_inode_cache(void)
-+{
-+ if (unionfs_inode_cachep)
-+ kmem_cache_destroy(unionfs_inode_cachep);
-+}
-+
-+/*
-+ * Called when we have a dirty inode, right here we only throw out
-+ * parts of our readdir list that are too old.
-+ *
-+ * No need to grab sb info's rwsem.
-+ */
-+static int unionfs_write_inode(struct inode *inode,
-+ struct writeback_control *wbc)
-+{
-+ struct list_head *pos, *n;
-+ struct unionfs_dir_state *rdstate;
-+
-+ spin_lock(&UNIONFS_I(inode)->rdlock);
-+ list_for_each_safe(pos, n, &UNIONFS_I(inode)->readdircache) {
-+ rdstate = list_entry(pos, struct unionfs_dir_state, cache);
-+ /* We keep this list in LRU order. */
-+ if ((rdstate->access + RDCACHE_JIFFIES) > jiffies)
-+ break;
-+ UNIONFS_I(inode)->rdcount--;
-+ list_del(&rdstate->cache);
-+ free_rdstate(rdstate);
-+ }
-+ spin_unlock(&UNIONFS_I(inode)->rdlock);
-+
-+ return 0;
-+}
-+
-+/*
-+ * Used only in nfs, to kill any pending RPC tasks, so that subsequent
-+ * code can actually succeed and won't leave tasks that need handling.
-+ */
-+static void unionfs_umount_begin(struct super_block *sb)
-+{
-+ struct super_block *lower_sb;
-+ int bindex, bstart, bend;
-+
-+ unionfs_read_lock(sb, UNIONFS_SMUTEX_CHILD);
-+
-+ bstart = sbstart(sb);
-+ bend = sbend(sb);
-+ for (bindex = bstart; bindex <= bend; bindex++) {
-+ lower_sb = unionfs_lower_super_idx(sb, bindex);
-+
-+ if (lower_sb && lower_sb->s_op &&
-+ lower_sb->s_op->umount_begin)
-+ lower_sb->s_op->umount_begin(lower_sb);
-+ }
-+
-+ unionfs_read_unlock(sb);
-+}
-+
-+static int unionfs_show_options(struct seq_file *m, struct dentry *root)
-+{
-+ struct super_block *sb = root->d_sb;
-+ int ret = 0;
-+ char *tmp_page;
-+ char *path;
-+ int bindex, bstart, bend;
-+ int perms;
-+
-+ /* to prevent a silly lockdep warning with namespace_sem */
-+ lockdep_off();
-+ unionfs_read_lock(sb, UNIONFS_SMUTEX_CHILD);
-+ unionfs_lock_dentry(sb->s_root, UNIONFS_DMUTEX_CHILD);
-+
-+ tmp_page = (char *) __get_free_page(GFP_KERNEL);
-+ if (unlikely(!tmp_page)) {
-+ ret = -ENOMEM;
-+ goto out;
-+ }
-+
-+ bstart = sbstart(sb);
-+ bend = sbend(sb);
-+
-+ seq_printf(m, ",dirs=");
-+ for (bindex = bstart; bindex <= bend; bindex++) {
-+ struct path p;
-+ p.dentry = unionfs_lower_dentry_idx(sb->s_root, bindex);
-+ p.mnt = unionfs_lower_mnt_idx(sb->s_root, bindex);
-+ path = d_path(&p, tmp_page, PAGE_SIZE);
-+ if (IS_ERR(path)) {
-+ ret = PTR_ERR(path);
-+ goto out;
-+ }
-+
-+ perms = branchperms(sb, bindex);
-+
-+ seq_printf(m, "%s=%s", path,
-+ perms & MAY_WRITE ? "rw" : "ro");
-+ if (bindex != bend)
-+ seq_printf(m, ":");
-+ }
-+
-+out:
-+ free_page((unsigned long) tmp_page);
-+
-+ unionfs_unlock_dentry(sb->s_root);
-+ unionfs_read_unlock(sb);
-+ lockdep_on();
-+
-+ return ret;
-+}
-+
-+struct super_operations unionfs_sops = {
-+ .put_super = unionfs_put_super,
-+ .statfs = unionfs_statfs,
-+ .remount_fs = unionfs_remount_fs,
-+ .evict_inode = unionfs_evict_inode,
-+ .umount_begin = unionfs_umount_begin,
-+ .show_options = unionfs_show_options,
-+ .write_inode = unionfs_write_inode,
-+ .alloc_inode = unionfs_alloc_inode,
-+ .destroy_inode = unionfs_destroy_inode,
-+};
-diff --git a/fs/unionfs/union.h b/fs/unionfs/union.h
-new file mode 100644
-index 0000000..8e7fcfb
---- /dev/null
-+++ b/fs/unionfs/union.h
-@@ -0,0 +1,681 @@
-+/*
-+ * Copyright (c) 2003-2011 Erez Zadok
-+ * Copyright (c) 2003-2006 Charles P. Wright
-+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2005 Arun M. Krishnakumar
-+ * Copyright (c) 2004-2006 David P. Quigley
-+ * Copyright (c) 2003-2004 Mohammad Nayyer Zubair
-+ * Copyright (c) 2003 Puja Gupta
-+ * Copyright (c) 2003 Harikesavan Krishnan
-+ * Copyright (c) 2003-2011 Stony Brook University
-+ * Copyright (c) 2003-2011 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#ifndef _UNION_H_
-+#define _UNION_H_
-+
-+#include <linux/dcache.h>
-+#include <linux/file.h>
-+#include <linux/list.h>
-+#include <linux/fs.h>
-+#include <linux/mm.h>
-+#include <linux/module.h>
-+#include <linux/mount.h>
-+#include <linux/namei.h>
-+#include <linux/page-flags.h>
-+#include <linux/pagemap.h>
-+#include <linux/poll.h>
-+#include <linux/security.h>
-+#include <linux/seq_file.h>
-+#include <linux/slab.h>
-+#include <linux/spinlock.h>
-+#include <linux/statfs.h>
-+#include <linux/string.h>
-+#include <linux/vmalloc.h>
-+#include <linux/writeback.h>
-+#include <linux/buffer_head.h>
-+#include <linux/xattr.h>
-+#include <linux/fs_stack.h>
-+#include <linux/magic.h>
-+#include <linux/log2.h>
-+#include <linux/poison.h>
-+#include <linux/mman.h>
-+#include <linux/backing-dev.h>
-+#include <linux/splice.h>
-+#include <linux/sched.h>
-+
-+
-+
-+#include <linux/union_fs.h>
-+
-+/* the file system name */
-+#define UNIONFS_NAME "unionfs"
-+
-+/* unionfs root inode number */
-+#define UNIONFS_ROOT_INO 1
-+
-+/* number of times we try to get a unique temporary file name */
-+#define GET_TMPNAM_MAX_RETRY 5
-+
-+/* maximum number of branches we support, to avoid memory blowup */
-+#define UNIONFS_MAX_BRANCHES 128
-+
-+/* minimum time (seconds) required for time-based cache-coherency */
-+#define UNIONFS_MIN_CC_TIME 3
-+
-+/* Operations vectors defined in specific files. */
-+extern struct file_operations unionfs_main_fops;
-+extern struct file_operations unionfs_dir_fops;
-+extern struct inode_operations unionfs_main_iops;
-+extern struct inode_operations unionfs_dir_iops;
-+extern struct inode_operations unionfs_symlink_iops;
-+extern struct super_operations unionfs_sops;
-+extern struct dentry_operations unionfs_dops;
-+extern struct address_space_operations unionfs_aops, unionfs_dummy_aops;
-+extern struct vm_operations_struct unionfs_vm_ops;
-+
-+/* How long should an entry be allowed to persist */
-+#define RDCACHE_JIFFIES (5*HZ)
-+
-+/* compatibility with Real-Time patches */
-+#ifdef CONFIG_PREEMPT_RT
-+# define unionfs_rw_semaphore compat_rw_semaphore
-+#else /* not CONFIG_PREEMPT_RT */
-+# define unionfs_rw_semaphore rw_semaphore
-+#endif /* not CONFIG_PREEMPT_RT */
-+
-+/* file private data. */
-+struct unionfs_file_info {
-+ int bstart;
-+ int bend;
-+ atomic_t generation;
-+
-+ struct unionfs_dir_state *rdstate;
-+ struct file **lower_files;
-+ int *saved_branch_ids; /* IDs of branches when file was opened */
-+ const struct vm_operations_struct *lower_vm_ops;
-+ bool wrote_to_file; /* for delayed copyup */
-+};
-+
-+/* unionfs inode data in memory */
-+struct unionfs_inode_info {
-+ int bstart;
-+ int bend;
-+ atomic_t generation;
-+ /* Stuff for readdir over NFS. */
-+ spinlock_t rdlock;
-+ struct list_head readdircache;
-+ int rdcount;
-+ int hashsize;
-+ int cookie;
-+
-+ /* The lower inodes */
-+ struct inode **lower_inodes;
-+
-+ struct inode vfs_inode;
-+};
-+
-+/* unionfs dentry data in memory */
-+struct unionfs_dentry_info {
-+ /*
-+ * The semaphore is used to lock the dentry as soon as we get into a
-+ * unionfs function from the VFS. Our lock ordering is that children
-+ * go before their parents.
-+ */
-+ struct mutex lock;
-+ int bstart;
-+ int bend;
-+ int bopaque;
-+ int bcount;
-+ atomic_t generation;
-+ struct path *lower_paths;
-+};
-+
-+/* These are the pointers to our various objects. */
-+struct unionfs_data {
-+ struct super_block *sb; /* lower super_block */
-+ atomic_t open_files; /* number of open files on branch */
-+ int branchperms;
-+ int branch_id; /* unique branch ID at re/mount time */
-+};
-+
-+/* unionfs super-block data in memory */
-+struct unionfs_sb_info {
-+ int bend;
-+
-+ atomic_t generation;
-+
-+ /*
-+ * This rwsem is used to make sure that a branch management
-+ * operation...
-+ * 1) will not begin before all currently in-flight operations
-+ * complete.
-+ * 2) any new operations do not execute until the currently
-+ * running branch management operation completes.
-+ *
-+ * The write_lock_owner records the PID of the task which grabbed
-+ * the rw_sem for writing. If the same task also tries to grab the
-+ * read lock, we allow it. This prevents a self-deadlock when
-+ * branch-management is used on a pivot_root'ed union, because we
-+ * have to ->lookup paths which belong to the same union.
-+ */
-+ struct unionfs_rw_semaphore rwsem;
-+ pid_t write_lock_owner; /* PID of rw_sem owner (write lock) */
-+ int high_branch_id; /* last unique branch ID given */
-+ char *dev_name; /* to identify different unions in pr_debug */
-+ struct unionfs_data *data;
-+};
-+
-+/*
-+ * structure for making the linked list of entries by readdir on left branch
-+ * to compare with entries on right branch
-+ */
-+struct filldir_node {
-+ struct list_head file_list; /* list for directory entries */
-+ char *name; /* name entry */
-+ int hash; /* name hash */
-+ int namelen; /* name len since name is not 0 terminated */
-+
-+ /*
-+ * we can check for duplicate whiteouts and files in the same branch
-+ * in order to return -EIO.
-+ */
-+ int bindex;
-+
-+ /* is this a whiteout entry? */
-+ int whiteout;
-+
-+ /* Inline name, so we don't need to separately kmalloc small ones */
-+ char iname[DNAME_INLINE_LEN];
-+};
-+
-+/* Directory hash table. */
-+struct unionfs_dir_state {
-+ unsigned int cookie; /* the cookie, based off of rdversion */
-+ unsigned int offset; /* The entry we have returned. */
-+ int bindex;
-+ loff_t dirpos; /* offset within the lower level directory */
-+ int size; /* How big is the hash table? */
-+ int hashentries; /* How many entries have been inserted? */
-+ unsigned long access;
-+
-+ /* This cache list is used when the inode keeps us around. */
-+ struct list_head cache;
-+ struct list_head list[0];
-+};
-+
-+/* externs needed for fanout.h or sioq.h */
-+extern int unionfs_get_nlinks(const struct inode *inode);
-+extern void unionfs_copy_attr_times(struct inode *upper);
-+extern void unionfs_copy_attr_all(struct inode *dest, const struct inode *src);
-+
-+/* include miscellaneous macros */
-+#include "fanout.h"
-+#include "sioq.h"
-+
-+/* externs for cache creation/deletion routines */
-+extern void unionfs_destroy_filldir_cache(void);
-+extern int unionfs_init_filldir_cache(void);
-+extern int unionfs_init_inode_cache(void);
-+extern void unionfs_destroy_inode_cache(void);
-+extern int unionfs_init_dentry_cache(void);
-+extern void unionfs_destroy_dentry_cache(void);
-+
-+/* Initialize and free readdir-specific state. */
-+extern int init_rdstate(struct file *file);
-+extern struct unionfs_dir_state *alloc_rdstate(struct inode *inode,
-+ int bindex);
-+extern struct unionfs_dir_state *find_rdstate(struct inode *inode,
-+ loff_t fpos);
-+extern void free_rdstate(struct unionfs_dir_state *state);
-+extern int add_filldir_node(struct unionfs_dir_state *rdstate,
-+ const char *name, int namelen, int bindex,
-+ int whiteout);
-+extern struct filldir_node *find_filldir_node(struct unionfs_dir_state *rdstate,
-+ const char *name, int namelen,
-+ int is_whiteout);
-+
-+extern struct dentry **alloc_new_dentries(int objs);
-+extern struct unionfs_data *alloc_new_data(int objs);
-+
-+/* We can only use 32-bits of offset for rdstate --- blech! */
-+#define DIREOF (0xfffff)
-+#define RDOFFBITS 20 /* This is the number of bits in DIREOF. */
-+#define MAXRDCOOKIE (0xfff)
-+/* Turn an rdstate into an offset. */
-+static inline off_t rdstate2offset(struct unionfs_dir_state *buf)
-+{
-+ off_t tmp;
-+
-+ tmp = ((buf->cookie & MAXRDCOOKIE) << RDOFFBITS)
-+ | (buf->offset & DIREOF);
-+ return tmp;
-+}
-+
-+/* Macros for locking a super_block. */
-+enum unionfs_super_lock_class {
-+ UNIONFS_SMUTEX_NORMAL,
-+ UNIONFS_SMUTEX_PARENT, /* when locking on behalf of file */
-+ UNIONFS_SMUTEX_CHILD, /* when locking on behalf of dentry */
-+};
-+static inline void unionfs_read_lock(struct super_block *sb, int subclass)
-+{
-+ if (UNIONFS_SB(sb)->write_lock_owner &&
-+ UNIONFS_SB(sb)->write_lock_owner == current->pid)
-+ return;
-+ down_read_nested(&UNIONFS_SB(sb)->rwsem, subclass);
-+}
-+static inline void unionfs_read_unlock(struct super_block *sb)
-+{
-+ if (UNIONFS_SB(sb)->write_lock_owner &&
-+ UNIONFS_SB(sb)->write_lock_owner == current->pid)
-+ return;
-+ up_read(&UNIONFS_SB(sb)->rwsem);
-+}
-+static inline void unionfs_write_lock(struct super_block *sb)
-+{
-+ down_write(&UNIONFS_SB(sb)->rwsem);
-+ UNIONFS_SB(sb)->write_lock_owner = current->pid;
-+}
-+static inline void unionfs_write_unlock(struct super_block *sb)
-+{
-+ up_write(&UNIONFS_SB(sb)->rwsem);
-+ UNIONFS_SB(sb)->write_lock_owner = 0;
-+}
-+
-+static inline void unionfs_double_lock_dentry(struct dentry *d1,
-+ struct dentry *d2)
-+{
-+ BUG_ON(d1 == d2);
-+ if (d1 < d2) {
-+ unionfs_lock_dentry(d1, UNIONFS_DMUTEX_PARENT);
-+ unionfs_lock_dentry(d2, UNIONFS_DMUTEX_CHILD);
-+ } else {
-+ unionfs_lock_dentry(d2, UNIONFS_DMUTEX_PARENT);
-+ unionfs_lock_dentry(d1, UNIONFS_DMUTEX_CHILD);
-+ }
-+}
-+
-+static inline void unionfs_double_unlock_dentry(struct dentry *d1,
-+ struct dentry *d2)
-+{
-+ BUG_ON(d1 == d2);
-+ if (d1 < d2) { /* unlock in reverse order than double_lock_dentry */
-+ unionfs_unlock_dentry(d1);
-+ unionfs_unlock_dentry(d2);
-+ } else {
-+ unionfs_unlock_dentry(d2);
-+ unionfs_unlock_dentry(d1);
-+ }
-+}
-+
-+static inline void unionfs_double_lock_parents(struct dentry *p1,
-+ struct dentry *p2)
-+{
-+ if (p1 == p2) {
-+ unionfs_lock_dentry(p1, UNIONFS_DMUTEX_REVAL_PARENT);
-+ return;
-+ }
-+ if (p1 < p2) {
-+ unionfs_lock_dentry(p1, UNIONFS_DMUTEX_REVAL_PARENT);
-+ unionfs_lock_dentry(p2, UNIONFS_DMUTEX_REVAL_CHILD);
-+ } else {
-+ unionfs_lock_dentry(p2, UNIONFS_DMUTEX_REVAL_PARENT);
-+ unionfs_lock_dentry(p1, UNIONFS_DMUTEX_REVAL_CHILD);
-+ }
-+}
-+
-+static inline void unionfs_double_unlock_parents(struct dentry *p1,
-+ struct dentry *p2)
-+{
-+ if (p1 == p2) {
-+ unionfs_unlock_dentry(p1);
-+ return;
-+ }
-+ if (p1 < p2) { /* unlock in reverse order of double_lock_parents */
-+ unionfs_unlock_dentry(p1);
-+ unionfs_unlock_dentry(p2);
-+ } else {
-+ unionfs_unlock_dentry(p2);
-+ unionfs_unlock_dentry(p1);
-+ }
-+}
-+
-+extern int new_dentry_private_data(struct dentry *dentry, int subclass);
-+extern int realloc_dentry_private_data(struct dentry *dentry);
-+extern void free_dentry_private_data(struct dentry *dentry);
-+extern void update_bstart(struct dentry *dentry);
-+extern int init_lower_nd(struct nameidata *nd, unsigned int flags);
-+extern void release_lower_nd(struct nameidata *nd, int err);
-+
-+/*
-+ * EXTERNALS:
-+ */
-+
-+/* replicates the directory structure up to given dentry in given branch */
-+extern struct dentry *create_parents(struct inode *dir, struct dentry *dentry,
-+ const char *name, int bindex);
-+
-+/* partial lookup */
-+extern int unionfs_partial_lookup(struct dentry *dentry,
-+ struct dentry *parent);
-+extern struct dentry *unionfs_lookup_full(struct dentry *dentry,
-+ struct dentry *parent,
-+ int lookupmode);
-+
-+/* copies a file from dbstart to newbindex branch */
-+extern int copyup_file(struct inode *dir, struct file *file, int bstart,
-+ int newbindex, loff_t size);
-+extern int copyup_named_file(struct inode *dir, struct file *file,
-+ char *name, int bstart, int new_bindex,
-+ loff_t len);
-+/* copies a dentry from dbstart to newbindex branch */
-+extern int copyup_dentry(struct inode *dir, struct dentry *dentry,
-+ int bstart, int new_bindex, const char *name,
-+ int namelen, struct file **copyup_file, loff_t len);
-+/* helper functions for post-copyup actions */
-+extern void unionfs_postcopyup_setmnt(struct dentry *dentry);
-+extern void unionfs_postcopyup_release(struct dentry *dentry);
-+
-+/* Is this directory empty: 0 if it is empty, -ENOTEMPTY if not. */
-+extern int check_empty(struct dentry *dentry, struct dentry *parent,
-+ struct unionfs_dir_state **namelist);
-+/* whiteout and opaque directory helpers */
-+extern char *alloc_whname(const char *name, int len);
-+extern bool is_whiteout_name(char **namep, int *namelenp);
-+extern bool is_validname(const char *name);
-+extern struct dentry *lookup_whiteout(const char *name,
-+ struct dentry *lower_parent);
-+extern struct dentry *find_first_whiteout(struct dentry *dentry);
-+extern int unlink_whiteout(struct dentry *wh_dentry);
-+extern int check_unlink_whiteout(struct dentry *dentry,
-+ struct dentry *lower_dentry, int bindex);
-+extern int create_whiteout(struct dentry *dentry, int start);
-+extern int delete_whiteouts(struct dentry *dentry, int bindex,
-+ struct unionfs_dir_state *namelist);
-+extern int is_opaque_dir(struct dentry *dentry, int bindex);
-+extern int make_dir_opaque(struct dentry *dir, int bindex);
-+extern void unionfs_set_max_namelen(long *namelen);
-+
-+extern void unionfs_reinterpose(struct dentry *this_dentry);
-+extern struct super_block *unionfs_duplicate_super(struct super_block *sb);
-+
-+/* Locking functions. */
-+extern int unionfs_setlk(struct file *file, int cmd, struct file_lock *fl);
-+extern int unionfs_getlk(struct file *file, struct file_lock *fl);
-+
-+/* Common file operations. */
-+extern int unionfs_file_revalidate(struct file *file, struct dentry *parent,
-+ bool willwrite);
-+extern int unionfs_open(struct inode *inode, struct file *file);
-+extern int unionfs_file_release(struct inode *inode, struct file *file);
-+extern int unionfs_flush(struct file *file, fl_owner_t id);
-+extern long unionfs_ioctl(struct file *file, unsigned int cmd,
-+ unsigned long arg);
-+extern int unionfs_fsync(struct file *file, loff_t start, loff_t end,
-+ int datasync);
-+extern int unionfs_fasync(int fd, struct file *file, int flag);
-+
-+/* Inode operations */
-+extern struct inode *unionfs_iget(struct super_block *sb, unsigned long ino);
-+extern int unionfs_rename(struct inode *old_dir, struct dentry *old_dentry,
-+ struct inode *new_dir, struct dentry *new_dentry);
-+extern int unionfs_unlink(struct inode *dir, struct dentry *dentry);
-+extern int unionfs_rmdir(struct inode *dir, struct dentry *dentry);
-+
-+extern bool __unionfs_d_revalidate(struct dentry *dentry,
-+ struct dentry *parent, bool willwrite);
-+extern bool is_negative_lower(const struct dentry *dentry);
-+extern bool is_newer_lower(const struct dentry *dentry);
-+extern void purge_sb_data(struct super_block *sb);
-+
-+/* The values for unionfs_interpose's flag. */
-+#define INTERPOSE_DEFAULT 0
-+#define INTERPOSE_LOOKUP 1
-+#define INTERPOSE_REVAL 2
-+#define INTERPOSE_REVAL_NEG 3
-+#define INTERPOSE_PARTIAL 4
-+
-+extern struct dentry *unionfs_interpose(struct dentry *this_dentry,
-+ struct super_block *sb, int flag);
-+
-+#ifdef CONFIG_UNION_FS_XATTR
-+/* Extended attribute functions. */
-+extern void *unionfs_xattr_alloc(size_t size, size_t limit);
-+static inline void unionfs_xattr_kfree(const void *p)
-+{
-+ kfree(p);
-+}
-+extern ssize_t unionfs_getxattr(struct dentry *dentry, const char *name,
-+ void *value, size_t size);
-+extern int unionfs_removexattr(struct dentry *dentry, const char *name);
-+extern ssize_t unionfs_listxattr(struct dentry *dentry, char *list,
-+ size_t size);
-+extern int unionfs_setxattr(struct dentry *dentry, const char *name,
-+ const void *value, size_t size, int flags);
-+#endif /* CONFIG_UNION_FS_XATTR */
-+
-+/* The root directory is unhashed, but isn't deleted. */
-+static inline int d_deleted(struct dentry *d)
-+{
-+ return d_unhashed(d) && (d != d->d_sb->s_root);
-+}
-+
-+/* unionfs_permission, check if we should bypass error to facilitate copyup */
-+#define IS_COPYUP_ERR(err) ((err) == -EROFS)
-+
-+/* unionfs_open, check if we need to copyup the file */
-+#define OPEN_WRITE_FLAGS (O_WRONLY | O_RDWR | O_APPEND)
-+#define IS_WRITE_FLAG(flag) ((flag) & OPEN_WRITE_FLAGS)
-+
-+static inline int branchperms(const struct super_block *sb, int index)
-+{
-+ BUG_ON(index < 0);
-+ return UNIONFS_SB(sb)->data[index].branchperms;
-+}
-+
-+static inline int set_branchperms(struct super_block *sb, int index, int perms)
-+{
-+ BUG_ON(index < 0);
-+ UNIONFS_SB(sb)->data[index].branchperms = perms;
-+ return perms;
-+}
-+
-+/* check if readonly lower inode, but possibly unlinked (no inode->i_sb) */
-+static inline int __is_rdonly(const struct inode *inode)
-+{
-+ /* if unlinked, can't be readonly (?) */
-+ if (!inode->i_sb)
-+ return 0;
-+ return IS_RDONLY(inode);
-+
-+}
-+/* Is this file on a read-only branch? */
-+static inline int is_robranch_super(const struct super_block *sb, int index)
-+{
-+ int ret;
-+
-+ ret = (!(branchperms(sb, index) & MAY_WRITE)) ? -EROFS : 0;
-+ return ret;
-+}
-+
-+/* Is this file on a read-only branch? */
-+static inline int is_robranch_idx(const struct dentry *dentry, int index)
-+{
-+ struct super_block *lower_sb;
-+
-+ BUG_ON(index < 0);
-+
-+ if (!(branchperms(dentry->d_sb, index) & MAY_WRITE))
-+ return -EROFS;
-+
-+ lower_sb = unionfs_lower_super_idx(dentry->d_sb, index);
-+ BUG_ON(lower_sb == NULL);
-+ /*
-+ * test sb flags directly, not IS_RDONLY(lower_inode) because the
-+ * lower_dentry could be a negative.
-+ */
-+ if (lower_sb->s_flags & MS_RDONLY)
-+ return -EROFS;
-+
-+ return 0;
-+}
-+
-+static inline int is_robranch(const struct dentry *dentry)
-+{
-+ int index;
-+
-+ index = UNIONFS_D(dentry)->bstart;
-+ BUG_ON(index < 0);
-+
-+ return is_robranch_idx(dentry, index);
-+}
-+
-+/*
-+ * EXTERNALS:
-+ */
-+extern int check_branch(const struct path *path);
-+extern int parse_branch_mode(const char *name, int *perms);
-+
-+/* locking helpers */
-+static inline struct dentry *lock_parent(struct dentry *dentry)
-+{
-+ struct dentry *dir = dget_parent(dentry);
-+ mutex_lock_nested(&dir->d_inode->i_mutex, I_MUTEX_PARENT);
-+ return dir;
-+}
-+static inline struct dentry *lock_parent_wh(struct dentry *dentry)
-+{
-+ struct dentry *dir = dget_parent(dentry);
-+
-+ mutex_lock_nested(&dir->d_inode->i_mutex, UNIONFS_DMUTEX_WHITEOUT);
-+ return dir;
-+}
-+
-+static inline void unlock_dir(struct dentry *dir)
-+{
-+ mutex_unlock(&dir->d_inode->i_mutex);
-+ dput(dir);
-+}
-+
-+/* lock base inode mutex before calling lookup_one_len */
-+static inline struct dentry *lookup_lck_len(const char *name,
-+ struct dentry *base, int len)
-+{
-+ struct dentry *d;
-+ struct nameidata lower_nd;
-+ int err;
-+
-+ err = init_lower_nd(&lower_nd, LOOKUP_OPEN);
-+ if (unlikely(err < 0)) {
-+ d = ERR_PTR(err);
-+ goto out;
-+ }
-+ mutex_lock(&base->d_inode->i_mutex);
-+ d = lookup_one_len_nd(name, base, len, &lower_nd);
-+ release_lower_nd(&lower_nd, err);
-+ mutex_unlock(&base->d_inode->i_mutex);
-+out:
-+ return d;
-+}
-+
-+static inline struct vfsmount *unionfs_mntget(struct dentry *dentry,
-+ int bindex)
-+{
-+ struct vfsmount *mnt;
-+
-+ BUG_ON(!dentry || bindex < 0);
-+
-+ mnt = mntget(unionfs_lower_mnt_idx(dentry, bindex));
-+#ifdef CONFIG_UNION_FS_DEBUG
-+ if (!mnt)
-+ pr_debug("unionfs: mntget: mnt=%p bindex=%d\n",
-+ mnt, bindex);
-+#endif /* CONFIG_UNION_FS_DEBUG */
-+
-+ return mnt;
-+}
-+
-+static inline void unionfs_mntput(struct dentry *dentry, int bindex)
-+{
-+ struct vfsmount *mnt;
-+
-+ if (!dentry && bindex < 0)
-+ return;
-+ BUG_ON(!dentry || bindex < 0);
-+
-+ mnt = unionfs_lower_mnt_idx(dentry, bindex);
-+#ifdef CONFIG_UNION_FS_DEBUG
-+ /*
-+ * Directories can have NULL lower objects in between start/end, but
-+ * NOT if at the start/end range. We cannot verify that this dentry
-+ * is a type=DIR, because it may already be a negative dentry. But
-+ * if dbstart is greater than dbend, we know that this couldn't have
-+ * been a regular file: it had to have been a directory.
-+ */
-+ if (!mnt && !(bindex > dbstart(dentry) && bindex < dbend(dentry)))
-+ pr_debug("unionfs: mntput: mnt=%p bindex=%d\n", mnt, bindex);
-+#endif /* CONFIG_UNION_FS_DEBUG */
-+ mntput(mnt);
-+}
-+
-+#ifdef CONFIG_UNION_FS_DEBUG
-+
-+/* useful for tracking code reachability */
-+#define UDBG pr_debug("DBG:%s:%s:%d\n", __FILE__, __func__, __LINE__)
-+
-+#define unionfs_check_inode(i) __unionfs_check_inode((i), \
-+ __FILE__, __func__, __LINE__)
-+#define unionfs_check_dentry(d) __unionfs_check_dentry((d), \
-+ __FILE__, __func__, __LINE__)
-+#define unionfs_check_file(f) __unionfs_check_file((f), \
-+ __FILE__, __func__, __LINE__)
-+#define unionfs_check_nd(n) __unionfs_check_nd((n), \
-+ __FILE__, __func__, __LINE__)
-+#define show_branch_counts(sb) __show_branch_counts((sb), \
-+ __FILE__, __func__, __LINE__)
-+#define show_inode_times(i) __show_inode_times((i), \
-+ __FILE__, __func__, __LINE__)
-+#define show_dinode_times(d) __show_dinode_times((d), \
-+ __FILE__, __func__, __LINE__)
-+#define show_inode_counts(i) __show_inode_counts((i), \
-+ __FILE__, __func__, __LINE__)
-+
-+extern void __unionfs_check_inode(const struct inode *inode, const char *fname,
-+ const char *fxn, int line);
-+extern void __unionfs_check_dentry(const struct dentry *dentry,
-+ const char *fname, const char *fxn,
-+ int line);
-+extern void __unionfs_check_file(const struct file *file,
-+ const char *fname, const char *fxn, int line);
-+extern void __unionfs_check_nd(const struct nameidata *nd,
-+ const char *fname, const char *fxn, int line);
-+extern void __show_branch_counts(const struct super_block *sb,
-+ const char *file, const char *fxn, int line);
-+extern void __show_inode_times(const struct inode *inode,
-+ const char *file, const char *fxn, int line);
-+extern void __show_dinode_times(const struct dentry *dentry,
-+ const char *file, const char *fxn, int line);
-+extern void __show_inode_counts(const struct inode *inode,
-+ const char *file, const char *fxn, int line);
-+
-+#else /* not CONFIG_UNION_FS_DEBUG */
-+
-+/* we leave useful hooks for these check functions throughout the code */
-+#define unionfs_check_inode(i) do { } while (0)
-+#define unionfs_check_dentry(d) do { } while (0)
-+#define unionfs_check_file(f) do { } while (0)
-+#define unionfs_check_nd(n) do { } while (0)
-+#define show_branch_counts(sb) do { } while (0)
-+#define show_inode_times(i) do { } while (0)
-+#define show_dinode_times(d) do { } while (0)
-+#define show_inode_counts(i) do { } while (0)
-+#define UDBG do { } while (0)
-+
-+#endif /* not CONFIG_UNION_FS_DEBUG */
-+
-+#endif /* not _UNION_H_ */
-diff --git a/fs/unionfs/unlink.c b/fs/unionfs/unlink.c
-new file mode 100644
-index 0000000..25943a5
---- /dev/null
-+++ b/fs/unionfs/unlink.c
-@@ -0,0 +1,278 @@
-+/*
-+ * Copyright (c) 2003-2011 Erez Zadok
-+ * Copyright (c) 2003-2006 Charles P. Wright
-+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2005-2006 Junjiro Okajima
-+ * Copyright (c) 2005 Arun M. Krishnakumar
-+ * Copyright (c) 2004-2006 David P. Quigley
-+ * Copyright (c) 2003-2004 Mohammad Nayyer Zubair
-+ * Copyright (c) 2003 Puja Gupta
-+ * Copyright (c) 2003 Harikesavan Krishnan
-+ * Copyright (c) 2003-2011 Stony Brook University
-+ * Copyright (c) 2003-2011 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#include "union.h"
-+
-+/*
-+ * Helper function for Unionfs's unlink operation.
-+ *
-+ * The main goal of this function is to optimize the unlinking of non-dir
-+ * objects in unionfs by deleting all possible lower inode objects from the
-+ * underlying branches having same dentry name as the non-dir dentry on
-+ * which this unlink operation is called. This way we delete as many lower
-+ * inodes as possible, and save space. Whiteouts need to be created in
-+ * branch0 only if unlinking fails on any of the lower branch other than
-+ * branch0, or if a lower branch is marked read-only.
-+ *
-+ * Also, while unlinking a file, if we encounter any dir type entry in any
-+ * intermediate branch, then we remove the directory by calling vfs_rmdir.
-+ * The following special cases are also handled:
-+
-+ * (1) If an error occurs in branch0 during vfs_unlink, then we return
-+ * appropriate error.
-+ *
-+ * (2) If we get an error during unlink in any of other lower branch other
-+ * than branch0, then we create a whiteout in branch0.
-+ *
-+ * (3) If a whiteout already exists in any intermediate branch, we delete
-+ * all possible inodes only up to that branch (this is an "opaqueness"
-+ * as as per Documentation/filesystems/unionfs/concepts.txt).
-+ *
-+ */
-+static int unionfs_unlink_whiteout(struct inode *dir, struct dentry *dentry,
-+ struct dentry *parent)
-+{
-+ struct dentry *lower_dentry;
-+ struct dentry *lower_dir_dentry;
-+ int bindex;
-+ int err = 0;
-+
-+ err = unionfs_partial_lookup(dentry, parent);
-+ if (err)
-+ goto out;
-+
-+ /* trying to unlink all possible valid instances */
-+ for (bindex = dbstart(dentry); bindex <= dbend(dentry); bindex++) {
-+ lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
-+ if (!lower_dentry || !lower_dentry->d_inode)
-+ continue;
-+
-+ lower_dir_dentry = lock_parent(lower_dentry);
-+
-+ /* avoid destroying the lower inode if the object is in use */
-+ dget(lower_dentry);
-+ err = is_robranch_super(dentry->d_sb, bindex);
-+ if (!err) {
-+ /* see Documentation/filesystems/unionfs/issues.txt */
-+ lockdep_off();
-+ if (!S_ISDIR(lower_dentry->d_inode->i_mode))
-+ err = vfs_unlink(lower_dir_dentry->d_inode,
-+ lower_dentry);
-+ else
-+ err = vfs_rmdir(lower_dir_dentry->d_inode,
-+ lower_dentry);
-+ lockdep_on();
-+ }
-+
-+ /* if lower object deletion succeeds, update inode's times */
-+ if (!err)
-+ unionfs_copy_attr_times(dentry->d_inode);
-+ dput(lower_dentry);
-+ fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
-+ unlock_dir(lower_dir_dentry);
-+
-+ if (err)
-+ break;
-+ }
-+
-+ /*
-+ * Create the whiteout in branch 0 (highest priority) only if (a)
-+ * there was an error in any intermediate branch other than branch 0
-+ * due to failure of vfs_unlink/vfs_rmdir or (b) a branch marked or
-+ * mounted read-only.
-+ */
-+ if (err) {
-+ if ((bindex == 0) ||
-+ ((bindex == dbstart(dentry)) &&
-+ (!IS_COPYUP_ERR(err))))
-+ goto out;
-+ else {
-+ if (!IS_COPYUP_ERR(err))
-+ pr_debug("unionfs: lower object deletion "
-+ "failed in branch:%d\n", bindex);
-+ err = create_whiteout(dentry, sbstart(dentry->d_sb));
-+ }
-+ }
-+
-+out:
-+ if (!err)
-+ inode_dec_link_count(dentry->d_inode);
-+
-+ /* We don't want to leave negative leftover dentries for revalidate. */
-+ if (!err && (dbopaque(dentry) != -1))
-+ update_bstart(dentry);
-+
-+ return err;
-+}
-+
-+int unionfs_unlink(struct inode *dir, struct dentry *dentry)
-+{
-+ int err = 0;
-+ struct inode *inode = dentry->d_inode;
-+ struct dentry *parent;
-+ int valid;
-+
-+ BUG_ON(S_ISDIR(inode->i_mode));
-+ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
-+ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
-+ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+ valid = __unionfs_d_revalidate(dentry, parent, false);
-+ if (unlikely(!valid)) {
-+ err = -ESTALE;
-+ goto out;
-+ }
-+ unionfs_check_dentry(dentry);
-+
-+ err = unionfs_unlink_whiteout(dir, dentry, parent);
-+ /* call d_drop so the system "forgets" about us */
-+ if (!err) {
-+ unionfs_postcopyup_release(dentry);
-+ unionfs_postcopyup_setmnt(parent);
-+ if (inode->i_nlink == 0) /* drop lower inodes */
-+ iput_lowers_all(inode, false);
-+ d_drop(dentry);
-+ /*
-+ * if unlink/whiteout succeeded, parent dir mtime has
-+ * changed
-+ */
-+ unionfs_copy_attr_times(dir);
-+ }
-+
-+out:
-+ if (!err) {
-+ unionfs_check_dentry(dentry);
-+ unionfs_check_inode(dir);
-+ }
-+ unionfs_unlock_dentry(dentry);
-+ unionfs_unlock_parent(dentry, parent);
-+ unionfs_read_unlock(dentry->d_sb);
-+ return err;
-+}
-+
-+static int unionfs_rmdir_first(struct inode *dir, struct dentry *dentry,
-+ struct unionfs_dir_state *namelist)
-+{
-+ int err;
-+ struct dentry *lower_dentry;
-+ struct dentry *lower_dir_dentry = NULL;
-+
-+ /* Here we need to remove whiteout entries. */
-+ err = delete_whiteouts(dentry, dbstart(dentry), namelist);
-+ if (err)
-+ goto out;
-+
-+ lower_dentry = unionfs_lower_dentry(dentry);
-+
-+ lower_dir_dentry = lock_parent(lower_dentry);
-+
-+ /* avoid destroying the lower inode if the file is in use */
-+ dget(lower_dentry);
-+ err = is_robranch(dentry);
-+ if (!err)
-+ err = vfs_rmdir(lower_dir_dentry->d_inode, lower_dentry);
-+ dput(lower_dentry);
-+
-+ fsstack_copy_attr_times(dir, lower_dir_dentry->d_inode);
-+ /* propagate number of hard-links */
-+ set_nlink(dentry->d_inode, unionfs_get_nlinks(dentry->d_inode));
-+
-+out:
-+ if (lower_dir_dentry)
-+ unlock_dir(lower_dir_dentry);
-+ return err;
-+}
-+
-+int unionfs_rmdir(struct inode *dir, struct dentry *dentry)
-+{
-+ int err = 0;
-+ struct unionfs_dir_state *namelist = NULL;
-+ struct dentry *parent;
-+ int dstart, dend;
-+ bool valid;
-+
-+ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
-+ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
-+ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+ valid = __unionfs_d_revalidate(dentry, parent, false);
-+ if (unlikely(!valid)) {
-+ err = -ESTALE;
-+ goto out;
-+ }
-+ unionfs_check_dentry(dentry);
-+
-+ /* check if this unionfs directory is empty or not */
-+ err = check_empty(dentry, parent, &namelist);
-+ if (err)
-+ goto out;
-+
-+ err = unionfs_rmdir_first(dir, dentry, namelist);
-+ dstart = dbstart(dentry);
-+ dend = dbend(dentry);
-+ /*
-+ * We create a whiteout for the directory if there was an error to
-+ * rmdir the first directory entry in the union. Otherwise, we
-+ * create a whiteout only if there is no chance that a lower
-+ * priority branch might also have the same named directory. IOW,
-+ * if there is not another same-named directory at a lower priority
-+ * branch, then we don't need to create a whiteout for it.
-+ */
-+ if (!err) {
-+ if (dstart < dend)
-+ err = create_whiteout(dentry, dstart);
-+ } else {
-+ int new_err;
-+
-+ if (dstart == 0)
-+ goto out;
-+
-+ /* exit if the error returned was NOT -EROFS */
-+ if (!IS_COPYUP_ERR(err))
-+ goto out;
-+
-+ new_err = create_whiteout(dentry, dstart - 1);
-+ if (new_err != -EEXIST)
-+ err = new_err;
-+ }
-+
-+out:
-+ /*
-+ * Drop references to lower dentry/inode so storage space for them
-+ * can be reclaimed. Then, call d_drop so the system "forgets"
-+ * about us.
-+ */
-+ if (!err) {
-+ iput_lowers_all(dentry->d_inode, false);
-+ dput(unionfs_lower_dentry_idx(dentry, dstart));
-+ unionfs_set_lower_dentry_idx(dentry, dstart, NULL);
-+ d_drop(dentry);
-+ /* update our lower vfsmnts, in case a copyup took place */
-+ unionfs_postcopyup_setmnt(dentry);
-+ unionfs_check_dentry(dentry);
-+ unionfs_check_inode(dir);
-+ }
-+
-+ if (namelist)
-+ free_rdstate(namelist);
-+
-+ unionfs_unlock_dentry(dentry);
-+ unionfs_unlock_parent(dentry, parent);
-+ unionfs_read_unlock(dentry->d_sb);
-+ return err;
-+}
-diff --git a/fs/unionfs/whiteout.c b/fs/unionfs/whiteout.c
-new file mode 100644
-index 0000000..582cef2
---- /dev/null
-+++ b/fs/unionfs/whiteout.c
-@@ -0,0 +1,601 @@
-+/*
-+ * Copyright (c) 2003-2011 Erez Zadok
-+ * Copyright (c) 2003-2006 Charles P. Wright
-+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2005-2006 Junjiro Okajima
-+ * Copyright (c) 2005 Arun M. Krishnakumar
-+ * Copyright (c) 2004-2006 David P. Quigley
-+ * Copyright (c) 2003-2004 Mohammad Nayyer Zubair
-+ * Copyright (c) 2003 Puja Gupta
-+ * Copyright (c) 2003 Harikesavan Krishnan
-+ * Copyright (c) 2003-2011 Stony Brook University
-+ * Copyright (c) 2003-2011 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#include "union.h"
-+
-+/*
-+ * whiteout and opaque directory helpers
-+ */
-+
-+/* What do we use for whiteouts. */
-+#define UNIONFS_WHPFX ".wh."
-+#define UNIONFS_WHLEN 4
-+/*
-+ * If a directory contains this file, then it is opaque. We start with the
-+ * .wh. flag so that it is blocked by lookup.
-+ */
-+#define UNIONFS_DIR_OPAQUE_NAME "__dir_opaque"
-+#define UNIONFS_DIR_OPAQUE UNIONFS_WHPFX UNIONFS_DIR_OPAQUE_NAME
-+
-+/* construct whiteout filename */
-+char *alloc_whname(const char *name, int len)
-+{
-+ char *buf;
-+
-+ buf = kmalloc(len + UNIONFS_WHLEN + 1, GFP_KERNEL);
-+ if (unlikely(!buf))
-+ return ERR_PTR(-ENOMEM);
-+
-+ strcpy(buf, UNIONFS_WHPFX);
-+ strlcat(buf, name, len + UNIONFS_WHLEN + 1);
-+
-+ return buf;
-+}
-+
-+/*
-+ * XXX: this can be inline or CPP macro, but is here to keep all whiteout
-+ * code in one place.
-+ */
-+void unionfs_set_max_namelen(long *namelen)
-+{
-+ *namelen -= UNIONFS_WHLEN;
-+}
-+
-+/* check if @namep is a whiteout, update @namep and @namelenp accordingly */
-+bool is_whiteout_name(char **namep, int *namelenp)
-+{
-+ if (*namelenp > UNIONFS_WHLEN &&
-+ !strncmp(*namep, UNIONFS_WHPFX, UNIONFS_WHLEN)) {
-+ *namep += UNIONFS_WHLEN;
-+ *namelenp -= UNIONFS_WHLEN;
-+ return true;
-+ }
-+ return false;
-+}
-+
-+/* is the filename valid == !(whiteout for a file or opaque dir marker) */
-+bool is_validname(const char *name)
-+{
-+ if (!strncmp(name, UNIONFS_WHPFX, UNIONFS_WHLEN))
-+ return false;
-+ if (!strncmp(name, UNIONFS_DIR_OPAQUE_NAME,
-+ sizeof(UNIONFS_DIR_OPAQUE_NAME) - 1))
-+ return false;
-+ return true;
-+}
-+
-+/*
-+ * Look for a whiteout @name in @lower_parent directory. If error, return
-+ * ERR_PTR. Caller must dput() the returned dentry if not an error.
-+ *
-+ * XXX: some callers can reuse the whname allocated buffer to avoid repeated
-+ * free then re-malloc calls. Need to provide a different API for those
-+ * callers.
-+ */
-+struct dentry *lookup_whiteout(const char *name, struct dentry *lower_parent)
-+{
-+ char *whname = NULL;
-+ int err = 0, namelen;
-+ struct dentry *wh_dentry = NULL;
-+
-+ namelen = strlen(name);
-+ whname = alloc_whname(name, namelen);
-+ if (unlikely(IS_ERR(whname))) {
-+ err = PTR_ERR(whname);
-+ goto out;
-+ }
-+
-+ /* check if whiteout exists in this branch: lookup .wh.foo */
-+ wh_dentry = lookup_lck_len(whname, lower_parent, strlen(whname));
-+ if (IS_ERR(wh_dentry)) {
-+ err = PTR_ERR(wh_dentry);
-+ goto out;
-+ }
-+
-+ /* check if negative dentry (ENOENT) */
-+ if (!wh_dentry->d_inode)
-+ goto out;
-+
-+ /* whiteout found: check if valid type */
-+ if (!S_ISREG(wh_dentry->d_inode->i_mode)) {
-+ printk(KERN_ERR "unionfs: invalid whiteout %s entry type %d\n",
-+ whname, wh_dentry->d_inode->i_mode);
-+ dput(wh_dentry);
-+ err = -EIO;
-+ goto out;
-+ }
-+
-+out:
-+ kfree(whname);
-+ if (err)
-+ wh_dentry = ERR_PTR(err);
-+ return wh_dentry;
-+}
-+
-+/* find and return first whiteout in parent directory, else ENOENT */
-+struct dentry *find_first_whiteout(struct dentry *dentry)
-+{
-+ int bindex, bstart, bend;
-+ struct dentry *parent, *lower_parent, *wh_dentry;
-+
-+ parent = dget_parent(dentry);
-+
-+ bstart = dbstart(parent);
-+ bend = dbend(parent);
-+ wh_dentry = ERR_PTR(-ENOENT);
-+
-+ for (bindex = bstart; bindex <= bend; bindex++) {
-+ lower_parent = unionfs_lower_dentry_idx(parent, bindex);
-+ if (!lower_parent)
-+ continue;
-+ wh_dentry = lookup_whiteout(dentry->d_name.name, lower_parent);
-+ if (IS_ERR(wh_dentry))
-+ continue;
-+ if (wh_dentry->d_inode)
-+ break;
-+ dput(wh_dentry);
-+ wh_dentry = ERR_PTR(-ENOENT);
-+ }
-+
-+ dput(parent);
-+
-+ return wh_dentry;
-+}
-+
-+/*
-+ * Unlink a whiteout dentry. Returns 0 or -errno. Caller must hold and
-+ * release dentry reference.
-+ */
-+int unlink_whiteout(struct dentry *wh_dentry)
-+{
-+ int err;
-+ struct dentry *lower_dir_dentry;
-+
-+ /* dget and lock parent dentry */
-+ lower_dir_dentry = lock_parent_wh(wh_dentry);
-+
-+ /* see Documentation/filesystems/unionfs/issues.txt */
-+ lockdep_off();
-+ err = vfs_unlink(lower_dir_dentry->d_inode, wh_dentry);
-+ lockdep_on();
-+ unlock_dir(lower_dir_dentry);
-+
-+ /*
-+ * Whiteouts are special files and should be deleted no matter what
-+ * (as if they never existed), in order to allow this create
-+ * operation to succeed. This is especially important in sticky
-+ * directories: a whiteout may have been created by one user, but
-+ * the newly created file may be created by another user.
-+ * Therefore, in order to maintain Unix semantics, if the vfs_unlink
-+ * above failed, then we have to try to directly unlink the
-+ * whiteout. Note: in the ODF version of unionfs, whiteout are
-+ * handled much more cleanly.
-+ */
-+ if (err == -EPERM) {
-+ struct inode *inode = lower_dir_dentry->d_inode;
-+ err = inode->i_op->unlink(inode, wh_dentry);
-+ }
-+ if (err)
-+ printk(KERN_ERR "unionfs: could not unlink whiteout %s, "
-+ "err = %d\n", wh_dentry->d_name.name, err);
-+
-+ return err;
-+
-+}
-+
-+/*
-+ * Helper function when creating new objects (create, symlink, mknod, etc.).
-+ * Checks to see if there's a whiteout in @lower_dentry's parent directory,
-+ * whose name is taken from @dentry. Then tries to remove that whiteout, if
-+ * found. If <dentry,bindex> is a branch marked readonly, return -EROFS.
-+ * If it finds both a regular file and a whiteout, delete whiteout (this
-+ * should never happen).
-+ *
-+ * Return 0 if no whiteout was found. Return 1 if one was found and
-+ * successfully removed. Therefore a value >= 0 tells the caller that
-+ * @lower_dentry belongs to a good branch to create the new object in).
-+ * Return -ERRNO if an error occurred during whiteout lookup or in trying to
-+ * unlink the whiteout.
-+ */
-+int check_unlink_whiteout(struct dentry *dentry, struct dentry *lower_dentry,
-+ int bindex)
-+{
-+ int err;
-+ struct dentry *wh_dentry = NULL;
-+ struct dentry *lower_dir_dentry = NULL;
-+
-+ /* look for whiteout dentry first */
-+ lower_dir_dentry = dget_parent(lower_dentry);
-+ wh_dentry = lookup_whiteout(dentry->d_name.name, lower_dir_dentry);
-+ dput(lower_dir_dentry);
-+ if (IS_ERR(wh_dentry)) {
-+ err = PTR_ERR(wh_dentry);
-+ goto out;
-+ }
-+
-+ if (!wh_dentry->d_inode) { /* no whiteout exists*/
-+ err = 0;
-+ goto out_dput;
-+ }
-+
-+ /* check if regular file and whiteout were both found */
-+ if (unlikely(lower_dentry->d_inode))
-+ printk(KERN_WARNING "unionfs: removing whiteout; regular "
-+ "file exists in directory %s (branch %d)\n",
-+ lower_dir_dentry->d_name.name, bindex);
-+
-+ /* check if branch is writeable */
-+ err = is_robranch_super(dentry->d_sb, bindex);
-+ if (err)
-+ goto out_dput;
-+
-+ /* .wh.foo has been found, so let's unlink it */
-+ err = unlink_whiteout(wh_dentry);
-+ if (!err)
-+ err = 1; /* a whiteout was found and successfully removed */
-+out_dput:
-+ dput(wh_dentry);
-+out:
-+ return err;
-+}
-+
-+/*
-+ * Pass an unionfs dentry and an index. It will try to create a whiteout
-+ * for the filename in dentry, and will try in branch 'index'. On error,
-+ * it will proceed to a branch to the left.
-+ */
-+int create_whiteout(struct dentry *dentry, int start)
-+{
-+ int bstart, bend, bindex;
-+ struct dentry *lower_dir_dentry;
-+ struct dentry *lower_dentry;
-+ struct dentry *lower_wh_dentry;
-+ struct nameidata nd;
-+ char *name = NULL;
-+ int err = -EINVAL;
-+
-+ verify_locked(dentry);
-+
-+ bstart = dbstart(dentry);
-+ bend = dbend(dentry);
-+
-+ /* create dentry's whiteout equivalent */
-+ name = alloc_whname(dentry->d_name.name, dentry->d_name.len);
-+ if (unlikely(IS_ERR(name))) {
-+ err = PTR_ERR(name);
-+ goto out;
-+ }
-+
-+ for (bindex = start; bindex >= 0; bindex--) {
-+ lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
-+
-+ if (!lower_dentry) {
-+ /*
-+ * if lower dentry is not present, create the
-+ * entire lower dentry directory structure and go
-+ * ahead. Since we want to just create whiteout, we
-+ * only want the parent dentry, and hence get rid of
-+ * this dentry.
-+ */
-+ lower_dentry = create_parents(dentry->d_inode,
-+ dentry,
-+ dentry->d_name.name,
-+ bindex);
-+ if (!lower_dentry || IS_ERR(lower_dentry)) {
-+ int ret = PTR_ERR(lower_dentry);
-+ if (!IS_COPYUP_ERR(ret))
-+ printk(KERN_ERR
-+ "unionfs: create_parents for "
-+ "whiteout failed: bindex=%d "
-+ "err=%d\n", bindex, ret);
-+ continue;
-+ }
-+ }
-+
-+ lower_wh_dentry =
-+ lookup_lck_len(name, lower_dentry->d_parent,
-+ dentry->d_name.len + UNIONFS_WHLEN);
-+ if (IS_ERR(lower_wh_dentry))
-+ continue;
-+
-+ /*
-+ * The whiteout already exists. This used to be impossible,
-+ * but now is possible because of opaqueness.
-+ */
-+ if (lower_wh_dentry->d_inode) {
-+ dput(lower_wh_dentry);
-+ err = 0;
-+ goto out;
-+ }
-+
-+ err = init_lower_nd(&nd, LOOKUP_CREATE);
-+ if (unlikely(err < 0))
-+ goto out;
-+ lower_dir_dentry = lock_parent_wh(lower_wh_dentry);
-+ err = is_robranch_super(dentry->d_sb, bindex);
-+ if (!err)
-+ err = vfs_create(lower_dir_dentry->d_inode,
-+ lower_wh_dentry,
-+ current_umask() & S_IRUGO,
-+ &nd);
-+ unlock_dir(lower_dir_dentry);
-+ dput(lower_wh_dentry);
-+ release_lower_nd(&nd, err);
-+
-+ if (!err || !IS_COPYUP_ERR(err))
-+ break;
-+ }
-+
-+ /* set dbopaque so that lookup will not proceed after this branch */
-+ if (!err)
-+ dbopaque(dentry) = bindex;
-+
-+out:
-+ kfree(name);
-+ return err;
-+}
-+
-+/*
-+ * Delete all of the whiteouts in a given directory for rmdir.
-+ *
-+ * lower directory inode should be locked
-+ */
-+static int do_delete_whiteouts(struct dentry *dentry, int bindex,
-+ struct unionfs_dir_state *namelist)
-+{
-+ int err = 0;
-+ struct dentry *lower_dir_dentry = NULL;
-+ struct dentry *lower_dentry;
-+ char *name = NULL, *p;
-+ struct inode *lower_dir;
-+ int i;
-+ struct list_head *pos;
-+ struct filldir_node *cursor;
-+
-+ /* Find out lower parent dentry */
-+ lower_dir_dentry = unionfs_lower_dentry_idx(dentry, bindex);
-+ BUG_ON(!S_ISDIR(lower_dir_dentry->d_inode->i_mode));
-+ lower_dir = lower_dir_dentry->d_inode;
-+ BUG_ON(!S_ISDIR(lower_dir->i_mode));
-+
-+ err = -ENOMEM;
-+ name = __getname();
-+ if (unlikely(!name))
-+ goto out;
-+ strcpy(name, UNIONFS_WHPFX);
-+ p = name + UNIONFS_WHLEN;
-+
-+ err = 0;
-+ for (i = 0; !err && i < namelist->size; i++) {
-+ list_for_each(pos, &namelist->list[i]) {
-+ cursor =
-+ list_entry(pos, struct filldir_node,
-+ file_list);
-+ /* Only operate on whiteouts in this branch. */
-+ if (cursor->bindex != bindex)
-+ continue;
-+ if (!cursor->whiteout)
-+ continue;
-+
-+ strlcpy(p, cursor->name, PATH_MAX - UNIONFS_WHLEN);
-+ lower_dentry =
-+ lookup_lck_len(name, lower_dir_dentry,
-+ cursor->namelen +
-+ UNIONFS_WHLEN);
-+ if (IS_ERR(lower_dentry)) {
-+ err = PTR_ERR(lower_dentry);
-+ break;
-+ }
-+ if (lower_dentry->d_inode)
-+ err = vfs_unlink(lower_dir, lower_dentry);
-+ dput(lower_dentry);
-+ if (err)
-+ break;
-+ }
-+ }
-+
-+ __putname(name);
-+
-+ /* After all of the removals, we should copy the attributes once. */
-+ fsstack_copy_attr_times(dentry->d_inode, lower_dir_dentry->d_inode);
-+
-+out:
-+ return err;
-+}
-+
-+
-+void __delete_whiteouts(struct work_struct *work)
-+{
-+ struct sioq_args *args = container_of(work, struct sioq_args, work);
-+ struct deletewh_args *d = &args->deletewh;
-+
-+ args->err = do_delete_whiteouts(d->dentry, d->bindex, d->namelist);
-+ complete(&args->comp);
-+}
-+
-+/* delete whiteouts in a dir (for rmdir operation) using sioq if necessary */
-+int delete_whiteouts(struct dentry *dentry, int bindex,
-+ struct unionfs_dir_state *namelist)
-+{
-+ int err;
-+ struct super_block *sb;
-+ struct dentry *lower_dir_dentry;
-+ struct inode *lower_dir;
-+ struct sioq_args args;
-+
-+ sb = dentry->d_sb;
-+
-+ BUG_ON(!S_ISDIR(dentry->d_inode->i_mode));
-+ BUG_ON(bindex < dbstart(dentry));
-+ BUG_ON(bindex > dbend(dentry));
-+ err = is_robranch_super(sb, bindex);
-+ if (err)
-+ goto out;
-+
-+ lower_dir_dentry = unionfs_lower_dentry_idx(dentry, bindex);
-+ BUG_ON(!S_ISDIR(lower_dir_dentry->d_inode->i_mode));
-+ lower_dir = lower_dir_dentry->d_inode;
-+ BUG_ON(!S_ISDIR(lower_dir->i_mode));
-+
-+ if (!inode_permission(lower_dir, MAY_WRITE | MAY_EXEC)) {
-+ err = do_delete_whiteouts(dentry, bindex, namelist);
-+ } else {
-+ args.deletewh.namelist = namelist;
-+ args.deletewh.dentry = dentry;
-+ args.deletewh.bindex = bindex;
-+ run_sioq(__delete_whiteouts, &args);
-+ err = args.err;
-+ }
-+
-+out:
-+ return err;
-+}
-+
-+/****************************************************************************
-+ * Opaque directory helpers *
-+ ****************************************************************************/
-+
-+/*
-+ * is_opaque_dir: returns 0 if it is NOT an opaque dir, 1 if it is, and
-+ * -errno if an error occurred trying to figure this out.
-+ */
-+int is_opaque_dir(struct dentry *dentry, int bindex)
-+{
-+ int err = 0;
-+ struct dentry *lower_dentry;
-+ struct dentry *wh_lower_dentry;
-+ struct inode *lower_inode;
-+ struct sioq_args args;
-+ struct nameidata lower_nd;
-+
-+ lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
-+ lower_inode = lower_dentry->d_inode;
-+
-+ BUG_ON(!S_ISDIR(lower_inode->i_mode));
-+
-+ mutex_lock(&lower_inode->i_mutex);
-+
-+ if (!inode_permission(lower_inode, MAY_EXEC)) {
-+ err = init_lower_nd(&lower_nd, LOOKUP_OPEN);
-+ if (unlikely(err < 0)) {
-+ mutex_unlock(&lower_inode->i_mutex);
-+ goto out;
-+ }
-+ wh_lower_dentry =
-+ lookup_one_len_nd(UNIONFS_DIR_OPAQUE, lower_dentry,
-+ sizeof(UNIONFS_DIR_OPAQUE) - 1,
-+ &lower_nd);
-+ release_lower_nd(&lower_nd, err);
-+ } else {
-+ args.is_opaque.dentry = lower_dentry;
-+ run_sioq(__is_opaque_dir, &args);
-+ wh_lower_dentry = args.ret;
-+ }
-+
-+ mutex_unlock(&lower_inode->i_mutex);
-+
-+ if (IS_ERR(wh_lower_dentry)) {
-+ err = PTR_ERR(wh_lower_dentry);
-+ goto out;
-+ }
-+
-+ /* This is an opaque dir iff wh_lower_dentry is positive */
-+ err = !!wh_lower_dentry->d_inode;
-+
-+ dput(wh_lower_dentry);
-+out:
-+ return err;
-+}
-+
-+void __is_opaque_dir(struct work_struct *work)
-+{
-+ struct sioq_args *args = container_of(work, struct sioq_args, work);
-+ struct nameidata lower_nd;
-+ int err;
-+
-+ err = init_lower_nd(&lower_nd, LOOKUP_OPEN);
-+ if (unlikely(err < 0))
-+ return;
-+ args->ret = lookup_one_len_nd(UNIONFS_DIR_OPAQUE,
-+ args->is_opaque.dentry,
-+ sizeof(UNIONFS_DIR_OPAQUE) - 1,
-+ &lower_nd);
-+ release_lower_nd(&lower_nd, err);
-+ complete(&args->comp);
-+}
-+
-+int make_dir_opaque(struct dentry *dentry, int bindex)
-+{
-+ int err = 0;
-+ struct dentry *lower_dentry, *diropq;
-+ struct inode *lower_dir;
-+ struct nameidata nd;
-+ const struct cred *old_creds;
-+ struct cred *new_creds;
-+
-+ /*
-+ * Opaque directory whiteout markers are special files (like regular
-+ * whiteouts), and should appear to the users as if they don't
-+ * exist. They should be created/deleted regardless of directory
-+ * search/create permissions, but only for the duration of this
-+ * creation of the .wh.__dir_opaque: file. Note, this does not
-+ * circumvent normal ->permission).
-+ */
-+ new_creds = prepare_creds();
-+ if (unlikely(!new_creds)) {
-+ err = -ENOMEM;
-+ goto out_err;
-+ }
-+ cap_raise(new_creds->cap_effective, CAP_DAC_READ_SEARCH);
-+ cap_raise(new_creds->cap_effective, CAP_DAC_OVERRIDE);
-+ old_creds = override_creds(new_creds);
-+
-+ lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
-+ lower_dir = lower_dentry->d_inode;
-+ BUG_ON(!S_ISDIR(dentry->d_inode->i_mode) ||
-+ !S_ISDIR(lower_dir->i_mode));
-+
-+ mutex_lock(&lower_dir->i_mutex);
-+ err = init_lower_nd(&nd, LOOKUP_OPEN);
-+ if (unlikely(err < 0))
-+ goto out;
-+ diropq = lookup_one_len_nd(UNIONFS_DIR_OPAQUE, lower_dentry,
-+ sizeof(UNIONFS_DIR_OPAQUE) - 1, &nd);
-+ release_lower_nd(&nd, err);
-+ if (IS_ERR(diropq)) {
-+ err = PTR_ERR(diropq);
-+ goto out;
-+ }
-+
-+ err = init_lower_nd(&nd, LOOKUP_CREATE);
-+ if (unlikely(err < 0))
-+ goto out;
-+ if (!diropq->d_inode)
-+ err = vfs_create(lower_dir, diropq, S_IRUGO, &nd);
-+ if (!err)
-+ dbopaque(dentry) = bindex;
-+ release_lower_nd(&nd, err);
-+
-+ dput(diropq);
-+
-+out:
-+ mutex_unlock(&lower_dir->i_mutex);
-+ revert_creds(old_creds);
-+out_err:
-+ return err;
-+}
-diff --git a/fs/unionfs/xattr.c b/fs/unionfs/xattr.c
-new file mode 100644
-index 0000000..a93d803
---- /dev/null
-+++ b/fs/unionfs/xattr.c
-@@ -0,0 +1,173 @@
-+/*
-+ * Copyright (c) 2003-2011 Erez Zadok
-+ * Copyright (c) 2003-2006 Charles P. Wright
-+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2005-2006 Junjiro Okajima
-+ * Copyright (c) 2005 Arun M. Krishnakumar
-+ * Copyright (c) 2004-2006 David P. Quigley
-+ * Copyright (c) 2003-2004 Mohammad Nayyer Zubair
-+ * Copyright (c) 2003 Puja Gupta
-+ * Copyright (c) 2003 Harikesavan Krishnan
-+ * Copyright (c) 2003-2011 Stony Brook University
-+ * Copyright (c) 2003-2011 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#include "union.h"
-+
-+/* This is lifted from fs/xattr.c */
-+void *unionfs_xattr_alloc(size_t size, size_t limit)
-+{
-+ void *ptr;
-+
-+ if (size > limit)
-+ return ERR_PTR(-E2BIG);
-+
-+ if (!size) /* size request, no buffer is needed */
-+ return NULL;
-+
-+ ptr = kmalloc(size, GFP_KERNEL);
-+ if (unlikely(!ptr))
-+ return ERR_PTR(-ENOMEM);
-+ return ptr;
-+}
-+
-+/*
-+ * BKL held by caller.
-+ * dentry->d_inode->i_mutex locked
-+ */
-+ssize_t unionfs_getxattr(struct dentry *dentry, const char *name, void *value,
-+ size_t size)
-+{
-+ struct dentry *lower_dentry = NULL;
-+ struct dentry *parent;
-+ int err = -EOPNOTSUPP;
-+ bool valid;
-+
-+ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
-+ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
-+ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+ valid = __unionfs_d_revalidate(dentry, parent, false);
-+ if (unlikely(!valid)) {
-+ err = -ESTALE;
-+ goto out;
-+ }
-+
-+ lower_dentry = unionfs_lower_dentry(dentry);
-+
-+ err = vfs_getxattr(lower_dentry, (char *) name, value, size);
-+
-+out:
-+ unionfs_check_dentry(dentry);
-+ unionfs_unlock_dentry(dentry);
-+ unionfs_unlock_parent(dentry, parent);
-+ unionfs_read_unlock(dentry->d_sb);
-+ return err;
-+}
-+
-+/*
-+ * BKL held by caller.
-+ * dentry->d_inode->i_mutex locked
-+ */
-+int unionfs_setxattr(struct dentry *dentry, const char *name,
-+ const void *value, size_t size, int flags)
-+{
-+ struct dentry *lower_dentry = NULL;
-+ struct dentry *parent;
-+ int err = -EOPNOTSUPP;
-+ bool valid;
-+
-+ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
-+ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
-+ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+ valid = __unionfs_d_revalidate(dentry, parent, false);
-+ if (unlikely(!valid)) {
-+ err = -ESTALE;
-+ goto out;
-+ }
-+
-+ lower_dentry = unionfs_lower_dentry(dentry);
-+
-+ err = vfs_setxattr(lower_dentry, (char *) name, (void *) value,
-+ size, flags);
-+
-+out:
-+ unionfs_check_dentry(dentry);
-+ unionfs_unlock_dentry(dentry);
-+ unionfs_unlock_parent(dentry, parent);
-+ unionfs_read_unlock(dentry->d_sb);
-+ return err;
-+}
-+
-+/*
-+ * BKL held by caller.
-+ * dentry->d_inode->i_mutex locked
-+ */
-+int unionfs_removexattr(struct dentry *dentry, const char *name)
-+{
-+ struct dentry *lower_dentry = NULL;
-+ struct dentry *parent;
-+ int err = -EOPNOTSUPP;
-+ bool valid;
-+
-+ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
-+ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
-+ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+ valid = __unionfs_d_revalidate(dentry, parent, false);
-+ if (unlikely(!valid)) {
-+ err = -ESTALE;
-+ goto out;
-+ }
-+
-+ lower_dentry = unionfs_lower_dentry(dentry);
-+
-+ err = vfs_removexattr(lower_dentry, (char *) name);
-+
-+out:
-+ unionfs_check_dentry(dentry);
-+ unionfs_unlock_dentry(dentry);
-+ unionfs_unlock_parent(dentry, parent);
-+ unionfs_read_unlock(dentry->d_sb);
-+ return err;
-+}
-+
-+/*
-+ * BKL held by caller.
-+ * dentry->d_inode->i_mutex locked
-+ */
-+ssize_t unionfs_listxattr(struct dentry *dentry, char *list, size_t size)
-+{
-+ struct dentry *lower_dentry = NULL;
-+ struct dentry *parent;
-+ int err = -EOPNOTSUPP;
-+ char *encoded_list = NULL;
-+ bool valid;
-+
-+ unionfs_read_lock(dentry->d_sb, UNIONFS_SMUTEX_CHILD);
-+ parent = unionfs_lock_parent(dentry, UNIONFS_DMUTEX_PARENT);
-+ unionfs_lock_dentry(dentry, UNIONFS_DMUTEX_CHILD);
-+
-+ valid = __unionfs_d_revalidate(dentry, parent, false);
-+ if (unlikely(!valid)) {
-+ err = -ESTALE;
-+ goto out;
-+ }
-+
-+ lower_dentry = unionfs_lower_dentry(dentry);
-+
-+ encoded_list = list;
-+ err = vfs_listxattr(lower_dentry, encoded_list, size);
-+
-+out:
-+ unionfs_check_dentry(dentry);
-+ unionfs_unlock_dentry(dentry);
-+ unionfs_unlock_parent(dentry, parent);
-+ unionfs_read_unlock(dentry->d_sb);
-+ return err;
-+}
-diff --git a/include/linux/fs_stack.h b/include/linux/fs_stack.h
-index da317c7..64f1ced 100644
---- a/include/linux/fs_stack.h
-+++ b/include/linux/fs_stack.h
-@@ -1,7 +1,19 @@
-+/*
-+ * Copyright (c) 2006-2009 Erez Zadok
-+ * Copyright (c) 2006-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2006-2009 Stony Brook University
-+ * Copyright (c) 2006-2009 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
- #ifndef _LINUX_FS_STACK_H
- #define _LINUX_FS_STACK_H
-
--/* This file defines generic functions used primarily by stackable
-+/*
-+ * This file defines generic functions used primarily by stackable
- * filesystems; none of these functions require i_mutex to be held.
- */
-
-diff --git a/include/linux/magic.h b/include/linux/magic.h
-index 2d4beab..39f5798 100644
---- a/include/linux/magic.h
-+++ b/include/linux/magic.h
-@@ -50,6 +50,8 @@
- #define REISER2FS_SUPER_MAGIC_STRING "ReIsEr2Fs"
- #define REISER2FS_JR_SUPER_MAGIC_STRING "ReIsEr3Fs"
-
-+#define UNIONFS_SUPER_MAGIC 0xf15f083d
-+
- #define SMB_SUPER_MAGIC 0x517B
- #define USBDEVICE_SUPER_MAGIC 0x9fa2
- #define CGROUP_SUPER_MAGIC 0x27e0eb
-diff --git a/include/linux/namei.h b/include/linux/namei.h
-index ffc0213..99802c3 100644
---- a/include/linux/namei.h
-+++ b/include/linux/namei.h
-@@ -84,8 +84,11 @@ extern int vfs_path_lookup(struct dentry *, struct vfsmount *,
- extern struct dentry *kern_path_locked(const char *, struct path *);
- extern int vfs_path_lookup(struct dentry *, struct vfsmount *,
- const char *, unsigned int, struct path *);
-+extern void release_open_intent(struct nameidata *);
-
- extern struct dentry *lookup_one_len(const char *, struct dentry *, int);
-+extern struct dentry *lookup_one_len_nd(const char *, struct dentry *, int,
-+ struct nameidata *nd);
-
- extern int follow_down_one(struct path *);
- extern int follow_down(struct path *);
-diff --git a/include/linux/splice.h b/include/linux/splice.h
-index 26e5b61..28213e6 100644
---- a/include/linux/splice.h
-+++ b/include/linux/splice.h
-@@ -81,6 +81,11 @@ extern ssize_t splice_to_pipe(struct pipe_inode_info *,
- struct splice_pipe_desc *);
- extern ssize_t splice_direct_to_actor(struct file *, struct splice_desc *,
- splice_direct_actor *);
-+extern long vfs_splice_from(struct pipe_inode_info *pipe, struct file *out,
-+ loff_t *ppos, size_t len, unsigned int flags);
-+extern long vfs_splice_to(struct file *in, loff_t *ppos,
-+ struct pipe_inode_info *pipe, size_t len,
-+ unsigned int flags);
-
- /*
- * for dynamic pipe sizing
-diff --git a/include/linux/union_fs.h b/include/linux/union_fs.h
-new file mode 100644
-index 0000000..c84d97e
---- /dev/null
-+++ b/include/linux/union_fs.h
-@@ -0,0 +1,22 @@
-+/*
-+ * Copyright (c) 2003-2009 Erez Zadok
-+ * Copyright (c) 2005-2007 Josef 'Jeff' Sipek
-+ * Copyright (c) 2003-2009 Stony Brook University
-+ * Copyright (c) 2003-2009 The Research Foundation of SUNY
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#ifndef _LINUX_UNION_FS_H
-+#define _LINUX_UNION_FS_H
-+
-+/*
-+ * DEFINITIONS FOR USER AND KERNEL CODE:
-+ */
-+# define UNIONFS_IOCTL_INCGEN _IOR(0x15, 11, int)
-+# define UNIONFS_IOCTL_QUERYFILE _IOR(0x15, 15, int)
-+
-+#endif /* _LINUX_UNIONFS_H */
-+
-diff --git a/security/security.c b/security/security.c
-index d754249..f7e8373 100644
---- a/security/security.c
-+++ b/security/security.c
-@@ -538,6 +538,7 @@ int security_inode_permission(struct inode *inode, int mask)
- return 0;
- return security_ops->inode_permission(inode, mask);
- }
-+EXPORT_SYMBOL(security_inode_permission);
-
- int security_inode_setattr(struct dentry *dentry, struct iattr *attr)
- {
-
---- linux-3.4/fs/unionfs/commonfops.c.org 2012-05-29 20:40:20.756489877 +0200
-+++ linux-3.4/fs/unionfs/commonfops.c 2012-05-29 21:07:12.021252743 +0200
-@@ -766,7 +766,7 @@
- unsigned int cmd, unsigned long arg)
- {
- int err = 0;
-- fd_set branchlist;
-+ unsigned long branchlist = 0;
- int bstart = 0, bend = 0, bindex = 0;
- int orig_bstart, orig_bend;
- struct dentry *dentry, *lower_dentry;
-@@ -781,14 +781,12 @@
- bstart = dbstart(dentry);
- bend = dbend(dentry);
-
-- FD_ZERO(&branchlist);
--
- for (bindex = bstart; bindex <= bend; bindex++) {
- lower_dentry = unionfs_lower_dentry_idx(dentry, bindex);
- if (!lower_dentry)
- continue;
- if (likely(lower_dentry->d_inode))
-- FD_SET(bindex, &branchlist);
-+ __set_bit(bindex, &branchlist);
- /* purge any lower objects after partial_lookup */
- if (bindex < orig_bstart || bindex > orig_bend) {
- dput(lower_dentry);
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