- up to 2.6.27.10

[packages/kernel.git] / kernel-ext4.patch

Patchset: 2.6.26-ext4-7

This patch was created by combining the ext4-pushed-post-2.6.27-rc1.gz
patches with the stable patches in 2.6.27-rc3-ext4-1 series.

 Documentation/filesystems/ext4.txt |  131 ++-
 fs/buffer.c                        |   19 +-
 fs/ext4/acl.c                      |  188 ++--
 fs/ext4/balloc.c                   |  221 +++--
 fs/ext4/dir.c                      |   37 +-
 fs/ext4/ext4.h                     |   64 +-
 fs/ext4/ext4_extents.h             |    5 +-
 fs/ext4/ext4_i.h                   |   10 +-
 fs/ext4/ext4_jbd2.h                |   29 +-
 fs/ext4/ext4_sb.h                  |    5 +-
 fs/ext4/extents.c                  |  277 +++---
 fs/ext4/file.c                     |   20 +-
 fs/ext4/fsync.c                    |    4 +
 fs/ext4/group.h                    |    2 +-
 fs/ext4/ialloc.c                   |  169 +++-
 fs/ext4/inode.c                    | 1931 ++++++++++++++++++++++++++++++------
 fs/ext4/mballoc.c                  |  744 +++++++++++----
 fs/ext4/mballoc.h                  |   10 +-
 fs/ext4/migrate.c                  |    3 +-
 fs/ext4/namei.c                    |   45 +-
 fs/ext4/resize.c                   |  134 ++-
 fs/ext4/super.c                    |  451 ++++++---
 fs/ext4/xattr.c                    |    4 +-
 fs/ext4/xattr_trusted.c            |    4 +-
 fs/ext4/xattr_user.c               |    4 +-
 fs/jbd2/checkpoint.c               |    1 -
 fs/jbd2/commit.c                   |  308 +++----
 fs/jbd2/journal.c                  |   54 +-
 fs/jbd2/transaction.c              |  365 +++----
 fs/mpage.c                         |   14 +-
 include/linux/fs.h                 |    2 +
 include/linux/jbd2.h               |   73 +-
 include/linux/mpage.h              |   10 +
 include/linux/percpu_counter.h     |   12 +-
 include/linux/writeback.h          |    1 +
 lib/percpu_counter.c               |    7 +-
 mm/filemap.c                       |    3 +-
 mm/page-writeback.c                |    3 +
 38 files changed, 3822 insertions(+), 1542 deletions(-)

diff --git a/Documentation/filesystems/ext4.txt b/Documentation/filesystems/ext4.txt
index 0c5086d..0d53949 100644
--- a/Documentation/filesystems/ext4.txt
+++ b/Documentation/filesystems/ext4.txt
@@ -13,72 +13,99 @@ Mailing list: linux-ext4@vger.kernel.org
 1. Quick usage instructions:
 ===========================
 
-  - Grab updated e2fsprogs from
-    ftp://ftp.kernel.org/pub/linux/kernel/people/tytso/e2fsprogs-interim/
-    This is a patchset on top of e2fsprogs-1.39, which can be found at
+  - Compile and install the latest version of e2fsprogs (as of this
+    writing version 1.41) from:
+
+    http://sourceforge.net/project/showfiles.php?group_id=2406
+	
+	or
+
     ftp://ftp.kernel.org/pub/linux/kernel/people/tytso/e2fsprogs/
 
-  - It's still mke2fs -j /dev/hda1
+	or grab the latest git repository from:
+
+    git://git.kernel.org/pub/scm/fs/ext2/e2fsprogs.git
+
+  - Note that it is highly important to install the mke2fs.conf file
+    that comes with the e2fsprogs 1.41.x sources in /etc/mke2fs.conf. If
+    you have edited the /etc/mke2fs.conf file installed on your system,
+    you will need to merge your changes with the version from e2fsprogs
+    1.41.x.
+
+  - Create a new filesystem using the ext4dev filesystem type:
+
+    	# mke2fs -t ext4dev /dev/hda1
+
+    Or configure an existing ext3 filesystem to support extents and set
+    the test_fs flag to indicate that it's ok for an in-development
+    filesystem to touch this filesystem:
 
-  - mount /dev/hda1 /wherever -t ext4dev
+	# tune2fs -O extents -E test_fs /dev/hda1
 
-  - To enable extents,
+    If the filesystem was created with 128 byte inodes, it can be
+    converted to use 256 byte for greater efficiency via:
 
-	mount /dev/hda1 /wherever -t ext4dev -o extents
+        # tune2fs -I 256 /dev/hda1
 
-  - The filesystem is compatible with the ext3 driver until you add a file
-    which has extents (ie: `mount -o extents', then create a file).
+    (Note: we currently do not have tools to convert an ext4dev
+    filesystem back to ext3; so please do not do try this on production
+    filesystems.)
 
-    NOTE: The "extents" mount flag is temporary.  It will soon go away and
-    extents will be enabled by the "-o extents" flag to mke2fs or tune2fs
+  - Mounting:
+
+	# mount -t ext4dev /dev/hda1 /wherever
 
   - When comparing performance with other filesystems, remember that
-    ext3/4 by default offers higher data integrity guarantees than most.  So
-    when comparing with a metadata-only journalling filesystem, use `mount -o
-    data=writeback'.  And you might as well use `mount -o nobh' too along
-    with it.  Making the journal larger than the mke2fs default often helps
-    performance with metadata-intensive workloads.
+    ext3/4 by default offers higher data integrity guarantees than most.
+    So when comparing with a metadata-only journalling filesystem, such
+    as ext3, use `mount -o data=writeback'.  And you might as well use
+    `mount -o nobh' too along with it.  Making the journal larger than
+    the mke2fs default often helps performance with metadata-intensive
+    workloads.
 
 2. Features
 ===========
 
 2.1 Currently available
 
-* ability to use filesystems > 16TB
+* ability to use filesystems > 16TB (e2fsprogs support not available yet)
 * extent format reduces metadata overhead (RAM, IO for access, transactions)
 * extent format more robust in face of on-disk corruption due to magics,
 * internal redunancy in tree
-
-2.1 Previously available, soon to be enabled by default by "mkefs.ext4":
-
-* dir_index and resize inode will be on by default
-* large inodes will be used by default for fast EAs, nsec timestamps, etc
+* improved file allocation (multi-block alloc)
+* fix 32000 subdirectory limit
+* nsec timestamps for mtime, atime, ctime, create time
+* inode version field on disk (NFSv4, Lustre)
+* reduced e2fsck time via uninit_bg feature
+* journal checksumming for robustness, performance
+* persistent file preallocation (e.g for streaming media, databases)
+* ability to pack bitmaps and inode tables into larger virtual groups via the
+  flex_bg feature
+* large file support
+* Inode allocation using large virtual block groups via flex_bg
+* delayed allocation
+* large block (up to pagesize) support
+* efficent new ordered mode in JBD2 and ext4(avoid using buffer head to force
+  the ordering)
 
 2.2 Candidate features for future inclusion
 
-There are several under discussion, whether they all make it in is
-partly a function of how much time everyone has to work on them:
+* Online defrag (patches available but not well tested)
+* reduced mke2fs time via lazy itable initialization in conjuction with
+  the uninit_bg feature (capability to do this is available in e2fsprogs
+  but a kernel thread to do lazy zeroing of unused inode table blocks
+  after filesystem is first mounted is required for safety)
 
-* improved file allocation (multi-block alloc, delayed alloc; basically done)
-* fix 32000 subdirectory limit (patch exists, needs some e2fsck work)
-* nsec timestamps for mtime, atime, ctime, create time (patch exists,
-  needs some e2fsck work)
-* inode version field on disk (NFSv4, Lustre; prototype exists)
-* reduced mke2fs/e2fsck time via uninitialized groups (prototype exists)
-* journal checksumming for robustness, performance (prototype exists)
-* persistent file preallocation (e.g for streaming media, databases)
+There are several others under discussion, whether they all make it in is
+partly a function of how much time everyone has to work on them. Features like
+metadata checksumming have been discussed and planned for a bit but no patches
+exist yet so I'm not sure they're in the near-term roadmap.
 
-Features like metadata checksumming have been discussed and planned for
-a bit but no patches exist yet so I'm not sure they're in the near-term
-roadmap.
+The big performance win will come with mballoc, delalloc and flex_bg
+grouping of bitmaps and inode tables.  Some test results available here:
 
-The big performance win will come with mballoc and delalloc.  CFS has
-been using mballoc for a few years already with Lustre, and IBM + Bull
-did a lot of benchmarking on it.  The reason it isn't in the first set of
-patches is partly a manageability issue, and partly because it doesn't
-directly affect the on-disk format (outside of much better allocation)
-so it isn't critical to get into the first round of changes.  I believe
-Alex is working on a new set of patches right now.
+ - http://www.bullopensource.org/ext4/20080530/ffsb-write-2.6.26-rc2.html
+ - http://www.bullopensource.org/ext4/20080530/ffsb-readwrite-2.6.26-rc2.html
 
 3. Options
 ==========
@@ -222,9 +249,11 @@ stripe=n		Number of filesystem blocks that mballoc will try
 			to use for allocation size and alignment. For RAID5/6
 			systems this should be the number of data
 			disks *  RAID chunk size in file system blocks.
-
+delalloc	(*)	Deferring block allocation until write-out time.
+nodelalloc		Disable delayed allocation. Blocks are allocation
+			when data is copied from user to page cache.
 Data Mode
----------
+=========
 There are 3 different data modes:
 
 * writeback mode
@@ -236,10 +265,10 @@ typically provide the best ext4 performance.
 
 * ordered mode
 In data=ordered mode, ext4 only officially journals metadata, but it logically
-groups metadata and data blocks into a single unit called a transaction.  When
-it's time to write the new metadata out to disk, the associated data blocks
-are written first.  In general, this mode performs slightly slower than
-writeback but significantly faster than journal mode.
+groups metadata information related to data changes with the data blocks into a
+single unit called a transaction.  When it's time to write the new metadata
+out to disk, the associated data blocks are written first.  In general,
+this mode performs slightly slower than writeback but significantly faster than journal mode.
 
 * journal mode
 data=journal mode provides full data and metadata journaling.  All new data is
@@ -247,7 +276,8 @@ written to the journal first, and then to its final location.
 In the event of a crash, the journal can be replayed, bringing both data and
 metadata into a consistent state.  This mode is the slowest except when data
 needs to be read from and written to disk at the same time where it
-outperforms all others modes.
+outperforms all others modes.  Curently ext4 does not have delayed
+allocation support if this data journalling mode is selected.
 
 References
 ==========
@@ -256,7 +286,8 @@ kernel source:	<file:fs/ext4/>
 		<file:fs/jbd2/>
 
 programs:	http://e2fsprogs.sourceforge.net/
-		http://ext2resize.sourceforge.net
 
 useful links:	http://fedoraproject.org/wiki/ext3-devel
 		http://www.bullopensource.org/ext4/
+		http://ext4.wiki.kernel.org/index.php/Main_Page
+		http://fedoraproject.org/wiki/Features/Ext4
diff --git a/fs/buffer.c b/fs/buffer.c
index 0f51c0f..5fa1512 100644
--- a/fs/buffer.c
+++ b/fs/buffer.c
@@ -1691,11 +1691,13 @@ static int __block_write_full_page(struct inode *inode, struct page *page,
 			 */
 			clear_buffer_dirty(bh);
 			set_buffer_uptodate(bh);
-		} else if (!buffer_mapped(bh) && buffer_dirty(bh)) {
+		} else if ((!buffer_mapped(bh) || buffer_delay(bh)) &&
+			   buffer_dirty(bh)) {
 			WARN_ON(bh->b_size != blocksize);
 			err = get_block(inode, block, bh, 1);
 			if (err)
 				goto recover;
+			clear_buffer_delay(bh);
 			if (buffer_new(bh)) {
 				/* blockdev mappings never come here */
 				clear_buffer_new(bh);
@@ -1774,7 +1776,8 @@ recover:
 	bh = head;
 	/* Recovery: lock and submit the mapped buffers */
 	do {
-		if (buffer_mapped(bh) && buffer_dirty(bh)) {
+		if (buffer_mapped(bh) && buffer_dirty(bh) &&
+		    !buffer_delay(bh)) {
 			lock_buffer(bh);
 			mark_buffer_async_write(bh);
 		} else {
@@ -2061,6 +2064,7 @@ int generic_write_end(struct file *file, struct address_space *mapping,
 			struct page *page, void *fsdata)
 {
 	struct inode *inode = mapping->host;
+	int i_size_changed = 0;
 
 	copied = block_write_end(file, mapping, pos, len, copied, page, fsdata);
 
@@ -2073,12 +2077,21 @@ int generic_write_end(struct file *file, struct address_space *mapping,
 	 */
 	if (pos+copied > inode->i_size) {
 		i_size_write(inode, pos+copied);
-		mark_inode_dirty(inode);
+		i_size_changed = 1;
 	}
 
 	unlock_page(page);
 	page_cache_release(page);
 
+	/*
+	 * Don't mark the inode dirty under page lock. First, it unnecessarily
+	 * makes the holding time of page lock longer. Second, it forces lock
+	 * ordering of page lock and transaction start for journaling
+	 * filesystems.
+	 */
+	if (i_size_changed)
+		mark_inode_dirty(inode);
+
 	return copied;
 }
 EXPORT_SYMBOL(generic_write_end);
diff --git a/fs/ext4/acl.c b/fs/ext4/acl.c
index 3c8dab8..a234b54 100644
--- a/fs/ext4/acl.c
+++ b/fs/ext4/acl.c
@@ -40,34 +40,35 @@ ext4_acl_from_disk(const void *value, size_t size)
 	acl = posix_acl_alloc(count, GFP_NOFS);
 	if (!acl)
 		return ERR_PTR(-ENOMEM);
-	for (n=0; n < count; n++) {
+	for (n = 0; n < count; n++) {
 		ext4_acl_entry *entry =
 			(ext4_acl_entry *)value;
 		if ((char *)value + sizeof(ext4_acl_entry_short) > end)
 			goto fail;
 		acl->a_entries[n].e_tag  = le16_to_cpu(entry->e_tag);
 		acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm);
-		switch(acl->a_entries[n].e_tag) {
-			case ACL_USER_OBJ:
-			case ACL_GROUP_OBJ:
-			case ACL_MASK:
-			case ACL_OTHER:
-				value = (char *)value +
-					sizeof(ext4_acl_entry_short);
-				acl->a_entries[n].e_id = ACL_UNDEFINED_ID;
-				break;
-
-			case ACL_USER:
-			case ACL_GROUP:
-				value = (char *)value + sizeof(ext4_acl_entry);
-				if ((char *)value > end)
-					goto fail;
-				acl->a_entries[n].e_id =
-					le32_to_cpu(entry->e_id);
-				break;
-
-			default:
+
+		switch (acl->a_entries[n].e_tag) {
+		case ACL_USER_OBJ:
+		case ACL_GROUP_OBJ:
+		case ACL_MASK:
+		case ACL_OTHER:
+			value = (char *)value +
+				sizeof(ext4_acl_entry_short);
+			acl->a_entries[n].e_id = ACL_UNDEFINED_ID;
+			break;
+
+		case ACL_USER:
+		case ACL_GROUP:
+			value = (char *)value + sizeof(ext4_acl_entry);
+			if ((char *)value > end)
 				goto fail;
+			acl->a_entries[n].e_id =
+				le32_to_cpu(entry->e_id);
+			break;
+
+		default:
+			goto fail;
 		}
 	}
 	if (value != end)
@@ -96,27 +97,26 @@ ext4_acl_to_disk(const struct posix_acl *acl, size_t *size)
 		return ERR_PTR(-ENOMEM);
 	ext_acl->a_version = cpu_to_le32(EXT4_ACL_VERSION);
 	e = (char *)ext_acl + sizeof(ext4_acl_header);
-	for (n=0; n < acl->a_count; n++) {
+	for (n = 0; n < acl->a_count; n++) {
 		ext4_acl_entry *entry = (ext4_acl_entry *)e;
 		entry->e_tag  = cpu_to_le16(acl->a_entries[n].e_tag);
 		entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm);
-		switch(acl->a_entries[n].e_tag) {
-			case ACL_USER:
-			case ACL_GROUP:
-				entry->e_id =
-					cpu_to_le32(acl->a_entries[n].e_id);
-				e += sizeof(ext4_acl_entry);
-				break;
-
-			case ACL_USER_OBJ:
-			case ACL_GROUP_OBJ:
-			case ACL_MASK:
-			case ACL_OTHER:
-				e += sizeof(ext4_acl_entry_short);
-				break;
-
-			default:
-				goto fail;
+		switch (acl->a_entries[n].e_tag) {
+		case ACL_USER:
+		case ACL_GROUP:
+			entry->e_id = cpu_to_le32(acl->a_entries[n].e_id);
+			e += sizeof(ext4_acl_entry);
+			break;
+
+		case ACL_USER_OBJ:
+		case ACL_GROUP_OBJ:
+		case ACL_MASK:
+		case ACL_OTHER:
+			e += sizeof(ext4_acl_entry_short);
+			break;
+
+		default:
+			goto fail;
 		}
 	}
 	return (char *)ext_acl;
@@ -167,23 +167,23 @@ ext4_get_acl(struct inode *inode, int type)
 	if (!test_opt(inode->i_sb, POSIX_ACL))
 		return NULL;
 
-	switch(type) {
-		case ACL_TYPE_ACCESS:
-			acl = ext4_iget_acl(inode, &ei->i_acl);
-			if (acl != EXT4_ACL_NOT_CACHED)
-				return acl;
-			name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
-			break;
-
-		case ACL_TYPE_DEFAULT:
-			acl = ext4_iget_acl(inode, &ei->i_default_acl);
-			if (acl != EXT4_ACL_NOT_CACHED)
-				return acl;
-			name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
-			break;
-
-		default:
-			return ERR_PTR(-EINVAL);
+	switch (type) {
+	case ACL_TYPE_ACCESS:
+		acl = ext4_iget_acl(inode, &ei->i_acl);
+		if (acl != EXT4_ACL_NOT_CACHED)
+			return acl;
+		name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
+		break;
+
+	case ACL_TYPE_DEFAULT:
+		acl = ext4_iget_acl(inode, &ei->i_default_acl);
+		if (acl != EXT4_ACL_NOT_CACHED)
+			return acl;
+		name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
+		break;
+
+	default:
+		return ERR_PTR(-EINVAL);
 	}
 	retval = ext4_xattr_get(inode, name_index, "", NULL, 0);
 	if (retval > 0) {
@@ -201,14 +201,14 @@ ext4_get_acl(struct inode *inode, int type)
 	kfree(value);
 
 	if (!IS_ERR(acl)) {
-		switch(type) {
-			case ACL_TYPE_ACCESS:
-				ext4_iset_acl(inode, &ei->i_acl, acl);
-				break;
-
-			case ACL_TYPE_DEFAULT:
-				ext4_iset_acl(inode, &ei->i_default_acl, acl);
-				break;
+		switch (type) {
+		case ACL_TYPE_ACCESS:
+			ext4_iset_acl(inode, &ei->i_acl, acl);
+			break;
+
+		case ACL_TYPE_DEFAULT:
+			ext4_iset_acl(inode, &ei->i_default_acl, acl);
+			break;
 		}
 	}
 	return acl;
@@ -232,31 +232,31 @@ ext4_set_acl(handle_t *handle, struct inode *inode, int type,
 	if (S_ISLNK(inode->i_mode))
 		return -EOPNOTSUPP;
 
-	switch(type) {
-		case ACL_TYPE_ACCESS:
-			name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
-			if (acl) {
-				mode_t mode = inode->i_mode;
-				error = posix_acl_equiv_mode(acl, &mode);
-				if (error < 0)
-					return error;
-				else {
-					inode->i_mode = mode;
-					ext4_mark_inode_dirty(handle, inode);
-					if (error == 0)
-						acl = NULL;
-				}
+	switch (type) {
+	case ACL_TYPE_ACCESS:
+		name_index = EXT4_XATTR_INDEX_POSIX_ACL_ACCESS;
+		if (acl) {
+			mode_t mode = inode->i_mode;
+			error = posix_acl_equiv_mode(acl, &mode);
+			if (error < 0)
+				return error;
+			else {
+				inode->i_mode = mode;
+				ext4_mark_inode_dirty(handle, inode);
+				if (error == 0)
+					acl = NULL;
 			}
-			break;
+		}
+		break;
 
-		case ACL_TYPE_DEFAULT:
-			name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
-			if (!S_ISDIR(inode->i_mode))
-				return acl ? -EACCES : 0;
-			break;
+	case ACL_TYPE_DEFAULT:
+		name_index = EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT;
+		if (!S_ISDIR(inode->i_mode))
+			return acl ? -EACCES : 0;
+		break;
 
-		default:
-			return -EINVAL;
+	default:
+		return -EINVAL;
 	}
 	if (acl) {
 		value = ext4_acl_to_disk(acl, &size);
@@ -269,14 +269,14 @@ ext4_set_acl(handle_t *handle, struct inode *inode, int type,
 
 	kfree(value);
 	if (!error) {
-		switch(type) {
-			case ACL_TYPE_ACCESS:
-				ext4_iset_acl(inode, &ei->i_acl, acl);
-				break;
-
-			case ACL_TYPE_DEFAULT:
-				ext4_iset_acl(inode, &ei->i_default_acl, acl);
-				break;
+		switch (type) {
+		case ACL_TYPE_ACCESS:
+			ext4_iset_acl(inode, &ei->i_acl, acl);
+			break;
+
+		case ACL_TYPE_DEFAULT:
+			ext4_iset_acl(inode, &ei->i_default_acl, acl);
+			break;
 		}
 	}
 	return error;
diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
index 9cc80b9..e9fa960 100644
--- a/fs/ext4/balloc.c
+++ b/fs/ext4/balloc.c
@@ -47,7 +47,7 @@ static int ext4_block_in_group(struct super_block *sb, ext4_fsblk_t block,
 			ext4_group_t block_group)
 {
 	ext4_group_t actual_group;
-	ext4_get_group_no_and_offset(sb, block, &actual_group, 0);
+	ext4_get_group_no_and_offset(sb, block, &actual_group, NULL);
 	if (actual_group == block_group)
 		return 1;
 	return 0;
@@ -121,12 +121,7 @@ unsigned ext4_init_block_bitmap(struct super_block *sb, struct buffer_head *bh,
 				le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks);
 		}
 	} else { /* For META_BG_BLOCK_GROUPS */
-		int group_rel = (block_group -
-				 le32_to_cpu(sbi->s_es->s_first_meta_bg)) %
-				EXT4_DESC_PER_BLOCK(sb);
-		if (group_rel == 0 || group_rel == 1 ||
-		    (group_rel == EXT4_DESC_PER_BLOCK(sb) - 1))
-			bit_max += 1;
+		bit_max += ext4_bg_num_gdb(sb, block_group);
 	}
 
 	if (block_group == sbi->s_groups_count - 1) {
@@ -295,7 +290,7 @@ err_out:
 	return 0;
 }
 /**
- * read_block_bitmap()
+ * ext4_read_block_bitmap()
  * @sb:			super block
  * @block_group:	given block group
  *
@@ -305,7 +300,7 @@ err_out:
  * Return buffer_head on success or NULL in case of failure.
  */
 struct buffer_head *
-read_block_bitmap(struct super_block *sb, ext4_group_t block_group)
+ext4_read_block_bitmap(struct super_block *sb, ext4_group_t block_group)
 {
 	struct ext4_group_desc * desc;
 	struct buffer_head * bh = NULL;
@@ -319,25 +314,28 @@ read_block_bitmap(struct super_block *sb, ext4_group_t block_group)
 	if (unlikely(!bh)) {
 		ext4_error(sb, __func__,
 			    "Cannot read block bitmap - "
-			    "block_group = %d, block_bitmap = %llu",
-			    (int)block_group, (unsigned long long)bitmap_blk);
+			    "block_group = %lu, block_bitmap = %llu",
+			    block_group, bitmap_blk);
 		return NULL;
 	}
 	if (bh_uptodate_or_lock(bh))
 		return bh;
 
+	spin_lock(sb_bgl_lock(EXT4_SB(sb), block_group));
 	if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
 		ext4_init_block_bitmap(sb, bh, block_group, desc);
 		set_buffer_uptodate(bh);
 		unlock_buffer(bh);
+		spin_unlock(sb_bgl_lock(EXT4_SB(sb), block_group));
 		return bh;
 	}
+	spin_unlock(sb_bgl_lock(EXT4_SB(sb), block_group));
 	if (bh_submit_read(bh) < 0) {
 		put_bh(bh);
 		ext4_error(sb, __func__,
 			    "Cannot read block bitmap - "
-			    "block_group = %d, block_bitmap = %llu",
-			    (int)block_group, (unsigned long long)bitmap_blk);
+			    "block_group = %lu, block_bitmap = %llu",
+			    block_group, bitmap_blk);
 		return NULL;
 	}
 	ext4_valid_block_bitmap(sb, desc, block_group, bh);
@@ -409,8 +407,7 @@ restart:
 		prev = rsv;
 	}
 	printk("Window map complete.\n");
-	if (bad)
-		BUG();
+	BUG_ON(bad);
 }
 #define rsv_window_dump(root, verbose) \
 	__rsv_window_dump((root), (verbose), __func__)
@@ -694,7 +691,7 @@ do_more:
 		count -= overflow;
 	}
 	brelse(bitmap_bh);
-	bitmap_bh = read_block_bitmap(sb, block_group);
+	bitmap_bh = ext4_read_block_bitmap(sb, block_group);
 	if (!bitmap_bh)
 		goto error_return;
 	desc = ext4_get_group_desc (sb, block_group, &gd_bh);
@@ -810,6 +807,13 @@ do_more:
 	spin_unlock(sb_bgl_lock(sbi, block_group));
 	percpu_counter_add(&sbi->s_freeblocks_counter, count);
 
+	if (sbi->s_log_groups_per_flex) {
+		ext4_group_t flex_group = ext4_flex_group(sbi, block_group);
+		spin_lock(sb_bgl_lock(sbi, flex_group));
+		sbi->s_flex_groups[flex_group].free_blocks += count;
+		spin_unlock(sb_bgl_lock(sbi, flex_group));
+	}
+
 	/* We dirtied the bitmap block */
 	BUFFER_TRACE(bitmap_bh, "dirtied bitmap block");
 	err = ext4_journal_dirty_metadata(handle, bitmap_bh);
@@ -1598,23 +1602,38 @@ out:
 
 /**
  * ext4_has_free_blocks()
- * @sbi:		in-core super block structure.
+ * @sbi:	in-core super block structure.
+ * @nblocks:	number of neeed blocks
  *
- * Check if filesystem has at least 1 free block available for allocation.
+ * Check if filesystem has free blocks available for allocation.
+ * Return the number of blocks avaible for allocation for this request
+ * On success, return nblocks
  */
-static int ext4_has_free_blocks(struct ext4_sb_info *sbi)
+ext4_fsblk_t ext4_has_free_blocks(struct ext4_sb_info *sbi,
+						ext4_fsblk_t nblocks)
 {
-	ext4_fsblk_t free_blocks, root_blocks;
+	ext4_fsblk_t free_blocks;
+	ext4_fsblk_t root_blocks = 0;
 
 	free_blocks = percpu_counter_read_positive(&sbi->s_freeblocks_counter);
-	root_blocks = ext4_r_blocks_count(sbi->s_es);
-	if (free_blocks < root_blocks + 1 && !capable(CAP_SYS_RESOURCE) &&
+
+	if (!capable(CAP_SYS_RESOURCE) &&
 		sbi->s_resuid != current->fsuid &&
-		(sbi->s_resgid == 0 || !in_group_p (sbi->s_resgid))) {
+		(sbi->s_resgid == 0 || !in_group_p(sbi->s_resgid)))
+		root_blocks = ext4_r_blocks_count(sbi->s_es);
+#ifdef CONFIG_SMP
+	if (free_blocks - root_blocks < FBC_BATCH)
+		free_blocks =
+			percpu_counter_sum_and_set(&sbi->s_freeblocks_counter);
+#endif
+	if (free_blocks <= root_blocks)
+		/* we don't have free space */
 		return 0;
-	}
-	return 1;
-}
+	if (free_blocks - root_blocks < nblocks)
+		return free_blocks - root_blocks;
+	return nblocks;
+ }
+
 
 /**
  * ext4_should_retry_alloc()
@@ -1630,7 +1649,7 @@ static int ext4_has_free_blocks(struct ext4_sb_info *sbi)
  */
 int ext4_should_retry_alloc(struct super_block *sb, int *retries)
 {
-	if (!ext4_has_free_blocks(EXT4_SB(sb)) || (*retries)++ > 3)
+	if (!ext4_has_free_blocks(EXT4_SB(sb), 1) || (*retries)++ > 3)
 		return 0;
 
 	jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id);
@@ -1639,20 +1658,24 @@ int ext4_should_retry_alloc(struct super_block *sb, int *retries)
 }
 
 /**
- * ext4_new_blocks_old() -- core block(s) allocation function
+ * ext4_old_new_blocks() -- core block bitmap based block allocation function
+ *
  * @handle:		handle to this transaction
  * @inode:		file inode
  * @goal:		given target block(filesystem wide)
  * @count:		target number of blocks to allocate
  * @errp:		error code
  *
- * ext4_new_blocks uses a goal block to assist allocation.  It tries to
- * allocate block(s) from the block group contains the goal block first. If that
- * fails, it will try to allocate block(s) from other block groups without
- * any specific goal block.
+ * ext4_old_new_blocks uses a goal block to assist allocation and look up
+ * the block bitmap directly to do block allocation.  It tries to
+ * allocate block(s) from the block group contains the goal block first. If
+ * that fails, it will try to allocate block(s) from other block groups
+ * without any specific goal block.
+ *
+ * This function is called when -o nomballoc mount option is enabled
  *
  */
-ext4_fsblk_t ext4_new_blocks_old(handle_t *handle, struct inode *inode,
+ext4_fsblk_t ext4_old_new_blocks(handle_t *handle, struct inode *inode,
 			ext4_fsblk_t goal, unsigned long *count, int *errp)
 {
 	struct buffer_head *bitmap_bh = NULL;
@@ -1676,13 +1699,26 @@ ext4_fsblk_t ext4_new_blocks_old(handle_t *handle, struct inode *inode,
 	ext4_group_t ngroups;
 	unsigned long num = *count;
 
-	*errp = -ENOSPC;
 	sb = inode->i_sb;
 	if (!sb) {
+		*errp = -ENODEV;
 		printk("ext4_new_block: nonexistent device");
 		return 0;
 	}
 
+	sbi = EXT4_SB(sb);
+	if (!EXT4_I(inode)->i_delalloc_reserved_flag) {
+		/*
+		 * With delalloc we already reserved the blocks
+		 */
+		*count = ext4_has_free_blocks(sbi, *count);
+	}
+	if (*count == 0) {
+		*errp = -ENOSPC;
+		return 0;	/*return with ENOSPC error */
+	}
+	num = *count;
+
 	/*
 	 * Check quota for allocation of this block.
 	 */
@@ -1706,11 +1742,6 @@ ext4_fsblk_t ext4_new_blocks_old(handle_t *handle, struct inode *inode,
 	if (block_i && ((windowsz = block_i->rsv_window_node.rsv_goal_size) > 0))
 		my_rsv = &block_i->rsv_window_node;
 
-	if (!ext4_has_free_blocks(sbi)) {
-		*errp = -ENOSPC;
-		goto out;
-	}
-
 	/*
 	 * First, test whether the goal block is free.
 	 */
@@ -1734,7 +1765,7 @@ retry_alloc:
 		my_rsv = NULL;
 
 	if (free_blocks > 0) {
-		bitmap_bh = read_block_bitmap(sb, group_no);
+		bitmap_bh = ext4_read_block_bitmap(sb, group_no);
 		if (!bitmap_bh)
 			goto io_error;
 		grp_alloc_blk = ext4_try_to_allocate_with_rsv(sb, handle,
@@ -1770,7 +1801,7 @@ retry_alloc:
 			continue;
 
 		brelse(bitmap_bh);
-		bitmap_bh = read_block_bitmap(sb, group_no);
+		bitmap_bh = ext4_read_block_bitmap(sb, group_no);
 		if (!bitmap_bh)
 			goto io_error;
 		/*
@@ -1882,7 +1913,15 @@ allocated:
 	le16_add_cpu(&gdp->bg_free_blocks_count, -num);
 	gdp->bg_checksum = ext4_group_desc_csum(sbi, group_no, gdp);
 	spin_unlock(sb_bgl_lock(sbi, group_no));
-	percpu_counter_sub(&sbi->s_freeblocks_counter, num);
+	if (!EXT4_I(inode)->i_delalloc_reserved_flag)
+		percpu_counter_sub(&sbi->s_freeblocks_counter, num);
+
+	if (sbi->s_log_groups_per_flex) {
+		ext4_group_t flex_group = ext4_flex_group(sbi, group_no);
+		spin_lock(sb_bgl_lock(sbi, flex_group));
+		sbi->s_flex_groups[flex_group].free_blocks -= num;
+		spin_unlock(sb_bgl_lock(sbi, flex_group));
+	}
 
 	BUFFER_TRACE(gdp_bh, "journal_dirty_metadata for group descriptor");
 	err = ext4_journal_dirty_metadata(handle, gdp_bh);
@@ -1915,46 +1954,104 @@ out:
 	return 0;
 }
 
-ext4_fsblk_t ext4_new_block(handle_t *handle, struct inode *inode,
-		ext4_fsblk_t goal, int *errp)
+#define EXT4_META_BLOCK 0x1
+
+static ext4_fsblk_t do_blk_alloc(handle_t *handle, struct inode *inode,
+				ext4_lblk_t iblock, ext4_fsblk_t goal,
+				unsigned long *count, int *errp, int flags)
 {
 	struct ext4_allocation_request ar;
 	ext4_fsblk_t ret;
 
 	if (!test_opt(inode->i_sb, MBALLOC)) {
-		unsigned long count = 1;
-		ret = ext4_new_blocks_old(handle, inode, goal, &count, errp);
-		return ret;
+		return ext4_old_new_blocks(handle, inode, goal, count, errp);
 	}
 
 	memset(&ar, 0, sizeof(ar));
+	/* Fill with neighbour allocated blocks */
+
 	ar.inode = inode;
 	ar.goal = goal;
-	ar.len = 1;
+	ar.len = *count;
+	ar.logical = iblock;
+
+	if (S_ISREG(inode->i_mode) && !(flags & EXT4_META_BLOCK))
+		/* enable in-core preallocation for data block allocation */
+		ar.flags = EXT4_MB_HINT_DATA;
+	else
+		/* disable in-core preallocation for non-regular files */
+		ar.flags = 0;
+
 	ret = ext4_mb_new_blocks(handle, &ar, errp);
+	*count = ar.len;
 	return ret;
 }
 
-ext4_fsblk_t ext4_new_blocks(handle_t *handle, struct inode *inode,
+/*
+ * ext4_new_meta_blocks() -- allocate block for meta data (indexing) blocks
+ *
+ * @handle:             handle to this transaction
+ * @inode:              file inode
+ * @goal:               given target block(filesystem wide)
+ * @count:		total number of blocks need
+ * @errp:               error code
+ *
+ * Return 1st allocated block numberon success, *count stores total account
+ * error stores in errp pointer
+ */
+ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode,
 		ext4_fsblk_t goal, unsigned long *count, int *errp)
 {
-	struct ext4_allocation_request ar;
 	ext4_fsblk_t ret;
-
-	if (!test_opt(inode->i_sb, MBALLOC)) {
-		ret = ext4_new_blocks_old(handle, inode, goal, count, errp);
-		return ret;
+	ret = do_blk_alloc(handle, inode, 0, goal,
+				count, errp, EXT4_META_BLOCK);
+	/*
+	 * Account for the allocated meta blocks
+	 */
+	if (!(*errp)) {
+		spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
+		EXT4_I(inode)->i_allocated_meta_blocks += *count;
+		spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
 	}
-
-	memset(&ar, 0, sizeof(ar));
-	ar.inode = inode;
-	ar.goal = goal;
-	ar.len = *count;
-	ret = ext4_mb_new_blocks(handle, &ar, errp);
-	*count = ar.len;
 	return ret;
 }
 
+/*
+ * ext4_new_meta_block() -- allocate block for meta data (indexing) blocks
+ *
+ * @handle:             handle to this transaction
+ * @inode:              file inode
+ * @goal:               given target block(filesystem wide)
+ * @errp:               error code
+ *
+ * Return allocated block number on success
+ */
+ext4_fsblk_t ext4_new_meta_block(handle_t *handle, struct inode *inode,
+		ext4_fsblk_t goal, int *errp)
+{
+	unsigned long count = 1;
+	return ext4_new_meta_blocks(handle, inode, goal, &count, errp);
+}
+
+/*
+ * ext4_new_blocks() -- allocate data blocks
+ *
+ * @handle:             handle to this transaction
+ * @inode:              file inode
+ * @goal:               given target block(filesystem wide)
+ * @count:		total number of blocks need
+ * @errp:               error code
+ *
+ * Return 1st allocated block numberon success, *count stores total account
+ * error stores in errp pointer
+ */
+
+ext4_fsblk_t ext4_new_blocks(handle_t *handle, struct inode *inode,
+				ext4_lblk_t iblock, ext4_fsblk_t goal,
+				unsigned long *count, int *errp)
+{
+	return do_blk_alloc(handle, inode, iblock, goal, count, errp, 0);
+}
 
 /**
  * ext4_count_free_blocks() -- count filesystem free blocks
@@ -1986,7 +2083,7 @@ ext4_fsblk_t ext4_count_free_blocks(struct super_block *sb)
 			continue;
 		desc_count += le16_to_cpu(gdp->bg_free_blocks_count);
 		brelse(bitmap_bh);
-		bitmap_bh = read_block_bitmap(sb, i);
+		bitmap_bh = ext4_read_block_bitmap(sb, i);
 		if (bitmap_bh == NULL)
 			continue;
 
diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c
index 2bf0331..ec8e33b 100644
--- a/fs/ext4/dir.c
+++ b/fs/ext4/dir.c
@@ -129,7 +129,8 @@ static int ext4_readdir(struct file * filp,
 		struct buffer_head *bh = NULL;
 
 		map_bh.b_state = 0;
-		err = ext4_get_blocks_wrap(NULL, inode, blk, 1, &map_bh, 0, 0);
+		err = ext4_get_blocks_wrap(NULL, inode, blk, 1, &map_bh,
+						0, 0, 0);
 		if (err > 0) {
 			pgoff_t index = map_bh.b_blocknr >>
 					(PAGE_CACHE_SHIFT - inode->i_blkbits);
@@ -272,7 +273,7 @@ static void free_rb_tree_fname(struct rb_root *root)
 
 	while (n) {
 		/* Do the node's children first */
-		if ((n)->rb_left) {
+		if (n->rb_left) {
 			n = n->rb_left;
 			continue;
 		}
@@ -301,24 +302,18 @@ static void free_rb_tree_fname(struct rb_root *root)
 			parent->rb_right = NULL;
 		n = parent;
 	}
-	root->rb_node = NULL;
 }
 
 
-static struct dir_private_info *create_dir_info(loff_t pos)
+static struct dir_private_info *ext4_htree_create_dir_info(loff_t pos)
 {
 	struct dir_private_info *p;
 
-	p = kmalloc(sizeof(struct dir_private_info), GFP_KERNEL);
+	p = kzalloc(sizeof(struct dir_private_info), GFP_KERNEL);
 	if (!p)
 		return NULL;
-	p->root.rb_node = NULL;
-	p->curr_node = NULL;
-	p->extra_fname = NULL;
-	p->last_pos = 0;
 	p->curr_hash = pos2maj_hash(pos);
 	p->curr_minor_hash = pos2min_hash(pos);
-	p->next_hash = 0;
 	return p;
 }
 
@@ -416,7 +411,7 @@ static int call_filldir(struct file * filp, void * dirent,
 				get_dtype(sb, fname->file_type));
 		if (error) {
 			filp->f_pos = curr_pos;
-			info->extra_fname = fname->next;
+			info->extra_fname = fname;
 			return error;
 		}
 		fname = fname->next;
@@ -433,7 +428,7 @@ static int ext4_dx_readdir(struct file * filp,
 	int	ret;
 
 	if (!info) {
-		info = create_dir_info(filp->f_pos);
+		info = ext4_htree_create_dir_info(filp->f_pos);
 		if (!info)
 			return -ENOMEM;
 		filp->private_data = info;
@@ -455,11 +450,21 @@ static int ext4_dx_readdir(struct file * filp,
 	 * If there are any leftover names on the hash collision
 	 * chain, return them first.
 	 */
-	if (info->extra_fname &&
-	    call_filldir(filp, dirent, filldir, info->extra_fname))
-		goto finished;
+	if (info->extra_fname) {
+		if (call_filldir(filp, dirent, filldir, info->extra_fname))
+			goto finished;
 
-	if (!info->curr_node)
+		info->extra_fname = NULL;
+		info->curr_node = rb_next(info->curr_node);
+		if (!info->curr_node) {
+			if (info->next_hash == ~0) {
+				filp->f_pos = EXT4_HTREE_EOF;
+				goto finished;
+			}
+			info->curr_hash = info->next_hash;
+			info->curr_minor_hash = 0;
+		}
+	} else if (!info->curr_node)
 		info->curr_node = rb_first(&info->root);
 
 	while (1) {
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 8158083..2950032 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -22,7 +22,7 @@
 #include "ext4_i.h"
 
 /*
- * The second extended filesystem constants/structures
+ * The fourth extended filesystem constants/structures
  */
 
 /*
@@ -45,7 +45,7 @@
 #define ext4_debug(f, a...)						\
 	do {								\
 		printk (KERN_DEBUG "EXT4-fs DEBUG (%s, %d): %s:",	\
-			__FILE__, __LINE__, __FUNCTION__);		\
+			__FILE__, __LINE__, __func__);			\
 		printk (KERN_DEBUG f, ## a);				\
 	} while (0)
 #else
@@ -74,6 +74,9 @@
 #define EXT4_MB_HINT_GOAL_ONLY		256
 /* goal is meaningful */
 #define EXT4_MB_HINT_TRY_GOAL		512
+/* blocks already pre-reserved by delayed allocation */
+#define EXT4_MB_DELALLOC_RESERVED      1024
+
 
 struct ext4_allocation_request {
 	/* target inode for block we're allocating */
@@ -170,6 +173,15 @@ struct ext4_group_desc
 	__u32	bg_reserved2[3];
 };
 
+/*
+ * Structure of a flex block group info
+ */
+
+struct flex_groups {
+	__u32 free_inodes;
+	__u32 free_blocks;
+};
+
 #define EXT4_BG_INODE_UNINIT	0x0001 /* Inode table/bitmap not in use */
 #define EXT4_BG_BLOCK_UNINIT	0x0002 /* Block bitmap not in use */
 #define EXT4_BG_INODE_ZEROED	0x0004 /* On-disk itable initialized to zero */
@@ -527,6 +539,7 @@ do {									       \
 #define EXT4_MOUNT_JOURNAL_ASYNC_COMMIT	0x1000000 /* Journal Async Commit */
 #define EXT4_MOUNT_I_VERSION            0x2000000 /* i_version support */
 #define EXT4_MOUNT_MBALLOC		0x4000000 /* Buddy allocation support */
+#define EXT4_MOUNT_DELALLOC		0x8000000 /* Delalloc support */
 /* Compatibility, for having both ext2_fs.h and ext4_fs.h included at once */
 #ifndef _LINUX_EXT2_FS_H
 #define clear_opt(o, opt)		o &= ~EXT4_MOUNT_##opt
@@ -647,7 +660,10 @@ struct ext4_super_block {
 	__le16  s_mmp_interval;         /* # seconds to wait in MMP checking */
 	__le64  s_mmp_block;            /* Block for multi-mount protection */
 	__le32  s_raid_stripe_width;    /* blocks on all data disks (N*stride)*/
-	__u32   s_reserved[163];        /* Padding to the end of the block */
+	__u8	s_log_groups_per_flex;  /* FLEX_BG group size */
+	__u8	s_reserved_char_pad2;
+	__le16  s_reserved_pad;
+	__u32   s_reserved[162];        /* Padding to the end of the block */
 };
 
 #ifdef __KERNEL__
@@ -958,12 +974,17 @@ extern ext4_grpblk_t ext4_block_group_offset(struct super_block *sb,
 extern int ext4_bg_has_super(struct super_block *sb, ext4_group_t group);
 extern unsigned long ext4_bg_num_gdb(struct super_block *sb,
 			ext4_group_t group);
-extern ext4_fsblk_t ext4_new_block (handle_t *handle, struct inode *inode,
+extern ext4_fsblk_t ext4_new_meta_block(handle_t *handle, struct inode *inode,
 			ext4_fsblk_t goal, int *errp);
-extern ext4_fsblk_t ext4_new_blocks (handle_t *handle, struct inode *inode,
+extern ext4_fsblk_t ext4_new_meta_blocks(handle_t *handle, struct inode *inode,
 			ext4_fsblk_t goal, unsigned long *count, int *errp);
-extern ext4_fsblk_t ext4_new_blocks_old(handle_t *handle, struct inode *inode,
+extern ext4_fsblk_t ext4_new_blocks(handle_t *handle, struct inode *inode,
+					ext4_lblk_t iblock, ext4_fsblk_t goal,
+					unsigned long *count, int *errp);
+extern ext4_fsblk_t ext4_old_new_blocks(handle_t *handle, struct inode *inode,
 			ext4_fsblk_t goal, unsigned long *count, int *errp);
+extern ext4_fsblk_t ext4_has_free_blocks(struct ext4_sb_info *sbi,
+						ext4_fsblk_t nblocks);
 extern void ext4_free_blocks (handle_t *handle, struct inode *inode,
 			ext4_fsblk_t block, unsigned long count, int metadata);
 extern void ext4_free_blocks_sb (handle_t *handle, struct super_block *sb,
@@ -1016,6 +1037,10 @@ extern int __init init_ext4_mballoc(void);
 extern void exit_ext4_mballoc(void);
 extern void ext4_mb_free_blocks(handle_t *, struct inode *,
 		unsigned long, unsigned long, int, unsigned long *);
+extern int ext4_mb_add_more_groupinfo(struct super_block *sb,
+		ext4_group_t i, struct ext4_group_desc *desc);
+extern void ext4_mb_update_group_info(struct ext4_group_info *grp,
+		ext4_grpblk_t add);
 
 
 /* inode.c */
@@ -1033,19 +1058,25 @@ int ext4_get_blocks_handle(handle_t *handle, struct inode *inode,
 extern struct inode *ext4_iget(struct super_block *, unsigned long);
 extern int  ext4_write_inode (struct inode *, int);
 extern int  ext4_setattr (struct dentry *, struct iattr *);
+extern int  ext4_getattr(struct vfsmount *mnt, struct dentry *dentry,
+				struct kstat *stat);
 extern void ext4_delete_inode (struct inode *);
 extern int  ext4_sync_inode (handle_t *, struct inode *);
 extern void ext4_discard_reservation (struct inode *);
 extern void ext4_dirty_inode(struct inode *);
 extern int ext4_change_inode_journal_flag(struct inode *, int);
 extern int ext4_get_inode_loc(struct inode *, struct ext4_iloc *);
+extern int ext4_can_truncate(struct inode *inode);
 extern void ext4_truncate (struct inode *);
 extern void ext4_set_inode_flags(struct inode *);
 extern void ext4_get_inode_flags(struct ext4_inode_info *);
 extern void ext4_set_aops(struct inode *inode);
 extern int ext4_writepage_trans_blocks(struct inode *);
-extern int ext4_block_truncate_page(handle_t *handle, struct page *page,
+extern int ext4_meta_trans_blocks(struct inode *, int nrblocks, int idxblocks);
+extern int ext4_chunk_trans_blocks(struct inode *, int nrblocks);
+extern int ext4_block_truncate_page(handle_t *handle,
 		struct address_space *mapping, loff_t from);
+extern int ext4_page_mkwrite(struct vm_area_struct *vma, struct page *page);
 
 /* ioctl.c */
 extern long ext4_ioctl(struct file *, unsigned int, unsigned long);
@@ -1159,10 +1190,21 @@ struct ext4_group_info *ext4_get_group_info(struct super_block *sb,
 }
 
 
+static inline ext4_group_t ext4_flex_group(struct ext4_sb_info *sbi,
+					     ext4_group_t block_group)
+{
+	return block_group >> sbi->s_log_groups_per_flex;
+}
+
+static inline unsigned int ext4_flex_bg_size(struct ext4_sb_info *sbi)
+{
+	return 1 << sbi->s_log_groups_per_flex;
+}
+
 #define ext4_std_error(sb, errno)				\
 do {								\
 	if ((errno))						\
-		__ext4_std_error((sb), __FUNCTION__, (errno));	\
+		__ext4_std_error((sb), __func__, (errno));	\
 } while (0)
 
 /*
@@ -1187,11 +1229,13 @@ extern const struct inode_operations ext4_fast_symlink_inode_operations;
 /* extents.c */
 extern int ext4_ext_tree_init(handle_t *handle, struct inode *);
 extern int ext4_ext_writepage_trans_blocks(struct inode *, int);
+extern int ext4_ext_index_trans_blocks(struct inode *inode, int nrblocks,
+				       int chunk);
 extern int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
 			ext4_lblk_t iblock,
 			unsigned long max_blocks, struct buffer_head *bh_result,
 			int create, int extend_disksize);
-extern void ext4_ext_truncate(struct inode *, struct page *);
+extern void ext4_ext_truncate(struct inode *);
 extern void ext4_ext_init(struct super_block *);
 extern void ext4_ext_release(struct super_block *);
 extern long ext4_fallocate(struct inode *inode, int mode, loff_t offset,
@@ -1199,7 +1243,7 @@ extern long ext4_fallocate(struct inode *inode, int mode, loff_t offset,
 extern int ext4_get_blocks_wrap(handle_t *handle, struct inode *inode,
 			sector_t block, unsigned long max_blocks,
 			struct buffer_head *bh, int create,
-			int extend_disksize);
+			int extend_disksize, int flag);
 #endif	/* __KERNEL__ */
 
 #endif	/* _EXT4_H */
diff --git a/fs/ext4/ext4_extents.h b/fs/ext4/ext4_extents.h
index 75333b5..d33dc56 100644
--- a/fs/ext4/ext4_extents.h
+++ b/fs/ext4/ext4_extents.h
@@ -212,10 +212,13 @@ static inline int ext4_ext_get_actual_len(struct ext4_extent *ext)
 		(le16_to_cpu(ext->ee_len) - EXT_INIT_MAX_LEN));
 }
 
+extern int ext4_ext_calc_metadata_amount(struct inode *inode, int blocks);
 extern ext4_fsblk_t idx_pblock(struct ext4_extent_idx *);
 extern void ext4_ext_store_pblock(struct ext4_extent *, ext4_fsblk_t);
 extern int ext4_extent_tree_init(handle_t *, struct inode *);
-extern int ext4_ext_calc_credits_for_insert(struct inode *, struct ext4_ext_path *);
+extern int ext4_ext_calc_credits_for_single_extent(struct inode *inode,
+						   int num,
+						   struct ext4_ext_path *path);
 extern int ext4_ext_try_to_merge(struct inode *inode,
 				 struct ext4_ext_path *path,
 				 struct ext4_extent *);
diff --git a/fs/ext4/ext4_i.h b/fs/ext4/ext4_i.h
index 26a4ae2..ef7409f 100644
--- a/fs/ext4/ext4_i.h
+++ b/fs/ext4/ext4_i.h
@@ -79,7 +79,7 @@ struct ext4_ext_cache {
 };
 
 /*
- * third extended file system inode data in memory
+ * fourth extended file system inode data in memory
  */
 struct ext4_inode_info {
 	__le32	i_data[15];	/* unconverted */
@@ -150,6 +150,7 @@ struct ext4_inode_info {
 	 */
 	struct rw_semaphore i_data_sem;
 	struct inode vfs_inode;
+	struct jbd2_inode jinode;
 
 	unsigned long i_ext_generation;
 	struct ext4_ext_cache i_cached_extent;
@@ -162,6 +163,13 @@ struct ext4_inode_info {
 	/* mballoc */
 	struct list_head i_prealloc_list;
 	spinlock_t i_prealloc_lock;
+
+	/* allocation reservation info for delalloc */
+	unsigned long i_reserved_data_blocks;
+	unsigned long i_reserved_meta_blocks;
+	unsigned long i_allocated_meta_blocks;
+	unsigned short i_delalloc_reserved_flag;
+	spinlock_t i_block_reservation_lock;
 };
 
 #endif	/* _EXT4_I */
diff --git a/fs/ext4/ext4_jbd2.h b/fs/ext4/ext4_jbd2.h
index 9255a7d..b455c68 100644
--- a/fs/ext4/ext4_jbd2.h
+++ b/fs/ext4/ext4_jbd2.h
@@ -51,6 +51,14 @@
 					 EXT4_XATTR_TRANS_BLOCKS - 2 + \
 					 2*EXT4_QUOTA_TRANS_BLOCKS(sb))
 
+/*
+ * Define the number of metadata blocks we need to account to modify data.
+ *
+ * This include super block, inode block, quota blocks and xattr blocks
+ */
+#define EXT4_META_TRANS_BLOCKS(sb)	(EXT4_XATTR_TRANS_BLOCKS + \
+					2*EXT4_QUOTA_TRANS_BLOCKS(sb))
+
 /* Delete operations potentially hit one directory's namespace plus an
  * entire inode, plus arbitrary amounts of bitmap/indirection data.  Be
  * generous.  We can grow the delete transaction later if necessary. */
@@ -142,19 +150,17 @@ int __ext4_journal_dirty_metadata(const char *where,
 				handle_t *handle, struct buffer_head *bh);
 
 #define ext4_journal_get_undo_access(handle, bh) \
-	__ext4_journal_get_undo_access(__FUNCTION__, (handle), (bh))
+	__ext4_journal_get_undo_access(__func__, (handle), (bh))
 #define ext4_journal_get_write_access(handle, bh) \
-	__ext4_journal_get_write_access(__FUNCTION__, (handle), (bh))
+	__ext4_journal_get_write_access(__func__, (handle), (bh))
 #define ext4_journal_revoke(handle, blocknr, bh) \
-	__ext4_journal_revoke(__FUNCTION__, (handle), (blocknr), (bh))
+	__ext4_journal_revoke(__func__, (handle), (blocknr), (bh))
 #define ext4_journal_get_create_access(handle, bh) \
-	__ext4_journal_get_create_access(__FUNCTION__, (handle), (bh))
+	__ext4_journal_get_create_access(__func__, (handle), (bh))
 #define ext4_journal_dirty_metadata(handle, bh) \
-	__ext4_journal_dirty_metadata(__FUNCTION__, (handle), (bh))
+	__ext4_journal_dirty_metadata(__func__, (handle), (bh))
 #define ext4_journal_forget(handle, bh) \
-	__ext4_journal_forget(__FUNCTION__, (handle), (bh))
-
-int ext4_journal_dirty_data(handle_t *handle, struct buffer_head *bh);
+	__ext4_journal_forget(__func__, (handle), (bh))
 
 handle_t *ext4_journal_start_sb(struct super_block *sb, int nblocks);
 int __ext4_journal_stop(const char *where, handle_t *handle);
@@ -165,7 +171,7 @@ static inline handle_t *ext4_journal_start(struct inode *inode, int nblocks)
 }
 
 #define ext4_journal_stop(handle) \
-	__ext4_journal_stop(__FUNCTION__, (handle))
+	__ext4_journal_stop(__func__, (handle))
 
 static inline handle_t *ext4_journal_current_handle(void)
 {
@@ -192,6 +198,11 @@ static inline int ext4_journal_force_commit(journal_t *journal)
 	return jbd2_journal_force_commit(journal);
 }
 
+static inline int ext4_jbd2_file_inode(handle_t *handle, struct inode *inode)
+{
+	return jbd2_journal_file_inode(handle, &EXT4_I(inode)->jinode);
+}
+
 /* super.c */
 int ext4_force_commit(struct super_block *sb);
 
diff --git a/fs/ext4/ext4_sb.h b/fs/ext4/ext4_sb.h
index 5802e69..6300226 100644
--- a/fs/ext4/ext4_sb.h
+++ b/fs/ext4/ext4_sb.h
@@ -25,7 +25,7 @@
 #include <linux/rbtree.h>
 
 /*
- * third extended-fs super-block data in memory
+ * fourth extended-fs super-block data in memory
  */
 struct ext4_sb_info {
 	unsigned long s_desc_size;	/* Size of a group descriptor in bytes */
@@ -143,6 +143,9 @@ struct ext4_sb_info {
 
 	/* locality groups */
 	struct ext4_locality_group *s_locality_groups;
+
+	unsigned int s_log_groups_per_flex;
+	struct flex_groups *s_flex_groups;
 };
 
 #endif	/* _EXT4_SB */
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 47929c4..b24d3c5 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -92,17 +92,16 @@ static void ext4_idx_store_pblock(struct ext4_extent_idx *ix, ext4_fsblk_t pb)
 	ix->ei_leaf_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) & 0xffff);
 }
 
-static handle_t *ext4_ext_journal_restart(handle_t *handle, int needed)
+static int ext4_ext_journal_restart(handle_t *handle, int needed)
 {
 	int err;
 
 	if (handle->h_buffer_credits > needed)
-		return handle;
-	if (!ext4_journal_extend(handle, needed))
-		return handle;
-	err = ext4_journal_restart(handle, needed);
-
-	return handle;
+		return 0;
+	err = ext4_journal_extend(handle, needed);
+	if (err <= 0)
+		return err;
+	return ext4_journal_restart(handle, needed);
 }
 
 /*
@@ -180,15 +179,18 @@ static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
 	return bg_start + colour + block;
 }
 
+/*
+ * Allocation for a meta data block
+ */
 static ext4_fsblk_t
-ext4_ext_new_block(handle_t *handle, struct inode *inode,
+ext4_ext_new_meta_block(handle_t *handle, struct inode *inode,
 			struct ext4_ext_path *path,
 			struct ext4_extent *ex, int *err)
 {
 	ext4_fsblk_t goal, newblock;
 
 	goal = ext4_ext_find_goal(inode, path, le32_to_cpu(ex->ee_block));
-	newblock = ext4_new_block(handle, inode, goal, err);
+	newblock = ext4_new_meta_block(handle, inode, goal, err);
 	return newblock;
 }
 
@@ -246,6 +248,36 @@ static int ext4_ext_space_root_idx(struct inode *inode)
 	return size;
 }
 
+/*
+ * Calculate the number of metadata blocks needed
+ * to allocate @blocks
+ * Worse case is one block per extent
+ */
+int ext4_ext_calc_metadata_amount(struct inode *inode, int blocks)
+{
+	int lcap, icap, rcap, leafs, idxs, num;
+	int newextents = blocks;
+
+	rcap = ext4_ext_space_root_idx(inode);
+	lcap = ext4_ext_space_block(inode);
+	icap = ext4_ext_space_block_idx(inode);
+
+	/* number of new leaf blocks needed */
+	num = leafs = (newextents + lcap - 1) / lcap;
+
+	/*
+	 * Worse case, we need separate index block(s)
+	 * to link all new leaf blocks
+	 */
+	idxs = (leafs + icap - 1) / icap;
+	do {
+		num += idxs;
+		idxs = (idxs + icap - 1) / icap;
+	} while (idxs > rcap);
+
+	return num;
+}
+
 static int
 ext4_ext_max_entries(struct inode *inode, int depth)
 {
@@ -524,6 +556,7 @@ ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block,
 		alloc = 1;
 	}
 	path[0].p_hdr = eh;
+	path[0].p_bh = NULL;
 
 	i = depth;
 	/* walk through the tree */
@@ -552,12 +585,14 @@ ext4_ext_find_extent(struct inode *inode, ext4_lblk_t block,
 	}
 
 	path[ppos].p_depth = i;
-	path[ppos].p_hdr = eh;
 	path[ppos].p_ext = NULL;
 	path[ppos].p_idx = NULL;
 
 	/* find extent */
 	ext4_ext_binsearch(inode, path + ppos, block);
+	/* if not an empty leaf */
+	if (path[ppos].p_ext)
+		path[ppos].p_block = ext_pblock(path[ppos].p_ext);
 
 	ext4_ext_show_path(inode, path);
 
@@ -688,7 +723,8 @@ static int ext4_ext_split(handle_t *handle, struct inode *inode,
 	/* allocate all needed blocks */
 	ext_debug("allocate %d blocks for indexes/leaf\n", depth - at);
 	for (a = 0; a < depth - at; a++) {
-		newblock = ext4_ext_new_block(handle, inode, path, newext, &err);
+		newblock = ext4_ext_new_meta_block(handle, inode, path,
+						   newext, &err);
 		if (newblock == 0)
 			goto cleanup;
 		ablocks[a] = newblock;
@@ -884,7 +920,7 @@ static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
 	ext4_fsblk_t newblock;
 	int err = 0;
 
-	newblock = ext4_ext_new_block(handle, inode, path, newext, &err);
+	newblock = ext4_ext_new_meta_block(handle, inode, path, newext, &err);
 	if (newblock == 0)
 		return err;
 
@@ -981,6 +1017,8 @@ repeat:
 		/* if we found index with free entry, then use that
 		 * entry: create all needed subtree and add new leaf */
 		err = ext4_ext_split(handle, inode, path, newext, i);
+		if (err)
+			goto out;
 
 		/* refill path */
 		ext4_ext_drop_refs(path);
@@ -1403,7 +1441,7 @@ unsigned int ext4_ext_check_overlap(struct inode *inode,
 
 	/*
 	 * get the next allocated block if the extent in the path
-	 * is before the requested block(s) 
+	 * is before the requested block(s)
 	 */
 	if (b2 < b1) {
 		b2 = ext4_ext_next_allocated_block(path);
@@ -1709,54 +1747,61 @@ static int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
 }
 
 /*
- * ext4_ext_calc_credits_for_insert:
- * This routine returns max. credits that the extent tree can consume.
- * It should be OK for low-performance paths like ->writepage()
- * To allow many writing processes to fit into a single transaction,
- * the caller should calculate credits under i_data_sem and
- * pass the actual path.
+ * ext4_ext_calc_credits_for_single_extent:
+ * This routine returns max. credits that needed to insert an extent
+ * to the extent tree.
+ * When pass the actual path, the caller should calculate credits
+ * under i_data_sem.
  */
-int ext4_ext_calc_credits_for_insert(struct inode *inode,
+int ext4_ext_calc_credits_for_single_extent(struct inode *inode, int nrblocks,
 						struct ext4_ext_path *path)
 {
-	int depth, needed;
-
 	if (path) {
+		int depth = ext_depth(inode);
+		int ret = 0;
+
 		/* probably there is space in leaf? */
-		depth = ext_depth(inode);
 		if (le16_to_cpu(path[depth].p_hdr->eh_entries)
-				< le16_to_cpu(path[depth].p_hdr->eh_max))
-			return 1;
-	}
+				< le16_to_cpu(path[depth].p_hdr->eh_max)) {
 
-	/*
-	 * given 32-bit logical block (4294967296 blocks), max. tree
-	 * can be 4 levels in depth -- 4 * 340^4 == 53453440000.
-	 * Let's also add one more level for imbalance.
-	 */
-	depth = 5;
-
-	/* allocation of new data block(s) */
-	needed = 2;
+			/*
+			 *  There are some space in the leaf tree, no
+			 *  need to account for leaf block credit
+			 *
+			 *  bitmaps and block group descriptor blocks
+			 *  and other metadat blocks still need to be
+			 *  accounted.
+			 */
+			/* 1 bitmap, 1 block group descriptor */
+			ret = 2 + EXT4_META_TRANS_BLOCKS(inode->i_sb);
+		}
+	}
 
-	/*
-	 * tree can be full, so it would need to grow in depth:
-	 * we need one credit to modify old root, credits for
-	 * new root will be added in split accounting
-	 */
-	needed += 1;
+	return ext4_chunk_trans_blocks(inode, nrblocks);
+}
 
-	/*
-	 * Index split can happen, we would need:
-	 *    allocate intermediate indexes (bitmap + group)
-	 *  + change two blocks at each level, but root (already included)
-	 */
-	needed += (depth * 2) + (depth * 2);
+/*
+ * How many index/leaf blocks need to change/allocate to modify nrblocks?
+ *
+ * if nrblocks are fit in a single extent (chunk flag is 1), then
+ * in the worse case, each tree level index/leaf need to be changed
+ * if the tree split due to insert a new extent, then the old tree
+ * index/leaf need to be updated too
+ *
+ * If the nrblocks are discontiguous, they could cause
+ * the whole tree split more than once, but this is really rare.
+ */
+int ext4_ext_index_trans_blocks(struct inode *inode, int nrblocks, int chunk)
+{
+	int index;
+	int depth = ext_depth(inode);
 
-	/* any allocation modifies superblock */
-	needed += 1;
+	if (chunk)
+		index = depth * 2;
+	else
+		index = depth * 3;
 
-	return needed;
+	return index;
 }
 
 static int ext4_remove_blocks(handle_t *handle, struct inode *inode,
@@ -1872,22 +1917,22 @@ ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
 			BUG_ON(b != ex_ee_block + ex_ee_len - 1);
 		}
 
-		/* at present, extent can't cross block group: */
-		/* leaf + bitmap + group desc + sb + inode */
-		credits = 5;
+		/*
+		 * 3 for leaf, sb, and inode plus 2 (bmap and group
+		 * descriptor) for each block group; assume two block
+		 * groups plus ex_ee_len/blocks_per_block_group for
+		 * the worst case
+		 */
+		credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb));
 		if (ex == EXT_FIRST_EXTENT(eh)) {
 			correct_index = 1;
 			credits += (ext_depth(inode)) + 1;
 		}
-#ifdef CONFIG_QUOTA
 		credits += 2 * EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb);
-#endif
 
-		handle = ext4_ext_journal_restart(handle, credits);
-		if (IS_ERR(handle)) {
-			err = PTR_ERR(handle);
+		err = ext4_ext_journal_restart(handle, credits);
+		if (err)
 			goto out;
-		}
 
 		err = ext4_ext_get_access(handle, inode, path + depth);
 		if (err)
@@ -2287,7 +2332,10 @@ static int ext4_ext_convert_to_initialized(handle_t *handle,
 		unsigned int newdepth;
 		/* If extent has less than EXT4_EXT_ZERO_LEN zerout directly */
 		if (allocated <= EXT4_EXT_ZERO_LEN) {
-			/* Mark first half uninitialized.
+			/*
+			 * iblock == ee_block is handled by the zerouout
+			 * at the beginning.
+			 * Mark first half uninitialized.
 			 * Mark second half initialized and zero out the
 			 * initialized extent
 			 */
@@ -2310,7 +2358,7 @@ static int ext4_ext_convert_to_initialized(handle_t *handle,
 				ex->ee_len   = orig_ex.ee_len;
 				ext4_ext_store_pblock(ex, ext_pblock(&orig_ex));
 				ext4_ext_dirty(handle, inode, path + depth);
-				/* zeroed the full extent */
+				/* blocks available from iblock */
 				return allocated;
 
 			} else if (err)
@@ -2338,6 +2386,7 @@ static int ext4_ext_convert_to_initialized(handle_t *handle,
 					err = PTR_ERR(path);
 					return err;
 				}
+				/* get the second half extent details */
 				ex = path[depth].p_ext;
 				err = ext4_ext_get_access(handle, inode,
 								path + depth);
@@ -2367,6 +2416,7 @@ static int ext4_ext_convert_to_initialized(handle_t *handle,
 			ext4_ext_store_pblock(ex, ext_pblock(&orig_ex));
 			ext4_ext_dirty(handle, inode, path + depth);
 			/* zeroed the full extent */
+			/* blocks available from iblock */
 			return allocated;
 
 		} else if (err)
@@ -2382,23 +2432,22 @@ static int ext4_ext_convert_to_initialized(handle_t *handle,
 		 */
 		orig_ex.ee_len = cpu_to_le16(ee_len -
 						ext4_ext_get_actual_len(ex3));
-		if (newdepth != depth) {
-			depth = newdepth;
-			ext4_ext_drop_refs(path);
-			path = ext4_ext_find_extent(inode, iblock, path);
-			if (IS_ERR(path)) {
-				err = PTR_ERR(path);
-				goto out;
-			}
-			eh = path[depth].p_hdr;
-			ex = path[depth].p_ext;
-			if (ex2 != &newex)
-				ex2 = ex;
-
-			err = ext4_ext_get_access(handle, inode, path + depth);
-			if (err)
-				goto out;
+		depth = newdepth;
+		ext4_ext_drop_refs(path);
+		path = ext4_ext_find_extent(inode, iblock, path);
+		if (IS_ERR(path)) {
+			err = PTR_ERR(path);
+			goto out;
 		}
+		eh = path[depth].p_hdr;
+		ex = path[depth].p_ext;
+		if (ex2 != &newex)
+			ex2 = ex;
+
+		err = ext4_ext_get_access(handle, inode, path + depth);
+		if (err)
+			goto out;
+
 		allocated = max_blocks;
 
 		/* If extent has less than EXT4_EXT_ZERO_LEN and we are trying
@@ -2416,6 +2465,7 @@ static int ext4_ext_convert_to_initialized(handle_t *handle,
 			ext4_ext_store_pblock(ex, ext_pblock(&orig_ex));
 			ext4_ext_dirty(handle, inode, path + depth);
 			/* zero out the first half */
+			/* blocks available from iblock */
 			return allocated;
 		}
 	}
@@ -2529,6 +2579,7 @@ int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
 	int err = 0, depth, ret;
 	unsigned long allocated = 0;
 	struct ext4_allocation_request ar;
+	loff_t disksize;
 
 	__clear_bit(BH_New, &bh_result->b_state);
 	ext_debug("blocks %u/%lu requested for inode %u\n",
@@ -2616,8 +2667,7 @@ int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
 				 */
 				if (allocated > max_blocks)
 					allocated = max_blocks;
-				/* mark the buffer unwritten */
-				__set_bit(BH_Unwritten, &bh_result->b_state);
+				set_buffer_unwritten(bh_result);
 				goto out2;
 			}
 
@@ -2716,14 +2766,19 @@ int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
 		goto out2;
 	}
 
-	if (extend_disksize && inode->i_size > EXT4_I(inode)->i_disksize)
-		EXT4_I(inode)->i_disksize = inode->i_size;
-
 	/* previous routine could use block we allocated */
 	newblock = ext_pblock(&newex);
 	allocated = ext4_ext_get_actual_len(&newex);
 outnew:
-	__set_bit(BH_New, &bh_result->b_state);
+	if (extend_disksize) {
+		disksize = ((loff_t) iblock + ar.len) << inode->i_blkbits;
+		if (disksize > i_size_read(inode))
+			disksize = i_size_read(inode);
+		if (disksize > EXT4_I(inode)->i_disksize)
+			EXT4_I(inode)->i_disksize = disksize;
+	}
+
+	set_buffer_new(bh_result);
 
 	/* Cache only when it is _not_ an uninitialized extent */
 	if (create != EXT4_CREATE_UNINITIALIZED_EXT)
@@ -2733,7 +2788,7 @@ out:
 	if (allocated > max_blocks)
 		allocated = max_blocks;
 	ext4_ext_show_leaf(inode, path);
-	__set_bit(BH_Mapped, &bh_result->b_state);
+	set_buffer_mapped(bh_result);
 	bh_result->b_bdev = inode->i_sb->s_bdev;
 	bh_result->b_blocknr = newblock;
 out2:
@@ -2744,7 +2799,7 @@ out2:
 	return err ? err : allocated;
 }
 
-void ext4_ext_truncate(struct inode * inode, struct page *page)
+void ext4_ext_truncate(struct inode *inode)
 {
 	struct address_space *mapping = inode->i_mapping;
 	struct super_block *sb = inode->i_sb;
@@ -2755,33 +2810,27 @@ void ext4_ext_truncate(struct inode * inode, struct page *page)
 	/*
 	 * probably first extent we're gonna free will be last in block
 	 */
-	err = ext4_writepage_trans_blocks(inode) + 3;
+	err = ext4_writepage_trans_blocks(inode);
 	handle = ext4_journal_start(inode, err);
-	if (IS_ERR(handle)) {
-		if (page) {
-			clear_highpage(page);
-			flush_dcache_page(page);
-			unlock_page(page);
-			page_cache_release(page);
-		}
+	if (IS_ERR(handle))
 		return;
-	}
 
-	if (page)
-		ext4_block_truncate_page(handle, page, mapping, inode->i_size);
+	if (inode->i_size & (sb->s_blocksize - 1))
+		ext4_block_truncate_page(handle, mapping, inode->i_size);
+
+	if (ext4_orphan_add(handle, inode))
+		goto out_stop;
 
 	down_write(&EXT4_I(inode)->i_data_sem);
 	ext4_ext_invalidate_cache(inode);
 
-	ext4_mb_discard_inode_preallocations(inode);
+	ext4_discard_reservation(inode);
 
 	/*
 	 * TODO: optimization is possible here.
 	 * Probably we need not scan at all,
 	 * because page truncation is enough.
 	 */
-	if (ext4_orphan_add(handle, inode))
-		goto out_stop;
 
 	/* we have to know where to truncate from in crash case */
 	EXT4_I(inode)->i_disksize = inode->i_size;
@@ -2798,6 +2847,7 @@ void ext4_ext_truncate(struct inode * inode, struct page *page)
 		handle->h_sync = 1;
 
 out_stop:
+	up_write(&EXT4_I(inode)->i_data_sem);
 	/*
 	 * If this was a simple ftruncate() and the file will remain alive,
 	 * then we need to clear up the orphan record which we created above.
@@ -2808,33 +2858,11 @@ out_stop:
 	if (inode->i_nlink)
 		ext4_orphan_del(handle, inode);
 
-	up_write(&EXT4_I(inode)->i_data_sem);
 	inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
 	ext4_mark_inode_dirty(handle, inode);
 	ext4_journal_stop(handle);
 }
 
-/*
- * ext4_ext_writepage_trans_blocks:
- * calculate max number of blocks we could modify
- * in order to allocate new block for an inode
- */
-int ext4_ext_writepage_trans_blocks(struct inode *inode, int num)
-{
-	int needed;
-
-	needed = ext4_ext_calc_credits_for_insert(inode, NULL);
-
-	/* caller wants to allocate num blocks, but note it includes sb */
-	needed = needed * num - (num - 1);
-
-#ifdef CONFIG_QUOTA
-	needed += 2 * EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb);
-#endif
-
-	return needed;
-}
-
 static void ext4_falloc_update_inode(struct inode *inode,
 				int mode, loff_t new_size, int update_ctime)
 {
@@ -2895,10 +2923,9 @@ long ext4_fallocate(struct inode *inode, int mode, loff_t offset, loff_t len)
 	max_blocks = (EXT4_BLOCK_ALIGN(len + offset, blkbits) >> blkbits)
 							- block;
 	/*
-	 * credits to insert 1 extent into extent tree + buffers to be able to
-	 * modify 1 super block, 1 block bitmap and 1 group descriptor.
+	 * credits to insert 1 extent into extent tree
 	 */
-	credits = EXT4_DATA_TRANS_BLOCKS(inode->i_sb) + 3;
+	credits = ext4_chunk_trans_blocks(inode, max_blocks);
 	mutex_lock(&inode->i_mutex);
 retry:
 	while (ret >= 0 && ret < max_blocks) {
@@ -2911,7 +2938,7 @@ retry:
 		}
 		ret = ext4_get_blocks_wrap(handle, inode, block,
 					  max_blocks, &map_bh,
-					  EXT4_CREATE_UNINITIALIZED_EXT, 0);
+					  EXT4_CREATE_UNINITIALIZED_EXT, 0, 0);
 		if (ret <= 0) {
 #ifdef EXT4FS_DEBUG
 			WARN_ON(ret <= 0);
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 4159be6..430eb79 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -123,6 +123,23 @@ force_commit:
 	return ret;
 }
 
+static struct vm_operations_struct ext4_file_vm_ops = {
+	.fault		= filemap_fault,
+	.page_mkwrite   = ext4_page_mkwrite,
+};
+
+static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	struct address_space *mapping = file->f_mapping;
+
+	if (!mapping->a_ops->readpage)
+		return -ENOEXEC;
+	file_accessed(file);
+	vma->vm_ops = &ext4_file_vm_ops;
+	vma->vm_flags |= VM_CAN_NONLINEAR;
+	return 0;
+}
+
 const struct file_operations ext4_file_operations = {
 	.llseek		= generic_file_llseek,
 	.read		= do_sync_read,
@@ -133,7 +150,7 @@ const struct file_operations ext4_file_operations = {
 #ifdef CONFIG_COMPAT
 	.compat_ioctl	= ext4_compat_ioctl,
 #endif
-	.mmap		= generic_file_mmap,
+	.mmap		= ext4_file_mmap,
 	.open		= generic_file_open,
 	.release	= ext4_release_file,
 	.fsync		= ext4_sync_file,
@@ -144,6 +161,7 @@ const struct file_operations ext4_file_operations = {
 const struct inode_operations ext4_file_inode_operations = {
 	.truncate	= ext4_truncate,
 	.setattr	= ext4_setattr,
+	.getattr	= ext4_getattr,
 #ifdef CONFIG_EXT4DEV_FS_XATTR
 	.setxattr	= generic_setxattr,
 	.getxattr	= generic_getxattr,
diff --git a/fs/ext4/fsync.c b/fs/ext4/fsync.c
index 1c8ba48..a45c373 100644
--- a/fs/ext4/fsync.c
+++ b/fs/ext4/fsync.c
@@ -27,6 +27,7 @@
 #include <linux/sched.h>
 #include <linux/writeback.h>
 #include <linux/jbd2.h>
+#include <linux/blkdev.h>
 #include "ext4.h"
 #include "ext4_jbd2.h"
 
@@ -45,6 +46,7 @@
 int ext4_sync_file(struct file * file, struct dentry *dentry, int datasync)
 {
 	struct inode *inode = dentry->d_inode;
+	journal_t *journal = EXT4_SB(inode->i_sb)->s_journal;
 	int ret = 0;
 
 	J_ASSERT(ext4_journal_current_handle() == NULL);
@@ -85,6 +87,8 @@ int ext4_sync_file(struct file * file, struct dentry *dentry, int datasync)
 			.nr_to_write = 0, /* sys_fsync did this */
 		};
 		ret = sync_inode(inode, &wbc);
+		if (journal && (journal->j_flags & JBD2_BARRIER))
+			blkdev_issue_flush(inode->i_sb->s_bdev, NULL);
 	}
 out:
 	return ret;
diff --git a/fs/ext4/group.h b/fs/ext4/group.h
index 7eb0604..c2c0a8d 100644
--- a/fs/ext4/group.h
+++ b/fs/ext4/group.h
@@ -13,7 +13,7 @@ extern __le16 ext4_group_desc_csum(struct ext4_sb_info *sbi, __u32 group,
 				   struct ext4_group_desc *gdp);
 extern int ext4_group_desc_csum_verify(struct ext4_sb_info *sbi, __u32 group,
 				       struct ext4_group_desc *gdp);
-struct buffer_head *read_block_bitmap(struct super_block *sb,
+struct buffer_head *ext4_read_block_bitmap(struct super_block *sb,
 				      ext4_group_t block_group);
 extern unsigned ext4_init_block_bitmap(struct super_block *sb,
 				       struct buffer_head *bh,
diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index c6efbab..f344834 100644
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -97,34 +97,44 @@ unsigned ext4_init_inode_bitmap(struct super_block *sb, struct buffer_head *bh,
  * Return buffer_head of bitmap on success or NULL.
  */
 static struct buffer_head *
-read_inode_bitmap(struct super_block *sb, ext4_group_t block_group)
+ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group)
 {
 	struct ext4_group_desc *desc;
 	struct buffer_head *bh = NULL;
+	ext4_fsblk_t bitmap_blk;
 
 	desc = ext4_get_group_desc(sb, block_group, NULL);
 	if (!desc)
-		goto error_out;
+		return NULL;
+	bitmap_blk = ext4_inode_bitmap(sb, desc);
+	bh = sb_getblk(sb, bitmap_blk);
+	if (unlikely(!bh)) {
+		ext4_error(sb, __func__,
+			    "Cannot read inode bitmap - "
+			    "block_group = %lu, inode_bitmap = %llu",
+			    block_group, bitmap_blk);
+		return NULL;
+	}
+	if (bh_uptodate_or_lock(bh))
+		return bh;
+
+	spin_lock(sb_bgl_lock(EXT4_SB(sb), block_group));
 	if (desc->bg_flags & cpu_to_le16(EXT4_BG_INODE_UNINIT)) {
-		bh = sb_getblk(sb, ext4_inode_bitmap(sb, desc));
-		if (!buffer_uptodate(bh)) {
-			lock_buffer(bh);
-			if (!buffer_uptodate(bh)) {
-				ext4_init_inode_bitmap(sb, bh, block_group,
-						       desc);
-				set_buffer_uptodate(bh);
-			}
-			unlock_buffer(bh);
-		}
-	} else {
-		bh = sb_bread(sb, ext4_inode_bitmap(sb, desc));
+		ext4_init_inode_bitmap(sb, bh, block_group, desc);
+		set_buffer_uptodate(bh);
+		unlock_buffer(bh);
+		spin_unlock(sb_bgl_lock(EXT4_SB(sb), block_group));
+		return bh;
 	}
-	if (!bh)
-		ext4_error(sb, "read_inode_bitmap",
+	spin_unlock(sb_bgl_lock(EXT4_SB(sb), block_group));
+	if (bh_submit_read(bh) < 0) {
+		put_bh(bh);
+		ext4_error(sb, __func__,
 			    "Cannot read inode bitmap - "
 			    "block_group = %lu, inode_bitmap = %llu",
-			    block_group, ext4_inode_bitmap(sb, desc));
-error_out:
+			    block_group, bitmap_blk);
+		return NULL;
+	}
 	return bh;
 }
 
@@ -157,6 +167,7 @@ void ext4_free_inode (handle_t *handle, struct inode * inode)
 	struct ext4_super_block * es;
 	struct ext4_sb_info *sbi;
 	int fatal = 0, err;
+	ext4_group_t flex_group;
 
 	if (atomic_read(&inode->i_count) > 1) {
 		printk ("ext4_free_inode: inode has count=%d\n",
@@ -199,7 +210,7 @@ void ext4_free_inode (handle_t *handle, struct inode * inode)
 	}
 	block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
 	bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
-	bitmap_bh = read_inode_bitmap(sb, block_group);
+	bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
 	if (!bitmap_bh)
 		goto error_return;
 
@@ -232,6 +243,12 @@ void ext4_free_inode (handle_t *handle, struct inode * inode)
 			if (is_directory)
 				percpu_counter_dec(&sbi->s_dirs_counter);
 
+			if (sbi->s_log_groups_per_flex) {
+				flex_group = ext4_flex_group(sbi, block_group);
+				spin_lock(sb_bgl_lock(sbi, flex_group));
+				sbi->s_flex_groups[flex_group].free_inodes++;
+				spin_unlock(sb_bgl_lock(sbi, flex_group));
+			}
 		}
 		BUFFER_TRACE(bh2, "call ext4_journal_dirty_metadata");
 		err = ext4_journal_dirty_metadata(handle, bh2);
@@ -286,6 +303,80 @@ static int find_group_dir(struct super_block *sb, struct inode *parent,
 	return ret;
 }
 
+#define free_block_ratio 10
+
+static int find_group_flex(struct super_block *sb, struct inode *parent,
+			   ext4_group_t *best_group)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_group_desc *desc;
+	struct buffer_head *bh;
+	struct flex_groups *flex_group = sbi->s_flex_groups;
+	ext4_group_t parent_group = EXT4_I(parent)->i_block_group;
+	ext4_group_t parent_fbg_group = ext4_flex_group(sbi, parent_group);
+	ext4_group_t ngroups = sbi->s_groups_count;
+	int flex_size = ext4_flex_bg_size(sbi);
+	ext4_group_t best_flex = parent_fbg_group;
+	int blocks_per_flex = sbi->s_blocks_per_group * flex_size;
+	int flexbg_free_blocks;
+	int flex_freeb_ratio;
+	ext4_group_t n_fbg_groups;
+	ext4_group_t i;
+
+	n_fbg_groups = (sbi->s_groups_count + flex_size - 1) >>
+		sbi->s_log_groups_per_flex;
+
+find_close_to_parent:
+	flexbg_free_blocks = flex_group[best_flex].free_blocks;
+	flex_freeb_ratio = flexbg_free_blocks * 100 / blocks_per_flex;
+	if (flex_group[best_flex].free_inodes &&
+	    flex_freeb_ratio > free_block_ratio)
+		goto found_flexbg;
+
+	if (best_flex && best_flex == parent_fbg_group) {
+		best_flex--;
+		goto find_close_to_parent;
+	}
+
+	for (i = 0; i < n_fbg_groups; i++) {
+		if (i == parent_fbg_group || i == parent_fbg_group - 1)
+			continue;
+
+		flexbg_free_blocks = flex_group[i].free_blocks;
+		flex_freeb_ratio = flexbg_free_blocks * 100 / blocks_per_flex;
+
+		if (flex_freeb_ratio > free_block_ratio &&
+		    flex_group[i].free_inodes) {
+			best_flex = i;
+			goto found_flexbg;
+		}
+
+		if (flex_group[best_flex].free_inodes == 0 ||
+		    (flex_group[i].free_blocks >
+		     flex_group[best_flex].free_blocks &&
+		     flex_group[i].free_inodes))
+			best_flex = i;
+	}
+
+	if (!flex_group[best_flex].free_inodes ||
+	    !flex_group[best_flex].free_blocks)
+		return -1;
+
+found_flexbg:
+	for (i = best_flex * flex_size; i < ngroups &&
+		     i < (best_flex + 1) * flex_size; i++) {
+		desc = ext4_get_group_desc(sb, i, &bh);
+		if (le16_to_cpu(desc->bg_free_inodes_count)) {
+			*best_group = i;
+			goto out;
+		}
+	}
+
+	return -1;
+out:
+	return 0;
+}
+
 /*
  * Orlov's allocator for directories.
  *
@@ -501,6 +592,7 @@ struct inode *ext4_new_inode(handle_t *handle, struct inode * dir, int mode)
 	struct inode *ret;
 	ext4_group_t i;
 	int free = 0;
+	ext4_group_t flex_group;
 
 	/* Cannot create files in a deleted directory */
 	if (!dir || !dir->i_nlink)
@@ -514,6 +606,12 @@ struct inode *ext4_new_inode(handle_t *handle, struct inode * dir, int mode)
 
 	sbi = EXT4_SB(sb);
 	es = sbi->s_es;
+
+	if (sbi->s_log_groups_per_flex) {
+		ret2 = find_group_flex(sb, dir, &group);
+		goto got_group;
+	}
+
 	if (S_ISDIR(mode)) {
 		if (test_opt (sb, OLDALLOC))
 			ret2 = find_group_dir(sb, dir, &group);
@@ -522,6 +620,7 @@ struct inode *ext4_new_inode(handle_t *handle, struct inode * dir, int mode)
 	} else
 		ret2 = find_group_other(sb, dir, &group);
 
+got_group:
 	err = -ENOSPC;
 	if (ret2 == -1)
 		goto out;
@@ -534,7 +633,7 @@ struct inode *ext4_new_inode(handle_t *handle, struct inode * dir, int mode)
 			goto fail;
 
 		brelse(bitmap_bh);
-		bitmap_bh = read_inode_bitmap(sb, group);
+		bitmap_bh = ext4_read_inode_bitmap(sb, group);
 		if (!bitmap_bh)
 			goto fail;
 
@@ -600,7 +699,7 @@ got:
 	/* We may have to initialize the block bitmap if it isn't already */
 	if (EXT4_HAS_RO_COMPAT_FEATURE(sb, EXT4_FEATURE_RO_COMPAT_GDT_CSUM) &&
 	    gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
-		struct buffer_head *block_bh = read_block_bitmap(sb, group);
+		struct buffer_head *block_bh = ext4_read_block_bitmap(sb, group);
 
 		BUFFER_TRACE(block_bh, "get block bitmap access");
 		err = ext4_journal_get_write_access(handle, block_bh);
@@ -639,7 +738,7 @@ got:
 
 			/* When marking the block group with
 			 * ~EXT4_BG_INODE_UNINIT we don't want to depend
-			 * on the value of bg_itable_unsed even though
+			 * on the value of bg_itable_unused even though
 			 * mke2fs could have initialized the same for us.
 			 * Instead we calculated the value below
 			 */
@@ -676,6 +775,13 @@ got:
 		percpu_counter_inc(&sbi->s_dirs_counter);
 	sb->s_dirt = 1;
 
+	if (sbi->s_log_groups_per_flex) {
+		flex_group = ext4_flex_group(sbi, group);
+		spin_lock(sb_bgl_lock(sbi, flex_group));
+		sbi->s_flex_groups[flex_group].free_inodes--;
+		spin_unlock(sb_bgl_lock(sbi, flex_group));
+	}
+
 	inode->i_uid = current->fsuid;
 	if (test_opt (sb, GRPID))
 		inode->i_gid = dir->i_gid;
@@ -740,14 +846,10 @@ got:
 		goto fail_free_drop;
 
 	if (test_opt(sb, EXTENTS)) {
-		/* set extent flag only for diretory, file and normal symlink*/
+		/* set extent flag only for directory, file and normal symlink*/
 		if (S_ISDIR(mode) || S_ISREG(mode) || S_ISLNK(mode)) {
 			EXT4_I(inode)->i_flags |= EXT4_EXTENTS_FL;
 			ext4_ext_tree_init(handle, inode);
-			err = ext4_update_incompat_feature(handle, sb,
-					EXT4_FEATURE_INCOMPAT_EXTENTS);
-			if (err)
-				goto fail_free_drop;
 		}
 	}
 
@@ -799,7 +901,7 @@ struct inode *ext4_orphan_get(struct super_block *sb, unsigned long ino)
 
 	block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
 	bit = (ino - 1) % EXT4_INODES_PER_GROUP(sb);
-	bitmap_bh = read_inode_bitmap(sb, block_group);
+	bitmap_bh = ext4_read_inode_bitmap(sb, block_group);
 	if (!bitmap_bh) {
 		ext4_warning(sb, __func__,
 			     "inode bitmap error for orphan %lu", ino);
@@ -817,6 +919,14 @@ struct inode *ext4_orphan_get(struct super_block *sb, unsigned long ino)
 	if (IS_ERR(inode))
 		goto iget_failed;
 
+	/*
+	 * If the orphans has i_nlinks > 0 then it should be able to be
+	 * truncated, otherwise it won't be removed from the orphan list
+	 * during processing and an infinite loop will result.
+	 */
+	if (inode->i_nlink && !ext4_can_truncate(inode))
+		goto bad_orphan;
+
 	if (NEXT_ORPHAN(inode) > max_ino)
 		goto bad_orphan;
 	brelse(bitmap_bh);
@@ -838,6 +948,7 @@ bad_orphan:
 		printk(KERN_NOTICE "NEXT_ORPHAN(inode)=%u\n",
 		       NEXT_ORPHAN(inode));
 		printk(KERN_NOTICE "max_ino=%lu\n", max_ino);
+		printk(KERN_NOTICE "i_nlink=%u\n", inode->i_nlink);
 		/* Avoid freeing blocks if we got a bad deleted inode */
 		if (inode->i_nlink == 0)
 			inode->i_blocks = 0;
@@ -868,7 +979,7 @@ unsigned long ext4_count_free_inodes (struct super_block * sb)
 			continue;
 		desc_count += le16_to_cpu(gdp->bg_free_inodes_count);
 		brelse(bitmap_bh);
-		bitmap_bh = read_inode_bitmap(sb, i);
+		bitmap_bh = ext4_read_inode_bitmap(sb, i);
 		if (!bitmap_bh)
 			continue;
 
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 8d97077..3c0195a 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -32,12 +32,25 @@
 #include <linux/string.h>
 #include <linux/buffer_head.h>
 #include <linux/writeback.h>
+#include <linux/pagevec.h>
 #include <linux/mpage.h>
 #include <linux/uio.h>
 #include <linux/bio.h>
 #include "ext4_jbd2.h"
 #include "xattr.h"
 #include "acl.h"
+#include "ext4_extents.h"
+
+#define MPAGE_DA_EXTENT_TAIL 0x01
+
+static inline int ext4_begin_ordered_truncate(struct inode *inode,
+					      loff_t new_size)
+{
+	return jbd2_journal_begin_ordered_truncate(&EXT4_I(inode)->jinode,
+						   new_size);
+}
+
+static void ext4_invalidatepage(struct page *page, unsigned long offset);
 
 /*
  * Test whether an inode is a fast symlink.
@@ -180,14 +193,18 @@ static int ext4_journal_test_restart(handle_t *handle, struct inode *inode)
 void ext4_delete_inode (struct inode * inode)
 {
 	handle_t *handle;
+	int err;
 
+	if (ext4_should_order_data(inode))
+		ext4_begin_ordered_truncate(inode, 0);
 	truncate_inode_pages(&inode->i_data, 0);
 
 	if (is_bad_inode(inode))
 		goto no_delete;
 
-	handle = start_transaction(inode);
+	handle = ext4_journal_start(inode, blocks_for_truncate(inode)+3);
 	if (IS_ERR(handle)) {
+		ext4_std_error(inode->i_sb, PTR_ERR(handle));
 		/*
 		 * If we're going to skip the normal cleanup, we still need to
 		 * make sure that the in-core orphan linked list is properly
@@ -200,8 +217,34 @@ void ext4_delete_inode (struct inode * inode)
 	if (IS_SYNC(inode))
 		handle->h_sync = 1;
 	inode->i_size = 0;
+	err = ext4_mark_inode_dirty(handle, inode);
+	if (err) {
+		ext4_warning(inode->i_sb, __func__,
+			     "couldn't mark inode dirty (err %d)", err);
+		goto stop_handle;
+	}
 	if (inode->i_blocks)
 		ext4_truncate(inode);
+
+	/*
+	 * ext4_ext_truncate() doesn't reserve any slop when it
+	 * restarts journal transactions; therefore there may not be
+	 * enough credits left in the handle to remove the inode from
+	 * the orphan list and set the dtime field.
+	 */
+	if (handle->h_buffer_credits < 3) {
+		err = ext4_journal_extend(handle, 3);
+		if (err > 0)
+			err = ext4_journal_restart(handle, 3);
+		if (err != 0) {
+			ext4_warning(inode->i_sb, __func__,
+				     "couldn't extend journal (err %d)", err);
+		stop_handle:
+			ext4_journal_stop(handle);
+			goto no_delete;
+		}
+	}
+
 	/*
 	 * Kill off the orphan record which ext4_truncate created.
 	 * AKPM: I think this can be inside the above `if'.
@@ -508,11 +551,12 @@ static int ext4_blks_to_allocate(Indirect *branch, int k, unsigned long blks,
  *		direct blocks
  */
 static int ext4_alloc_blocks(handle_t *handle, struct inode *inode,
-			ext4_fsblk_t goal, int indirect_blks, int blks,
-			ext4_fsblk_t new_blocks[4], int *err)
+				ext4_lblk_t iblock, ext4_fsblk_t goal,
+				int indirect_blks, int blks,
+				ext4_fsblk_t new_blocks[4], int *err)
 {
 	int target, i;
-	unsigned long count = 0;
+	unsigned long count = 0, blk_allocated = 0;
 	int index = 0;
 	ext4_fsblk_t current_block = 0;
 	int ret = 0;
@@ -525,12 +569,13 @@ static int ext4_alloc_blocks(handle_t *handle, struct inode *inode,
 	 * the first direct block of this branch.  That's the
 	 * minimum number of blocks need to allocate(required)
 	 */
-	target = blks + indirect_blks;
-
-	while (1) {
+	/* first we try to allocate the indirect blocks */
+	target = indirect_blks;
+	while (target > 0) {
 		count = target;
 		/* allocating blocks for indirect blocks and direct blocks */
-		current_block = ext4_new_blocks(handle,inode,goal,&count,err);
+		current_block = ext4_new_meta_blocks(handle, inode,
+							goal, &count, err);
 		if (*err)
 			goto failed_out;
 
@@ -540,16 +585,48 @@ static int ext4_alloc_blocks(handle_t *handle, struct inode *inode,
 			new_blocks[index++] = current_block++;
 			count--;
 		}
-
-		if (count > 0)
+		if (count > 0) {
+			/*
+			 * save the new block number
+			 * for the first direct block
+			 */
+			new_blocks[index] = current_block;
+			printk(KERN_INFO "%s returned more blocks than "
+						"requested\n", __func__);
+			WARN_ON(1);
 			break;
+		}
 	}
 
-	/* save the new block number for the first direct block */
-	new_blocks[index] = current_block;
-
+	target = blks - count ;
+	blk_allocated = count;
+	if (!target)
+		goto allocated;
+	/* Now allocate data blocks */
+	count = target;
+	/* allocating blocks for data blocks */
+	current_block = ext4_new_blocks(handle, inode, iblock,
+						goal, &count, err);
+	if (*err && (target == blks)) {
+		/*
+		 * if the allocation failed and we didn't allocate
+		 * any blocks before
+		 */
+		goto failed_out;
+	}
+	if (!*err) {
+		if (target == blks) {
+		/*
+		 * save the new block number
+		 * for the first direct block
+		 */
+			new_blocks[index] = current_block;
+		}
+		blk_allocated += count;
+	}
+allocated:
 	/* total number of blocks allocated for direct blocks */
-	ret = count;
+	ret = blk_allocated;
 	*err = 0;
 	return ret;
 failed_out:
@@ -584,8 +661,9 @@ failed_out:
  *	as described above and return 0.
  */
 static int ext4_alloc_branch(handle_t *handle, struct inode *inode,
-			int indirect_blks, int *blks, ext4_fsblk_t goal,
-			ext4_lblk_t *offsets, Indirect *branch)
+				ext4_lblk_t iblock, int indirect_blks,
+				int *blks, ext4_fsblk_t goal,
+				ext4_lblk_t *offsets, Indirect *branch)
 {
 	int blocksize = inode->i_sb->s_blocksize;
 	int i, n = 0;
@@ -595,7 +673,7 @@ static int ext4_alloc_branch(handle_t *handle, struct inode *inode,
 	ext4_fsblk_t new_blocks[4];
 	ext4_fsblk_t current_block;
 
-	num = ext4_alloc_blocks(handle, inode, goal, indirect_blks,
+	num = ext4_alloc_blocks(handle, inode, iblock, goal, indirect_blks,
 				*blks, new_blocks, &err);
 	if (err)
 		return err;
@@ -799,6 +877,7 @@ int ext4_get_blocks_handle(handle_t *handle, struct inode *inode,
 	struct ext4_inode_info *ei = EXT4_I(inode);
 	int count = 0;
 	ext4_fsblk_t first_block = 0;
+	loff_t disksize;
 
 
 	J_ASSERT(!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL));
@@ -855,8 +934,9 @@ int ext4_get_blocks_handle(handle_t *handle, struct inode *inode,
 	/*
 	 * Block out ext4_truncate while we alter the tree
 	 */
-	err = ext4_alloc_branch(handle, inode, indirect_blks, &count, goal,
-				offsets + (partial - chain), partial);
+	err = ext4_alloc_branch(handle, inode, iblock, indirect_blks,
+					&count, goal,
+					offsets + (partial - chain), partial);
 
 	/*
 	 * The ext4_splice_branch call will free and forget any buffers
@@ -873,8 +953,13 @@ int ext4_get_blocks_handle(handle_t *handle, struct inode *inode,
 	 * protect it if you're about to implement concurrent
 	 * ext4_get_block() -bzzz
 	*/
-	if (!err && extend_disksize && inode->i_size > ei->i_disksize)
-		ei->i_disksize = inode->i_size;
+	if (!err && extend_disksize) {
+		disksize = ((loff_t) iblock + count) << inode->i_blkbits;
+		if (disksize > i_size_read(inode))
+			disksize = i_size_read(inode);
+		if (disksize > ei->i_disksize)
+			ei->i_disksize = disksize;
+	}
 	if (err)
 		goto cleanup;
 
@@ -897,23 +982,74 @@ out:
 	return err;
 }
 
-/* Maximum number of blocks we map for direct IO at once. */
-#define DIO_MAX_BLOCKS 4096
 /*
- * Number of credits we need for writing DIO_MAX_BLOCKS:
- * We need sb + group descriptor + bitmap + inode -> 4
- * For B blocks with A block pointers per block we need:
- * 1 (triple ind.) + (B/A/A + 2) (doubly ind.) + (B/A + 2) (indirect).
- * If we plug in 4096 for B and 256 for A (for 1KB block size), we get 25.
+ * Calculate the number of metadata blocks need to reserve
+ * to allocate @blocks for non extent file based file
  */
-#define DIO_CREDITS 25
+static int ext4_indirect_calc_metadata_amount(struct inode *inode, int blocks)
+{
+	int icap = EXT4_ADDR_PER_BLOCK(inode->i_sb);
+	int ind_blks, dind_blks, tind_blks;
+
+	/* number of new indirect blocks needed */
+	ind_blks = (blocks + icap - 1) / icap;
+
+	dind_blks = (ind_blks + icap - 1) / icap;
 
+	tind_blks = 1;
+
+	return ind_blks + dind_blks + tind_blks;
+}
 
 /*
+ * Calculate the number of metadata blocks need to reserve
+ * to allocate given number of blocks
+ */
+static int ext4_calc_metadata_amount(struct inode *inode, int blocks)
+{
+	if (!blocks)
+		return 0;
+
+	if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)
+		return ext4_ext_calc_metadata_amount(inode, blocks);
+
+	return ext4_indirect_calc_metadata_amount(inode, blocks);
+}
+
+static void ext4_da_update_reserve_space(struct inode *inode, int used)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	int total, mdb, mdb_free;
+
+	spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
+	/* recalculate the number of metablocks still need to be reserved */
+	total = EXT4_I(inode)->i_reserved_data_blocks - used;
+	mdb = ext4_calc_metadata_amount(inode, total);
+
+	/* figure out how many metablocks to release */
+	BUG_ON(mdb > EXT4_I(inode)->i_reserved_meta_blocks);
+	mdb_free = EXT4_I(inode)->i_reserved_meta_blocks - mdb;
+
+	/* Account for allocated meta_blocks */
+	mdb_free -= EXT4_I(inode)->i_allocated_meta_blocks;
+
+	/* update fs free blocks counter for truncate case */
+	percpu_counter_add(&sbi->s_freeblocks_counter, mdb_free);
+
+	/* update per-inode reservations */
+	BUG_ON(used  > EXT4_I(inode)->i_reserved_data_blocks);
+	EXT4_I(inode)->i_reserved_data_blocks -= used;
+
+	BUG_ON(mdb > EXT4_I(inode)->i_reserved_meta_blocks);
+	EXT4_I(inode)->i_reserved_meta_blocks = mdb;
+	EXT4_I(inode)->i_allocated_meta_blocks = 0;
+	spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
+}
+
+/*
+ * The ext4_get_blocks_wrap() function try to look up the requested blocks,
+ * and returns if the blocks are already mapped.
  *
- *
- * ext4_ext4 get_block() wrapper function
- * It will do a look up first, and returns if the blocks already mapped.
  * Otherwise it takes the write lock of the i_data_sem and allocate blocks
  * and store the allocated blocks in the result buffer head and mark it
  * mapped.
@@ -934,7 +1070,7 @@ out:
  */
 int ext4_get_blocks_wrap(handle_t *handle, struct inode *inode, sector_t block,
 			unsigned long max_blocks, struct buffer_head *bh,
-			int create, int extend_disksize)
+			int create, int extend_disksize, int flag)
 {
 	int retval;
 
@@ -975,6 +1111,15 @@ int ext4_get_blocks_wrap(handle_t *handle, struct inode *inode, sector_t block,
 	 * with create == 1 flag.
 	 */
 	down_write((&EXT4_I(inode)->i_data_sem));
+
+	/*
+	 * if the caller is from delayed allocation writeout path
+	 * we have already reserved fs blocks for allocation
+	 * let the underlying get_block() function know to
+	 * avoid double accounting
+	 */
+	if (flag)
+		EXT4_I(inode)->i_delalloc_reserved_flag = 1;
 	/*
 	 * We need to check for EXT4 here because migrate
 	 * could have changed the inode type in between
@@ -996,23 +1141,39 @@ int ext4_get_blocks_wrap(handle_t *handle, struct inode *inode, sector_t block,
 							~EXT4_EXT_MIGRATE;
 		}
 	}
+
+	if (flag) {
+		EXT4_I(inode)->i_delalloc_reserved_flag = 0;
+		/*
+		 * Update reserved blocks/metadata blocks
+		 * after successful block allocation
+		 * which were deferred till now
+		 */
+		if ((retval > 0) && buffer_delay(bh))
+			ext4_da_update_reserve_space(inode, retval);
+	}
+
 	up_write((&EXT4_I(inode)->i_data_sem));
 	return retval;
 }
 
+/* Maximum number of blocks we map for direct IO at once. */
+#define DIO_MAX_BLOCKS 4096
+
 static int ext4_get_block(struct inode *inode, sector_t iblock,
 			struct buffer_head *bh_result, int create)
 {
 	handle_t *handle = ext4_journal_current_handle();
 	int ret = 0, started = 0;
 	unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
+	int dio_credits;
 
 	if (create && !handle) {
 		/* Direct IO write... */
 		if (max_blocks > DIO_MAX_BLOCKS)
 			max_blocks = DIO_MAX_BLOCKS;
-		handle = ext4_journal_start(inode, DIO_CREDITS +
-			      2 * EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb));
+		dio_credits = ext4_chunk_trans_blocks(inode, max_blocks);
+		handle = ext4_journal_start(inode, dio_credits);
 		if (IS_ERR(handle)) {
 			ret = PTR_ERR(handle);
 			goto out;
@@ -1021,7 +1182,7 @@ static int ext4_get_block(struct inode *inode, sector_t iblock,
 	}
 
 	ret = ext4_get_blocks_wrap(handle, inode, iblock,
-					max_blocks, bh_result, create, 0);
+					max_blocks, bh_result, create, 0, 0);
 	if (ret > 0) {
 		bh_result->b_size = (ret << inode->i_blkbits);
 		ret = 0;
@@ -1047,7 +1208,7 @@ struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
 	dummy.b_blocknr = -1000;
 	buffer_trace_init(&dummy.b_history);
 	err = ext4_get_blocks_wrap(handle, inode, block, 1,
-					&dummy, create, 1);
+					&dummy, create, 1, 0);
 	/*
 	 * ext4_get_blocks_handle() returns number of blocks
 	 * mapped. 0 in case of a HOLE.
@@ -1203,19 +1364,20 @@ static int ext4_write_begin(struct file *file, struct address_space *mapping,
  	to = from + len;
 
 retry:
- 	page = __grab_cache_page(mapping, index);
- 	if (!page)
- 		return -ENOMEM;
- 	*pagep = page;
-
   	handle = ext4_journal_start(inode, needed_blocks);
   	if (IS_ERR(handle)) {
- 		unlock_page(page);
- 		page_cache_release(page);
   		ret = PTR_ERR(handle);
   		goto out;
 	}
 
+	page = __grab_cache_page(mapping, index);
+	if (!page) {
+		ext4_journal_stop(handle);
+		ret = -ENOMEM;
+		goto out;
+	}
+	*pagep = page;
+
 	ret = block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
 							ext4_get_block);
 
@@ -1225,8 +1387,8 @@ retry:
 	}
 
 	if (ret) {
-		ext4_journal_stop(handle);
  		unlock_page(page);
+		ext4_journal_stop(handle);
  		page_cache_release(page);
 	}
 
@@ -1236,15 +1398,6 @@ out:
 	return ret;
 }
 
-int ext4_journal_dirty_data(handle_t *handle, struct buffer_head *bh)
-{
-	int err = jbd2_journal_dirty_data(handle, bh);
-	if (err)
-		ext4_journal_abort_handle(__func__, __func__,
-						bh, handle, err);
-	return err;
-}
-
 /* For write_end() in data=journal mode */
 static int write_end_fn(handle_t *handle, struct buffer_head *bh)
 {
@@ -1255,29 +1408,6 @@ static int write_end_fn(handle_t *handle, struct buffer_head *bh)
 }
 
 /*
- * Generic write_end handler for ordered and writeback ext4 journal modes.
- * We can't use generic_write_end, because that unlocks the page and we need to
- * unlock the page after ext4_journal_stop, but ext4_journal_stop must run
- * after block_write_end.
- */
-static int ext4_generic_write_end(struct file *file,
-				struct address_space *mapping,
-				loff_t pos, unsigned len, unsigned copied,
-				struct page *page, void *fsdata)
-{
-	struct inode *inode = file->f_mapping->host;
-
-	copied = block_write_end(file, mapping, pos, len, copied, page, fsdata);
-
-	if (pos+copied > inode->i_size) {
-		i_size_write(inode, pos+copied);
-		mark_inode_dirty(inode);
-	}
-
-	return copied;
-}
-
-/*
  * We need to pick up the new inode size which generic_commit_write gave us
  * `file' can be NULL - eg, when called from page_symlink().
  *
@@ -1290,15 +1420,10 @@ static int ext4_ordered_write_end(struct file *file,
 				struct page *page, void *fsdata)
 {
 	handle_t *handle = ext4_journal_current_handle();
-	struct inode *inode = file->f_mapping->host;
-	unsigned from, to;
+	struct inode *inode = mapping->host;
 	int ret = 0, ret2;
 
-	from = pos & (PAGE_CACHE_SIZE - 1);
-	to = from + len;
-
-	ret = walk_page_buffers(handle, page_buffers(page),
-		from, to, NULL, ext4_journal_dirty_data);
+	ret = ext4_jbd2_file_inode(handle, inode);
 
 	if (ret == 0) {
 		/*
@@ -1311,7 +1436,7 @@ static int ext4_ordered_write_end(struct file *file,
 		new_i_size = pos + copied;
 		if (new_i_size > EXT4_I(inode)->i_disksize)
 			EXT4_I(inode)->i_disksize = new_i_size;
-		ret2 = ext4_generic_write_end(file, mapping, pos, len, copied,
+		ret2 = generic_write_end(file, mapping, pos, len, copied,
 							page, fsdata);
 		copied = ret2;
 		if (ret2 < 0)
@@ -1320,8 +1445,6 @@ static int ext4_ordered_write_end(struct file *file,
 	ret2 = ext4_journal_stop(handle);
 	if (!ret)
 		ret = ret2;
-	unlock_page(page);
-	page_cache_release(page);
 
 	return ret ? ret : copied;
 }
@@ -1332,7 +1455,7 @@ static int ext4_writeback_write_end(struct file *file,
 				struct page *page, void *fsdata)
 {
 	handle_t *handle = ext4_journal_current_handle();
-	struct inode *inode = file->f_mapping->host;
+	struct inode *inode = mapping->host;
 	int ret = 0, ret2;
 	loff_t new_i_size;
 
@@ -1340,7 +1463,7 @@ static int ext4_writeback_write_end(struct file *file,
 	if (new_i_size > EXT4_I(inode)->i_disksize)
 		EXT4_I(inode)->i_disksize = new_i_size;
 
-	ret2 = ext4_generic_write_end(file, mapping, pos, len, copied,
+	ret2 = generic_write_end(file, mapping, pos, len, copied,
 							page, fsdata);
 	copied = ret2;
 	if (ret2 < 0)
@@ -1349,8 +1472,6 @@ static int ext4_writeback_write_end(struct file *file,
 	ret2 = ext4_journal_stop(handle);
 	if (!ret)
 		ret = ret2;
-	unlock_page(page);
-	page_cache_release(page);
 
 	return ret ? ret : copied;
 }
@@ -1389,15 +1510,1028 @@ static int ext4_journalled_write_end(struct file *file,
 			ret = ret2;
 	}
 
+	unlock_page(page);
 	ret2 = ext4_journal_stop(handle);
 	if (!ret)
 		ret = ret2;
-	unlock_page(page);
 	page_cache_release(page);
 
 	return ret ? ret : copied;
 }
 
+static int ext4_da_reserve_space(struct inode *inode, int nrblocks)
+{
+       struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+       unsigned long md_needed, mdblocks, total = 0;
+
+	/*
+	 * recalculate the amount of metadata blocks to reserve
+	 * in order to allocate nrblocks
+	 * worse case is one extent per block
+	 */
+	spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
+	total = EXT4_I(inode)->i_reserved_data_blocks + nrblocks;
+	mdblocks = ext4_calc_metadata_amount(inode, total);
+	BUG_ON(mdblocks < EXT4_I(inode)->i_reserved_meta_blocks);
+
+	md_needed = mdblocks - EXT4_I(inode)->i_reserved_meta_blocks;
+	total = md_needed + nrblocks;
+
+	if (ext4_has_free_blocks(sbi, total) < total) {
+		spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
+		return -ENOSPC;
+	}
+	/* reduce fs free blocks counter */
+	percpu_counter_sub(&sbi->s_freeblocks_counter, total);
+
+	EXT4_I(inode)->i_reserved_data_blocks += nrblocks;
+	EXT4_I(inode)->i_reserved_meta_blocks = mdblocks;
+
+	spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
+	return 0;       /* success */
+}
+
+static void ext4_da_release_space(struct inode *inode, int to_free)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
+	int total, mdb, mdb_free, release;
+
+	if (!to_free)
+		return;		/* Nothing to release, exit */
+
+	spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
+
+	if (!EXT4_I(inode)->i_reserved_data_blocks) {
+		/*
+		 * if there is no reserved blocks, but we try to free some
+		 * then the counter is messed up somewhere.
+		 * but since this function is called from invalidate
+		 * page, it's harmless to return without any action
+		 */
+		printk(KERN_INFO "ext4 delalloc try to release %d reserved "
+			    "blocks for inode %lu, but there is no reserved "
+			    "data blocks\n", to_free, inode->i_ino);
+		spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
+		return;
+	}
+
+	/* recalculate the number of metablocks still need to be reserved */
+	total = EXT4_I(inode)->i_reserved_data_blocks - to_free;
+	mdb = ext4_calc_metadata_amount(inode, total);
+
+	/* figure out how many metablocks to release */
+	BUG_ON(mdb > EXT4_I(inode)->i_reserved_meta_blocks);
+	mdb_free = EXT4_I(inode)->i_reserved_meta_blocks - mdb;
+
+	release = to_free + mdb_free;
+
+	/* update fs free blocks counter for truncate case */
+	percpu_counter_add(&sbi->s_freeblocks_counter, release);
+
+	/* update per-inode reservations */
+	BUG_ON(to_free > EXT4_I(inode)->i_reserved_data_blocks);
+	EXT4_I(inode)->i_reserved_data_blocks -= to_free;
+
+	BUG_ON(mdb > EXT4_I(inode)->i_reserved_meta_blocks);
+	EXT4_I(inode)->i_reserved_meta_blocks = mdb;
+	spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
+}
+
+static void ext4_da_page_release_reservation(struct page *page,
+						unsigned long offset)
+{
+	int to_release = 0;
+	struct buffer_head *head, *bh;
+	unsigned int curr_off = 0;
+
+	head = page_buffers(page);
+	bh = head;
+	do {
+		unsigned int next_off = curr_off + bh->b_size;
+
+		if ((offset <= curr_off) && (buffer_delay(bh))) {
+			to_release++;
+			clear_buffer_delay(bh);
+		}
+		curr_off = next_off;
+	} while ((bh = bh->b_this_page) != head);
+	ext4_da_release_space(page->mapping->host, to_release);
+}
+
+/*
+ * Delayed allocation stuff
+ */
+
+struct mpage_da_data {
+	struct inode *inode;
+	struct buffer_head lbh;			/* extent of blocks */
+	unsigned long first_page, next_page;	/* extent of pages */
+	get_block_t *get_block;
+	struct writeback_control *wbc;
+	int io_done;
+	long pages_written;
+};
+
+/*
+ * mpage_da_submit_io - walks through extent of pages and try to write
+ * them with writepage() call back
+ *
+ * @mpd->inode: inode
+ * @mpd->first_page: first page of the extent
+ * @mpd->next_page: page after the last page of the extent
+ * @mpd->get_block: the filesystem's block mapper function
+ *
+ * By the time mpage_da_submit_io() is called we expect all blocks
+ * to be allocated. this may be wrong if allocation failed.
+ *
+ * As pages are already locked by write_cache_pages(), we can't use it
+ */
+static int mpage_da_submit_io(struct mpage_da_data *mpd)
+{
+	struct address_space *mapping = mpd->inode->i_mapping;
+	int ret = 0, err, nr_pages, i;
+	unsigned long index, end;
+	struct pagevec pvec;
+
+	BUG_ON(mpd->next_page <= mpd->first_page);
+	pagevec_init(&pvec, 0);
+	index = mpd->first_page;
+	end = mpd->next_page - 1;
+
+	while (index <= end) {
+		/* XXX: optimize tail */
+		nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
+		if (nr_pages == 0)
+			break;
+		for (i = 0; i < nr_pages; i++) {
+			struct page *page = pvec.pages[i];
+
+			index = page->index;
+			if (index > end)
+				break;
+			index++;
+
+			err = mapping->a_ops->writepage(page, mpd->wbc);
+			if (!err)
+				mpd->pages_written++;
+			/*
+			 * In error case, we have to continue because
+			 * remaining pages are still locked
+			 * XXX: unlock and re-dirty them?
+			 */
+			if (ret == 0)
+				ret = err;
+		}
+		pagevec_release(&pvec);
+	}
+	return ret;
+}
+
+/*
+ * mpage_put_bnr_to_bhs - walk blocks and assign them actual numbers
+ *
+ * @mpd->inode - inode to walk through
+ * @exbh->b_blocknr - first block on a disk
+ * @exbh->b_size - amount of space in bytes
+ * @logical - first logical block to start assignment with
+ *
+ * the function goes through all passed space and put actual disk
+ * block numbers into buffer heads, dropping BH_Delay
+ */
+static void mpage_put_bnr_to_bhs(struct mpage_da_data *mpd, sector_t logical,
+				 struct buffer_head *exbh)
+{
+	struct inode *inode = mpd->inode;
+	struct address_space *mapping = inode->i_mapping;
+	int blocks = exbh->b_size >> inode->i_blkbits;
+	sector_t pblock = exbh->b_blocknr, cur_logical;
+	struct buffer_head *head, *bh;
+	pgoff_t index, end;
+	struct pagevec pvec;
+	int nr_pages, i;
+
+	index = logical >> (PAGE_CACHE_SHIFT - inode->i_blkbits);
+	end = (logical + blocks - 1) >> (PAGE_CACHE_SHIFT - inode->i_blkbits);
+	cur_logical = index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
+
+	pagevec_init(&pvec, 0);
+
+	while (index <= end) {
+		/* XXX: optimize tail */
+		nr_pages = pagevec_lookup(&pvec, mapping, index, PAGEVEC_SIZE);
+		if (nr_pages == 0)
+			break;
+		for (i = 0; i < nr_pages; i++) {
+			struct page *page = pvec.pages[i];
+
+			index = page->index;
+			if (index > end)
+				break;
+			index++;
+
+			BUG_ON(!PageLocked(page));
+			BUG_ON(PageWriteback(page));
+			BUG_ON(!page_has_buffers(page));
+
+			bh = page_buffers(page);
+			head = bh;
+
+			/* skip blocks out of the range */
+			do {
+				if (cur_logical >= logical)
+					break;
+				cur_logical++;
+			} while ((bh = bh->b_this_page) != head);
+
+			do {
+				if (cur_logical >= logical + blocks)
+					break;
+				if (buffer_delay(bh)) {
+					bh->b_blocknr = pblock;
+					clear_buffer_delay(bh);
+					bh->b_bdev = inode->i_sb->s_bdev;
+				} else if (buffer_unwritten(bh)) {
+					bh->b_blocknr = pblock;
+					clear_buffer_unwritten(bh);
+					set_buffer_mapped(bh);
+					set_buffer_new(bh);
+					bh->b_bdev = inode->i_sb->s_bdev;
+				} else if (buffer_mapped(bh))
+					BUG_ON(bh->b_blocknr != pblock);
+
+				cur_logical++;
+				pblock++;
+			} while ((bh = bh->b_this_page) != head);
+		}
+		pagevec_release(&pvec);
+	}
+}
+
+
+/*
+ * __unmap_underlying_blocks - just a helper function to unmap
+ * set of blocks described by @bh
+ */
+static inline void __unmap_underlying_blocks(struct inode *inode,
+					     struct buffer_head *bh)
+{
+	struct block_device *bdev = inode->i_sb->s_bdev;
+	int blocks, i;
+
+	blocks = bh->b_size >> inode->i_blkbits;
+	for (i = 0; i < blocks; i++)
+		unmap_underlying_metadata(bdev, bh->b_blocknr + i);
+}
+
+/*
+ * mpage_da_map_blocks - go through given space
+ *
+ * @mpd->lbh - bh describing space
+ * @mpd->get_block - the filesystem's block mapper function
+ *
+ * The function skips space we know is already mapped to disk blocks.
+ *
+ */
+static void mpage_da_map_blocks(struct mpage_da_data *mpd)
+{
+	int err = 0;
+	struct buffer_head *lbh = &mpd->lbh;
+	sector_t next = lbh->b_blocknr;
+	struct buffer_head new;
+
+	/*
+	 * We consider only non-mapped and non-allocated blocks
+	 */
+	if (buffer_mapped(lbh) && !buffer_delay(lbh))
+		return;
+
+	new.b_state = lbh->b_state;
+	new.b_blocknr = 0;
+	new.b_size = lbh->b_size;
+
+	/*
+	 * If we didn't accumulate anything
+	 * to write simply return
+	 */
+	if (!new.b_size)
+		return;
+	err = mpd->get_block(mpd->inode, next, &new, 1);
+	if (err)
+		return;
+	BUG_ON(new.b_size == 0);
+
+	if (buffer_new(&new))
+		__unmap_underlying_blocks(mpd->inode, &new);
+
+	/*
+	 * If blocks are delayed marked, we need to
+	 * put actual blocknr and drop delayed bit
+	 */
+	if (buffer_delay(lbh) || buffer_unwritten(lbh))
+		mpage_put_bnr_to_bhs(mpd, next, &new);
+
+	return;
+}
+
+#define BH_FLAGS ((1 << BH_Uptodate) | (1 << BH_Mapped) | \
+		(1 << BH_Delay) | (1 << BH_Unwritten))
+
+/*
+ * mpage_add_bh_to_extent - try to add one more block to extent of blocks
+ *
+ * @mpd->lbh - extent of blocks
+ * @logical - logical number of the block in the file
+ * @bh - bh of the block (used to access block's state)
+ *
+ * the function is used to collect contig. blocks in same state
+ */
+static void mpage_add_bh_to_extent(struct mpage_da_data *mpd,
+				   sector_t logical, struct buffer_head *bh)
+{
+	sector_t next;
+	size_t b_size = bh->b_size;
+	struct buffer_head *lbh = &mpd->lbh;
+	int nrblocks = lbh->b_size >> mpd->inode->i_blkbits;
+
+	/* check if thereserved journal credits might overflow */
+	if (!(EXT4_I(mpd->inode)->i_flags & EXT4_EXTENTS_FL)) {
+		if (nrblocks >= EXT4_MAX_TRANS_DATA) {
+			/*
+			 * With non-extent format we are limited by the journal
+			 * credit available.  Total credit needed to insert
+			 * nrblocks contiguous blocks is dependent on the
+			 * nrblocks.  So limit nrblocks.
+			 */
+			goto flush_it;
+		} else if ((nrblocks + (b_size >> mpd->inode->i_blkbits)) >
+				EXT4_MAX_TRANS_DATA) {
+			/*
+			 * Adding the new buffer_head would make it cross the
+			 * allowed limit for which we have journal credit
+			 * reserved. So limit the new bh->b_size
+			 */
+			b_size = (EXT4_MAX_TRANS_DATA - nrblocks) <<
+						mpd->inode->i_blkbits;
+			/* we will do mpage_da_submit_io in the next loop */
+		}
+	}
+	/*
+	 * First block in the extent
+	 */
+	if (lbh->b_size == 0) {
+		lbh->b_blocknr = logical;
+		lbh->b_size = b_size;
+		lbh->b_state = bh->b_state & BH_FLAGS;
+		return;
+	}
+
+	next = lbh->b_blocknr + nrblocks;
+	/*
+	 * Can we merge the block to our big extent?
+	 */
+	if (logical == next && (bh->b_state & BH_FLAGS) == lbh->b_state) {
+		lbh->b_size += b_size;
+		return;
+	}
+
+flush_it:
+	/*
+	 * We couldn't merge the block to our extent, so we
+	 * need to flush current  extent and start new one
+	 */
+	mpage_da_map_blocks(mpd);
+	mpage_da_submit_io(mpd);
+	mpd->io_done = 1;
+	return;
+}
+
+/*
+ * __mpage_da_writepage - finds extent of pages and blocks
+ *
+ * @page: page to consider
+ * @wbc: not used, we just follow rules
+ * @data: context
+ *
+ * The function finds extents of pages and scan them for all blocks.
+ */
+static int __mpage_da_writepage(struct page *page,
+				struct writeback_control *wbc, void *data)
+{
+	struct mpage_da_data *mpd = data;
+	struct inode *inode = mpd->inode;
+	struct buffer_head *bh, *head, fake;
+	sector_t logical;
+
+	if (mpd->io_done) {
+		/*
+		 * Rest of the page in the page_vec
+		 * redirty then and skip then. We will
+		 * try to to write them again after
+		 * starting a new transaction
+		 */
+		redirty_page_for_writepage(wbc, page);
+		unlock_page(page);
+		return MPAGE_DA_EXTENT_TAIL;
+	}
+	/*
+	 * Can we merge this page to current extent?
+	 */
+	if (mpd->next_page != page->index) {
+		/*
+		 * Nope, we can't. So, we map non-allocated blocks
+		 * and start IO on them using writepage()
+		 */
+		if (mpd->next_page != mpd->first_page) {
+			mpage_da_map_blocks(mpd);
+			mpage_da_submit_io(mpd);
+			/*
+			 * skip rest of the page in the page_vec
+			 */
+			mpd->io_done = 1;
+			redirty_page_for_writepage(wbc, page);
+			unlock_page(page);
+			return MPAGE_DA_EXTENT_TAIL;
+		}
+
+		/*
+		 * Start next extent of pages ...
+		 */
+		mpd->first_page = page->index;
+
+		/*
+		 * ... and blocks
+		 */
+		mpd->lbh.b_size = 0;
+		mpd->lbh.b_state = 0;
+		mpd->lbh.b_blocknr = 0;
+	}
+
+	mpd->next_page = page->index + 1;
+	logical = (sector_t) page->index <<
+		  (PAGE_CACHE_SHIFT - inode->i_blkbits);
+
+	if (!page_has_buffers(page)) {
+		/*
+		 * There is no attached buffer heads yet (mmap?)
+		 * we treat the page asfull of dirty blocks
+		 */
+		bh = &fake;
+		bh->b_size = PAGE_CACHE_SIZE;
+		bh->b_state = 0;
+		set_buffer_dirty(bh);
+		set_buffer_uptodate(bh);
+		mpage_add_bh_to_extent(mpd, logical, bh);
+		if (mpd->io_done)
+			return MPAGE_DA_EXTENT_TAIL;
+	} else {
+		/*
+		 * Page with regular buffer heads, just add all dirty ones
+		 */
+		head = page_buffers(page);
+		bh = head;
+		do {
+			BUG_ON(buffer_locked(bh));
+			if (buffer_dirty(bh) &&
+				(!buffer_mapped(bh) || buffer_delay(bh))) {
+				mpage_add_bh_to_extent(mpd, logical, bh);
+				if (mpd->io_done)
+					return MPAGE_DA_EXTENT_TAIL;
+			}
+			logical++;
+		} while ((bh = bh->b_this_page) != head);
+	}
+
+	return 0;
+}
+
+/*
+ * mpage_da_writepages - walk the list of dirty pages of the given
+ * address space, allocates non-allocated blocks, maps newly-allocated
+ * blocks to existing bhs and issue IO them
+ *
+ * @mapping: address space structure to write
+ * @wbc: subtract the number of written pages from *@wbc->nr_to_write
+ * @get_block: the filesystem's block mapper function.
+ *
+ * This is a library function, which implements the writepages()
+ * address_space_operation.
+ */
+static int mpage_da_writepages(struct address_space *mapping,
+			       struct writeback_control *wbc,
+			       get_block_t get_block)
+{
+	struct mpage_da_data mpd;
+	long to_write;
+	int ret;
+
+	if (!get_block)
+		return generic_writepages(mapping, wbc);
+
+	mpd.wbc = wbc;
+	mpd.inode = mapping->host;
+	mpd.lbh.b_size = 0;
+	mpd.lbh.b_state = 0;
+	mpd.lbh.b_blocknr = 0;
+	mpd.first_page = 0;
+	mpd.next_page = 0;
+	mpd.get_block = get_block;
+	mpd.io_done = 0;
+	mpd.pages_written = 0;
+
+	to_write = wbc->nr_to_write;
+
+	ret = write_cache_pages(mapping, wbc, __mpage_da_writepage, &mpd);
+
+	/*
+	 * Handle last extent of pages
+	 */
+	if (!mpd.io_done && mpd.next_page != mpd.first_page) {
+		mpage_da_map_blocks(&mpd);
+		mpage_da_submit_io(&mpd);
+	}
+
+	wbc->nr_to_write = to_write - mpd.pages_written;
+	return ret;
+}
+
+/*
+ * this is a special callback for ->write_begin() only
+ * it's intention is to return mapped block or reserve space
+ */
+static int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
+				  struct buffer_head *bh_result, int create)
+{
+	int ret = 0;
+
+	BUG_ON(create == 0);
+	BUG_ON(bh_result->b_size != inode->i_sb->s_blocksize);
+
+	/*
+	 * first, we need to know whether the block is allocated already
+	 * preallocated blocks are unmapped but should treated
+	 * the same as allocated blocks.
+	 */
+	ret = ext4_get_blocks_wrap(NULL, inode, iblock, 1,  bh_result, 0, 0, 0);
+	if ((ret == 0) && !buffer_delay(bh_result)) {
+		/* the block isn't (pre)allocated yet, let's reserve space */
+		/*
+		 * XXX: __block_prepare_write() unmaps passed block,
+		 * is it OK?
+		 */
+		ret = ext4_da_reserve_space(inode, 1);
+		if (ret)
+			/* not enough space to reserve */
+			return ret;
+
+		map_bh(bh_result, inode->i_sb, 0);
+		set_buffer_new(bh_result);
+		set_buffer_delay(bh_result);
+	} else if (ret > 0) {
+		bh_result->b_size = (ret << inode->i_blkbits);
+		ret = 0;
+	}
+
+	return ret;
+}
+#define		EXT4_DELALLOC_RSVED	1
+static int ext4_da_get_block_write(struct inode *inode, sector_t iblock,
+				   struct buffer_head *bh_result, int create)
+{
+	int ret;
+	unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
+	loff_t disksize = EXT4_I(inode)->i_disksize;
+	handle_t *handle = NULL;
+
+	handle = ext4_journal_current_handle();
+	if (!handle) {
+		ret = ext4_get_blocks_wrap(handle, inode, iblock, max_blocks,
+				   bh_result, 0, 0, 0);
+		BUG_ON(!ret);
+	} else {
+		ret = ext4_get_blocks_wrap(handle, inode, iblock, max_blocks,
+				   bh_result, create, 0, EXT4_DELALLOC_RSVED);
+	}
+
+	if (ret > 0) {
+		bh_result->b_size = (ret << inode->i_blkbits);
+
+		/*
+		 * Update on-disk size along with block allocation
+		 * we don't use 'extend_disksize' as size may change
+		 * within already allocated block -bzzz
+		 */
+		disksize = ((loff_t) iblock + ret) << inode->i_blkbits;
+		if (disksize > i_size_read(inode))
+			disksize = i_size_read(inode);
+		if (disksize > EXT4_I(inode)->i_disksize) {
+			/*
+			 * XXX: replace with spinlock if seen contended -bzzz
+			 */
+			down_write(&EXT4_I(inode)->i_data_sem);
+			if (disksize > EXT4_I(inode)->i_disksize)
+				EXT4_I(inode)->i_disksize = disksize;
+			up_write(&EXT4_I(inode)->i_data_sem);
+
+			if (EXT4_I(inode)->i_disksize == disksize) {
+				ret = ext4_mark_inode_dirty(handle, inode);
+				return ret;
+			}
+		}
+		ret = 0;
+	}
+	return ret;
+}
+
+static int ext4_bh_unmapped_or_delay(handle_t *handle, struct buffer_head *bh)
+{
+	/*
+	 * unmapped buffer is possible for holes.
+	 * delay buffer is possible with delayed allocation
+	 */
+	return ((!buffer_mapped(bh) || buffer_delay(bh)) && buffer_dirty(bh));
+}
+
+static int ext4_normal_get_block_write(struct inode *inode, sector_t iblock,
+				   struct buffer_head *bh_result, int create)
+{
+	int ret = 0;
+	unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
+
+	/*
+	 * we don't want to do block allocation in writepage
+	 * so call get_block_wrap with create = 0
+	 */
+	ret = ext4_get_blocks_wrap(NULL, inode, iblock, max_blocks,
+				   bh_result, 0, 0, 0);
+	if (ret > 0) {
+		bh_result->b_size = (ret << inode->i_blkbits);
+		ret = 0;
+	}
+	return ret;
+}
+
+/*
+ * get called vi ext4_da_writepages after taking page lock (have journal handle)
+ * get called via journal_submit_inode_data_buffers (no journal handle)
+ * get called via shrink_page_list via pdflush (no journal handle)
+ * or grab_page_cache when doing write_begin (have journal handle)
+ */
+static int ext4_da_writepage(struct page *page,
+				struct writeback_control *wbc)
+{
+	int ret = 0;
+	loff_t size;
+	unsigned long len;
+	struct buffer_head *page_bufs;
+	struct inode *inode = page->mapping->host;
+
+	size = i_size_read(inode);
+	if (page->index == size >> PAGE_CACHE_SHIFT)
+		len = size & ~PAGE_CACHE_MASK;
+	else
+		len = PAGE_CACHE_SIZE;
+
+	if (page_has_buffers(page)) {
+		page_bufs = page_buffers(page);
+		if (walk_page_buffers(NULL, page_bufs, 0, len, NULL,
+					ext4_bh_unmapped_or_delay)) {
+			/*
+			 * We don't want to do  block allocation
+			 * So redirty the page and return
+			 * We may reach here when we do a journal commit
+			 * via journal_submit_inode_data_buffers.
+			 * If we don't have mapping block we just ignore
+			 * them. We can also reach here via shrink_page_list
+			 */
+			redirty_page_for_writepage(wbc, page);
+			unlock_page(page);
+			return 0;
+		}
+	} else {
+		/*
+		 * The test for page_has_buffers() is subtle:
+		 * We know the page is dirty but it lost buffers. That means
+		 * that at some moment in time after write_begin()/write_end()
+		 * has been called all buffers have been clean and thus they
+		 * must have been written at least once. So they are all
+		 * mapped and we can happily proceed with mapping them
+		 * and writing the page.
+		 *
+		 * Try to initialize the buffer_heads and check whether
+		 * all are mapped and non delay. We don't want to
+		 * do block allocation here.
+		 */
+		ret = block_prepare_write(page, 0, PAGE_CACHE_SIZE,
+						ext4_normal_get_block_write);
+		if (!ret) {
+			page_bufs = page_buffers(page);
+			/* check whether all are mapped and non delay */
+			if (walk_page_buffers(NULL, page_bufs, 0, len, NULL,
+						ext4_bh_unmapped_or_delay)) {
+				redirty_page_for_writepage(wbc, page);
+				unlock_page(page);
+				return 0;
+			}
+		} else {
+			/*
+			 * We can't do block allocation here
+			 * so just redity the page and unlock
+			 * and return
+			 */
+			redirty_page_for_writepage(wbc, page);
+			unlock_page(page);
+			return 0;
+		}
+	}
+
+	if (test_opt(inode->i_sb, NOBH) && ext4_should_writeback_data(inode))
+		ret = nobh_writepage(page, ext4_normal_get_block_write, wbc);
+	else
+		ret = block_write_full_page(page,
+						ext4_normal_get_block_write,
+						wbc);
+
+	return ret;
+}
+
+/*
+ * This is called via ext4_da_writepages() to
+ * calulate the total number of credits to reserve to fit
+ * a single extent allocation into a single transaction,
+ * ext4_da_writpeages() will loop calling this before
+ * the block allocation.
+ */
+
+static int ext4_da_writepages_trans_blocks(struct inode *inode)
+{
+	int max_blocks = EXT4_I(inode)->i_reserved_data_blocks;
+
+	/*
+	 * With non-extent format the journal credit needed to
+	 * insert nrblocks contiguous block is dependent on
+	 * number of contiguous block. So we will limit
+	 * number of contiguous block to a sane value
+	 */
+	if (!(inode->i_flags & EXT4_EXTENTS_FL) &&
+	    (max_blocks > EXT4_MAX_TRANS_DATA))
+		max_blocks = EXT4_MAX_TRANS_DATA;
+
+	return ext4_chunk_trans_blocks(inode, max_blocks);
+}
+
+static int ext4_da_writepages(struct address_space *mapping,
+			      struct writeback_control *wbc)
+{
+	handle_t *handle = NULL;
+	loff_t range_start = 0;
+	struct inode *inode = mapping->host;
+	int needed_blocks, ret = 0, nr_to_writebump = 0;
+	long to_write, pages_skipped = 0;
+	struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb);
+
+	/*
+	 * No pages to write? This is mainly a kludge to avoid starting
+	 * a transaction for special inodes like journal inode on last iput()
+	 * because that could violate lock ordering on umount
+	 */
+	if (!mapping->nrpages || !mapping_tagged(mapping, PAGECACHE_TAG_DIRTY))
+		return 0;
+	/*
+	 * Make sure nr_to_write is >= sbi->s_mb_stream_request
+	 * This make sure small files blocks are allocated in
+	 * single attempt. This ensure that small files
+	 * get less fragmented.
+	 */
+	if (wbc->nr_to_write < sbi->s_mb_stream_request) {
+		nr_to_writebump = sbi->s_mb_stream_request - wbc->nr_to_write;
+		wbc->nr_to_write = sbi->s_mb_stream_request;
+	}
+
+	if (!wbc->range_cyclic)
+		/*
+		 * If range_cyclic is not set force range_cont
+		 * and save the old writeback_index
+		 */
+		wbc->range_cont = 1;
+
+	range_start =  wbc->range_start;
+	pages_skipped = wbc->pages_skipped;
+
+restart_loop:
+	to_write = wbc->nr_to_write;
+	while (!ret && to_write > 0) {
+
+		/*
+		 * we  insert one extent at a time. So we need
+		 * credit needed for single extent allocation.
+		 * journalled mode is currently not supported
+		 * by delalloc
+		 */
+		BUG_ON(ext4_should_journal_data(inode));
+		needed_blocks = ext4_da_writepages_trans_blocks(inode);
+
+		/* start a new transaction*/
+		handle = ext4_journal_start(inode, needed_blocks);
+		if (IS_ERR(handle)) {
+			ret = PTR_ERR(handle);
+			printk(KERN_EMERG "%s: jbd2_start: "
+			       "%ld pages, ino %lu; err %d\n", __func__,
+				wbc->nr_to_write, inode->i_ino, ret);
+			dump_stack();
+			goto out_writepages;
+		}
+		if (ext4_should_order_data(inode)) {
+			/*
+			 * With ordered mode we need to add
+			 * the inode to the journal handl
+			 * when we do block allocation.
+			 */
+			ret = ext4_jbd2_file_inode(handle, inode);
+			if (ret) {
+				ext4_journal_stop(handle);
+				goto out_writepages;
+			}
+		}
+
+		to_write -= wbc->nr_to_write;
+		ret = mpage_da_writepages(mapping, wbc,
+					  ext4_da_get_block_write);
+		ext4_journal_stop(handle);
+		if (ret == MPAGE_DA_EXTENT_TAIL) {
+			/*
+			 * got one extent now try with
+			 * rest of the pages
+			 */
+			to_write += wbc->nr_to_write;
+			ret = 0;
+		} else if (wbc->nr_to_write) {
+			/*
+			 * There is no more writeout needed
+			 * or we requested for a noblocking writeout
+			 * and we found the device congested
+			 */
+			to_write += wbc->nr_to_write;
+			break;
+		}
+		wbc->nr_to_write = to_write;
+	}
+
+	if (wbc->range_cont && (pages_skipped != wbc->pages_skipped)) {
+		/* We skipped pages in this loop */
+		wbc->range_start = range_start;
+		wbc->nr_to_write = to_write +
+				wbc->pages_skipped - pages_skipped;
+		wbc->pages_skipped = pages_skipped;
+		goto restart_loop;
+	}
+
+out_writepages:
+	wbc->nr_to_write = to_write - nr_to_writebump;
+	wbc->range_start = range_start;
+	return ret;
+}
+
+static int ext4_da_write_begin(struct file *file, struct address_space *mapping,
+				loff_t pos, unsigned len, unsigned flags,
+				struct page **pagep, void **fsdata)
+{
+	int ret, retries = 0;
+	struct page *page;
+	pgoff_t index;
+	unsigned from, to;
+	struct inode *inode = mapping->host;
+	handle_t *handle;
+
+	index = pos >> PAGE_CACHE_SHIFT;
+	from = pos & (PAGE_CACHE_SIZE - 1);
+	to = from + len;
+
+retry:
+	/*
+	 * With delayed allocation, we don't log the i_disksize update
+	 * if there is delayed block allocation. But we still need
+	 * to journalling the i_disksize update if writes to the end
+	 * of file which has an already mapped buffer.
+	 */
+	handle = ext4_journal_start(inode, 1);
+	if (IS_ERR(handle)) {
+		ret = PTR_ERR(handle);
+		goto out;
+	}
+
+	page = __grab_cache_page(mapping, index);
+	if (!page) {
+		ext4_journal_stop(handle);
+		ret = -ENOMEM;
+		goto out;
+	}
+	*pagep = page;
+
+	ret = block_write_begin(file, mapping, pos, len, flags, pagep, fsdata,
+							ext4_da_get_block_prep);
+	if (ret < 0) {
+		unlock_page(page);
+		ext4_journal_stop(handle);
+		page_cache_release(page);
+	}
+
+	if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
+		goto retry;
+out:
+	return ret;
+}
+
+/*
+ * Check if we should update i_disksize
+ * when write to the end of file but not require block allocation
+ */
+static int ext4_da_should_update_i_disksize(struct page *page,
+					 unsigned long offset)
+{
+	struct buffer_head *bh;
+	struct inode *inode = page->mapping->host;
+	unsigned int idx;
+	int i;
+
+	bh = page_buffers(page);
+	idx = offset >> inode->i_blkbits;
+
+	for (i=0; i < idx; i++)
+		bh = bh->b_this_page;
+
+	if (!buffer_mapped(bh) || (buffer_delay(bh)))
+		return 0;
+	return 1;
+}
+
+static int ext4_da_write_end(struct file *file,
+				struct address_space *mapping,
+				loff_t pos, unsigned len, unsigned copied,
+				struct page *page, void *fsdata)
+{
+	struct inode *inode = mapping->host;
+	int ret = 0, ret2;
+	handle_t *handle = ext4_journal_current_handle();
+	loff_t new_i_size;
+	unsigned long start, end;
+
+	start = pos & (PAGE_CACHE_SIZE - 1);
+	end = start + copied -1;
+
+	/*
+	 * generic_write_end() will run mark_inode_dirty() if i_size
+	 * changes.  So let's piggyback the i_disksize mark_inode_dirty
+	 * into that.
+	 */
+
+	new_i_size = pos + copied;
+	if (new_i_size > EXT4_I(inode)->i_disksize) {
+		if (ext4_da_should_update_i_disksize(page, end)) {
+			down_write(&EXT4_I(inode)->i_data_sem);
+			if (new_i_size > EXT4_I(inode)->i_disksize) {
+				/*
+				 * Updating i_disksize when extending file
+				 * without needing block allocation
+				 */
+				if (ext4_should_order_data(inode))
+					ret = ext4_jbd2_file_inode(handle,
+								   inode);
+
+				EXT4_I(inode)->i_disksize = new_i_size;
+			}
+			up_write(&EXT4_I(inode)->i_data_sem);
+		}
+	}
+	ret2 = generic_write_end(file, mapping, pos, len, copied,
+							page, fsdata);
+	copied = ret2;
+	if (ret2 < 0)
+		ret = ret2;
+	ret2 = ext4_journal_stop(handle);
+	if (!ret)
+		ret = ret2;
+
+	return ret ? ret : copied;
+}
+
+static void ext4_da_invalidatepage(struct page *page, unsigned long offset)
+{
+	/*
+	 * Drop reserved blocks
+	 */
+	BUG_ON(!PageLocked(page));
+	if (!page_has_buffers(page))
+		goto out;
+
+	ext4_da_page_release_reservation(page, offset);
+
+out:
+	ext4_invalidatepage(page, offset);
+
+	return;
+}
+
+
 /*
  * bmap() is special.  It gets used by applications such as lilo and by
  * the swapper to find the on-disk block of a specific piece of data.
@@ -1418,6 +2552,16 @@ static sector_t ext4_bmap(struct address_space *mapping, sector_t block)
 	journal_t *journal;
 	int err;
 
+	if (mapping_tagged(mapping, PAGECACHE_TAG_DIRTY) &&
+			test_opt(inode->i_sb, DELALLOC)) {
+		/*
+		 * With delalloc we want to sync the file
+		 * so that we can make sure we allocate
+		 * blocks for file
+		 */
+		filemap_write_and_wait(mapping);
+	}
+
 	if (EXT4_I(inode)->i_state & EXT4_STATE_JDATA) {
 		/*
 		 * This is a REALLY heavyweight approach, but the use of
@@ -1462,21 +2606,17 @@ static int bput_one(handle_t *handle, struct buffer_head *bh)
 	return 0;
 }
 
-static int jbd2_journal_dirty_data_fn(handle_t *handle, struct buffer_head *bh)
-{
-	if (buffer_mapped(bh))
-		return ext4_journal_dirty_data(handle, bh);
-	return 0;
-}
-
 /*
- * Note that we always start a transaction even if we're not journalling
- * data.  This is to preserve ordering: any hole instantiation within
- * __block_write_full_page -> ext4_get_block() should be journalled
- * along with the data so we don't crash and then get metadata which
- * refers to old data.
+ * Note that we don't need to start a transaction unless we're journaling data
+ * because we should have holes filled from ext4_page_mkwrite(). We even don't
+ * need to file the inode to the transaction's list in ordered mode because if
+ * we are writing back data added by write(), the inode is already there and if
+ * we are writing back data modified via mmap(), noone guarantees in which
+ * transaction the data will hit the disk. In case we are journaling data, we
+ * cannot start transaction directly because transaction start ranks above page
+ * lock so we have to do some magic.
  *
- * In all journalling modes block_write_full_page() will start the I/O.
+ * In all journaling modes block_write_full_page() will start the I/O.
  *
  * Problem:
  *
@@ -1518,105 +2658,103 @@ static int jbd2_journal_dirty_data_fn(handle_t *handle, struct buffer_head *bh)
  * disastrous.  Any write() or metadata operation will sync the fs for
  * us.
  *
- * AKPM2: if all the page's buffers are mapped to disk and !data=journal,
- * we don't need to open a transaction here.
  */
-static int ext4_ordered_writepage(struct page *page,
+static int __ext4_normal_writepage(struct page *page,
 				struct writeback_control *wbc)
 {
 	struct inode *inode = page->mapping->host;
-	struct buffer_head *page_bufs;
-	handle_t *handle = NULL;
-	int ret = 0;
-	int err;
 
-	J_ASSERT(PageLocked(page));
-
-	/*
-	 * We give up here if we're reentered, because it might be for a
-	 * different filesystem.
-	 */
-	if (ext4_journal_current_handle())
-		goto out_fail;
-
-	handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode));
+	if (test_opt(inode->i_sb, NOBH))
+		return nobh_writepage(page,
+					ext4_normal_get_block_write, wbc);
+	else
+		return block_write_full_page(page,
+						ext4_normal_get_block_write,
+						wbc);
+}
 
-	if (IS_ERR(handle)) {
-		ret = PTR_ERR(handle);
-		goto out_fail;
-	}
+static int ext4_normal_writepage(struct page *page,
+				struct writeback_control *wbc)
+{
+	struct inode *inode = page->mapping->host;
+	loff_t size = i_size_read(inode);
+	loff_t len;
 
-	if (!page_has_buffers(page)) {
-		create_empty_buffers(page, inode->i_sb->s_blocksize,
-				(1 << BH_Dirty)|(1 << BH_Uptodate));
+	J_ASSERT(PageLocked(page));
+	if (page->index == size >> PAGE_CACHE_SHIFT)
+		len = size & ~PAGE_CACHE_MASK;
+	else
+		len = PAGE_CACHE_SIZE;
+
+	if (page_has_buffers(page)) {
+		/* if page has buffers it should all be mapped
+		 * and allocated. If there are not buffers attached
+		 * to the page we know the page is dirty but it lost
+		 * buffers. That means that at some moment in time
+		 * after write_begin() / write_end() has been called
+		 * all buffers have been clean and thus they must have been
+		 * written at least once. So they are all mapped and we can
+		 * happily proceed with mapping them and writing the page.
+		 */
+		BUG_ON(walk_page_buffers(NULL, page_buffers(page), 0, len, NULL,
+					ext4_bh_unmapped_or_delay));
 	}
-	page_bufs = page_buffers(page);
-	walk_page_buffers(handle, page_bufs, 0,
-			PAGE_CACHE_SIZE, NULL, bget_one);
-
-	ret = block_write_full_page(page, ext4_get_block, wbc);
-
-	/*
-	 * The page can become unlocked at any point now, and
-	 * truncate can then come in and change things.  So we
-	 * can't touch *page from now on.  But *page_bufs is
-	 * safe due to elevated refcount.
-	 */
 
-	/*
-	 * And attach them to the current transaction.  But only if
-	 * block_write_full_page() succeeded.  Otherwise they are unmapped,
-	 * and generally junk.
-	 */
-	if (ret == 0) {
-		err = walk_page_buffers(handle, page_bufs, 0, PAGE_CACHE_SIZE,
-					NULL, jbd2_journal_dirty_data_fn);
-		if (!ret)
-			ret = err;
-	}
-	walk_page_buffers(handle, page_bufs, 0,
-			PAGE_CACHE_SIZE, NULL, bput_one);
-	err = ext4_journal_stop(handle);
-	if (!ret)
-		ret = err;
-	return ret;
+	if (!ext4_journal_current_handle())
+		return __ext4_normal_writepage(page, wbc);
 
-out_fail:
 	redirty_page_for_writepage(wbc, page);
 	unlock_page(page);
-	return ret;
+	return 0;
 }
 
-static int ext4_writeback_writepage(struct page *page,
+static int __ext4_journalled_writepage(struct page *page,
 				struct writeback_control *wbc)
 {
-	struct inode *inode = page->mapping->host;
+	struct address_space *mapping = page->mapping;
+	struct inode *inode = mapping->host;
+	struct buffer_head *page_bufs;
 	handle_t *handle = NULL;
 	int ret = 0;
 	int err;
 
-	if (ext4_journal_current_handle())
-		goto out_fail;
+	ret = block_prepare_write(page, 0, PAGE_CACHE_SIZE,
+					ext4_normal_get_block_write);
+	if (ret != 0)
+		goto out_unlock;
+
+	page_bufs = page_buffers(page);
+	walk_page_buffers(handle, page_bufs, 0, PAGE_CACHE_SIZE, NULL,
+								bget_one);
+	/* As soon as we unlock the page, it can go away, but we have
+	 * references to buffers so we are safe */
+	unlock_page(page);
 
 	handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode));
 	if (IS_ERR(handle)) {
 		ret = PTR_ERR(handle);
-		goto out_fail;
+		goto out;
 	}
 
-	if (test_opt(inode->i_sb, NOBH) && ext4_should_writeback_data(inode))
-		ret = nobh_writepage(page, ext4_get_block, wbc);
-	else
-		ret = block_write_full_page(page, ext4_get_block, wbc);
+	ret = walk_page_buffers(handle, page_bufs, 0,
+			PAGE_CACHE_SIZE, NULL, do_journal_get_write_access);
 
+	err = walk_page_buffers(handle, page_bufs, 0,
+				PAGE_CACHE_SIZE, NULL, write_end_fn);
+	if (ret == 0)
+		ret = err;
 	err = ext4_journal_stop(handle);
 	if (!ret)
 		ret = err;
-	return ret;
 
-out_fail:
-	redirty_page_for_writepage(wbc, page);
+	walk_page_buffers(handle, page_bufs, 0,
+				PAGE_CACHE_SIZE, NULL, bput_one);
+	EXT4_I(inode)->i_state |= EXT4_STATE_JDATA;
+	goto out;
+
+out_unlock:
 	unlock_page(page);
+out:
 	return ret;
 }
 
@@ -1624,59 +2762,53 @@ static int ext4_journalled_writepage(struct page *page,
 				struct writeback_control *wbc)
 {
 	struct inode *inode = page->mapping->host;
-	handle_t *handle = NULL;
-	int ret = 0;
-	int err;
+	loff_t size = i_size_read(inode);
+	loff_t len;
 
-	if (ext4_journal_current_handle())
-		goto no_write;
+	J_ASSERT(PageLocked(page));
+	if (page->index == size >> PAGE_CACHE_SHIFT)
+		len = size & ~PAGE_CACHE_MASK;
+	else
+		len = PAGE_CACHE_SIZE;
+
+	if (page_has_buffers(page)) {
+		/* if page has buffers it should all be mapped
+		 * and allocated. If there are not buffers attached
+		 * to the page we know the page is dirty but it lost
+		 * buffers. That means that at some moment in time
+		 * after write_begin() / write_end() has been called
+		 * all buffers have been clean and thus they must have been
+		 * written at least once. So they are all mapped and we can
+		 * happily proceed with mapping them and writing the page.
+		 */
+		BUG_ON(walk_page_buffers(NULL, page_buffers(page), 0, len, NULL,
+					ext4_bh_unmapped_or_delay));
+	}
 
-	handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode));
-	if (IS_ERR(handle)) {
-		ret = PTR_ERR(handle);
+	if (ext4_journal_current_handle())
 		goto no_write;
-	}
 
-	if (!page_has_buffers(page) || PageChecked(page)) {
+	if (PageChecked(page)) {
 		/*
 		 * It's mmapped pagecache.  Add buffers and journal it.  There
 		 * doesn't seem much point in redirtying the page here.
 		 */
 		ClearPageChecked(page);
-		ret = block_prepare_write(page, 0, PAGE_CACHE_SIZE,
-					ext4_get_block);
-		if (ret != 0) {
-			ext4_journal_stop(handle);
-			goto out_unlock;
-		}
-		ret = walk_page_buffers(handle, page_buffers(page), 0,
-			PAGE_CACHE_SIZE, NULL, do_journal_get_write_access);
-
-		err = walk_page_buffers(handle, page_buffers(page), 0,
-				PAGE_CACHE_SIZE, NULL, write_end_fn);
-		if (ret == 0)
-			ret = err;
-		EXT4_I(inode)->i_state |= EXT4_STATE_JDATA;
-		unlock_page(page);
+		return __ext4_journalled_writepage(page, wbc);
 	} else {
 		/*
 		 * It may be a page full of checkpoint-mode buffers.  We don't
 		 * really know unless we go poke around in the buffer_heads.
 		 * But block_write_full_page will do the right thing.
 		 */
-		ret = block_write_full_page(page, ext4_get_block, wbc);
+		return block_write_full_page(page,
+						ext4_normal_get_block_write,
+						wbc);
 	}
-	err = ext4_journal_stop(handle);
-	if (!ret)
-		ret = err;
-out:
-	return ret;
-
 no_write:
 	redirty_page_for_writepage(wbc, page);
-out_unlock:
 	unlock_page(page);
-	goto out;
+	return 0;
 }
 
 static int ext4_readpage(struct file *file, struct page *page)
@@ -1819,7 +2951,7 @@ static int ext4_journalled_set_page_dirty(struct page *page)
 static const struct address_space_operations ext4_ordered_aops = {
 	.readpage	= ext4_readpage,
 	.readpages	= ext4_readpages,
-	.writepage	= ext4_ordered_writepage,
+	.writepage	= ext4_normal_writepage,
 	.sync_page	= block_sync_page,
 	.write_begin	= ext4_write_begin,
 	.write_end	= ext4_ordered_write_end,
@@ -1833,7 +2965,7 @@ static const struct address_space_operations ext4_ordered_aops = {
 static const struct address_space_operations ext4_writeback_aops = {
 	.readpage	= ext4_readpage,
 	.readpages	= ext4_readpages,
-	.writepage	= ext4_writeback_writepage,
+	.writepage	= ext4_normal_writepage,
 	.sync_page	= block_sync_page,
 	.write_begin	= ext4_write_begin,
 	.write_end	= ext4_writeback_write_end,
@@ -1857,10 +2989,31 @@ static const struct address_space_operations ext4_journalled_aops = {
 	.releasepage	= ext4_releasepage,
 };
 
+static const struct address_space_operations ext4_da_aops = {
+	.readpage	= ext4_readpage,
+	.readpages	= ext4_readpages,
+	.writepage	= ext4_da_writepage,
+	.writepages	= ext4_da_writepages,
+	.sync_page	= block_sync_page,
+	.write_begin	= ext4_da_write_begin,
+	.write_end	= ext4_da_write_end,
+	.bmap		= ext4_bmap,
+	.invalidatepage	= ext4_da_invalidatepage,
+	.releasepage	= ext4_releasepage,
+	.direct_IO	= ext4_direct_IO,
+	.migratepage	= buffer_migrate_page,
+};
+
 void ext4_set_aops(struct inode *inode)
 {
-	if (ext4_should_order_data(inode))
+	if (ext4_should_order_data(inode) &&
+		test_opt(inode->i_sb, DELALLOC))
+		inode->i_mapping->a_ops = &ext4_da_aops;
+	else if (ext4_should_order_data(inode))
 		inode->i_mapping->a_ops = &ext4_ordered_aops;
+	else if (ext4_should_writeback_data(inode) &&
+		 test_opt(inode->i_sb, DELALLOC))
+		inode->i_mapping->a_ops = &ext4_da_aops;
 	else if (ext4_should_writeback_data(inode))
 		inode->i_mapping->a_ops = &ext4_writeback_aops;
 	else
@@ -1873,7 +3026,7 @@ void ext4_set_aops(struct inode *inode)
  * This required during truncate. We need to physically zero the tail end
  * of that block so it doesn't yield old data if the file is later grown.
  */
-int ext4_block_truncate_page(handle_t *handle, struct page *page,
+int ext4_block_truncate_page(handle_t *handle,
 		struct address_space *mapping, loff_t from)
 {
 	ext4_fsblk_t index = from >> PAGE_CACHE_SHIFT;
@@ -1882,8 +3035,13 @@ int ext4_block_truncate_page(handle_t *handle, struct page *page,
 	ext4_lblk_t iblock;
 	struct inode *inode = mapping->host;
 	struct buffer_head *bh;
+	struct page *page;
 	int err = 0;
 
+	page = grab_cache_page(mapping, from >> PAGE_CACHE_SHIFT);
+	if (!page)
+		return -EINVAL;
+
 	blocksize = inode->i_sb->s_blocksize;
 	length = blocksize - (offset & (blocksize - 1));
 	iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
@@ -1956,7 +3114,7 @@ int ext4_block_truncate_page(handle_t *handle, struct page *page,
 		err = ext4_journal_dirty_metadata(handle, bh);
 	} else {
 		if (ext4_should_order_data(inode))
-			err = ext4_journal_dirty_data(handle, bh);
+			err = ext4_jbd2_file_inode(handle, inode);
 		mark_buffer_dirty(bh);
 	}
 
@@ -2179,7 +3337,21 @@ static void ext4_free_data(handle_t *handle, struct inode *inode,
 
 	if (this_bh) {
 		BUFFER_TRACE(this_bh, "call ext4_journal_dirty_metadata");
-		ext4_journal_dirty_metadata(handle, this_bh);
+
+		/*
+		 * The buffer head should have an attached journal head at this
+		 * point. However, if the data is corrupted and an indirect
+		 * block pointed to itself, it would have been detached when
+		 * the block was cleared. Check for this instead of OOPSing.
+		 */
+		if (bh2jh(this_bh))
+			ext4_journal_dirty_metadata(handle, this_bh);
+		else
+			ext4_error(inode->i_sb, __func__,
+				   "circular indirect block detected, "
+				   "inode=%lu, block=%llu",
+				   inode->i_ino,
+				   (unsigned long long) this_bh->b_blocknr);
 	}
 }
 
@@ -2305,6 +3477,19 @@ static void ext4_free_branches(handle_t *handle, struct inode *inode,
 	}
 }
 
+int ext4_can_truncate(struct inode *inode)
+{
+	if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
+		return 0;
+	if (S_ISREG(inode->i_mode))
+		return 1;
+	if (S_ISDIR(inode->i_mode))
+		return 1;
+	if (S_ISLNK(inode->i_mode))
+		return !ext4_inode_is_fast_symlink(inode);
+	return 0;
+}
+
 /*
  * ext4_truncate()
  *
@@ -2347,51 +3532,25 @@ void ext4_truncate(struct inode *inode)
 	int n;
 	ext4_lblk_t last_block;
 	unsigned blocksize = inode->i_sb->s_blocksize;
-	struct page *page;
 
-	if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
-	    S_ISLNK(inode->i_mode)))
-		return;
-	if (ext4_inode_is_fast_symlink(inode))
-		return;
-	if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
+	if (!ext4_can_truncate(inode))
 		return;
 
-	/*
-	 * We have to lock the EOF page here, because lock_page() nests
-	 * outside jbd2_journal_start().
-	 */
-	if ((inode->i_size & (blocksize - 1)) == 0) {
-		/* Block boundary? Nothing to do */
-		page = NULL;
-	} else {
-		page = grab_cache_page(mapping,
-				inode->i_size >> PAGE_CACHE_SHIFT);
-		if (!page)
-			return;
-	}
-
 	if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL) {
-		ext4_ext_truncate(inode, page);
+		ext4_ext_truncate(inode);
 		return;
 	}
 
 	handle = start_transaction(inode);
-	if (IS_ERR(handle)) {
-		if (page) {
-			clear_highpage(page);
-			flush_dcache_page(page);
-			unlock_page(page);
-			page_cache_release(page);
-		}
+	if (IS_ERR(handle))
 		return;		/* AKPM: return what? */
-	}
 
 	last_block = (inode->i_size + blocksize-1)
 					>> EXT4_BLOCK_SIZE_BITS(inode->i_sb);
 
-	if (page)
-		ext4_block_truncate_page(handle, page, mapping, inode->i_size);
+	if (inode->i_size & (blocksize - 1))
+		if (ext4_block_truncate_page(handle, mapping, inode->i_size))
+			goto out_stop;
 
 	n = ext4_block_to_path(inode, last_block, offsets, NULL);
 	if (n == 0)
@@ -2410,6 +3569,14 @@ void ext4_truncate(struct inode *inode)
 		goto out_stop;
 
 	/*
+	 * From here we block out all ext4_get_block() callers who want to
+	 * modify the block allocation tree.
+	 */
+	down_write(&ei->i_data_sem);
+
+	ext4_discard_reservation(inode);
+
+	/*
 	 * The orphan list entry will now protect us from any crash which
 	 * occurs before the truncate completes, so it is now safe to propagate
 	 * the new, shorter inode size (held for now in i_size) into the
@@ -2418,12 +3585,6 @@ void ext4_truncate(struct inode *inode)
 	 */
 	ei->i_disksize = inode->i_size;
 
-	/*
-	 * From here we block out all ext4_get_block() callers who want to
-	 * modify the block allocation tree.
-	 */
-	down_write(&ei->i_data_sem);
-
 	if (n == 1) {		/* direct blocks */
 		ext4_free_data(handle, inode, NULL, i_data+offsets[0],
 			       i_data + EXT4_NDIR_BLOCKS);
@@ -2484,8 +3645,6 @@ do_indirects:
 		;
 	}
 
-	ext4_discard_reservation(inode);
-
 	up_write(&ei->i_data_sem);
 	inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
 	ext4_mark_inode_dirty(handle, inode);
@@ -2571,6 +3730,16 @@ static int __ext4_get_inode_loc(struct inode *inode,
 	}
 	if (!buffer_uptodate(bh)) {
 		lock_buffer(bh);
+
+		/*
+		 * If the buffer has the write error flag, we have failed
+		 * to write out another inode in the same block.  In this
+		 * case, we don't have to read the block because we may
+		 * read the old inode data successfully.
+		 */
+		if (buffer_write_io_error(bh) && !buffer_uptodate(bh))
+			set_buffer_uptodate(bh);
+
 		if (buffer_uptodate(bh)) {
 			/* someone brought it uptodate while we waited */
 			unlock_buffer(bh);
@@ -3107,7 +4276,14 @@ int ext4_write_inode(struct inode *inode, int wait)
  * be freed, so we have a strong guarantee that no future commit will
  * leave these blocks visible to the user.)
  *
- * Called with inode->sem down.
+ * Another thing we have to assure is that if we are in ordered mode
+ * and inode is still attached to the committing transaction, we must
+ * we start writeout of all the dirty pages which are being truncated.
+ * This way we are sure that all the data written in the previous
+ * transaction are already on disk (truncate waits for pages under
+ * writeback).
+ *
+ * Called with inode->i_mutex down.
  */
 int ext4_setattr(struct dentry *dentry, struct iattr *attr)
 {
@@ -3173,6 +4349,22 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr)
 		if (!error)
 			error = rc;
 		ext4_journal_stop(handle);
+
+		if (ext4_should_order_data(inode)) {
+			error = ext4_begin_ordered_truncate(inode,
+							    attr->ia_size);
+			if (error) {
+				/* Do as much error cleanup as possible */
+				handle = ext4_journal_start(inode, 3);
+				if (IS_ERR(handle)) {
+					ext4_orphan_del(NULL, inode);
+					goto err_out;
+				}
+				ext4_orphan_del(handle, inode);
+				ext4_journal_stop(handle);
+				goto err_out;
+			}
+		}
 	}
 
 	rc = inode_setattr(inode, attr);
@@ -3193,58 +4385,156 @@ err_out:
 	return error;
 }
 
+int ext4_getattr(struct vfsmount *mnt, struct dentry *dentry,
+		 struct kstat *stat)
+{
+	struct inode *inode;
+	unsigned long delalloc_blocks;
+
+	inode = dentry->d_inode;
+	generic_fillattr(inode, stat);
 
+	/*
+	 * We can't update i_blocks if the block allocation is delayed
+	 * otherwise in the case of system crash before the real block
+	 * allocation is done, we will have i_blocks inconsistent with
+	 * on-disk file blocks.
+	 * We always keep i_blocks updated together with real
+	 * allocation. But to not confuse with user, stat
+	 * will return the blocks that include the delayed allocation
+	 * blocks for this file.
+	 */
+	spin_lock(&EXT4_I(inode)->i_block_reservation_lock);
+	delalloc_blocks = EXT4_I(inode)->i_reserved_data_blocks;
+	spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
+
+	stat->blocks += (delalloc_blocks << inode->i_sb->s_blocksize_bits)>>9;
+	return 0;
+}
+
+static int ext4_indirect_trans_blocks(struct inode *inode, int nrblocks,
+				      int chunk)
+{
+	int indirects;
+
+	/* if nrblocks are contiguous */
+	if (chunk) {
+		/*
+		 * With N contiguous data blocks, it need at most
+		 * N/EXT4_ADDR_PER_BLOCK(inode->i_sb) indirect blocks
+		 * 2 dindirect blocks
+		 * 1 tindirect block
+		 */
+		indirects = nrblocks / EXT4_ADDR_PER_BLOCK(inode->i_sb);
+		return indirects + 3;
+	}
+	/*
+	 * if nrblocks are not contiguous, worse case, each block touch
+	 * a indirect block, and each indirect block touch a double indirect
+	 * block, plus a triple indirect block
+	 */
+	indirects = nrblocks * 2 + 1;
+	return indirects;
+}
+
+static int ext4_index_trans_blocks(struct inode *inode, int nrblocks, int chunk)
+{
+	if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL))
+		return ext4_indirect_trans_blocks(inode, nrblocks, 0);
+	return ext4_ext_index_trans_blocks(inode, nrblocks, 0);
+}
 /*
- * How many blocks doth make a writepage()?
- *
- * With N blocks per page, it may be:
- * N data blocks
- * 2 indirect block
- * 2 dindirect
- * 1 tindirect
- * N+5 bitmap blocks (from the above)
- * N+5 group descriptor summary blocks
- * 1 inode block
- * 1 superblock.
- * 2 * EXT4_SINGLEDATA_TRANS_BLOCKS for the quote files
- *
- * 3 * (N + 5) + 2 + 2 * EXT4_SINGLEDATA_TRANS_BLOCKS
- *
- * With ordered or writeback data it's the same, less the N data blocks.
- *
- * If the inode's direct blocks can hold an integral number of pages then a
- * page cannot straddle two indirect blocks, and we can only touch one indirect
- * and dindirect block, and the "5" above becomes "3".
- *
- * This still overestimates under most circumstances.  If we were to pass the
- * start and end offsets in here as well we could do block_to_path() on each
- * block and work out the exact number of indirects which are touched.  Pah.
+ * Account for index blocks, block groups bitmaps and block group
+ * descriptor blocks if modify datablocks and index blocks
+ * worse case, the indexs blocks spread over different block groups
+ *
+ * If datablocks are discontiguous, they are possible to spread over
+ * different block groups too. If they are contiugous, with flexbg,
+ * they could still across block group boundary.
+ *
+ * Also account for superblock, inode, quota and xattr blocks
  */
+int ext4_meta_trans_blocks(struct inode *inode, int nrblocks, int chunk)
+{
+	int groups, gdpblocks;
+	int idxblocks;
+	int ret = 0;
+
+	/*
+	 * How many index blocks need to touch to modify nrblocks?
+	 * The "Chunk" flag indicating whether the nrblocks is
+	 * physically contiguous on disk
+	 *
+	 * For Direct IO and fallocate, they calls get_block to allocate
+	 * one single extent at a time, so they could set the "Chunk" flag
+	 */
+	idxblocks = ext4_index_trans_blocks(inode, nrblocks, chunk);
 
+	ret = idxblocks;
+
+	/*
+	 * Now let's see how many group bitmaps and group descriptors need
+	 * to account
+	 */
+	groups = idxblocks;
+	if (chunk)
+		groups += 1;
+	else
+		groups += nrblocks;
+
+	gdpblocks = groups;
+	if (groups > EXT4_SB(inode->i_sb)->s_groups_count)
+		groups = EXT4_SB(inode->i_sb)->s_groups_count;
+	if (groups > EXT4_SB(inode->i_sb)->s_gdb_count)
+		gdpblocks = EXT4_SB(inode->i_sb)->s_gdb_count;
+
+	/* bitmaps and block group descriptor blocks */
+	ret += groups + gdpblocks;
+
+	/* Blocks for super block, inode, quota and xattr blocks */
+	ret += EXT4_META_TRANS_BLOCKS(inode->i_sb);
+
+	return ret;
+}
+
+/*
+ * Calulate the total number of credits to reserve to fit
+ * the modification of a single pages into a single transaction,
+ * which may include multiple chunks of block allocations.
+ *
+ * This could be called via ext4_write_begin()
+ *
+ * We need to consider the worse case, when
+ * one new block per extent.
+ */
 int ext4_writepage_trans_blocks(struct inode *inode)
 {
 	int bpp = ext4_journal_blocks_per_page(inode);
-	int indirects = (EXT4_NDIR_BLOCKS % bpp) ? 5 : 3;
 	int ret;
 
-	if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)
-		return ext4_ext_writepage_trans_blocks(inode, bpp);
+	ret = ext4_meta_trans_blocks(inode, bpp, 0);
 
+	/* Account for data blocks for journalled mode */
 	if (ext4_should_journal_data(inode))
-		ret = 3 * (bpp + indirects) + 2;
-	else
-		ret = 2 * (bpp + indirects) + 2;
-
-#ifdef CONFIG_QUOTA
-	/* We know that structure was already allocated during DQUOT_INIT so
-	 * we will be updating only the data blocks + inodes */
-	ret += 2*EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb);
-#endif
-
+		ret += bpp;
 	return ret;
 }
 
 /*
+ * Calculate the journal credits for a chunk of data modification.
+ *
+ * This is called from DIO, fallocate or whoever calling
+ * ext4_get_blocks_wrap() to map/allocate a chunk of contigous disk blocks.
+ *
+ * journal buffers for data blocks are not included here, as DIO
+ * and fallocate do no need to journal data buffers.
+ */
+int ext4_chunk_trans_blocks(struct inode *inode, int nrblocks)
+{
+	return ext4_meta_trans_blocks(inode, nrblocks, 1);
+}
+
+/*
  * The caller must have previously called ext4_reserve_inode_write().
  * Give this, we know that the caller already has write access to iloc->bh.
  */
@@ -3506,3 +4796,64 @@ int ext4_change_inode_journal_flag(struct inode *inode, int val)
 
 	return err;
 }
+
+static int ext4_bh_unmapped(handle_t *handle, struct buffer_head *bh)
+{
+	return !buffer_mapped(bh);
+}
+
+int ext4_page_mkwrite(struct vm_area_struct *vma, struct page *page)
+{
+	loff_t size;
+	unsigned long len;
+	int ret = -EINVAL;
+	struct file *file = vma->vm_file;
+	struct inode *inode = file->f_path.dentry->d_inode;
+	struct address_space *mapping = inode->i_mapping;
+
+	/*
+	 * Get i_alloc_sem to stop truncates messing with the inode. We cannot
+	 * get i_mutex because we are already holding mmap_sem.
+	 */
+	down_read(&inode->i_alloc_sem);
+	size = i_size_read(inode);
+	if (page->mapping != mapping || size <= page_offset(page)
+	    || !PageUptodate(page)) {
+		/* page got truncated from under us? */
+		goto out_unlock;
+	}
+	ret = 0;
+	if (PageMappedToDisk(page))
+		goto out_unlock;
+
+	if (page->index == size >> PAGE_CACHE_SHIFT)
+		len = size & ~PAGE_CACHE_MASK;
+	else
+		len = PAGE_CACHE_SIZE;
+
+	if (page_has_buffers(page)) {
+		/* return if we have all the buffers mapped */
+		if (!walk_page_buffers(NULL, page_buffers(page), 0, len, NULL,
+				       ext4_bh_unmapped))
+			goto out_unlock;
+	}
+	/*
+	 * OK, we need to fill the hole... Do write_begin write_end
+	 * to do block allocation/reservation.We are not holding
+	 * inode.i__mutex here. That allow * parallel write_begin,
+	 * write_end call. lock_page prevent this from happening
+	 * on the same page though
+	 */
+	ret = mapping->a_ops->write_begin(file, mapping, page_offset(page),
+			len, AOP_FLAG_UNINTERRUPTIBLE, &page, NULL);
+	if (ret < 0)
+		goto out_unlock;
+	ret = mapping->a_ops->write_end(file, mapping, page_offset(page),
+			len, len, page, NULL);
+	if (ret < 0)
+		goto out_unlock;
+	ret = 0;
+out_unlock:
+	up_read(&inode->i_alloc_sem);
+	return ret;
+}
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index c9900aa..e0e3a5e 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -381,22 +381,28 @@ static inline void mb_clear_bit_atomic(spinlock_t *lock, int bit, void *addr)
 
 static inline int mb_find_next_zero_bit(void *addr, int max, int start)
 {
-	int fix = 0;
+	int fix = 0, ret, tmpmax;
 	addr = mb_correct_addr_and_bit(&fix, addr);
-	max += fix;
+	tmpmax = max + fix;
 	start += fix;
 
-	return ext4_find_next_zero_bit(addr, max, start) - fix;
+	ret = ext4_find_next_zero_bit(addr, tmpmax, start) - fix;
+	if (ret > max)
+		return max;
+	return ret;
 }
 
 static inline int mb_find_next_bit(void *addr, int max, int start)
 {
-	int fix = 0;
+	int fix = 0, ret, tmpmax;
 	addr = mb_correct_addr_and_bit(&fix, addr);
-	max += fix;
+	tmpmax = max + fix;
 	start += fix;
 
-	return ext4_find_next_bit(addr, max, start) - fix;
+	ret = ext4_find_next_bit(addr, tmpmax, start) - fix;
+	if (ret > max)
+		return max;
+	return ret;
 }
 
 static void *mb_find_buddy(struct ext4_buddy *e4b, int order, int *max)
@@ -781,13 +787,16 @@ static int ext4_mb_init_cache(struct page *page, char *incore)
 		if (bh_uptodate_or_lock(bh[i]))
 			continue;
 
+		spin_lock(sb_bgl_lock(EXT4_SB(sb), first_group + i));
 		if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
 			ext4_init_block_bitmap(sb, bh[i],
 						first_group + i, desc);
 			set_buffer_uptodate(bh[i]);
 			unlock_buffer(bh[i]);
+			spin_unlock(sb_bgl_lock(EXT4_SB(sb), first_group + i));
 			continue;
 		}
+		spin_unlock(sb_bgl_lock(EXT4_SB(sb), first_group + i));
 		get_bh(bh[i]);
 		bh[i]->b_end_io = end_buffer_read_sync;
 		submit_bh(READ, bh[i]);
@@ -803,6 +812,7 @@ static int ext4_mb_init_cache(struct page *page, char *incore)
 		if (!buffer_uptodate(bh[i]))
 			goto out;
 
+	err = 0;
 	first_block = page->index * blocks_per_page;
 	for (i = 0; i < blocks_per_page; i++) {
 		int group;
@@ -883,6 +893,7 @@ ext4_mb_load_buddy(struct super_block *sb, ext4_group_t group,
 	int pnum;
 	int poff;
 	struct page *page;
+	int ret;
 
 	mb_debug("load group %lu\n", group);
 
@@ -914,15 +925,21 @@ ext4_mb_load_buddy(struct super_block *sb, ext4_group_t group,
 		if (page) {
 			BUG_ON(page->mapping != inode->i_mapping);
 			if (!PageUptodate(page)) {
-				ext4_mb_init_cache(page, NULL);
+				ret = ext4_mb_init_cache(page, NULL);
+				if (ret) {
+					unlock_page(page);
+					goto err;
+				}
 				mb_cmp_bitmaps(e4b, page_address(page) +
 					       (poff * sb->s_blocksize));
 			}
 			unlock_page(page);
 		}
 	}
-	if (page == NULL || !PageUptodate(page))
+	if (page == NULL || !PageUptodate(page)) {
+		ret = -EIO;
 		goto err;
+	}
 	e4b->bd_bitmap_page = page;
 	e4b->bd_bitmap = page_address(page) + (poff * sb->s_blocksize);
 	mark_page_accessed(page);
@@ -938,14 +955,20 @@ ext4_mb_load_buddy(struct super_block *sb, ext4_group_t group,
 		page = find_or_create_page(inode->i_mapping, pnum, GFP_NOFS);
 		if (page) {
 			BUG_ON(page->mapping != inode->i_mapping);
-			if (!PageUptodate(page))
-				ext4_mb_init_cache(page, e4b->bd_bitmap);
-
+			if (!PageUptodate(page)) {
+				ret = ext4_mb_init_cache(page, e4b->bd_bitmap);
+				if (ret) {
+					unlock_page(page);
+					goto err;
+				}
+			}
 			unlock_page(page);
 		}
 	}
-	if (page == NULL || !PageUptodate(page))
+	if (page == NULL || !PageUptodate(page)) {
+		ret = -EIO;
 		goto err;
+	}
 	e4b->bd_buddy_page = page;
 	e4b->bd_buddy = page_address(page) + (poff * sb->s_blocksize);
 	mark_page_accessed(page);
@@ -962,7 +985,7 @@ err:
 		page_cache_release(e4b->bd_buddy_page);
 	e4b->bd_buddy = NULL;
 	e4b->bd_bitmap = NULL;
-	return -EIO;
+	return ret;
 }
 
 static void ext4_mb_release_desc(struct ext4_buddy *e4b)
@@ -1031,7 +1054,7 @@ static void mb_set_bits(spinlock_t *lock, void *bm, int cur, int len)
 	}
 }
 
-static int mb_free_blocks(struct inode *inode, struct ext4_buddy *e4b,
+static void mb_free_blocks(struct inode *inode, struct ext4_buddy *e4b,
 			  int first, int count)
 {
 	int block = 0;
@@ -1071,11 +1094,12 @@ static int mb_free_blocks(struct inode *inode, struct ext4_buddy *e4b,
 			blocknr += block;
 			blocknr +=
 			    le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block);
-
+			ext4_unlock_group(sb, e4b->bd_group);
 			ext4_error(sb, __func__, "double-free of inode"
 				   " %lu's block %llu(bit %u in group %lu)\n",
 				   inode ? inode->i_ino : 0, blocknr, block,
 				   e4b->bd_group);
+			ext4_lock_group(sb, e4b->bd_group);
 		}
 		mb_clear_bit(block, EXT4_MB_BITMAP(e4b));
 		e4b->bd_info->bb_counters[order]++;
@@ -1113,8 +1137,6 @@ static int mb_free_blocks(struct inode *inode, struct ext4_buddy *e4b,
 		} while (1);
 	}
 	mb_check_buddy(e4b);
-
-	return 0;
 }
 
 static int mb_find_extent(struct ext4_buddy *e4b, int order, int block,
@@ -1730,10 +1752,6 @@ ext4_mb_regular_allocator(struct ext4_allocation_context *ac)
 		ac->ac_g_ex.fe_start = sbi->s_mb_last_start;
 		spin_unlock(&sbi->s_md_lock);
 	}
-
-	/* searching for the right group start from the goal value specified */
-	group = ac->ac_g_ex.fe_group;
-
 	/* Let's just scan groups to find more-less suitable blocks */
 	cr = ac->ac_2order ? 0 : 1;
 	/*
@@ -1743,6 +1761,12 @@ ext4_mb_regular_allocator(struct ext4_allocation_context *ac)
 repeat:
 	for (; cr < 4 && ac->ac_status == AC_STATUS_CONTINUE; cr++) {
 		ac->ac_criteria = cr;
+		/*
+		 * searching for the right group start
+		 * from the goal value specified
+		 */
+		group = ac->ac_g_ex.fe_group;
+
 		for (i = 0; i < EXT4_SB(sb)->s_groups_count; group++, i++) {
 			struct ext4_group_info *grp;
 			struct ext4_group_desc *desc;
@@ -1963,6 +1987,8 @@ static int ext4_mb_seq_history_open(struct inode *inode, struct file *file)
 	int rc;
 	int size;
 
+	if (unlikely(sbi->s_mb_history == NULL))
+		return -ENOMEM;
 	s = kmalloc(sizeof(*s), GFP_KERNEL);
 	if (s == NULL)
 		return -ENOMEM;
@@ -2165,9 +2191,7 @@ static void ext4_mb_history_init(struct super_block *sb)
 	sbi->s_mb_history_cur = 0;
 	spin_lock_init(&sbi->s_mb_history_lock);
 	i = sbi->s_mb_history_max * sizeof(struct ext4_mb_history);
-	sbi->s_mb_history = kmalloc(i, GFP_KERNEL);
-	if (likely(sbi->s_mb_history != NULL))
-		memset(sbi->s_mb_history, 0, i);
+	sbi->s_mb_history = kzalloc(i, GFP_KERNEL);
 	/* if we can't allocate history, then we simple won't use it */
 }
 
@@ -2215,21 +2239,192 @@ ext4_mb_store_history(struct ext4_allocation_context *ac)
 #define ext4_mb_history_init(sb)
 #endif
 
+
+/* Create and initialize ext4_group_info data for the given group. */
+int ext4_mb_add_groupinfo(struct super_block *sb, ext4_group_t group,
+			  struct ext4_group_desc *desc)
+{
+	int i, len;
+	int metalen = 0;
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_group_info **meta_group_info;
+
+	/*
+	 * First check if this group is the first of a reserved block.
+	 * If it's true, we have to allocate a new table of pointers
+	 * to ext4_group_info structures
+	 */
+	if (group % EXT4_DESC_PER_BLOCK(sb) == 0) {
+		metalen = sizeof(*meta_group_info) <<
+			EXT4_DESC_PER_BLOCK_BITS(sb);
+		meta_group_info = kmalloc(metalen, GFP_KERNEL);
+		if (meta_group_info == NULL) {
+			printk(KERN_ERR "EXT4-fs: can't allocate mem for a "
+			       "buddy group\n");
+			goto exit_meta_group_info;
+		}
+		sbi->s_group_info[group >> EXT4_DESC_PER_BLOCK_BITS(sb)] =
+			meta_group_info;
+	}
+
+	/*
+	 * calculate needed size. if change bb_counters size,
+	 * don't forget about ext4_mb_generate_buddy()
+	 */
+	len = offsetof(typeof(**meta_group_info),
+		       bb_counters[sb->s_blocksize_bits + 2]);
+
+	meta_group_info =
+		sbi->s_group_info[group >> EXT4_DESC_PER_BLOCK_BITS(sb)];
+	i = group & (EXT4_DESC_PER_BLOCK(sb) - 1);
+
+	meta_group_info[i] = kzalloc(len, GFP_KERNEL);
+	if (meta_group_info[i] == NULL) {
+		printk(KERN_ERR "EXT4-fs: can't allocate buddy mem\n");
+		goto exit_group_info;
+	}
+	set_bit(EXT4_GROUP_INFO_NEED_INIT_BIT,
+		&(meta_group_info[i]->bb_state));
+
+	/*
+	 * initialize bb_free to be able to skip
+	 * empty groups without initialization
+	 */
+	if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
+		meta_group_info[i]->bb_free =
+			ext4_free_blocks_after_init(sb, group, desc);
+	} else {
+		meta_group_info[i]->bb_free =
+			le16_to_cpu(desc->bg_free_blocks_count);
+	}
+
+	INIT_LIST_HEAD(&meta_group_info[i]->bb_prealloc_list);
+
+#ifdef DOUBLE_CHECK
+	{
+		struct buffer_head *bh;
+		meta_group_info[i]->bb_bitmap =
+			kmalloc(sb->s_blocksize, GFP_KERNEL);
+		BUG_ON(meta_group_info[i]->bb_bitmap == NULL);
+		bh = ext4_read_block_bitmap(sb, group);
+		BUG_ON(bh == NULL);
+		memcpy(meta_group_info[i]->bb_bitmap, bh->b_data,
+			sb->s_blocksize);
+		put_bh(bh);
+	}
+#endif
+
+	return 0;
+
+exit_group_info:
+	/* If a meta_group_info table has been allocated, release it now */
+	if (group % EXT4_DESC_PER_BLOCK(sb) == 0)
+		kfree(sbi->s_group_info[group >> EXT4_DESC_PER_BLOCK_BITS(sb)]);
+exit_meta_group_info:
+	return -ENOMEM;
+} /* ext4_mb_add_groupinfo */
+
+/*
+ * Add a group to the existing groups.
+ * This function is used for online resize
+ */
+int ext4_mb_add_more_groupinfo(struct super_block *sb, ext4_group_t group,
+			       struct ext4_group_desc *desc)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct inode *inode = sbi->s_buddy_cache;
+	int blocks_per_page;
+	int block;
+	int pnum;
+	struct page *page;
+	int err;
+
+	/* Add group based on group descriptor*/
+	err = ext4_mb_add_groupinfo(sb, group, desc);
+	if (err)
+		return err;
+
+	/*
+	 * Cache pages containing dynamic mb_alloc datas (buddy and bitmap
+	 * datas) are set not up to date so that they will be re-initilaized
+	 * during the next call to ext4_mb_load_buddy
+	 */
+
+	/* Set buddy page as not up to date */
+	blocks_per_page = PAGE_CACHE_SIZE / sb->s_blocksize;
+	block = group * 2;
+	pnum = block / blocks_per_page;
+	page = find_get_page(inode->i_mapping, pnum);
+	if (page != NULL) {
+		ClearPageUptodate(page);
+		page_cache_release(page);
+	}
+
+	/* Set bitmap page as not up to date */
+	block++;
+	pnum = block / blocks_per_page;
+	page = find_get_page(inode->i_mapping, pnum);
+	if (page != NULL) {
+		ClearPageUptodate(page);
+		page_cache_release(page);
+	}
+
+	return 0;
+}
+
+/*
+ * Update an existing group.
+ * This function is used for online resize
+ */
+void ext4_mb_update_group_info(struct ext4_group_info *grp, ext4_grpblk_t add)
+{
+	grp->bb_free += add;
+}
+
 static int ext4_mb_init_backend(struct super_block *sb)
 {
 	ext4_group_t i;
-	int j, len, metalen;
+	int metalen;
 	struct ext4_sb_info *sbi = EXT4_SB(sb);
-	int num_meta_group_infos =
-		(sbi->s_groups_count + EXT4_DESC_PER_BLOCK(sb) - 1) >>
-			EXT4_DESC_PER_BLOCK_BITS(sb);
+	struct ext4_super_block *es = sbi->s_es;
+	int num_meta_group_infos;
+	int num_meta_group_infos_max;
+	int array_size;
 	struct ext4_group_info **meta_group_info;
+	struct ext4_group_desc *desc;
 
+	/* This is the number of blocks used by GDT */
+	num_meta_group_infos = (sbi->s_groups_count + EXT4_DESC_PER_BLOCK(sb) -
+				1) >> EXT4_DESC_PER_BLOCK_BITS(sb);
+
+	/*
+	 * This is the total number of blocks used by GDT including
+	 * the number of reserved blocks for GDT.
+	 * The s_group_info array is allocated with this value
+	 * to allow a clean online resize without a complex
+	 * manipulation of pointer.
+	 * The drawback is the unused memory when no resize
+	 * occurs but it's very low in terms of pages
+	 * (see comments below)
+	 * Need to handle this properly when META_BG resizing is allowed
+	 */
+	num_meta_group_infos_max = num_meta_group_infos +
+				le16_to_cpu(es->s_reserved_gdt_blocks);
+
+	/*
+	 * array_size is the size of s_group_info array. We round it
+	 * to the next power of two because this approximation is done
+	 * internally by kmalloc so we can have some more memory
+	 * for free here (e.g. may be used for META_BG resize).
+	 */
+	array_size = 1;
+	while (array_size < sizeof(*sbi->s_group_info) *
+	       num_meta_group_infos_max)
+		array_size = array_size << 1;
 	/* An 8TB filesystem with 64-bit pointers requires a 4096 byte
 	 * kmalloc. A 128kb malloc should suffice for a 256TB filesystem.
 	 * So a two level scheme suffices for now. */
-	sbi->s_group_info = kmalloc(sizeof(*sbi->s_group_info) *
-				    num_meta_group_infos, GFP_KERNEL);
+	sbi->s_group_info = kmalloc(array_size, GFP_KERNEL);
 	if (sbi->s_group_info == NULL) {
 		printk(KERN_ERR "EXT4-fs: can't allocate buddy meta group\n");
 		return -ENOMEM;
@@ -2256,63 +2451,15 @@ static int ext4_mb_init_backend(struct super_block *sb)
 		sbi->s_group_info[i] = meta_group_info;
 	}
 
-	/*
-	 * calculate needed size. if change bb_counters size,
-	 * don't forget about ext4_mb_generate_buddy()
-	 */
-	len = sizeof(struct ext4_group_info);
-	len += sizeof(unsigned short) * (sb->s_blocksize_bits + 2);
 	for (i = 0; i < sbi->s_groups_count; i++) {
-		struct ext4_group_desc *desc;
-
-		meta_group_info =
-			sbi->s_group_info[i >> EXT4_DESC_PER_BLOCK_BITS(sb)];
-		j = i & (EXT4_DESC_PER_BLOCK(sb) - 1);
-
-		meta_group_info[j] = kzalloc(len, GFP_KERNEL);
-		if (meta_group_info[j] == NULL) {
-			printk(KERN_ERR "EXT4-fs: can't allocate buddy mem\n");
-			goto err_freebuddy;
-		}
 		desc = ext4_get_group_desc(sb, i, NULL);
 		if (desc == NULL) {
 			printk(KERN_ERR
 				"EXT4-fs: can't read descriptor %lu\n", i);
-			i++;
 			goto err_freebuddy;
 		}
-		memset(meta_group_info[j], 0, len);
-		set_bit(EXT4_GROUP_INFO_NEED_INIT_BIT,
-			&(meta_group_info[j]->bb_state));
-
-		/*
-		 * initialize bb_free to be able to skip
-		 * empty groups without initialization
-		 */
-		if (desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)) {
-			meta_group_info[j]->bb_free =
-				ext4_free_blocks_after_init(sb, i, desc);
-		} else {
-			meta_group_info[j]->bb_free =
-				le16_to_cpu(desc->bg_free_blocks_count);
-		}
-
-		INIT_LIST_HEAD(&meta_group_info[j]->bb_prealloc_list);
-
-#ifdef DOUBLE_CHECK
-		{
-			struct buffer_head *bh;
-			meta_group_info[j]->bb_bitmap =
-				kmalloc(sb->s_blocksize, GFP_KERNEL);
-			BUG_ON(meta_group_info[j]->bb_bitmap == NULL);
-			bh = read_block_bitmap(sb, i);
-			BUG_ON(bh == NULL);
-			memcpy(meta_group_info[j]->bb_bitmap, bh->b_data,
-					sb->s_blocksize);
-			put_bh(bh);
-		}
-#endif
-
+		if (ext4_mb_add_groupinfo(sb, i, desc) != 0)
+			goto err_freebuddy;
 	}
 
 	return 0;
@@ -2333,9 +2480,10 @@ err_freesgi:
 int ext4_mb_init(struct super_block *sb, int needs_recovery)
 {
 	struct ext4_sb_info *sbi = EXT4_SB(sb);
-	unsigned i;
+	unsigned i, j;
 	unsigned offset;
 	unsigned max;
+	int ret;
 
 	if (!test_opt(sb, MBALLOC))
 		return 0;
@@ -2370,12 +2518,12 @@ int ext4_mb_init(struct super_block *sb, int needs_recovery)
 	} while (i <= sb->s_blocksize_bits + 1);
 
 	/* init file for buddy data */
-	i = ext4_mb_init_backend(sb);
-	if (i) {
+	ret = ext4_mb_init_backend(sb);
+	if (ret != 0) {
 		clear_opt(sbi->s_mount_opt, MBALLOC);
 		kfree(sbi->s_mb_offsets);
 		kfree(sbi->s_mb_maxs);
-		return i;
+		return ret;
 	}
 
 	spin_lock_init(&sbi->s_md_lock);
@@ -2392,7 +2540,7 @@ int ext4_mb_init(struct super_block *sb, int needs_recovery)
 	sbi->s_mb_history_filter = EXT4_MB_HISTORY_DEFAULT;
 	sbi->s_mb_group_prealloc = MB_DEFAULT_GROUP_PREALLOC;
 
-	i = sizeof(struct ext4_locality_group) * NR_CPUS;
+	i = sizeof(struct ext4_locality_group) * nr_cpu_ids;
 	sbi->s_locality_groups = kmalloc(i, GFP_KERNEL);
 	if (sbi->s_locality_groups == NULL) {
 		clear_opt(sbi->s_mount_opt, MBALLOC);
@@ -2400,11 +2548,12 @@ int ext4_mb_init(struct super_block *sb, int needs_recovery)
 		kfree(sbi->s_mb_maxs);
 		return -ENOMEM;
 	}
-	for (i = 0; i < NR_CPUS; i++) {
+	for (i = 0; i < nr_cpu_ids; i++) {
 		struct ext4_locality_group *lg;
 		lg = &sbi->s_locality_groups[i];
 		mutex_init(&lg->lg_mutex);
-		INIT_LIST_HEAD(&lg->lg_prealloc_list);
+		for (j = 0; j < PREALLOC_TB_SIZE; j++)
+			INIT_LIST_HEAD(&lg->lg_prealloc_list[j]);
 		spin_lock_init(&lg->lg_prealloc_lock);
 	}
 
@@ -2548,8 +2697,7 @@ ext4_mb_free_committed_blocks(struct super_block *sb)
 		ext4_lock_group(sb, md->group);
 		for (i = 0; i < md->num; i++) {
 			mb_debug(" %u", md->blocks[i]);
-			err = mb_free_blocks(NULL, &e4b, md->blocks[i], 1);
-			BUG_ON(err != 0);
+			mb_free_blocks(NULL, &e4b, md->blocks[i], 1);
 		}
 		mb_debug("\n");
 		ext4_unlock_group(sb, md->group);
@@ -2575,25 +2723,24 @@ ext4_mb_free_committed_blocks(struct super_block *sb)
 
 
 
-#define MB_PROC_VALUE_READ(name)				\
-static int ext4_mb_read_##name(char *page, char **start,	\
-		off_t off, int count, int *eof, void *data)	\
+#define MB_PROC_FOPS(name)					\
+static int ext4_mb_##name##_proc_show(struct seq_file *m, void *v)	\
 {								\
-	struct ext4_sb_info *sbi = data;			\
-	int len;						\
-	*eof = 1;						\
-	if (off != 0)						\
-		return 0;					\
-	len = sprintf(page, "%ld\n", sbi->s_mb_##name);		\
-	*start = page;						\
-	return len;						\
-}
-
-#define MB_PROC_VALUE_WRITE(name)				\
-static int ext4_mb_write_##name(struct file *file,		\
-		const char __user *buf, unsigned long cnt, void *data)	\
+	struct ext4_sb_info *sbi = m->private;			\
+								\
+	seq_printf(m, "%ld\n", sbi->s_mb_##name);		\
+	return 0;						\
+}								\
+								\
+static int ext4_mb_##name##_proc_open(struct inode *inode, struct file *file)\
 {								\
-	struct ext4_sb_info *sbi = data;			\
+	return single_open(file, ext4_mb_##name##_proc_show, PDE(inode)->data);\
+}								\
+								\
+static ssize_t ext4_mb_##name##_proc_write(struct file *file,	\
+		const char __user *buf, size_t cnt, loff_t *ppos)	\
+{								\
+	struct ext4_sb_info *sbi = PDE(file->f_path.dentry->d_inode)->data;\
 	char str[32];						\
 	long value;						\
 	if (cnt >= sizeof(str))					\
@@ -2605,31 +2752,32 @@ static int ext4_mb_write_##name(struct file *file,		\
 		return -ERANGE;					\
 	sbi->s_mb_##name = value;				\
 	return cnt;						\
-}
+}								\
+								\
+static const struct file_operations ext4_mb_##name##_proc_fops = {	\
+	.owner		= THIS_MODULE,				\
+	.open		= ext4_mb_##name##_proc_open,		\
+	.read		= seq_read,				\
+	.llseek		= seq_lseek,				\
+	.release	= single_release,			\
+	.write		= ext4_mb_##name##_proc_write,		\
+};
 
-MB_PROC_VALUE_READ(stats);
-MB_PROC_VALUE_WRITE(stats);
-MB_PROC_VALUE_READ(max_to_scan);
-MB_PROC_VALUE_WRITE(max_to_scan);
-MB_PROC_VALUE_READ(min_to_scan);
-MB_PROC_VALUE_WRITE(min_to_scan);
-MB_PROC_VALUE_READ(order2_reqs);
-MB_PROC_VALUE_WRITE(order2_reqs);
-MB_PROC_VALUE_READ(stream_request);
-MB_PROC_VALUE_WRITE(stream_request);
-MB_PROC_VALUE_READ(group_prealloc);
-MB_PROC_VALUE_WRITE(group_prealloc);
+MB_PROC_FOPS(stats);
+MB_PROC_FOPS(max_to_scan);
+MB_PROC_FOPS(min_to_scan);
+MB_PROC_FOPS(order2_reqs);
+MB_PROC_FOPS(stream_request);
+MB_PROC_FOPS(group_prealloc);
 
 #define	MB_PROC_HANDLER(name, var)					\
 do {									\
-	proc = create_proc_entry(name, mode, sbi->s_mb_proc);		\
+	proc = proc_create_data(name, mode, sbi->s_mb_proc,		\
+				&ext4_mb_##var##_proc_fops, sbi);	\
 	if (proc == NULL) {						\
 		printk(KERN_ERR "EXT4-fs: can't to create %s\n", name);	\
 		goto err_out;						\
 	}								\
-	proc->data = sbi;						\
-	proc->read_proc  = ext4_mb_read_##var ;				\
-	proc->write_proc = ext4_mb_write_##var;				\
 } while (0)
 
 static int ext4_mb_init_per_dev_proc(struct super_block *sb)
@@ -2639,6 +2787,10 @@ static int ext4_mb_init_per_dev_proc(struct super_block *sb)
 	struct proc_dir_entry *proc;
 	char devname[64];
 
+	if (proc_root_ext4 == NULL) {
+		sbi->s_mb_proc = NULL;
+		return -EINVAL;
+	}
 	bdevname(sb->s_bdev, devname);
 	sbi->s_mb_proc = proc_mkdir(devname, proc_root_ext4);
 
@@ -2747,7 +2899,7 @@ ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac,
 
 
 	err = -EIO;
-	bitmap_bh = read_block_bitmap(sb, ac->ac_b_ex.fe_group);
+	bitmap_bh = ext4_read_block_bitmap(sb, ac->ac_b_ex.fe_group);
 	if (!bitmap_bh)
 		goto out_err;
 
@@ -2816,7 +2968,23 @@ ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac,
 	le16_add_cpu(&gdp->bg_free_blocks_count, -ac->ac_b_ex.fe_len);
 	gdp->bg_checksum = ext4_group_desc_csum(sbi, ac->ac_b_ex.fe_group, gdp);
 	spin_unlock(sb_bgl_lock(sbi, ac->ac_b_ex.fe_group));
-	percpu_counter_sub(&sbi->s_freeblocks_counter, ac->ac_b_ex.fe_len);
+
+	/*
+	 * free blocks account has already be reduced/reserved
+	 * at write_begin() time for delayed allocation
+	 * do not double accounting
+	 */
+	if (!(ac->ac_flags & EXT4_MB_DELALLOC_RESERVED))
+		percpu_counter_sub(&sbi->s_freeblocks_counter,
+					ac->ac_b_ex.fe_len);
+
+	if (sbi->s_log_groups_per_flex) {
+		ext4_group_t flex_group = ext4_flex_group(sbi,
+							  ac->ac_b_ex.fe_group);
+		spin_lock(sb_bgl_lock(sbi, flex_group));
+		sbi->s_flex_groups[flex_group].free_blocks -= ac->ac_b_ex.fe_len;
+		spin_unlock(sb_bgl_lock(sbi, flex_group));
+	}
 
 	err = ext4_journal_dirty_metadata(handle, bitmap_bh);
 	if (err)
@@ -3096,6 +3264,7 @@ static void ext4_mb_use_group_pa(struct ext4_allocation_context *ac,
 				struct ext4_prealloc_space *pa)
 {
 	unsigned int len = ac->ac_o_ex.fe_len;
+
 	ext4_get_group_no_and_offset(ac->ac_sb, pa->pa_pstart,
 					&ac->ac_b_ex.fe_group,
 					&ac->ac_b_ex.fe_start);
@@ -3113,14 +3282,45 @@ static void ext4_mb_use_group_pa(struct ext4_allocation_context *ac,
 }
 
 /*
+ * Return the prealloc space that have minimal distance
+ * from the goal block. @cpa is the prealloc
+ * space that is having currently known minimal distance
+ * from the goal block.
+ */
+static struct ext4_prealloc_space *
+ext4_mb_check_group_pa(ext4_fsblk_t goal_block,
+			struct ext4_prealloc_space *pa,
+			struct ext4_prealloc_space *cpa)
+{
+	ext4_fsblk_t cur_distance, new_distance;
+
+	if (cpa == NULL) {
+		atomic_inc(&pa->pa_count);
+		return pa;
+	}
+	cur_distance = abs(goal_block - cpa->pa_pstart);
+	new_distance = abs(goal_block - pa->pa_pstart);
+
+	if (cur_distance < new_distance)
+		return cpa;
+
+	/* drop the previous reference */
+	atomic_dec(&cpa->pa_count);
+	atomic_inc(&pa->pa_count);
+	return pa;
+}
+
+/*
  * search goal blocks in preallocated space
  */
 static noinline_for_stack int
 ext4_mb_use_preallocated(struct ext4_allocation_context *ac)
 {
+	int order, i;
 	struct ext4_inode_info *ei = EXT4_I(ac->ac_inode);
 	struct ext4_locality_group *lg;
-	struct ext4_prealloc_space *pa;
+	struct ext4_prealloc_space *pa, *cpa = NULL;
+	ext4_fsblk_t goal_block;
 
 	/* only data can be preallocated */
 	if (!(ac->ac_flags & EXT4_MB_HINT_DATA))
@@ -3158,22 +3358,38 @@ ext4_mb_use_preallocated(struct ext4_allocation_context *ac)
 	lg = ac->ac_lg;
 	if (lg == NULL)
 		return 0;
+	order  = fls(ac->ac_o_ex.fe_len) - 1;
+	if (order > PREALLOC_TB_SIZE - 1)
+		/* The max size of hash table is PREALLOC_TB_SIZE */
+		order = PREALLOC_TB_SIZE - 1;
+
+	goal_block = ac->ac_g_ex.fe_group * EXT4_BLOCKS_PER_GROUP(ac->ac_sb) +
+		     ac->ac_g_ex.fe_start +
+		     le32_to_cpu(EXT4_SB(ac->ac_sb)->s_es->s_first_data_block);
+	/*
+	 * search for the prealloc space that is having
+	 * minimal distance from the goal block.
+	 */
+	for (i = order; i < PREALLOC_TB_SIZE; i++) {
+		rcu_read_lock();
+		list_for_each_entry_rcu(pa, &lg->lg_prealloc_list[i],
+					pa_inode_list) {
+			spin_lock(&pa->pa_lock);
+			if (pa->pa_deleted == 0 &&
+					pa->pa_free >= ac->ac_o_ex.fe_len) {
 
-	rcu_read_lock();
-	list_for_each_entry_rcu(pa, &lg->lg_prealloc_list, pa_inode_list) {
-		spin_lock(&pa->pa_lock);
-		if (pa->pa_deleted == 0 && pa->pa_free >= ac->ac_o_ex.fe_len) {
-			atomic_inc(&pa->pa_count);
-			ext4_mb_use_group_pa(ac, pa);
+				cpa = ext4_mb_check_group_pa(goal_block,
+								pa, cpa);
+			}
 			spin_unlock(&pa->pa_lock);
-			ac->ac_criteria = 20;
-			rcu_read_unlock();
-			return 1;
 		}
-		spin_unlock(&pa->pa_lock);
+		rcu_read_unlock();
+	}
+	if (cpa) {
+		ext4_mb_use_group_pa(ac, cpa);
+		ac->ac_criteria = 20;
+		return 1;
 	}
-	rcu_read_unlock();
-
 	return 0;
 }
 
@@ -3396,6 +3612,7 @@ ext4_mb_new_group_pa(struct ext4_allocation_context *ac)
 	pa->pa_free = pa->pa_len;
 	atomic_set(&pa->pa_count, 1);
 	spin_lock_init(&pa->pa_lock);
+	INIT_LIST_HEAD(&pa->pa_inode_list);
 	pa->pa_deleted = 0;
 	pa->pa_linear = 1;
 
@@ -3416,10 +3633,10 @@ ext4_mb_new_group_pa(struct ext4_allocation_context *ac)
 	list_add(&pa->pa_group_list, &grp->bb_prealloc_list);
 	ext4_unlock_group(sb, ac->ac_b_ex.fe_group);
 
-	spin_lock(pa->pa_obj_lock);
-	list_add_tail_rcu(&pa->pa_inode_list, &lg->lg_prealloc_list);
-	spin_unlock(pa->pa_obj_lock);
-
+	/*
+	 * We will later add the new pa to the right bucket
+	 * after updating the pa_free in ext4_mb_release_context
+	 */
 	return 0;
 }
 
@@ -3473,8 +3690,6 @@ ext4_mb_release_inode_pa(struct ext4_buddy *e4b, struct buffer_head *bitmap_bh,
 		if (bit >= end)
 			break;
 		next = mb_find_next_bit(bitmap_bh->b_data, end, bit);
-		if (next > end)
-			next = end;
 		start = group * EXT4_BLOCKS_PER_GROUP(sb) + bit +
 				le32_to_cpu(sbi->s_es->s_first_data_block);
 		mb_debug("    free preallocated %u/%u in group %u\n",
@@ -3569,22 +3784,25 @@ ext4_mb_discard_group_preallocations(struct super_block *sb,
 	if (list_empty(&grp->bb_prealloc_list))
 		return 0;
 
-	bitmap_bh = read_block_bitmap(sb, group);
+	bitmap_bh = ext4_read_block_bitmap(sb, group);
 	if (bitmap_bh == NULL) {
-		/* error handling here */
-		ext4_mb_release_desc(&e4b);
-		BUG_ON(bitmap_bh == NULL);
+		ext4_error(sb, __func__, "Error in reading block "
+				"bitmap for %lu\n", group);
+		return 0;
 	}
 
 	err = ext4_mb_load_buddy(sb, group, &e4b);
-	BUG_ON(err != 0); /* error handling here */
+	if (err) {
+		ext4_error(sb, __func__, "Error in loading buddy "
+				"information for %lu\n", group);
+		put_bh(bitmap_bh);
+		return 0;
+	}
 
 	if (needed == 0)
 		needed = EXT4_BLOCKS_PER_GROUP(sb) + 1;
 
-	grp = ext4_get_group_info(sb, group);
 	INIT_LIST_HEAD(&list);
-
 	ac = kmem_cache_alloc(ext4_ac_cachep, GFP_NOFS);
 repeat:
 	ext4_lock_group(sb, group);
@@ -3741,13 +3959,18 @@ repeat:
 		ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, NULL);
 
 		err = ext4_mb_load_buddy(sb, group, &e4b);
-		BUG_ON(err != 0); /* error handling here */
+		if (err) {
+			ext4_error(sb, __func__, "Error in loading buddy "
+					"information for %lu\n", group);
+			continue;
+		}
 
-		bitmap_bh = read_block_bitmap(sb, group);
+		bitmap_bh = ext4_read_block_bitmap(sb, group);
 		if (bitmap_bh == NULL) {
-			/* error handling here */
+			ext4_error(sb, __func__, "Error in reading block "
+					"bitmap for %lu\n", group);
 			ext4_mb_release_desc(&e4b);
-			BUG_ON(bitmap_bh == NULL);
+			continue;
 		}
 
 		ext4_lock_group(sb, group);
@@ -3950,22 +4173,168 @@ ext4_mb_initialize_context(struct ext4_allocation_context *ac,
 
 }
 
+static noinline_for_stack void
+ext4_mb_discard_lg_preallocations(struct super_block *sb,
+					struct ext4_locality_group *lg,
+					int order, int total_entries)
+{
+	ext4_group_t group = 0;
+	struct ext4_buddy e4b;
+	struct list_head discard_list;
+	struct ext4_prealloc_space *pa, *tmp;
+	struct ext4_allocation_context *ac;
+
+	mb_debug("discard locality group preallocation\n");
+
+	INIT_LIST_HEAD(&discard_list);
+	ac = kmem_cache_alloc(ext4_ac_cachep, GFP_NOFS);
+
+	spin_lock(&lg->lg_prealloc_lock);
+	list_for_each_entry_rcu(pa, &lg->lg_prealloc_list[order],
+						pa_inode_list) {
+		spin_lock(&pa->pa_lock);
+		if (atomic_read(&pa->pa_count)) {
+			/*
+			 * This is the pa that we just used
+			 * for block allocation. So don't
+			 * free that
+			 */
+			spin_unlock(&pa->pa_lock);
+			continue;
+		}
+		if (pa->pa_deleted) {
+			spin_unlock(&pa->pa_lock);
+			continue;
+		}
+		/* only lg prealloc space */
+		BUG_ON(!pa->pa_linear);
+
+		/* seems this one can be freed ... */
+		pa->pa_deleted = 1;
+		spin_unlock(&pa->pa_lock);
+
+		list_del_rcu(&pa->pa_inode_list);
+		list_add(&pa->u.pa_tmp_list, &discard_list);
+
+		total_entries--;
+		if (total_entries <= 5) {
+			/*
+			 * we want to keep only 5 entries
+			 * allowing it to grow to 8. This
+			 * mak sure we don't call discard
+			 * soon for this list.
+			 */
+			break;
+		}
+	}
+	spin_unlock(&lg->lg_prealloc_lock);
+
+	list_for_each_entry_safe(pa, tmp, &discard_list, u.pa_tmp_list) {
+
+		ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, NULL);
+		if (ext4_mb_load_buddy(sb, group, &e4b)) {
+			ext4_error(sb, __func__, "Error in loading buddy "
+					"information for %lu\n", group);
+			continue;
+		}
+		ext4_lock_group(sb, group);
+		list_del(&pa->pa_group_list);
+		ext4_mb_release_group_pa(&e4b, pa, ac);
+		ext4_unlock_group(sb, group);
+
+		ext4_mb_release_desc(&e4b);
+		list_del(&pa->u.pa_tmp_list);
+		call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
+	}
+	if (ac)
+		kmem_cache_free(ext4_ac_cachep, ac);
+}
+
+/*
+ * We have incremented pa_count. So it cannot be freed at this
+ * point. Also we hold lg_mutex. So no parallel allocation is
+ * possible from this lg. That means pa_free cannot be updated.
+ *
+ * A parallel ext4_mb_discard_group_preallocations is possible.
+ * which can cause the lg_prealloc_list to be updated.
+ */
+
+static void ext4_mb_add_n_trim(struct ext4_allocation_context *ac)
+{
+	int order, added = 0, lg_prealloc_count = 1;
+	struct super_block *sb = ac->ac_sb;
+	struct ext4_locality_group *lg = ac->ac_lg;
+	struct ext4_prealloc_space *tmp_pa, *pa = ac->ac_pa;
+
+	order = fls(pa->pa_free) - 1;
+	if (order > PREALLOC_TB_SIZE - 1)
+		/* The max size of hash table is PREALLOC_TB_SIZE */
+		order = PREALLOC_TB_SIZE - 1;
+	/* Add the prealloc space to lg */
+	rcu_read_lock();
+	list_for_each_entry_rcu(tmp_pa, &lg->lg_prealloc_list[order],
+						pa_inode_list) {
+		spin_lock(&tmp_pa->pa_lock);
+		if (tmp_pa->pa_deleted) {
+			spin_unlock(&pa->pa_lock);
+			continue;
+		}
+		if (!added && pa->pa_free < tmp_pa->pa_free) {
+			/* Add to the tail of the previous entry */
+			list_add_tail_rcu(&pa->pa_inode_list,
+						&tmp_pa->pa_inode_list);
+			added = 1;
+			/*
+			 * we want to count the total
+			 * number of entries in the list
+			 */
+		}
+		spin_unlock(&tmp_pa->pa_lock);
+		lg_prealloc_count++;
+	}
+	if (!added)
+		list_add_tail_rcu(&pa->pa_inode_list,
+					&lg->lg_prealloc_list[order]);
+	rcu_read_unlock();
+
+	/* Now trim the list to be not more than 8 elements */
+	if (lg_prealloc_count > 8) {
+		ext4_mb_discard_lg_preallocations(sb, lg,
+						order, lg_prealloc_count);
+		return;
+	}
+	return ;
+}
+
 /*
  * release all resource we used in allocation
  */
 static int ext4_mb_release_context(struct ext4_allocation_context *ac)
 {
-	if (ac->ac_pa) {
-		if (ac->ac_pa->pa_linear) {
+	struct ext4_prealloc_space *pa = ac->ac_pa;
+	if (pa) {
+		if (pa->pa_linear) {
 			/* see comment in ext4_mb_use_group_pa() */
-			spin_lock(&ac->ac_pa->pa_lock);
-			ac->ac_pa->pa_pstart += ac->ac_b_ex.fe_len;
-			ac->ac_pa->pa_lstart += ac->ac_b_ex.fe_len;
-			ac->ac_pa->pa_free -= ac->ac_b_ex.fe_len;
-			ac->ac_pa->pa_len -= ac->ac_b_ex.fe_len;
-			spin_unlock(&ac->ac_pa->pa_lock);
+			spin_lock(&pa->pa_lock);
+			pa->pa_pstart += ac->ac_b_ex.fe_len;
+			pa->pa_lstart += ac->ac_b_ex.fe_len;
+			pa->pa_free -= ac->ac_b_ex.fe_len;
+			pa->pa_len -= ac->ac_b_ex.fe_len;
+			spin_unlock(&pa->pa_lock);
+			/*
+			 * We want to add the pa to the right bucket.
+			 * Remove it from the list and while adding
+			 * make sure the list to which we are adding
+			 * doesn't grow big.
+			 */
+			if (likely(pa->pa_free)) {
+				spin_lock(pa->pa_obj_lock);
+				list_del_rcu(&pa->pa_inode_list);
+				spin_unlock(pa->pa_obj_lock);
+				ext4_mb_add_n_trim(ac);
+			}
 		}
-		ext4_mb_put_pa(ac, ac->ac_sb, ac->ac_pa);
+		ext4_mb_put_pa(ac, ac->ac_sb, pa);
 	}
 	if (ac->ac_bitmap_page)
 		page_cache_release(ac->ac_bitmap_page);
@@ -4011,10 +4380,21 @@ ext4_fsblk_t ext4_mb_new_blocks(handle_t *handle,
 	sbi = EXT4_SB(sb);
 
 	if (!test_opt(sb, MBALLOC)) {
-		block = ext4_new_blocks_old(handle, ar->inode, ar->goal,
+		block = ext4_old_new_blocks(handle, ar->inode, ar->goal,
 					    &(ar->len), errp);
 		return block;
 	}
+	if (!EXT4_I(ar->inode)->i_delalloc_reserved_flag) {
+		/*
+		 * With delalloc we already reserved the blocks
+		 */
+		ar->len = ext4_has_free_blocks(sbi, ar->len);
+	}
+
+	if (ar->len == 0) {
+		*errp = -ENOSPC;
+		return 0;
+	}
 
 	while (ar->len && DQUOT_ALLOC_BLOCK(ar->inode, ar->len)) {
 		ar->flags |= EXT4_MB_HINT_NOPREALLOC;
@@ -4026,10 +4406,14 @@ ext4_fsblk_t ext4_mb_new_blocks(handle_t *handle,
 	}
 	inquota = ar->len;
 
+	if (EXT4_I(ar->inode)->i_delalloc_reserved_flag)
+		ar->flags |= EXT4_MB_DELALLOC_RESERVED;
+
 	ac = kmem_cache_alloc(ext4_ac_cachep, GFP_NOFS);
 	if (!ac) {
+		ar->len = 0;
 		*errp = -ENOMEM;
-		return 0;
+		goto out1;
 	}
 
 	ext4_mb_poll_new_transaction(sb, handle);
@@ -4037,12 +4421,11 @@ ext4_fsblk_t ext4_mb_new_blocks(handle_t *handle,
 	*errp = ext4_mb_initialize_context(ac, ar);
 	if (*errp) {
 		ar->len = 0;
-		goto out;
+		goto out2;
 	}
 
 	ac->ac_op = EXT4_MB_HISTORY_PREALLOC;
 	if (!ext4_mb_use_preallocated(ac)) {
-
 		ac->ac_op = EXT4_MB_HISTORY_ALLOC;
 		ext4_mb_normalize_request(ac, ar);
 repeat:
@@ -4085,11 +4468,12 @@ repeat:
 
 	ext4_mb_release_context(ac);
 
-out:
+out2:
+	kmem_cache_free(ext4_ac_cachep, ac);
+out1:
 	if (ar->len < inquota)
 		DQUOT_FREE_BLOCK(ar->inode, inquota - ar->len);
 
-	kmem_cache_free(ext4_ac_cachep, ac);
 	return block;
 }
 static void ext4_mb_poll_new_transaction(struct super_block *sb,
@@ -4242,12 +4626,16 @@ do_more:
 		overflow = bit + count - EXT4_BLOCKS_PER_GROUP(sb);
 		count -= overflow;
 	}
-	bitmap_bh = read_block_bitmap(sb, block_group);
-	if (!bitmap_bh)
+	bitmap_bh = ext4_read_block_bitmap(sb, block_group);
+	if (!bitmap_bh) {
+		err = -EIO;
 		goto error_return;
+	}
 	gdp = ext4_get_group_desc(sb, block_group, &gd_bh);
-	if (!gdp)
+	if (!gdp) {
+		err = -EIO;
 		goto error_return;
+	}
 
 	if (in_range(ext4_block_bitmap(sb, gdp), block, count) ||
 	    in_range(ext4_inode_bitmap(sb, gdp), block, count) ||
@@ -4309,10 +4697,9 @@ do_more:
 		ext4_mb_free_metadata(handle, &e4b, block_group, bit, count);
 	} else {
 		ext4_lock_group(sb, block_group);
-		err = mb_free_blocks(inode, &e4b, bit, count);
+		mb_free_blocks(inode, &e4b, bit, count);
 		ext4_mb_return_to_preallocation(inode, &e4b, block, count);
 		ext4_unlock_group(sb, block_group);
-		BUG_ON(err != 0);
 	}
 
 	spin_lock(sb_bgl_lock(sbi, block_group));
@@ -4321,6 +4708,13 @@ do_more:
 	spin_unlock(sb_bgl_lock(sbi, block_group));
 	percpu_counter_add(&sbi->s_freeblocks_counter, count);
 
+	if (sbi->s_log_groups_per_flex) {
+		ext4_group_t flex_group = ext4_flex_group(sbi, block_group);
+		spin_lock(sb_bgl_lock(sbi, flex_group));
+		sbi->s_flex_groups[flex_group].free_blocks += count;
+		spin_unlock(sb_bgl_lock(sbi, flex_group));
+	}
+
 	ext4_mb_release_desc(&e4b);
 
 	*freed += count;
diff --git a/fs/ext4/mballoc.h b/fs/ext4/mballoc.h
index bfe6add..c7c9906 100644
--- a/fs/ext4/mballoc.h
+++ b/fs/ext4/mballoc.h
@@ -164,11 +164,17 @@ struct ext4_free_extent {
  * Locality group:
  *   we try to group all related changes together
  *   so that writeback can flush/allocate them together as well
+ *   Size of lg_prealloc_list hash is determined by MB_DEFAULT_GROUP_PREALLOC
+ *   (512). We store prealloc space into the hash based on the pa_free blocks
+ *   order value.ie, fls(pa_free)-1;
  */
+#define PREALLOC_TB_SIZE 10
 struct ext4_locality_group {
 	/* for allocator */
-	struct mutex		lg_mutex;	/* to serialize allocates */
-	struct list_head	lg_prealloc_list;/* list of preallocations */
+	/* to serialize allocates */
+	struct mutex		lg_mutex;
+	/* list of preallocations */
+	struct list_head	lg_prealloc_list[PREALLOC_TB_SIZE];
 	spinlock_t		lg_prealloc_lock;
 };
 
diff --git a/fs/ext4/migrate.c b/fs/ext4/migrate.c
index b9e077b..46fc0b5 100644
--- a/fs/ext4/migrate.c
+++ b/fs/ext4/migrate.c
@@ -53,7 +53,8 @@ static int finish_range(handle_t *handle, struct inode *inode,
 	 * credit. But below we try to not accumalate too much
 	 * of them by restarting the journal.
 	 */
-	needed = ext4_ext_calc_credits_for_insert(inode, path);
+	needed = ext4_ext_calc_credits_for_single_extent(inode,
+		    lb->last_block - lb->first_block + 1, path);
 
 	/*
 	 * Make sure the credit we accumalated is not really high
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index ab16bea..387ad98 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -183,6 +183,16 @@ static int ext4_dx_add_entry(handle_t *handle, struct dentry *dentry,
 			     struct inode *inode);
 
 /*
+ * p is at least 6 bytes before the end of page
+ */
+static inline struct ext4_dir_entry_2 *
+ext4_next_entry(struct ext4_dir_entry_2 *p)
+{
+	return (struct ext4_dir_entry_2 *)((char *)p +
+		ext4_rec_len_from_disk(p->rec_len));
+}
+
+/*
  * Future: use high four bits of block for coalesce-on-delete flags
  * Mask them off for now.
  */
@@ -231,13 +241,13 @@ static inline unsigned dx_root_limit (struct inode *dir, unsigned infosize)
 {
 	unsigned entry_space = dir->i_sb->s_blocksize - EXT4_DIR_REC_LEN(1) -
 		EXT4_DIR_REC_LEN(2) - infosize;
-	return 0? 20: entry_space / sizeof(struct dx_entry);
+	return entry_space / sizeof(struct dx_entry);
 }
 
 static inline unsigned dx_node_limit (struct inode *dir)
 {
 	unsigned entry_space = dir->i_sb->s_blocksize - EXT4_DIR_REC_LEN(0);
-	return 0? 22: entry_space / sizeof(struct dx_entry);
+	return entry_space / sizeof(struct dx_entry);
 }
 
 /*
@@ -554,15 +564,6 @@ static int ext4_htree_next_block(struct inode *dir, __u32 hash,
 
 
 /*
- * p is at least 6 bytes before the end of page
- */
-static inline struct ext4_dir_entry_2 *ext4_next_entry(struct ext4_dir_entry_2 *p)
-{
-	return (struct ext4_dir_entry_2 *)((char *)p +
-		ext4_rec_len_from_disk(p->rec_len));
-}
-
-/*
  * This function fills a red-black tree with information from a
  * directory block.  It returns the number directory entries loaded
  * into the tree.  If there is an error it is returned in err.
@@ -993,19 +994,21 @@ static struct buffer_head * ext4_dx_find_entry(struct dentry *dentry,
 		de = (struct ext4_dir_entry_2 *) bh->b_data;
 		top = (struct ext4_dir_entry_2 *) ((char *) de + sb->s_blocksize -
 				       EXT4_DIR_REC_LEN(0));
-		for (; de < top; de = ext4_next_entry(de))
-		if (ext4_match (namelen, name, de)) {
-			if (!ext4_check_dir_entry("ext4_find_entry",
-						  dir, de, bh,
-				  (block<<EXT4_BLOCK_SIZE_BITS(sb))
-					  +((char *)de - bh->b_data))) {
-				brelse (bh);
+		for (; de < top; de = ext4_next_entry(de)) {
+			int off = (block << EXT4_BLOCK_SIZE_BITS(sb))
+				  + ((char *) de - bh->b_data);
+
+			if (!ext4_check_dir_entry(__func__, dir, de, bh, off)) {
+				brelse(bh);
 				*err = ERR_BAD_DX_DIR;
 				goto errout;
 			}
-			*res_dir = de;
-			dx_release (frames);
-			return bh;
+
+			if (ext4_match(namelen, name, de)) {
+				*res_dir = de;
+				dx_release(frames);
+				return bh;
+			}
 		}
 		brelse (bh);
 		/* Check to see if we should continue to search */
diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index 9ff7b1c..b3d3560 100644
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -73,7 +73,7 @@ static int verify_group_input(struct super_block *sb,
 			     "Inode bitmap not in group (block %llu)",
 			     (unsigned long long)input->inode_bitmap);
 	else if (outside(input->inode_table, start, end) ||
-	         outside(itend - 1, start, end))
+		 outside(itend - 1, start, end))
 		ext4_warning(sb, __func__,
 			     "Inode table not in group (blocks %llu-%llu)",
 			     (unsigned long long)input->inode_table, itend - 1);
@@ -104,7 +104,7 @@ static int verify_group_input(struct super_block *sb,
 			     (unsigned long long)input->inode_bitmap,
 			     start, metaend - 1);
 	else if (inside(input->inode_table, start, metaend) ||
-	         inside(itend - 1, start, metaend))
+		 inside(itend - 1, start, metaend))
 		ext4_warning(sb, __func__,
 			     "Inode table (%llu-%llu) overlaps"
 			     "GDT table (%llu-%llu)",
@@ -158,9 +158,9 @@ static int extend_or_restart_transaction(handle_t *handle, int thresh,
 	if (err) {
 		if ((err = ext4_journal_restart(handle, EXT4_MAX_TRANS_DATA)))
 			return err;
-	        if ((err = ext4_journal_get_write_access(handle, bh)))
+		if ((err = ext4_journal_get_write_access(handle, bh)))
 			return err;
-        }
+	}
 
 	return 0;
 }
@@ -416,11 +416,11 @@ static int add_new_gdb(handle_t *handle, struct inode *inode,
 		       "EXT4-fs: ext4_add_new_gdb: adding group block %lu\n",
 		       gdb_num);
 
-	/*
-	 * If we are not using the primary superblock/GDT copy don't resize,
-	 * because the user tools have no way of handling this.  Probably a
-	 * bad time to do it anyways.
-	 */
+        /*
+         * If we are not using the primary superblock/GDT copy don't resize,
+         * because the user tools have no way of handling this.  Probably a
+         * bad time to do it anyways.
+         */
 	if (EXT4_SB(sb)->s_sbh->b_blocknr !=
 	    le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) {
 		ext4_warning(sb, __func__,
@@ -507,14 +507,14 @@ static int add_new_gdb(handle_t *handle, struct inode *inode,
 	return 0;
 
 exit_inode:
-	//ext4_journal_release_buffer(handle, iloc.bh);
+	/* ext4_journal_release_buffer(handle, iloc.bh); */
 	brelse(iloc.bh);
 exit_dindj:
-	//ext4_journal_release_buffer(handle, dind);
+	/* ext4_journal_release_buffer(handle, dind); */
 exit_primary:
-	//ext4_journal_release_buffer(handle, *primary);
+	/* ext4_journal_release_buffer(handle, *primary); */
 exit_sbh:
-	//ext4_journal_release_buffer(handle, *primary);
+	/* ext4_journal_release_buffer(handle, *primary); */
 exit_dind:
 	brelse(dind);
 exit_bh:
@@ -773,7 +773,8 @@ int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input)
 
 	if (reserved_gdb || gdb_off == 0) {
 		if (!EXT4_HAS_COMPAT_FEATURE(sb,
-					     EXT4_FEATURE_COMPAT_RESIZE_INODE)){
+					     EXT4_FEATURE_COMPAT_RESIZE_INODE)
+		    || !le16_to_cpu(es->s_reserved_gdt_blocks)) {
 			ext4_warning(sb, __func__,
 				     "No reserved GDT blocks, can't resize");
 			return -EPERM;
@@ -818,12 +819,12 @@ int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input)
 	if ((err = ext4_journal_get_write_access(handle, sbi->s_sbh)))
 		goto exit_journal;
 
-	/*
-	 * We will only either add reserved group blocks to a backup group
-	 * or remove reserved blocks for the first group in a new group block.
-	 * Doing both would be mean more complex code, and sane people don't
-	 * use non-sparse filesystems anymore.  This is already checked above.
-	 */
+        /*
+         * We will only either add reserved group blocks to a backup group
+         * or remove reserved blocks for the first group in a new group block.
+         * Doing both would be mean more complex code, and sane people don't
+         * use non-sparse filesystems anymore.  This is already checked above.
+         */
 	if (gdb_off) {
 		primary = sbi->s_group_desc[gdb_num];
 		if ((err = ext4_journal_get_write_access(handle, primary)))
@@ -835,24 +836,24 @@ int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input)
 	} else if ((err = add_new_gdb(handle, inode, input, &primary)))
 		goto exit_journal;
 
-	/*
-	 * OK, now we've set up the new group.  Time to make it active.
-	 *
-	 * Current kernels don't lock all allocations via lock_super(),
-	 * so we have to be safe wrt. concurrent accesses the group
-	 * data.  So we need to be careful to set all of the relevant
-	 * group descriptor data etc. *before* we enable the group.
-	 *
-	 * The key field here is sbi->s_groups_count: as long as
-	 * that retains its old value, nobody is going to access the new
-	 * group.
-	 *
-	 * So first we update all the descriptor metadata for the new
-	 * group; then we update the total disk blocks count; then we
-	 * update the groups count to enable the group; then finally we
-	 * update the free space counts so that the system can start
-	 * using the new disk blocks.
-	 */
+        /*
+         * OK, now we've set up the new group.  Time to make it active.
+         *
+         * Current kernels don't lock all allocations via lock_super(),
+         * so we have to be safe wrt. concurrent accesses the group
+         * data.  So we need to be careful to set all of the relevant
+         * group descriptor data etc. *before* we enable the group.
+         *
+         * The key field here is sbi->s_groups_count: as long as
+         * that retains its old value, nobody is going to access the new
+         * group.
+         *
+         * So first we update all the descriptor metadata for the new
+         * group; then we update the total disk blocks count; then we
+         * update the groups count to enable the group; then finally we
+         * update the free space counts so that the system can start
+         * using the new disk blocks.
+         */
 
 	/* Update group descriptor block for new group */
 	gdp = (struct ext4_group_desc *)((char *)primary->b_data +
@@ -866,6 +867,15 @@ int ext4_group_add(struct super_block *sb, struct ext4_new_group_data *input)
 	gdp->bg_checksum = ext4_group_desc_csum(sbi, input->group, gdp);
 
 	/*
+	 * We can allocate memory for mb_alloc based on the new group
+	 * descriptor
+	 */
+	if (test_opt(sb, MBALLOC)) {
+		err = ext4_mb_add_more_groupinfo(sb, input->group, gdp);
+		if (err)
+			goto exit_journal;
+	}
+	/*
 	 * Make the new blocks and inodes valid next.  We do this before
 	 * increasing the group count so that once the group is enabled,
 	 * all of its blocks and inodes are already valid.
@@ -937,7 +947,8 @@ exit_put:
 	return err;
 } /* ext4_group_add */
 
-/* Extend the filesystem to the new number of blocks specified.  This entry
+/*
+ * Extend the filesystem to the new number of blocks specified.  This entry
  * point is only used to extend the current filesystem to the end of the last
  * existing group.  It can be accessed via ioctl, or by "remount,resize=<size>"
  * for emergencies (because it has no dependencies on reserved blocks).
@@ -957,6 +968,8 @@ int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es,
 	handle_t *handle;
 	int err;
 	unsigned long freed_blocks;
+	ext4_group_t group;
+	struct ext4_group_info *grp;
 
 	/* We don't need to worry about locking wrt other resizers just
 	 * yet: we're going to revalidate es->s_blocks_count after
@@ -988,7 +1001,7 @@ int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es,
 	}
 
 	/* Handle the remaining blocks in the last group only. */
-	ext4_get_group_no_and_offset(sb, o_blocks_count, NULL, &last);
+	ext4_get_group_no_and_offset(sb, o_blocks_count, &group, &last);
 
 	if (last == 0) {
 		ext4_warning(sb, __func__,
@@ -1013,7 +1026,7 @@ int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es,
 			     o_blocks_count + add, add);
 
 	/* See if the device is actually as big as what was requested */
-	bh = sb_bread(sb, o_blocks_count + add -1);
+	bh = sb_bread(sb, o_blocks_count + add - 1);
 	if (!bh) {
 		ext4_warning(sb, __func__,
 			     "can't read last block, resize aborted");
@@ -1060,6 +1073,45 @@ int ext4_group_extend(struct super_block *sb, struct ext4_super_block *es,
 		   o_blocks_count + add);
 	if ((err = ext4_journal_stop(handle)))
 		goto exit_put;
+
+	/*
+	 * Mark mballoc pages as not up to date so that they will be updated
+	 * next time they are loaded by ext4_mb_load_buddy.
+	 */
+	if (test_opt(sb, MBALLOC)) {
+		struct ext4_sb_info *sbi = EXT4_SB(sb);
+		struct inode *inode = sbi->s_buddy_cache;
+		int blocks_per_page;
+		int block;
+		int pnum;
+		struct page *page;
+
+		/* Set buddy page as not up to date */
+		blocks_per_page = PAGE_CACHE_SIZE / sb->s_blocksize;
+		block = group * 2;
+		pnum = block / blocks_per_page;
+		page = find_get_page(inode->i_mapping, pnum);
+		if (page != NULL) {
+			ClearPageUptodate(page);
+			page_cache_release(page);
+		}
+
+		/* Set bitmap page as not up to date */
+		block++;
+		pnum = block / blocks_per_page;
+		page = find_get_page(inode->i_mapping, pnum);
+		if (page != NULL) {
+			ClearPageUptodate(page);
+			page_cache_release(page);
+		}
+
+		/* Get the info on the last group */
+		grp = ext4_get_group_info(sb, group);
+
+		/* Update free blocks in group info */
+		ext4_mb_update_group_info(grp, add);
+	}
+
 	if (test_opt(sb, DEBUG))
 		printk(KERN_DEBUG "EXT4-fs: extended group to %llu blocks\n",
 		       ext4_blocks_count(es));
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 02bf243..ed80f9f 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -49,20 +49,19 @@ static int ext4_load_journal(struct super_block *, struct ext4_super_block *,
 			     unsigned long journal_devnum);
 static int ext4_create_journal(struct super_block *, struct ext4_super_block *,
 			       unsigned int);
-static void ext4_commit_super (struct super_block * sb,
-			       struct ext4_super_block * es,
-			       int sync);
-static void ext4_mark_recovery_complete(struct super_block * sb,
-					struct ext4_super_block * es);
-static void ext4_clear_journal_err(struct super_block * sb,
-				   struct ext4_super_block * es);
+static void ext4_commit_super(struct super_block *sb,
+			      struct ext4_super_block *es, int sync);
+static void ext4_mark_recovery_complete(struct super_block *sb,
+					struct ext4_super_block *es);
+static void ext4_clear_journal_err(struct super_block *sb,
+				   struct ext4_super_block *es);
 static int ext4_sync_fs(struct super_block *sb, int wait);
-static const char *ext4_decode_error(struct super_block * sb, int errno,
+static const char *ext4_decode_error(struct super_block *sb, int errno,
 				     char nbuf[16]);
-static int ext4_remount (struct super_block * sb, int * flags, char * data);
-static int ext4_statfs (struct dentry * dentry, struct kstatfs * buf);
+static int ext4_remount(struct super_block *sb, int *flags, char *data);
+static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf);
 static void ext4_unlockfs(struct super_block *sb);
-static void ext4_write_super (struct super_block * sb);
+static void ext4_write_super(struct super_block *sb);
 static void ext4_write_super_lockfs(struct super_block *sb);
 
 
@@ -211,15 +210,15 @@ static void ext4_handle_error(struct super_block *sb)
 	if (sb->s_flags & MS_RDONLY)
 		return;
 
-	if (!test_opt (sb, ERRORS_CONT)) {
+	if (!test_opt(sb, ERRORS_CONT)) {
 		journal_t *journal = EXT4_SB(sb)->s_journal;
 
 		EXT4_SB(sb)->s_mount_opt |= EXT4_MOUNT_ABORT;
 		if (journal)
 			jbd2_journal_abort(journal, -EIO);
 	}
-	if (test_opt (sb, ERRORS_RO)) {
-		printk (KERN_CRIT "Remounting filesystem read-only\n");
+	if (test_opt(sb, ERRORS_RO)) {
+		printk(KERN_CRIT "Remounting filesystem read-only\n");
 		sb->s_flags |= MS_RDONLY;
 	}
 	ext4_commit_super(sb, es, 1);
@@ -228,13 +227,13 @@ static void ext4_handle_error(struct super_block *sb)
 			sb->s_id);
 }
 
-void ext4_error (struct super_block * sb, const char * function,
-		 const char * fmt, ...)
+void ext4_error(struct super_block *sb, const char *function,
+		const char *fmt, ...)
 {
 	va_list args;
 
 	va_start(args, fmt);
-	printk(KERN_CRIT "EXT4-fs error (device %s): %s: ",sb->s_id, function);
+	printk(KERN_CRIT "EXT4-fs error (device %s): %s: ", sb->s_id, function);
 	vprintk(fmt, args);
 	printk("\n");
 	va_end(args);
@@ -242,7 +241,7 @@ void ext4_error (struct super_block * sb, const char * function,
 	ext4_handle_error(sb);
 }
 
-static const char *ext4_decode_error(struct super_block * sb, int errno,
+static const char *ext4_decode_error(struct super_block *sb, int errno,
 				     char nbuf[16])
 {
 	char *errstr = NULL;
@@ -278,8 +277,7 @@ static const char *ext4_decode_error(struct super_block * sb, int errno,
 /* __ext4_std_error decodes expected errors from journaling functions
  * automatically and invokes the appropriate error response.  */
 
-void __ext4_std_error (struct super_block * sb, const char * function,
-		       int errno)
+void __ext4_std_error(struct super_block *sb, const char *function, int errno)
 {
 	char nbuf[16];
 	const char *errstr;
@@ -292,8 +290,8 @@ void __ext4_std_error (struct super_block * sb, const char * function,
 		return;
 
 	errstr = ext4_decode_error(sb, errno, nbuf);
-	printk (KERN_CRIT "EXT4-fs error (device %s) in %s: %s\n",
-		sb->s_id, function, errstr);
+	printk(KERN_CRIT "EXT4-fs error (device %s) in %s: %s\n",
+	       sb->s_id, function, errstr);
 
 	ext4_handle_error(sb);
 }
@@ -308,15 +306,15 @@ void __ext4_std_error (struct super_block * sb, const char * function,
  * case we take the easy way out and panic immediately.
  */
 
-void ext4_abort (struct super_block * sb, const char * function,
-		 const char * fmt, ...)
+void ext4_abort(struct super_block *sb, const char *function,
+		const char *fmt, ...)
 {
 	va_list args;
 
-	printk (KERN_CRIT "ext4_abort called.\n");
+	printk(KERN_CRIT "ext4_abort called.\n");
 
 	va_start(args, fmt);
-	printk(KERN_CRIT "EXT4-fs error (device %s): %s: ",sb->s_id, function);
+	printk(KERN_CRIT "EXT4-fs error (device %s): %s: ", sb->s_id, function);
 	vprintk(fmt, args);
 	printk("\n");
 	va_end(args);
@@ -334,8 +332,8 @@ void ext4_abort (struct super_block * sb, const char * function,
 	jbd2_journal_abort(EXT4_SB(sb)->s_journal, -EIO);
 }
 
-void ext4_warning (struct super_block * sb, const char * function,
-		   const char * fmt, ...)
+void ext4_warning(struct super_block *sb, const char *function,
+		  const char *fmt, ...)
 {
 	va_list args;
 
@@ -496,7 +494,7 @@ static void dump_orphan_list(struct super_block *sb, struct ext4_sb_info *sbi)
 	}
 }
 
-static void ext4_put_super (struct super_block * sb)
+static void ext4_put_super(struct super_block *sb)
 {
 	struct ext4_sb_info *sbi = EXT4_SB(sb);
 	struct ext4_super_block *es = sbi->s_es;
@@ -506,6 +504,7 @@ static void ext4_put_super (struct super_block * sb)
 	ext4_ext_release(sb);
 	ext4_xattr_put_super(sb);
 	jbd2_journal_destroy(sbi->s_journal);
+	sbi->s_journal = NULL;
 	if (!(sb->s_flags & MS_RDONLY)) {
 		EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER);
 		es->s_state = cpu_to_le16(sbi->s_mount_state);
@@ -517,6 +516,7 @@ static void ext4_put_super (struct super_block * sb)
 	for (i = 0; i < sbi->s_gdb_count; i++)
 		brelse(sbi->s_group_desc[i]);
 	kfree(sbi->s_group_desc);
+	kfree(sbi->s_flex_groups);
 	percpu_counter_destroy(&sbi->s_freeblocks_counter);
 	percpu_counter_destroy(&sbi->s_freeinodes_counter);
 	percpu_counter_destroy(&sbi->s_dirs_counter);
@@ -568,9 +568,16 @@ static struct inode *ext4_alloc_inode(struct super_block *sb)
 #endif
 	ei->i_block_alloc_info = NULL;
 	ei->vfs_inode.i_version = 1;
+	ei->vfs_inode.i_data.writeback_index = 0;
 	memset(&ei->i_cached_extent, 0, sizeof(struct ext4_ext_cache));
 	INIT_LIST_HEAD(&ei->i_prealloc_list);
 	spin_lock_init(&ei->i_prealloc_lock);
+	jbd2_journal_init_jbd_inode(&ei->jinode, &ei->vfs_inode);
+	ei->i_reserved_data_blocks = 0;
+	ei->i_reserved_meta_blocks = 0;
+	ei->i_allocated_meta_blocks = 0;
+	ei->i_delalloc_reserved_flag = 0;
+	spin_lock_init(&(ei->i_block_reservation_lock));
 	return &ei->vfs_inode;
 }
 
@@ -635,9 +642,12 @@ static void ext4_clear_inode(struct inode *inode)
 	EXT4_I(inode)->i_block_alloc_info = NULL;
 	if (unlikely(rsv))
 		kfree(rsv);
+	jbd2_journal_release_jbd_inode(EXT4_SB(inode->i_sb)->s_journal,
+				       &EXT4_I(inode)->jinode);
 }
 
-static inline void ext4_show_quota_options(struct seq_file *seq, struct super_block *sb)
+static inline void ext4_show_quota_options(struct seq_file *seq,
+					   struct super_block *sb)
 {
 #if defined(CONFIG_QUOTA)
 	struct ext4_sb_info *sbi = EXT4_SB(sb);
@@ -671,7 +681,6 @@ static int ext4_show_options(struct seq_file *seq, struct vfsmount *vfs)
 	unsigned long def_mount_opts;
 	struct super_block *sb = vfs->mnt_sb;
 	struct ext4_sb_info *sbi = EXT4_SB(sb);
-	journal_t *journal = sbi->s_journal;
 	struct ext4_super_block *es = sbi->s_es;
 
 	def_mount_opts = le32_to_cpu(es->s_default_mount_opts);
@@ -747,6 +756,9 @@ static int ext4_show_options(struct seq_file *seq, struct vfsmount *vfs)
 		seq_puts(seq, ",nomballoc");
 	if (test_opt(sb, I_VERSION))
 		seq_puts(seq, ",i_version");
+	if (!test_opt(sb, DELALLOC))
+		seq_puts(seq, ",nodelalloc");
+
 
 	if (sbi->s_stripe)
 		seq_printf(seq, ",stripe=%lu", sbi->s_stripe);
@@ -810,8 +822,8 @@ static struct dentry *ext4_fh_to_parent(struct super_block *sb, struct fid *fid,
 }
 
 #ifdef CONFIG_QUOTA
-#define QTYPE2NAME(t) ((t)==USRQUOTA?"user":"group")
-#define QTYPE2MOPT(on, t) ((t)==USRQUOTA?((on)##USRJQUOTA):((on)##GRPJQUOTA))
+#define QTYPE2NAME(t) ((t) == USRQUOTA?"user":"group")
+#define QTYPE2MOPT(on, t) ((t) == USRQUOTA?((on)##USRJQUOTA):((on)##GRPJQUOTA))
 
 static int ext4_dquot_initialize(struct inode *inode, int type);
 static int ext4_dquot_drop(struct inode *inode);
@@ -894,7 +906,7 @@ enum {
 	Opt_jqfmt_vfsold, Opt_jqfmt_vfsv0, Opt_quota, Opt_noquota,
 	Opt_ignore, Opt_barrier, Opt_err, Opt_resize, Opt_usrquota,
 	Opt_grpquota, Opt_extents, Opt_noextents, Opt_i_version,
-	Opt_mballoc, Opt_nomballoc, Opt_stripe,
+	Opt_mballoc, Opt_nomballoc, Opt_stripe, Opt_delalloc, Opt_nodelalloc,
 };
 
 static match_table_t tokens = {
@@ -953,6 +965,8 @@ static match_table_t tokens = {
 	{Opt_nomballoc, "nomballoc"},
 	{Opt_stripe, "stripe=%u"},
 	{Opt_resize, "resize"},
+	{Opt_delalloc, "delalloc"},
+	{Opt_nodelalloc, "nodelalloc"},
 	{Opt_err, NULL},
 };
 
@@ -977,12 +991,12 @@ static ext4_fsblk_t get_sb_block(void **data)
 	return sb_block;
 }
 
-static int parse_options (char *options, struct super_block *sb,
-			  unsigned int *inum, unsigned long *journal_devnum,
-			  ext4_fsblk_t *n_blocks_count, int is_remount)
+static int parse_options(char *options, struct super_block *sb,
+			 unsigned int *inum, unsigned long *journal_devnum,
+			 ext4_fsblk_t *n_blocks_count, int is_remount)
 {
 	struct ext4_sb_info *sbi = EXT4_SB(sb);
-	char * p;
+	char *p;
 	substring_t args[MAX_OPT_ARGS];
 	int data_opt = 0;
 	int option;
@@ -990,11 +1004,12 @@ static int parse_options (char *options, struct super_block *sb,
 	int qtype, qfmt;
 	char *qname;
 #endif
+	ext4_fsblk_t last_block;
 
 	if (!options)
 		return 1;
 
-	while ((p = strsep (&options, ",")) != NULL) {
+	while ((p = strsep(&options, ",")) != NULL) {
 		int token;
 		if (!*p)
 			continue;
@@ -1002,16 +1017,16 @@ static int parse_options (char *options, struct super_block *sb,
 		token = match_token(p, tokens, args);
 		switch (token) {
 		case Opt_bsd_df:
-			clear_opt (sbi->s_mount_opt, MINIX_DF);
+			clear_opt(sbi->s_mount_opt, MINIX_DF);
 			break;
 		case Opt_minix_df:
-			set_opt (sbi->s_mount_opt, MINIX_DF);
+			set_opt(sbi->s_mount_opt, MINIX_DF);
 			break;
 		case Opt_grpid:
-			set_opt (sbi->s_mount_opt, GRPID);
+			set_opt(sbi->s_mount_opt, GRPID);
 			break;
 		case Opt_nogrpid:
-			clear_opt (sbi->s_mount_opt, GRPID);
+			clear_opt(sbi->s_mount_opt, GRPID);
 			break;
 		case Opt_resuid:
 			if (match_int(&args[0], &option))
@@ -1028,41 +1043,41 @@ static int parse_options (char *options, struct super_block *sb,
 			/* *sb_block = match_int(&args[0]); */
 			break;
 		case Opt_err_panic:
-			clear_opt (sbi->s_mount_opt, ERRORS_CONT);
-			clear_opt (sbi->s_mount_opt, ERRORS_RO);
-			set_opt (sbi->s_mount_opt, ERRORS_PANIC);
+			clear_opt(sbi->s_mount_opt, ERRORS_CONT);
+			clear_opt(sbi->s_mount_opt, ERRORS_RO);
+			set_opt(sbi->s_mount_opt, ERRORS_PANIC);
 			break;
 		case Opt_err_ro:
-			clear_opt (sbi->s_mount_opt, ERRORS_CONT);
-			clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
-			set_opt (sbi->s_mount_opt, ERRORS_RO);
+			clear_opt(sbi->s_mount_opt, ERRORS_CONT);
+			clear_opt(sbi->s_mount_opt, ERRORS_PANIC);
+			set_opt(sbi->s_mount_opt, ERRORS_RO);
 			break;
 		case Opt_err_cont:
-			clear_opt (sbi->s_mount_opt, ERRORS_RO);
-			clear_opt (sbi->s_mount_opt, ERRORS_PANIC);
-			set_opt (sbi->s_mount_opt, ERRORS_CONT);
+			clear_opt(sbi->s_mount_opt, ERRORS_RO);
+			clear_opt(sbi->s_mount_opt, ERRORS_PANIC);
+			set_opt(sbi->s_mount_opt, ERRORS_CONT);
 			break;
 		case Opt_nouid32:
-			set_opt (sbi->s_mount_opt, NO_UID32);
+			set_opt(sbi->s_mount_opt, NO_UID32);
 			break;
 		case Opt_nocheck:
-			clear_opt (sbi->s_mount_opt, CHECK);
+			clear_opt(sbi->s_mount_opt, CHECK);
 			break;
 		case Opt_debug:
-			set_opt (sbi->s_mount_opt, DEBUG);
+			set_opt(sbi->s_mount_opt, DEBUG);
 			break;
 		case Opt_oldalloc:
-			set_opt (sbi->s_mount_opt, OLDALLOC);
+			set_opt(sbi->s_mount_opt, OLDALLOC);
 			break;
 		case Opt_orlov:
-			clear_opt (sbi->s_mount_opt, OLDALLOC);
+			clear_opt(sbi->s_mount_opt, OLDALLOC);
 			break;
 #ifdef CONFIG_EXT4DEV_FS_XATTR
 		case Opt_user_xattr:
-			set_opt (sbi->s_mount_opt, XATTR_USER);
+			set_opt(sbi->s_mount_opt, XATTR_USER);
 			break;
 		case Opt_nouser_xattr:
-			clear_opt (sbi->s_mount_opt, XATTR_USER);
+			clear_opt(sbi->s_mount_opt, XATTR_USER);
 			break;
 #else
 		case Opt_user_xattr:
@@ -1100,7 +1115,7 @@ static int parse_options (char *options, struct super_block *sb,
 				       "journal on remount\n");
 				return 0;
 			}
-			set_opt (sbi->s_mount_opt, UPDATE_JOURNAL);
+			set_opt(sbi->s_mount_opt, UPDATE_JOURNAL);
 			break;
 		case Opt_journal_inum:
 			if (is_remount) {
@@ -1130,7 +1145,7 @@ static int parse_options (char *options, struct super_block *sb,
 			set_opt(sbi->s_mount_opt, JOURNAL_CHECKSUM);
 			break;
 		case Opt_noload:
-			set_opt (sbi->s_mount_opt, NOLOAD);
+			set_opt(sbi->s_mount_opt, NOLOAD);
 			break;
 		case Opt_commit:
 			if (match_int(&args[0], &option))
@@ -1309,15 +1324,39 @@ set_qf_format:
 			clear_opt(sbi->s_mount_opt, NOBH);
 			break;
 		case Opt_extents:
-			set_opt (sbi->s_mount_opt, EXTENTS);
+			if (!EXT4_HAS_INCOMPAT_FEATURE(sb,
+					EXT4_FEATURE_INCOMPAT_EXTENTS)) {
+				ext4_warning(sb, __func__,
+					"extents feature not enabled "
+					"on this filesystem, use tune2fs\n");
+				return 0;
+			}
+			set_opt(sbi->s_mount_opt, EXTENTS);
 			break;
 		case Opt_noextents:
-			clear_opt (sbi->s_mount_opt, EXTENTS);
+			/*
+			 * When e2fsprogs support resizing an already existing
+			 * ext3 file system to greater than 2**32 we need to
+			 * add support to block allocator to handle growing
+			 * already existing block  mapped inode so that blocks
+			 * allocated for them fall within 2**32
+			 */
+			last_block = ext4_blocks_count(sbi->s_es) - 1;
+			if (last_block  > 0xffffffffULL) {
+				printk(KERN_ERR "EXT4-fs: Filesystem too "
+						"large to mount with "
+						"-o noextents options\n");
+				return 0;
+			}
+			clear_opt(sbi->s_mount_opt, EXTENTS);
 			break;
 		case Opt_i_version:
 			set_opt(sbi->s_mount_opt, I_VERSION);
 			sb->s_flags |= MS_I_VERSION;
 			break;
+		case Opt_nodelalloc:
+			clear_opt(sbi->s_mount_opt, DELALLOC);
+			break;
 		case Opt_mballoc:
 			set_opt(sbi->s_mount_opt, MBALLOC);
 			break;
@@ -1331,10 +1370,13 @@ set_qf_format:
 				return 0;
 			sbi->s_stripe = option;
 			break;
+		case Opt_delalloc:
+			set_opt(sbi->s_mount_opt, DELALLOC);
+			break;
 		default:
-			printk (KERN_ERR
-				"EXT4-fs: Unrecognized mount option \"%s\" "
-				"or missing value\n", p);
+			printk(KERN_ERR
+			       "EXT4-fs: Unrecognized mount option \"%s\" "
+			       "or missing value\n", p);
 			return 0;
 		}
 	}
@@ -1381,31 +1423,31 @@ static int ext4_setup_super(struct super_block *sb, struct ext4_super_block *es,
 	int res = 0;
 
 	if (le32_to_cpu(es->s_rev_level) > EXT4_MAX_SUPP_REV) {
-		printk (KERN_ERR "EXT4-fs warning: revision level too high, "
-			"forcing read-only mode\n");
+		printk(KERN_ERR "EXT4-fs warning: revision level too high, "
+		       "forcing read-only mode\n");
 		res = MS_RDONLY;
 	}
 	if (read_only)
 		return res;
 	if (!(sbi->s_mount_state & EXT4_VALID_FS))
-		printk (KERN_WARNING "EXT4-fs warning: mounting unchecked fs, "
-			"running e2fsck is recommended\n");
+		printk(KERN_WARNING "EXT4-fs warning: mounting unchecked fs, "
+		       "running e2fsck is recommended\n");
 	else if ((sbi->s_mount_state & EXT4_ERROR_FS))
-		printk (KERN_WARNING
-			"EXT4-fs warning: mounting fs with errors, "
-			"running e2fsck is recommended\n");
+		printk(KERN_WARNING
+		       "EXT4-fs warning: mounting fs with errors, "
+		       "running e2fsck is recommended\n");
 	else if ((__s16) le16_to_cpu(es->s_max_mnt_count) >= 0 &&
 		 le16_to_cpu(es->s_mnt_count) >=
 		 (unsigned short) (__s16) le16_to_cpu(es->s_max_mnt_count))
-		printk (KERN_WARNING
-			"EXT4-fs warning: maximal mount count reached, "
-			"running e2fsck is recommended\n");
+		printk(KERN_WARNING
+		       "EXT4-fs warning: maximal mount count reached, "
+		       "running e2fsck is recommended\n");
 	else if (le32_to_cpu(es->s_checkinterval) &&
 		(le32_to_cpu(es->s_lastcheck) +
 			le32_to_cpu(es->s_checkinterval) <= get_seconds()))
-		printk (KERN_WARNING
-			"EXT4-fs warning: checktime reached, "
-			"running e2fsck is recommended\n");
+		printk(KERN_WARNING
+		       "EXT4-fs warning: checktime reached, "
+		       "running e2fsck is recommended\n");
 #if 0
 		/* @@@ We _will_ want to clear the valid bit if we find
 		 * inconsistencies, to force a fsck at reboot.  But for
@@ -1443,6 +1485,53 @@ static int ext4_setup_super(struct super_block *sb, struct ext4_super_block *es,
 	return res;
 }
 
+static int ext4_fill_flex_info(struct super_block *sb)
+{
+	struct ext4_sb_info *sbi = EXT4_SB(sb);
+	struct ext4_group_desc *gdp = NULL;
+	struct buffer_head *bh;
+	ext4_group_t flex_group_count;
+	ext4_group_t flex_group;
+	int groups_per_flex = 0;
+	__u64 block_bitmap = 0;
+	int i;
+
+	if (!sbi->s_es->s_log_groups_per_flex) {
+		sbi->s_log_groups_per_flex = 0;
+		return 1;
+	}
+
+	sbi->s_log_groups_per_flex = sbi->s_es->s_log_groups_per_flex;
+	groups_per_flex = 1 << sbi->s_log_groups_per_flex;
+
+	flex_group_count = (sbi->s_groups_count + groups_per_flex - 1) /
+		groups_per_flex;
+	sbi->s_flex_groups = kzalloc(flex_group_count *
+				     sizeof(struct flex_groups), GFP_KERNEL);
+	if (sbi->s_flex_groups == NULL) {
+		printk(KERN_ERR "EXT4-fs: not enough memory for "
+				"%lu flex groups\n", flex_group_count);
+		goto failed;
+	}
+
+	gdp = ext4_get_group_desc(sb, 1, &bh);
+	block_bitmap = ext4_block_bitmap(sb, gdp) - 1;
+
+	for (i = 0; i < sbi->s_groups_count; i++) {
+		gdp = ext4_get_group_desc(sb, i, &bh);
+
+		flex_group = ext4_flex_group(sbi, i);
+		sbi->s_flex_groups[flex_group].free_inodes +=
+			le16_to_cpu(gdp->bg_free_inodes_count);
+		sbi->s_flex_groups[flex_group].free_blocks +=
+			le16_to_cpu(gdp->bg_free_blocks_count);
+	}
+
+	return 1;
+failed:
+	return 0;
+}
+
 __le16 ext4_group_desc_csum(struct ext4_sb_info *sbi, __u32 block_group,
 			    struct ext4_group_desc *gdp)
 {
@@ -1507,16 +1596,14 @@ static int ext4_check_descriptors(struct super_block *sb)
 				(EXT4_BLOCKS_PER_GROUP(sb) - 1);
 
 		block_bitmap = ext4_block_bitmap(sb, gdp);
-		if (block_bitmap < first_block || block_bitmap > last_block)
-		{
+		if (block_bitmap < first_block || block_bitmap > last_block) {
 			printk(KERN_ERR "EXT4-fs: ext4_check_descriptors: "
 			       "Block bitmap for group %lu not in group "
 			       "(block %llu)!", i, block_bitmap);
 			return 0;
 		}
 		inode_bitmap = ext4_inode_bitmap(sb, gdp);
-		if (inode_bitmap < first_block || inode_bitmap > last_block)
-		{
+		if (inode_bitmap < first_block || inode_bitmap > last_block) {
 			printk(KERN_ERR "EXT4-fs: ext4_check_descriptors: "
 			       "Inode bitmap for group %lu not in group "
 			       "(block %llu)!", i, inode_bitmap);
@@ -1524,26 +1611,28 @@ static int ext4_check_descriptors(struct super_block *sb)
 		}
 		inode_table = ext4_inode_table(sb, gdp);
 		if (inode_table < first_block ||
-		    inode_table + sbi->s_itb_per_group - 1 > last_block)
-		{
+		    inode_table + sbi->s_itb_per_group - 1 > last_block) {
 			printk(KERN_ERR "EXT4-fs: ext4_check_descriptors: "
 			       "Inode table for group %lu not in group "
 			       "(block %llu)!", i, inode_table);
 			return 0;
 		}
+		spin_lock(sb_bgl_lock(sbi, i));
 		if (!ext4_group_desc_csum_verify(sbi, i, gdp)) {
 			printk(KERN_ERR "EXT4-fs: ext4_check_descriptors: "
 			       "Checksum for group %lu failed (%u!=%u)\n",
 			       i, le16_to_cpu(ext4_group_desc_csum(sbi, i,
 			       gdp)), le16_to_cpu(gdp->bg_checksum));
-			return 0;
+			if (!(sb->s_flags & MS_RDONLY))
+				return 0;
 		}
+		spin_unlock(sb_bgl_lock(sbi, i));
 		if (!flexbg_flag)
 			first_block += EXT4_BLOCKS_PER_GROUP(sb);
 	}
 
 	ext4_free_blocks_count_set(sbi->s_es, ext4_count_free_blocks(sb));
-	sbi->s_es->s_free_inodes_count=cpu_to_le32(ext4_count_free_inodes(sb));
+	sbi->s_es->s_free_inodes_count = cpu_to_le32(ext4_count_free_inodes(sb));
 	return 1;
 }
 
@@ -1564,8 +1653,8 @@ static int ext4_check_descriptors(struct super_block *sb)
  * e2fsck was run on this filesystem, and it must have already done the orphan
  * inode cleanup for us, so we can safely abort without any further action.
  */
-static void ext4_orphan_cleanup (struct super_block * sb,
-				 struct ext4_super_block * es)
+static void ext4_orphan_cleanup(struct super_block *sb,
+				struct ext4_super_block *es)
 {
 	unsigned int s_flags = sb->s_flags;
 	int nr_orphans = 0, nr_truncates = 0;
@@ -1642,7 +1731,7 @@ static void ext4_orphan_cleanup (struct super_block * sb,
 		iput(inode);  /* The delete magic happens here! */
 	}
 
-#define PLURAL(x) (x), ((x)==1) ? "" : "s"
+#define PLURAL(x) (x), ((x) == 1) ? "" : "s"
 
 	if (nr_orphans)
 		printk(KERN_INFO "EXT4-fs: %s: %d orphan inode%s deleted\n",
@@ -1809,12 +1898,12 @@ static unsigned long ext4_get_stripe_size(struct ext4_sb_info *sbi)
 	return 0;
 }
 
-static int ext4_fill_super (struct super_block *sb, void *data, int silent)
-				__releases(kernel_sem)
-				__acquires(kernel_sem)
+static int ext4_fill_super(struct super_block *sb, void *data, int silent)
+				__releases(kernel_lock)
+				__acquires(kernel_lock)
 
 {
-	struct buffer_head * bh;
+	struct buffer_head *bh;
 	struct ext4_super_block *es = NULL;
 	struct ext4_sb_info *sbi;
 	ext4_fsblk_t block;
@@ -1851,11 +1940,6 @@ static int ext4_fill_super (struct super_block *sb, void *data, int silent)
 		goto out_fail;
 	}
 
-	if (!sb_set_blocksize(sb, blocksize)) {
-		printk(KERN_ERR "EXT4-fs: bad blocksize %d.\n", blocksize);
-		goto out_fail;
-	}
-
 	/*
 	 * The ext4 superblock will not be buffer aligned for other than 1kB
 	 * block sizes.  We need to calculate the offset from buffer start.
@@ -1868,7 +1952,7 @@ static int ext4_fill_super (struct super_block *sb, void *data, int silent)
 	}
 
 	if (!(bh = sb_bread(sb, logical_sb_block))) {
-		printk (KERN_ERR "EXT4-fs: unable to read superblock\n");
+		printk(KERN_ERR "EXT4-fs: unable to read superblock\n");
 		goto out_fail;
 	}
 	/*
@@ -1919,17 +2003,30 @@ static int ext4_fill_super (struct super_block *sb, void *data, int silent)
 
 	/*
 	 * turn on extents feature by default in ext4 filesystem
-	 * User -o noextents to turn it off
+	 * only if feature flag already set by mkfs or tune2fs.
+	 * Use -o noextents to turn it off
 	 */
-	set_opt(sbi->s_mount_opt, EXTENTS);
+	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS))
+		set_opt(sbi->s_mount_opt, EXTENTS);
+	else
+		ext4_warning(sb, __func__,
+			"extents feature not enabled on this filesystem, "
+			"use tune2fs.\n");
 	/*
-	 * turn on mballoc feature by default in ext4 filesystem
-	 * User -o nomballoc to turn it off
+	 * turn on mballoc code by default in ext4 filesystem
+	 * Use -o nomballoc to turn it off
 	 */
 	set_opt(sbi->s_mount_opt, MBALLOC);
 
-	if (!parse_options ((char *) data, sb, &journal_inum, &journal_devnum,
-			    NULL, 0))
+	/*
+	 * enable delayed allocation by default
+	 * Use -o nodelalloc to turn it off
+	 */
+	set_opt(sbi->s_mount_opt, DELALLOC);
+
+
+	if (!parse_options((char *) data, sb, &journal_inum, &journal_devnum,
+			   NULL, 0))
 		goto failed_mount;
 
 	sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
@@ -2004,7 +2101,7 @@ static int ext4_fill_super (struct super_block *sb, void *data, int silent)
 			goto failed_mount;
 		}
 
-		brelse (bh);
+		brelse(bh);
 		logical_sb_block = sb_block * EXT4_MIN_BLOCK_SIZE;
 		offset = do_div(logical_sb_block, blocksize);
 		bh = sb_bread(sb, logical_sb_block);
@@ -2016,8 +2113,8 @@ static int ext4_fill_super (struct super_block *sb, void *data, int silent)
 		es = (struct ext4_super_block *)(((char *)bh->b_data) + offset);
 		sbi->s_es = es;
 		if (es->s_magic != cpu_to_le16(EXT4_SUPER_MAGIC)) {
-			printk (KERN_ERR
-				"EXT4-fs: Magic mismatch, very weird !\n");
+			printk(KERN_ERR
+			       "EXT4-fs: Magic mismatch, very weird !\n");
 			goto failed_mount;
 		}
 	}
@@ -2034,9 +2131,9 @@ static int ext4_fill_super (struct super_block *sb, void *data, int silent)
 		if ((sbi->s_inode_size < EXT4_GOOD_OLD_INODE_SIZE) ||
 		    (!is_power_of_2(sbi->s_inode_size)) ||
 		    (sbi->s_inode_size > blocksize)) {
-			printk (KERN_ERR
-				"EXT4-fs: unsupported inode size: %d\n",
-				sbi->s_inode_size);
+			printk(KERN_ERR
+			       "EXT4-fs: unsupported inode size: %d\n",
+			       sbi->s_inode_size);
 			goto failed_mount;
 		}
 		if (sbi->s_inode_size > EXT4_GOOD_OLD_INODE_SIZE)
@@ -2068,20 +2165,20 @@ static int ext4_fill_super (struct super_block *sb, void *data, int silent)
 	sbi->s_mount_state = le16_to_cpu(es->s_state);
 	sbi->s_addr_per_block_bits = ilog2(EXT4_ADDR_PER_BLOCK(sb));
 	sbi->s_desc_per_block_bits = ilog2(EXT4_DESC_PER_BLOCK(sb));
-	for (i=0; i < 4; i++)
+	for (i = 0; i < 4; i++)
 		sbi->s_hash_seed[i] = le32_to_cpu(es->s_hash_seed[i]);
 	sbi->s_def_hash_version = es->s_def_hash_version;
 
 	if (sbi->s_blocks_per_group > blocksize * 8) {
-		printk (KERN_ERR
-			"EXT4-fs: #blocks per group too big: %lu\n",
-			sbi->s_blocks_per_group);
+		printk(KERN_ERR
+		       "EXT4-fs: #blocks per group too big: %lu\n",
+		       sbi->s_blocks_per_group);
 		goto failed_mount;
 	}
 	if (sbi->s_inodes_per_group > blocksize * 8) {
-		printk (KERN_ERR
-			"EXT4-fs: #inodes per group too big: %lu\n",
-			sbi->s_inodes_per_group);
+		printk(KERN_ERR
+		       "EXT4-fs: #inodes per group too big: %lu\n",
+		       sbi->s_inodes_per_group);
 		goto failed_mount;
 	}
 
@@ -2115,10 +2212,10 @@ static int ext4_fill_super (struct super_block *sb, void *data, int silent)
 	sbi->s_groups_count = blocks_count;
 	db_count = (sbi->s_groups_count + EXT4_DESC_PER_BLOCK(sb) - 1) /
 		   EXT4_DESC_PER_BLOCK(sb);
-	sbi->s_group_desc = kmalloc(db_count * sizeof (struct buffer_head *),
+	sbi->s_group_desc = kmalloc(db_count * sizeof(struct buffer_head *),
 				    GFP_KERNEL);
 	if (sbi->s_group_desc == NULL) {
-		printk (KERN_ERR "EXT4-fs: not enough memory\n");
+		printk(KERN_ERR "EXT4-fs: not enough memory\n");
 		goto failed_mount;
 	}
 
@@ -2128,16 +2225,24 @@ static int ext4_fill_super (struct super_block *sb, void *data, int silent)
 		block = descriptor_loc(sb, logical_sb_block, i);
 		sbi->s_group_desc[i] = sb_bread(sb, block);
 		if (!sbi->s_group_desc[i]) {
-			printk (KERN_ERR "EXT4-fs: "
-				"can't read group descriptor %d\n", i);
+			printk(KERN_ERR "EXT4-fs: "
+			       "can't read group descriptor %d\n", i);
 			db_count = i;
 			goto failed_mount2;
 		}
 	}
-	if (!ext4_check_descriptors (sb)) {
+	if (!ext4_check_descriptors(sb)) {
 		printk(KERN_ERR "EXT4-fs: group descriptors corrupted!\n");
 		goto failed_mount2;
 	}
+	if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG))
+		if (!ext4_fill_flex_info(sb)) {
+			printk(KERN_ERR
+			       "EXT4-fs: unable to initialize "
+			       "flex_bg meta info!\n");
+			goto failed_mount2;
+		}
+
 	sbi->s_gdb_count = db_count;
 	get_random_bytes(&sbi->s_next_generation, sizeof(u32));
 	spin_lock_init(&sbi->s_next_gen_lock);
@@ -2202,11 +2307,11 @@ static int ext4_fill_super (struct super_block *sb, void *data, int silent)
 		    EXT4_SB(sb)->s_journal->j_failed_commit) {
 			printk(KERN_CRIT "EXT4-fs error (device %s): "
 			       "ext4_fill_super: Journal transaction "
-			       "%u is corrupt\n", sb->s_id, 
+			       "%u is corrupt\n", sb->s_id,
 			       EXT4_SB(sb)->s_journal->j_failed_commit);
-			if (test_opt (sb, ERRORS_RO)) {
-				printk (KERN_CRIT
-					"Mounting filesystem read-only\n");
+			if (test_opt(sb, ERRORS_RO)) {
+				printk(KERN_CRIT
+				       "Mounting filesystem read-only\n");
 				sb->s_flags |= MS_RDONLY;
 				EXT4_SB(sb)->s_mount_state |= EXT4_ERROR_FS;
 				es->s_state |= cpu_to_le16(EXT4_ERROR_FS);
@@ -2226,9 +2331,9 @@ static int ext4_fill_super (struct super_block *sb, void *data, int silent)
 			goto failed_mount3;
 	} else {
 		if (!silent)
-			printk (KERN_ERR
-				"ext4: No journal on filesystem on %s\n",
-				sb->s_id);
+			printk(KERN_ERR
+			       "ext4: No journal on filesystem on %s\n",
+			       sb->s_id);
 		goto failed_mount3;
 	}
 
@@ -2312,7 +2417,7 @@ static int ext4_fill_super (struct super_block *sb, void *data, int silent)
 		goto failed_mount4;
 	}
 
-	ext4_setup_super (sb, es, sb->s_flags & MS_RDONLY);
+	ext4_setup_super(sb, es, sb->s_flags & MS_RDONLY);
 
 	/* determine the minimum size of new large inodes, if present */
 	if (sbi->s_inode_size > EXT4_GOOD_OLD_INODE_SIZE) {
@@ -2351,12 +2456,19 @@ static int ext4_fill_super (struct super_block *sb, void *data, int silent)
 	ext4_orphan_cleanup(sb, es);
 	EXT4_SB(sb)->s_mount_state &= ~EXT4_ORPHAN_FS;
 	if (needs_recovery)
-		printk (KERN_INFO "EXT4-fs: recovery complete.\n");
+		printk(KERN_INFO "EXT4-fs: recovery complete.\n");
 	ext4_mark_recovery_complete(sb, es);
-	printk (KERN_INFO "EXT4-fs: mounted filesystem with %s data mode.\n",
-		test_opt(sb,DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA ? "journal":
-		test_opt(sb,DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA ? "ordered":
-		"writeback");
+	printk(KERN_INFO "EXT4-fs: mounted filesystem with %s data mode.\n",
+	       test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA ? "journal":
+	       test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_ORDERED_DATA ? "ordered":
+	       "writeback");
+
+	if (test_opt(sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA) {
+		printk(KERN_WARNING "EXT4-fs: Ignoring delalloc option - "
+				"requested data journaling mode\n");
+		clear_opt(sbi->s_mount_opt, DELALLOC);
+	} else if (test_opt(sb, DELALLOC))
+		printk(KERN_INFO "EXT4-fs: delayed allocation enabled\n");
 
 	ext4_ext_init(sb);
 	ext4_mb_init(sb, needs_recovery);
@@ -2372,6 +2484,7 @@ cantfind_ext4:
 
 failed_mount4:
 	jbd2_journal_destroy(sbi->s_journal);
+	sbi->s_journal = NULL;
 failed_mount3:
 	percpu_counter_destroy(&sbi->s_freeblocks_counter);
 	percpu_counter_destroy(&sbi->s_freeinodes_counter);
@@ -2461,14 +2574,14 @@ static journal_t *ext4_get_journal(struct super_block *sb,
 static journal_t *ext4_get_dev_journal(struct super_block *sb,
 				       dev_t j_dev)
 {
-	struct buffer_head * bh;
+	struct buffer_head *bh;
 	journal_t *journal;
 	ext4_fsblk_t start;
 	ext4_fsblk_t len;
 	int hblock, blocksize;
 	ext4_fsblk_t sb_block;
 	unsigned long offset;
-	struct ext4_super_block * es;
+	struct ext4_super_block *es;
 	struct block_device *bdev;
 
 	bdev = ext4_blkdev_get(j_dev);
@@ -2583,8 +2696,8 @@ static int ext4_load_journal(struct super_block *sb,
 					"unavailable, cannot proceed.\n");
 				return -EROFS;
 			}
-			printk (KERN_INFO "EXT4-fs: write access will "
-					"be enabled during recovery.\n");
+			printk(KERN_INFO "EXT4-fs: write access will "
+			       "be enabled during recovery.\n");
 		}
 	}
 
@@ -2637,8 +2750,8 @@ static int ext4_load_journal(struct super_block *sb,
 	return 0;
 }
 
-static int ext4_create_journal(struct super_block * sb,
-			       struct ext4_super_block * es,
+static int ext4_create_journal(struct super_block *sb,
+			       struct ext4_super_block *es,
 			       unsigned int journal_inum)
 {
 	journal_t *journal;
@@ -2679,9 +2792,8 @@ static int ext4_create_journal(struct super_block * sb,
 	return 0;
 }
 
-static void ext4_commit_super (struct super_block * sb,
-			       struct ext4_super_block * es,
-			       int sync)
+static void ext4_commit_super(struct super_block *sb,
+			      struct ext4_super_block *es, int sync)
 {
 	struct buffer_head *sbh = EXT4_SB(sb)->s_sbh;
 
@@ -2702,8 +2814,8 @@ static void ext4_commit_super (struct super_block * sb,
  * remounting) the filesystem readonly, then we will end up with a
  * consistent fs on disk.  Record that fact.
  */
-static void ext4_mark_recovery_complete(struct super_block * sb,
-					struct ext4_super_block * es)
+static void ext4_mark_recovery_complete(struct super_block *sb,
+					struct ext4_super_block *es)
 {
 	journal_t *journal = EXT4_SB(sb)->s_journal;
 
@@ -2725,8 +2837,8 @@ static void ext4_mark_recovery_complete(struct super_block * sb,
  * has recorded an error from a previous lifetime, move that error to the
  * main filesystem now.
  */
-static void ext4_clear_journal_err(struct super_block * sb,
-				   struct ext4_super_block * es)
+static void ext4_clear_journal_err(struct super_block *sb,
+				   struct ext4_super_block *es)
 {
 	journal_t *journal;
 	int j_errno;
@@ -2751,7 +2863,7 @@ static void ext4_clear_journal_err(struct super_block * sb,
 
 		EXT4_SB(sb)->s_mount_state |= EXT4_ERROR_FS;
 		es->s_state |= cpu_to_le16(EXT4_ERROR_FS);
-		ext4_commit_super (sb, es, 1);
+		ext4_commit_super(sb, es, 1);
 
 		jbd2_journal_clear_err(journal);
 	}
@@ -2784,7 +2896,7 @@ int ext4_force_commit(struct super_block *sb)
  * This implicitly triggers the writebehind on sync().
  */
 
-static void ext4_write_super (struct super_block * sb)
+static void ext4_write_super(struct super_block *sb)
 {
 	if (mutex_trylock(&sb->s_lock) != 0)
 		BUG();
@@ -2840,13 +2952,14 @@ static void ext4_unlockfs(struct super_block *sb)
 	}
 }
 
-static int ext4_remount (struct super_block * sb, int * flags, char * data)
+static int ext4_remount(struct super_block *sb, int *flags, char *data)
 {
-	struct ext4_super_block * es;
+	struct ext4_super_block *es;
 	struct ext4_sb_info *sbi = EXT4_SB(sb);
 	ext4_fsblk_t n_blocks_count = 0;
 	unsigned long old_sb_flags;
 	struct ext4_mount_options old_opts;
+	ext4_group_t g;
 	int err;
 #ifdef CONFIG_QUOTA
 	int i;
@@ -2925,6 +3038,26 @@ static int ext4_remount (struct super_block * sb, int * flags, char * data)
 			}
 
 			/*
+			 * Make sure the group descriptor checksums
+			 * are sane.  If they aren't, refuse to
+			 * remount r/w.
+			 */
+			for (g = 0; g < sbi->s_groups_count; g++) {
+				struct ext4_group_desc *gdp =
+					ext4_get_group_desc(sb, g, NULL);
+
+				if (!ext4_group_desc_csum_verify(sbi, g, gdp)) {
+					printk(KERN_ERR
+	       "EXT4-fs: ext4_remount: "
+		"Checksum for group %lu failed (%u!=%u)\n",
+		g, le16_to_cpu(ext4_group_desc_csum(sbi, g, gdp)),
+					       le16_to_cpu(gdp->bg_checksum));
+					err = -EINVAL;
+					goto restore_opts;
+				}
+			}
+
+			/*
 			 * If we have an unprocessed orphan list hanging
 			 * around from a previously readonly bdev mount,
 			 * require a full umount/remount for now.
@@ -2949,7 +3082,7 @@ static int ext4_remount (struct super_block * sb, int * flags, char * data)
 			sbi->s_mount_state = le16_to_cpu(es->s_state);
 			if ((err = ext4_group_extend(sb, es, n_blocks_count)))
 				goto restore_opts;
-			if (!ext4_setup_super (sb, es, 0))
+			if (!ext4_setup_super(sb, es, 0))
 				sb->s_flags &= ~MS_RDONLY;
 		}
 	}
@@ -2979,7 +3112,7 @@ restore_opts:
 	return err;
 }
 
-static int ext4_statfs (struct dentry * dentry, struct kstatfs * buf)
+static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf)
 {
 	struct super_block *sb = dentry->d_sb;
 	struct ext4_sb_info *sbi = EXT4_SB(sb);
@@ -3217,12 +3350,12 @@ static int ext4_quota_on(struct super_block *sb, int type, int format_id,
 	}
 	/* Journaling quota? */
 	if (EXT4_SB(sb)->s_qf_names[type]) {
-		/* Quotafile not of fs root? */
+		/* Quotafile not in fs root? */
 		if (nd.path.dentry->d_parent->d_inode != sb->s_root->d_inode)
 			printk(KERN_WARNING
 				"EXT4-fs: Quota file not on filesystem root. "
 				"Journaled quota will not work.\n");
- 	}
+	}
 
 	/*
 	 * When we journal data on quota file, we have to flush journal to see
@@ -3325,7 +3458,7 @@ static ssize_t ext4_quota_write(struct super_block *sb, int type,
 			err = ext4_journal_dirty_metadata(handle, bh);
 		else {
 			/* Always do at least ordered writes for quotas */
-			err = ext4_journal_dirty_data(handle, bh);
+			err = ext4_jbd2_file_inode(handle, inode);
 			mark_buffer_dirty(bh);
 		}
 		brelse(bh);
diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index ff08633..8954208 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -810,7 +810,7 @@ inserted:
 			/* We need to allocate a new block */
 			ext4_fsblk_t goal = ext4_group_first_block_no(sb,
 						EXT4_I(inode)->i_block_group);
-			ext4_fsblk_t block = ext4_new_block(handle, inode,
+			ext4_fsblk_t block = ext4_new_meta_block(handle, inode,
 							goal, &error);
 			if (error)
 				goto cleanup;
@@ -1512,7 +1512,7 @@ static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header,
 	char *name = entry->e_name;
 	int n;
 
-	for (n=0; n < entry->e_name_len; n++) {
+	for (n = 0; n < entry->e_name_len; n++) {
 		hash = (hash << NAME_HASH_SHIFT) ^
 		       (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^
 		       *name++;
diff --git a/fs/ext4/xattr_trusted.c b/fs/ext4/xattr_trusted.c
index fff3338..ac1a52c 100644
--- a/fs/ext4/xattr_trusted.c
+++ b/fs/ext4/xattr_trusted.c
@@ -13,13 +13,11 @@
 #include "ext4.h"
 #include "xattr.h"
 
-#define XATTR_TRUSTED_PREFIX "trusted."
-
 static size_t
 ext4_xattr_trusted_list(struct inode *inode, char *list, size_t list_size,
 			const char *name, size_t name_len)
 {
-	const size_t prefix_len = sizeof(XATTR_TRUSTED_PREFIX)-1;
+	const size_t prefix_len = XATTR_TRUSTED_PREFIX_LEN;
 	const size_t total_len = prefix_len + name_len + 1;
 
 	if (!capable(CAP_SYS_ADMIN))
diff --git a/fs/ext4/xattr_user.c b/fs/ext4/xattr_user.c
index 67be723..d91aa61 100644
--- a/fs/ext4/xattr_user.c
+++ b/fs/ext4/xattr_user.c
@@ -12,13 +12,11 @@
 #include "ext4.h"
 #include "xattr.h"
 
-#define XATTR_USER_PREFIX "user."
-
 static size_t
 ext4_xattr_user_list(struct inode *inode, char *list, size_t list_size,
 		     const char *name, size_t name_len)
 {
-	const size_t prefix_len = sizeof(XATTR_USER_PREFIX)-1;
+	const size_t prefix_len = XATTR_USER_PREFIX_LEN;
 	const size_t total_len = prefix_len + name_len + 1;
 
 	if (!test_opt(inode->i_sb, XATTR_USER))
diff --git a/fs/jbd2/checkpoint.c b/fs/jbd2/checkpoint.c
index 6914598..91389c8 100644
--- a/fs/jbd2/checkpoint.c
+++ b/fs/jbd2/checkpoint.c
@@ -688,7 +688,6 @@ void __jbd2_journal_drop_transaction(journal_t *journal, transaction_t *transact
 
 	J_ASSERT(transaction->t_state == T_FINISHED);
 	J_ASSERT(transaction->t_buffers == NULL);
-	J_ASSERT(transaction->t_sync_datalist == NULL);
 	J_ASSERT(transaction->t_forget == NULL);
 	J_ASSERT(transaction->t_iobuf_list == NULL);
 	J_ASSERT(transaction->t_shadow_list == NULL);
diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index a2ed72f..adf0395 100644
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -22,6 +22,8 @@
 #include <linux/pagemap.h>
 #include <linux/jiffies.h>
 #include <linux/crc32.h>
+#include <linux/writeback.h>
+#include <linux/backing-dev.h>
 
 /*
  * Default IO end handler for temporary BJ_IO buffer_heads.
@@ -37,8 +39,8 @@ static void journal_end_buffer_io_sync(struct buffer_head *bh, int uptodate)
 }
 
 /*
- * When an ext3-ordered file is truncated, it is possible that many pages are
- * not sucessfully freed, because they are attached to a committing transaction.
+ * When an ext4 file is truncated, it is possible that some pages are not
+ * successfully freed, because they are attached to a committing transaction.
  * After the transaction commits, these pages are left on the LRU, with no
  * ->mapping, and with attached buffers.  These pages are trivially reclaimable
  * by the VM, but their apparent absence upsets the VM accounting, and it makes
@@ -80,21 +82,6 @@ nope:
 }
 
 /*
- * Try to acquire jbd_lock_bh_state() against the buffer, when j_list_lock is
- * held.  For ranking reasons we must trylock.  If we lose, schedule away and
- * return 0.  j_list_lock is dropped in this case.
- */
-static int inverted_lock(journal_t *journal, struct buffer_head *bh)
-{
-	if (!jbd_trylock_bh_state(bh)) {
-		spin_unlock(&journal->j_list_lock);
-		schedule();
-		return 0;
-	}
-	return 1;
-}
-
-/*
  * Done it all: now submit the commit record.  We should have
  * cleaned up our previous buffers by now, so if we are in abort
  * mode we can now just skip the rest of the journal write
@@ -112,6 +99,7 @@ static int journal_submit_commit_record(journal_t *journal,
 	struct buffer_head *bh;
 	int ret;
 	int barrier_done = 0;
+	struct timespec now = current_kernel_time();
 
 	if (is_journal_aborted(journal))
 		return 0;
@@ -126,6 +114,8 @@ static int journal_submit_commit_record(journal_t *journal,
 	tmp->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER);
 	tmp->h_blocktype = cpu_to_be32(JBD2_COMMIT_BLOCK);
 	tmp->h_sequence = cpu_to_be32(commit_transaction->t_tid);
+	tmp->h_commit_sec = cpu_to_be64(now.tv_sec);
+	tmp->h_commit_nsec = cpu_to_be32(now.tv_nsec);
 
 	if (JBD2_HAS_COMPAT_FEATURE(journal,
 				    JBD2_FEATURE_COMPAT_CHECKSUM)) {
@@ -197,159 +187,114 @@ static int journal_wait_on_commit_record(struct buffer_head *bh)
 }
 
 /*
- * Wait for all submitted IO to complete.
+ * write the filemap data using writepage() address_space_operations.
+ * We don't do block allocation here even for delalloc. We don't
+ * use writepages() because with dealyed allocation we may be doing
+ * block allocation in writepages().
  */
-static int journal_wait_on_locked_list(journal_t *journal,
-				       transaction_t *commit_transaction)
+static int journal_submit_inode_data_buffers(struct address_space *mapping)
 {
-	int ret = 0;
-	struct journal_head *jh;
-
-	while (commit_transaction->t_locked_list) {
-		struct buffer_head *bh;
-
-		jh = commit_transaction->t_locked_list->b_tprev;
-		bh = jh2bh(jh);
-		get_bh(bh);
-		if (buffer_locked(bh)) {
-			spin_unlock(&journal->j_list_lock);
-			wait_on_buffer(bh);
-			if (unlikely(!buffer_uptodate(bh)))
-				ret = -EIO;
-			spin_lock(&journal->j_list_lock);
-		}
-		if (!inverted_lock(journal, bh)) {
-			put_bh(bh);
-			spin_lock(&journal->j_list_lock);
-			continue;
-		}
-		if (buffer_jbd(bh) && jh->b_jlist == BJ_Locked) {
-			__jbd2_journal_unfile_buffer(jh);
-			jbd_unlock_bh_state(bh);
-			jbd2_journal_remove_journal_head(bh);
-			put_bh(bh);
-		} else {
-			jbd_unlock_bh_state(bh);
-		}
-		put_bh(bh);
-		cond_resched_lock(&journal->j_list_lock);
-	}
+	int ret;
+	struct writeback_control wbc = {
+		.sync_mode =  WB_SYNC_ALL,
+		.nr_to_write = mapping->nrpages * 2,
+		.range_start = 0,
+		.range_end = i_size_read(mapping->host),
+		.for_writepages = 1,
+	};
+
+	ret = generic_writepages(mapping, &wbc);
 	return ret;
-  }
+}
 
-static void journal_do_submit_data(struct buffer_head **wbuf, int bufs)
+/*
+ * Submit all the data buffers of inode associated with the transaction to
+ * disk.
+ *
+ * We are in a committing transaction. Therefore no new inode can be added to
+ * our inode list. We use JI_COMMIT_RUNNING flag to protect inode we currently
+ * operate on from being released while we write out pages.
+ */
+static int journal_submit_data_buffers(journal_t *journal,
+		transaction_t *commit_transaction)
 {
-	int i;
+	struct jbd2_inode *jinode;
+	int err, ret = 0;
+	struct address_space *mapping;
 
-	for (i = 0; i < bufs; i++) {
-		wbuf[i]->b_end_io = end_buffer_write_sync;
-		/* We use-up our safety reference in submit_bh() */
-		submit_bh(WRITE, wbuf[i]);
+	spin_lock(&journal->j_list_lock);
+	list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
+		mapping = jinode->i_vfs_inode->i_mapping;
+		jinode->i_flags |= JI_COMMIT_RUNNING;
+		spin_unlock(&journal->j_list_lock);
+		/*
+		 * submit the inode data buffers. We use writepage
+		 * instead of writepages. Because writepages can do
+		 * block allocation  with delalloc. We need to write
+		 * only allocated blocks here.
+		 */
+		err = journal_submit_inode_data_buffers(mapping);
+		if (!ret)
+			ret = err;
+		spin_lock(&journal->j_list_lock);
+		J_ASSERT(jinode->i_transaction == commit_transaction);
+		jinode->i_flags &= ~JI_COMMIT_RUNNING;
+		wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
 	}
+	spin_unlock(&journal->j_list_lock);
+	return ret;
 }
 
 /*
- *  Submit all the data buffers to disk
+ * Wait for data submitted for writeout, refile inodes to proper
+ * transaction if needed.
+ *
  */
-static void journal_submit_data_buffers(journal_t *journal,
-				transaction_t *commit_transaction)
+static int journal_finish_inode_data_buffers(journal_t *journal,
+		transaction_t *commit_transaction)
 {
-	struct journal_head *jh;
-	struct buffer_head *bh;
-	int locked;
-	int bufs = 0;
-	struct buffer_head **wbuf = journal->j_wbuf;
+	struct jbd2_inode *jinode, *next_i;
+	int err, ret = 0;
 
-	/*
-	 * Whenever we unlock the journal and sleep, things can get added
-	 * onto ->t_sync_datalist, so we have to keep looping back to
-	 * write_out_data until we *know* that the list is empty.
-	 *
-	 * Cleanup any flushed data buffers from the data list.  Even in
-	 * abort mode, we want to flush this out as soon as possible.
-	 */
-write_out_data:
-	cond_resched();
+	/* For locking, see the comment in journal_submit_data_buffers() */
 	spin_lock(&journal->j_list_lock);
-
-	while (commit_transaction->t_sync_datalist) {
-		jh = commit_transaction->t_sync_datalist;
-		bh = jh2bh(jh);
-		locked = 0;
-
-		/* Get reference just to make sure buffer does not disappear
-		 * when we are forced to drop various locks */
-		get_bh(bh);
-		/* If the buffer is dirty, we need to submit IO and hence
-		 * we need the buffer lock. We try to lock the buffer without
-		 * blocking. If we fail, we need to drop j_list_lock and do
-		 * blocking lock_buffer().
-		 */
-		if (buffer_dirty(bh)) {
-			if (test_set_buffer_locked(bh)) {
-				BUFFER_TRACE(bh, "needs blocking lock");
-				spin_unlock(&journal->j_list_lock);
-				/* Write out all data to prevent deadlocks */
-				journal_do_submit_data(wbuf, bufs);
-				bufs = 0;
-				lock_buffer(bh);
-				spin_lock(&journal->j_list_lock);
-			}
-			locked = 1;
-		}
-		/* We have to get bh_state lock. Again out of order, sigh. */
-		if (!inverted_lock(journal, bh)) {
-			jbd_lock_bh_state(bh);
-			spin_lock(&journal->j_list_lock);
-		}
-		/* Someone already cleaned up the buffer? */
-		if (!buffer_jbd(bh)
-			|| jh->b_transaction != commit_transaction
-			|| jh->b_jlist != BJ_SyncData) {
-			jbd_unlock_bh_state(bh);
-			if (locked)
-				unlock_buffer(bh);
-			BUFFER_TRACE(bh, "already cleaned up");
-			put_bh(bh);
-			continue;
-		}
-		if (locked && test_clear_buffer_dirty(bh)) {
-			BUFFER_TRACE(bh, "needs writeout, adding to array");
-			wbuf[bufs++] = bh;
-			__jbd2_journal_file_buffer(jh, commit_transaction,
-						BJ_Locked);
-			jbd_unlock_bh_state(bh);
-			if (bufs == journal->j_wbufsize) {
-				spin_unlock(&journal->j_list_lock);
-				journal_do_submit_data(wbuf, bufs);
-				bufs = 0;
-				goto write_out_data;
-			}
-		} else if (!locked && buffer_locked(bh)) {
-			__jbd2_journal_file_buffer(jh, commit_transaction,
-						BJ_Locked);
-			jbd_unlock_bh_state(bh);
-			put_bh(bh);
-		} else {
-			BUFFER_TRACE(bh, "writeout complete: unfile");
-			__jbd2_journal_unfile_buffer(jh);
-			jbd_unlock_bh_state(bh);
-			if (locked)
-				unlock_buffer(bh);
-			jbd2_journal_remove_journal_head(bh);
-			/* Once for our safety reference, once for
-			 * jbd2_journal_remove_journal_head() */
-			put_bh(bh);
-			put_bh(bh);
+	list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
+		jinode->i_flags |= JI_COMMIT_RUNNING;
+		spin_unlock(&journal->j_list_lock);
+		err = filemap_fdatawait(jinode->i_vfs_inode->i_mapping);
+		if (err) {
+			/*
+			 * Because AS_EIO is cleared by
+			 * wait_on_page_writeback_range(), set it again so
+			 * that user process can get -EIO from fsync().
+			 */
+			set_bit(AS_EIO,
+				&jinode->i_vfs_inode->i_mapping->flags);
+
+			if (!ret)
+				ret = err;
 		}
+		spin_lock(&journal->j_list_lock);
+		jinode->i_flags &= ~JI_COMMIT_RUNNING;
+		wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
+	}
 
-		if (need_resched() || spin_needbreak(&journal->j_list_lock)) {
-			spin_unlock(&journal->j_list_lock);
-			goto write_out_data;
+	/* Now refile inode to proper lists */
+	list_for_each_entry_safe(jinode, next_i,
+				 &commit_transaction->t_inode_list, i_list) {
+		list_del(&jinode->i_list);
+		if (jinode->i_next_transaction) {
+			jinode->i_transaction = jinode->i_next_transaction;
+			jinode->i_next_transaction = NULL;
+			list_add(&jinode->i_list,
+				&jinode->i_transaction->t_inode_list);
+		} else {
+			jinode->i_transaction = NULL;
 		}
 	}
 	spin_unlock(&journal->j_list_lock);
-	journal_do_submit_data(wbuf, bufs);
+
+	return ret;
 }
 
 static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh)
@@ -524,21 +469,7 @@ void jbd2_journal_commit_transaction(journal_t *journal)
 	 * Now start flushing things to disk, in the order they appear
 	 * on the transaction lists.  Data blocks go first.
 	 */
-	err = 0;
-	journal_submit_data_buffers(journal, commit_transaction);
-
-	/*
-	 * Wait for all previously submitted IO to complete if commit
-	 * record is to be written synchronously.
-	 */
-	spin_lock(&journal->j_list_lock);
-	if (!JBD2_HAS_INCOMPAT_FEATURE(journal,
-		JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT))
-		err = journal_wait_on_locked_list(journal,
-						commit_transaction);
-
-	spin_unlock(&journal->j_list_lock);
-
+	err = journal_submit_data_buffers(journal, commit_transaction);
 	if (err)
 		jbd2_journal_abort(journal, err);
 
@@ -547,16 +478,6 @@ void jbd2_journal_commit_transaction(journal_t *journal)
 	jbd_debug(3, "JBD: commit phase 2\n");
 
 	/*
-	 * If we found any dirty or locked buffers, then we should have
-	 * looped back up to the write_out_data label.  If there weren't
-	 * any then journal_clean_data_list should have wiped the list
-	 * clean by now, so check that it is in fact empty.
-	 */
-	J_ASSERT (commit_transaction->t_sync_datalist == NULL);
-
-	jbd_debug (3, "JBD: commit phase 3\n");
-
-	/*
 	 * Way to go: we have now written out all of the data for a
 	 * transaction!  Now comes the tricky part: we need to write out
 	 * metadata.  Loop over the transaction's entire buffer list:
@@ -574,6 +495,7 @@ void jbd2_journal_commit_transaction(journal_t *journal)
 	J_ASSERT(commit_transaction->t_nr_buffers <=
 		 commit_transaction->t_outstanding_credits);
 
+	err = 0;
 	descriptor = NULL;
 	bufs = 0;
 	while (commit_transaction->t_buffers) {
@@ -748,13 +670,23 @@ start_journal_io:
 						 &cbh, crc32_sum);
 		if (err)
 			__jbd2_journal_abort_hard(journal);
+	}
 
-		spin_lock(&journal->j_list_lock);
-		err = journal_wait_on_locked_list(journal,
-						commit_transaction);
-		spin_unlock(&journal->j_list_lock);
-		if (err)
-			__jbd2_journal_abort_hard(journal);
+	/*
+	 * This is the right place to wait for data buffers both for ASYNC
+	 * and !ASYNC commit. If commit is ASYNC, we need to wait only after
+	 * the commit block went to disk (which happens above). If commit is
+	 * SYNC, we need to wait for data buffers before we start writing
+	 * commit block, which happens below in such setting.
+	 */
+	err = journal_finish_inode_data_buffers(journal, commit_transaction);
+	if (err) {
+		char b[BDEVNAME_SIZE];
+
+		printk(KERN_WARNING
+			"JBD2: Detected IO errors while flushing file data "
+			"on %s\n", bdevname(journal->j_fs_dev, b));
+		err = 0;
 	}
 
 	/* Lo and behold: we have just managed to send a transaction to
@@ -768,7 +700,7 @@ start_journal_io:
 	   so we incur less scheduling load.
 	*/
 
-	jbd_debug(3, "JBD: commit phase 4\n");
+	jbd_debug(3, "JBD: commit phase 3\n");
 
 	/*
 	 * akpm: these are BJ_IO, and j_list_lock is not needed.
@@ -827,7 +759,7 @@ wait_for_iobuf:
 
 	J_ASSERT (commit_transaction->t_shadow_list == NULL);
 
-	jbd_debug(3, "JBD: commit phase 5\n");
+	jbd_debug(3, "JBD: commit phase 4\n");
 
 	/* Here we wait for the revoke record and descriptor record buffers */
  wait_for_ctlbuf:
@@ -854,7 +786,7 @@ wait_for_iobuf:
 		/* AKPM: bforget here */
 	}
 
-	jbd_debug(3, "JBD: commit phase 6\n");
+	jbd_debug(3, "JBD: commit phase 5\n");
 
 	if (!JBD2_HAS_INCOMPAT_FEATURE(journal,
 		JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) {
@@ -874,9 +806,9 @@ wait_for_iobuf:
            transaction can be removed from any checkpoint list it was on
            before. */
 
-	jbd_debug(3, "JBD: commit phase 7\n");
+	jbd_debug(3, "JBD: commit phase 6\n");
 
-	J_ASSERT(commit_transaction->t_sync_datalist == NULL);
+	J_ASSERT(list_empty(&commit_transaction->t_inode_list));
 	J_ASSERT(commit_transaction->t_buffers == NULL);
 	J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
 	J_ASSERT(commit_transaction->t_iobuf_list == NULL);
@@ -997,7 +929,7 @@ restart_loop:
 
 	/* Done with this transaction! */
 
-	jbd_debug(3, "JBD: commit phase 8\n");
+	jbd_debug(3, "JBD: commit phase 7\n");
 
 	J_ASSERT(commit_transaction->t_state == T_COMMIT);
 
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
index 2e24567..8207a01 100644
--- a/fs/jbd2/journal.c
+++ b/fs/jbd2/journal.c
@@ -50,7 +50,6 @@ EXPORT_SYMBOL(jbd2_journal_unlock_updates);
 EXPORT_SYMBOL(jbd2_journal_get_write_access);
 EXPORT_SYMBOL(jbd2_journal_get_create_access);
 EXPORT_SYMBOL(jbd2_journal_get_undo_access);
-EXPORT_SYMBOL(jbd2_journal_dirty_data);
 EXPORT_SYMBOL(jbd2_journal_dirty_metadata);
 EXPORT_SYMBOL(jbd2_journal_release_buffer);
 EXPORT_SYMBOL(jbd2_journal_forget);
@@ -69,7 +68,6 @@ EXPORT_SYMBOL(jbd2_journal_set_features);
 EXPORT_SYMBOL(jbd2_journal_create);
 EXPORT_SYMBOL(jbd2_journal_load);
 EXPORT_SYMBOL(jbd2_journal_destroy);
-EXPORT_SYMBOL(jbd2_journal_update_superblock);
 EXPORT_SYMBOL(jbd2_journal_abort);
 EXPORT_SYMBOL(jbd2_journal_errno);
 EXPORT_SYMBOL(jbd2_journal_ack_err);
@@ -82,6 +80,10 @@ EXPORT_SYMBOL(jbd2_journal_blocks_per_page);
 EXPORT_SYMBOL(jbd2_journal_invalidatepage);
 EXPORT_SYMBOL(jbd2_journal_try_to_free_buffers);
 EXPORT_SYMBOL(jbd2_journal_force_commit);
+EXPORT_SYMBOL(jbd2_journal_file_inode);
+EXPORT_SYMBOL(jbd2_journal_init_jbd_inode);
+EXPORT_SYMBOL(jbd2_journal_release_jbd_inode);
+EXPORT_SYMBOL(jbd2_journal_begin_ordered_truncate);
 
 static int journal_convert_superblock_v1(journal_t *, journal_superblock_t *);
 static void __journal_abort_soft (journal_t *journal, int errno);
@@ -2195,6 +2197,54 @@ void jbd2_journal_put_journal_head(struct journal_head *jh)
 }
 
 /*
+ * Initialize jbd inode head
+ */
+void jbd2_journal_init_jbd_inode(struct jbd2_inode *jinode, struct inode *inode)
+{
+	jinode->i_transaction = NULL;
+	jinode->i_next_transaction = NULL;
+	jinode->i_vfs_inode = inode;
+	jinode->i_flags = 0;
+	INIT_LIST_HEAD(&jinode->i_list);
+}
+
+/*
+ * Function to be called before we start removing inode from memory (i.e.,
+ * clear_inode() is a fine place to be called from). It removes inode from
+ * transaction's lists.
+ */
+void jbd2_journal_release_jbd_inode(journal_t *journal,
+				    struct jbd2_inode *jinode)
+{
+	int writeout = 0;
+
+	if (!journal)
+		return;
+restart:
+	spin_lock(&journal->j_list_lock);
+	/* Is commit writing out inode - we have to wait */
+	if (jinode->i_flags & JI_COMMIT_RUNNING) {
+		wait_queue_head_t *wq;
+		DEFINE_WAIT_BIT(wait, &jinode->i_flags, __JI_COMMIT_RUNNING);
+		wq = bit_waitqueue(&jinode->i_flags, __JI_COMMIT_RUNNING);
+		prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE);
+		spin_unlock(&journal->j_list_lock);
+		schedule();
+		finish_wait(wq, &wait.wait);
+		goto restart;
+	}
+
+	/* Do we need to wait for data writeback? */
+	if (journal->j_committing_transaction == jinode->i_transaction)
+		writeout = 1;
+	if (jinode->i_transaction) {
+		list_del(&jinode->i_list);
+		jinode->i_transaction = NULL;
+	}
+	spin_unlock(&journal->j_list_lock);
+}
+
+/*
  * debugfs tunables
  */
 #ifdef CONFIG_JBD2_DEBUG
diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
index d6e006e..4f7cadb 100644
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -41,7 +41,6 @@ static void __jbd2_journal_temp_unlink_buffer(struct journal_head *jh);
  *	new transaction	and we can't block without protecting against other
  *	processes trying to touch the journal while it is in transition.
  *
- * Called under j_state_lock
  */
 
 static transaction_t *
@@ -52,6 +51,7 @@ jbd2_get_transaction(journal_t *journal, transaction_t *transaction)
 	transaction->t_tid = journal->j_transaction_sequence++;
 	transaction->t_expires = jiffies + journal->j_commit_interval;
 	spin_lock_init(&transaction->t_handle_lock);
+	INIT_LIST_HEAD(&transaction->t_inode_list);
 
 	/* Set up the commit timer for the new transaction. */
 	journal->j_commit_timer.expires = round_jiffies(transaction->t_expires);
@@ -943,183 +943,6 @@ out:
 }
 
 /**
- * int jbd2_journal_dirty_data() -  mark a buffer as containing dirty data which
- *                             needs to be flushed before we can commit the
- *                             current transaction.
- * @handle: transaction
- * @bh: bufferhead to mark
- *
- * The buffer is placed on the transaction's data list and is marked as
- * belonging to the transaction.
- *
- * Returns error number or 0 on success.
- *
- * jbd2_journal_dirty_data() can be called via page_launder->ext3_writepage
- * by kswapd.
- */
-int jbd2_journal_dirty_data(handle_t *handle, struct buffer_head *bh)
-{
-	journal_t *journal = handle->h_transaction->t_journal;
-	int need_brelse = 0;
-	struct journal_head *jh;
-
-	if (is_handle_aborted(handle))
-		return 0;
-
-	jh = jbd2_journal_add_journal_head(bh);
-	JBUFFER_TRACE(jh, "entry");
-
-	/*
-	 * The buffer could *already* be dirty.  Writeout can start
-	 * at any time.
-	 */
-	jbd_debug(4, "jh: %p, tid:%d\n", jh, handle->h_transaction->t_tid);
-
-	/*
-	 * What if the buffer is already part of a running transaction?
-	 *
-	 * There are two cases:
-	 * 1) It is part of the current running transaction.  Refile it,
-	 *    just in case we have allocated it as metadata, deallocated
-	 *    it, then reallocated it as data.
-	 * 2) It is part of the previous, still-committing transaction.
-	 *    If all we want to do is to guarantee that the buffer will be
-	 *    written to disk before this new transaction commits, then
-	 *    being sure that the *previous* transaction has this same
-	 *    property is sufficient for us!  Just leave it on its old
-	 *    transaction.
-	 *
-	 * In case (2), the buffer must not already exist as metadata
-	 * --- that would violate write ordering (a transaction is free
-	 * to write its data at any point, even before the previous
-	 * committing transaction has committed).  The caller must
-	 * never, ever allow this to happen: there's nothing we can do
-	 * about it in this layer.
-	 */
-	jbd_lock_bh_state(bh);
-	spin_lock(&journal->j_list_lock);
-
-	/* Now that we have bh_state locked, are we really still mapped? */
-	if (!buffer_mapped(bh)) {
-		JBUFFER_TRACE(jh, "unmapped buffer, bailing out");
-		goto no_journal;
-	}
-
-	if (jh->b_transaction) {
-		JBUFFER_TRACE(jh, "has transaction");
-		if (jh->b_transaction != handle->h_transaction) {
-			JBUFFER_TRACE(jh, "belongs to older transaction");
-			J_ASSERT_JH(jh, jh->b_transaction ==
-					journal->j_committing_transaction);
-
-			/* @@@ IS THIS TRUE  ? */
-			/*
-			 * Not any more.  Scenario: someone does a write()
-			 * in data=journal mode.  The buffer's transaction has
-			 * moved into commit.  Then someone does another
-			 * write() to the file.  We do the frozen data copyout
-			 * and set b_next_transaction to point to j_running_t.
-			 * And while we're in that state, someone does a
-			 * writepage() in an attempt to pageout the same area
-			 * of the file via a shared mapping.  At present that
-			 * calls jbd2_journal_dirty_data(), and we get right here.
-			 * It may be too late to journal the data.  Simply
-			 * falling through to the next test will suffice: the
-			 * data will be dirty and wil be checkpointed.  The
-			 * ordering comments in the next comment block still
-			 * apply.
-			 */
-			//J_ASSERT_JH(jh, jh->b_next_transaction == NULL);
-
-			/*
-			 * If we're journalling data, and this buffer was
-			 * subject to a write(), it could be metadata, forget
-			 * or shadow against the committing transaction.  Now,
-			 * someone has dirtied the same darn page via a mapping
-			 * and it is being writepage()'d.
-			 * We *could* just steal the page from commit, with some
-			 * fancy locking there.  Instead, we just skip it -
-			 * don't tie the page's buffers to the new transaction
-			 * at all.
-			 * Implication: if we crash before the writepage() data
-			 * is written into the filesystem, recovery will replay
-			 * the write() data.
-			 */
-			if (jh->b_jlist != BJ_None &&
-					jh->b_jlist != BJ_SyncData &&
-					jh->b_jlist != BJ_Locked) {
-				JBUFFER_TRACE(jh, "Not stealing");
-				goto no_journal;
-			}
-
-			/*
-			 * This buffer may be undergoing writeout in commit.  We
-			 * can't return from here and let the caller dirty it
-			 * again because that can cause the write-out loop in
-			 * commit to never terminate.
-			 */
-			if (buffer_dirty(bh)) {
-				get_bh(bh);
-				spin_unlock(&journal->j_list_lock);
-				jbd_unlock_bh_state(bh);
-				need_brelse = 1;
-				sync_dirty_buffer(bh);
-				jbd_lock_bh_state(bh);
-				spin_lock(&journal->j_list_lock);
-				/* Since we dropped the lock... */
-				if (!buffer_mapped(bh)) {
-					JBUFFER_TRACE(jh, "buffer got unmapped");
-					goto no_journal;
-				}
-				/* The buffer may become locked again at any
-				   time if it is redirtied */
-			}
-
-			/* journal_clean_data_list() may have got there first */
-			if (jh->b_transaction != NULL) {
-				JBUFFER_TRACE(jh, "unfile from commit");
-				__jbd2_journal_temp_unlink_buffer(jh);
-				/* It still points to the committing
-				 * transaction; move it to this one so
-				 * that the refile assert checks are
-				 * happy. */
-				jh->b_transaction = handle->h_transaction;
-			}
-			/* The buffer will be refiled below */
-
-		}
-		/*
-		 * Special case --- the buffer might actually have been
-		 * allocated and then immediately deallocated in the previous,
-		 * committing transaction, so might still be left on that
-		 * transaction's metadata lists.
-		 */
-		if (jh->b_jlist != BJ_SyncData && jh->b_jlist != BJ_Locked) {
-			JBUFFER_TRACE(jh, "not on correct data list: unfile");
-			J_ASSERT_JH(jh, jh->b_jlist != BJ_Shadow);
-			__jbd2_journal_temp_unlink_buffer(jh);
-			jh->b_transaction = handle->h_transaction;
-			JBUFFER_TRACE(jh, "file as data");
-			__jbd2_journal_file_buffer(jh, handle->h_transaction,
-						BJ_SyncData);
-		}
-	} else {
-		JBUFFER_TRACE(jh, "not on a transaction");
-		__jbd2_journal_file_buffer(jh, handle->h_transaction, BJ_SyncData);
-	}
-no_journal:
-	spin_unlock(&journal->j_list_lock);
-	jbd_unlock_bh_state(bh);
-	if (need_brelse) {
-		BUFFER_TRACE(bh, "brelse");
-		__brelse(bh);
-	}
-	JBUFFER_TRACE(jh, "exit");
-	jbd2_journal_put_journal_head(jh);
-	return 0;
-}
-
-/**
  * int jbd2_journal_dirty_metadata() -  mark a buffer as containing dirty metadata
  * @handle: transaction to add buffer to.
  * @bh: buffer to mark
@@ -1541,10 +1364,10 @@ __blist_del_buffer(struct journal_head **list, struct journal_head *jh)
  * Remove a buffer from the appropriate transaction list.
  *
  * Note that this function can *change* the value of
- * bh->b_transaction->t_sync_datalist, t_buffers, t_forget,
- * t_iobuf_list, t_shadow_list, t_log_list or t_reserved_list.  If the caller
- * is holding onto a copy of one of thee pointers, it could go bad.
- * Generally the caller needs to re-read the pointer from the transaction_t.
+ * bh->b_transaction->t_buffers, t_forget, t_iobuf_list, t_shadow_list,
+ * t_log_list or t_reserved_list.  If the caller is holding onto a copy of one
+ * of these pointers, it could go bad.  Generally the caller needs to re-read
+ * the pointer from the transaction_t.
  *
  * Called under j_list_lock.  The journal may not be locked.
  */
@@ -1566,9 +1389,6 @@ void __jbd2_journal_temp_unlink_buffer(struct journal_head *jh)
 	switch (jh->b_jlist) {
 	case BJ_None:
 		return;
-	case BJ_SyncData:
-		list = &transaction->t_sync_datalist;
-		break;
 	case BJ_Metadata:
 		transaction->t_nr_buffers--;
 		J_ASSERT_JH(jh, transaction->t_nr_buffers >= 0);
@@ -1589,9 +1409,6 @@ void __jbd2_journal_temp_unlink_buffer(struct journal_head *jh)
 	case BJ_Reserved:
 		list = &transaction->t_reserved_list;
 		break;
-	case BJ_Locked:
-		list = &transaction->t_locked_list;
-		break;
 	}
 
 	__blist_del_buffer(list, jh);
@@ -1634,15 +1451,7 @@ __journal_try_to_free_buffer(journal_t *journal, struct buffer_head *bh)
 		goto out;
 
 	spin_lock(&journal->j_list_lock);
-	if (jh->b_transaction != NULL && jh->b_cp_transaction == NULL) {
-		if (jh->b_jlist == BJ_SyncData || jh->b_jlist == BJ_Locked) {
-			/* A written-back ordered data buffer */
-			JBUFFER_TRACE(jh, "release data");
-			__jbd2_journal_unfile_buffer(jh);
-			jbd2_journal_remove_journal_head(bh);
-			__brelse(bh);
-		}
-	} else if (jh->b_cp_transaction != NULL && jh->b_transaction == NULL) {
+	if (jh->b_cp_transaction != NULL && jh->b_transaction == NULL) {
 		/* written-back checkpointed metadata buffer */
 		if (jh->b_jlist == BJ_None) {
 			JBUFFER_TRACE(jh, "remove from checkpoint list");
@@ -1656,12 +1465,43 @@ out:
 	return;
 }
 
+/*
+ * jbd2_journal_try_to_free_buffers() could race with
+ * jbd2_journal_commit_transaction(). The later might still hold the
+ * reference count to the buffers when inspecting them on
+ * t_syncdata_list or t_locked_list.
+ *
+ * jbd2_journal_try_to_free_buffers() will call this function to
+ * wait for the current transaction to finish syncing data buffers, before
+ * try to free that buffer.
+ *
+ * Called with journal->j_state_lock hold.
+ */
+static void jbd2_journal_wait_for_transaction_sync_data(journal_t *journal)
+{
+	transaction_t *transaction;
+	tid_t tid;
+
+	spin_lock(&journal->j_state_lock);
+	transaction = journal->j_committing_transaction;
+
+	if (!transaction) {
+		spin_unlock(&journal->j_state_lock);
+		return;
+	}
+
+	tid = transaction->t_tid;
+	spin_unlock(&journal->j_state_lock);
+	jbd2_log_wait_commit(journal, tid);
+}
 
 /**
  * int jbd2_journal_try_to_free_buffers() - try to free page buffers.
  * @journal: journal for operation
  * @page: to try and free
- * @unused_gfp_mask: unused
+ * @gfp_mask: we use the mask to detect how hard should we try to release
+ * buffers. If __GFP_WAIT and __GFP_FS is set, we wait for commit code to
+ * release the buffers.
  *
  *
  * For all the buffers on this page,
@@ -1690,9 +1530,11 @@ out:
  * journal_try_to_free_buffer() is changing its state.  But that
  * cannot happen because we never reallocate freed data as metadata
  * while the data is part of a transaction.  Yes?
+ *
+ * Return 0 on failure, 1 on success
  */
 int jbd2_journal_try_to_free_buffers(journal_t *journal,
-				struct page *page, gfp_t unused_gfp_mask)
+				struct page *page, gfp_t gfp_mask)
 {
 	struct buffer_head *head;
 	struct buffer_head *bh;
@@ -1708,7 +1550,8 @@ int jbd2_journal_try_to_free_buffers(journal_t *journal,
 		/*
 		 * We take our own ref against the journal_head here to avoid
 		 * having to add tons of locking around each instance of
-		 * jbd2_journal_remove_journal_head() and jbd2_journal_put_journal_head().
+		 * jbd2_journal_remove_journal_head() and
+		 * jbd2_journal_put_journal_head().
 		 */
 		jh = jbd2_journal_grab_journal_head(bh);
 		if (!jh)
@@ -1721,7 +1564,28 @@ int jbd2_journal_try_to_free_buffers(journal_t *journal,
 		if (buffer_jbd(bh))
 			goto busy;
 	} while ((bh = bh->b_this_page) != head);
+
 	ret = try_to_free_buffers(page);
+
+	/*
+	 * There are a number of places where jbd2_journal_try_to_free_buffers()
+	 * could race with jbd2_journal_commit_transaction(), the later still
+	 * holds the reference to the buffers to free while processing them.
+	 * try_to_free_buffers() failed to free those buffers. Some of the
+	 * caller of releasepage() request page buffers to be dropped, otherwise
+	 * treat the fail-to-free as errors (such as generic_file_direct_IO())
+	 *
+	 * So, if the caller of try_to_release_page() wants the synchronous
+	 * behaviour(i.e make sure buffers are dropped upon return),
+	 * let's wait for the current transaction to finish flush of
+	 * dirty data buffers, then try to free those buffers again,
+	 * with the journal locked.
+	 */
+	if (ret == 0 && (gfp_mask & __GFP_WAIT) && (gfp_mask & __GFP_FS)) {
+		jbd2_journal_wait_for_transaction_sync_data(journal);
+		ret = try_to_free_buffers(page);
+	}
+
 busy:
 	return ret;
 }
@@ -1823,6 +1687,7 @@ static int journal_unmap_buffer(journal_t *journal, struct buffer_head *bh)
 	if (!buffer_jbd(bh))
 		goto zap_buffer_unlocked;
 
+	/* OK, we have data buffer in journaled mode */
 	spin_lock(&journal->j_state_lock);
 	jbd_lock_bh_state(bh);
 	spin_lock(&journal->j_list_lock);
@@ -1886,15 +1751,6 @@ static int journal_unmap_buffer(journal_t *journal, struct buffer_head *bh)
 		}
 	} else if (transaction == journal->j_committing_transaction) {
 		JBUFFER_TRACE(jh, "on committing transaction");
-		if (jh->b_jlist == BJ_Locked) {
-			/*
-			 * The buffer is on the committing transaction's locked
-			 * list.  We have the buffer locked, so I/O has
-			 * completed.  So we can nail the buffer now.
-			 */
-			may_free = __dispose_buffer(jh, transaction);
-			goto zap_buffer;
-		}
 		/*
 		 * If it is committing, we simply cannot touch it.  We
 		 * can remove it's next_transaction pointer from the
@@ -2027,9 +1883,6 @@ void __jbd2_journal_file_buffer(struct journal_head *jh,
 		J_ASSERT_JH(jh, !jh->b_committed_data);
 		J_ASSERT_JH(jh, !jh->b_frozen_data);
 		return;
-	case BJ_SyncData:
-		list = &transaction->t_sync_datalist;
-		break;
 	case BJ_Metadata:
 		transaction->t_nr_buffers++;
 		list = &transaction->t_buffers;
@@ -2049,9 +1902,6 @@ void __jbd2_journal_file_buffer(struct journal_head *jh,
 	case BJ_Reserved:
 		list = &transaction->t_reserved_list;
 		break;
-	case BJ_Locked:
-		list =  &transaction->t_locked_list;
-		break;
 	}
 
 	__blist_add_buffer(list, jh);
@@ -2141,3 +1991,88 @@ void jbd2_journal_refile_buffer(journal_t *journal, struct journal_head *jh)
 	spin_unlock(&journal->j_list_lock);
 	__brelse(bh);
 }
+
+/*
+ * File inode in the inode list of the handle's transaction
+ */
+int jbd2_journal_file_inode(handle_t *handle, struct jbd2_inode *jinode)
+{
+	transaction_t *transaction = handle->h_transaction;
+	journal_t *journal = transaction->t_journal;
+
+	if (is_handle_aborted(handle))
+		return -EIO;
+
+	jbd_debug(4, "Adding inode %lu, tid:%d\n", jinode->i_vfs_inode->i_ino,
+			transaction->t_tid);
+
+	/*
+	 * First check whether inode isn't already on the transaction's
+	 * lists without taking the lock. Note that this check is safe
+	 * without the lock as we cannot race with somebody removing inode
+	 * from the transaction. The reason is that we remove inode from the
+	 * transaction only in journal_release_jbd_inode() and when we commit
+	 * the transaction. We are guarded from the first case by holding
+	 * a reference to the inode. We are safe against the second case
+	 * because if jinode->i_transaction == transaction, commit code
+	 * cannot touch the transaction because we hold reference to it,
+	 * and if jinode->i_next_transaction == transaction, commit code
+	 * will only file the inode where we want it.
+	 */
+	if (jinode->i_transaction == transaction ||
+	    jinode->i_next_transaction == transaction)
+		return 0;
+
+	spin_lock(&journal->j_list_lock);
+
+	if (jinode->i_transaction == transaction ||
+	    jinode->i_next_transaction == transaction)
+		goto done;
+
+	/* On some different transaction's list - should be
+	 * the committing one */
+	if (jinode->i_transaction) {
+		J_ASSERT(jinode->i_next_transaction == NULL);
+		J_ASSERT(jinode->i_transaction ==
+					journal->j_committing_transaction);
+		jinode->i_next_transaction = transaction;
+		goto done;
+	}
+	/* Not on any transaction list... */
+	J_ASSERT(!jinode->i_next_transaction);
+	jinode->i_transaction = transaction;
+	list_add(&jinode->i_list, &transaction->t_inode_list);
+done:
+	spin_unlock(&journal->j_list_lock);
+
+	return 0;
+}
+
+/*
+ * This function must be called when inode is journaled in ordered mode
+ * before truncation happens. It starts writeout of truncated part in
+ * case it is in the committing transaction so that we stand to ordered
+ * mode consistency guarantees.
+ */
+int jbd2_journal_begin_ordered_truncate(struct jbd2_inode *inode,
+					loff_t new_size)
+{
+	journal_t *journal;
+	transaction_t *commit_trans;
+	int ret = 0;
+
+	if (!inode->i_transaction && !inode->i_next_transaction)
+		goto out;
+	journal = inode->i_transaction->t_journal;
+	spin_lock(&journal->j_state_lock);
+	commit_trans = journal->j_committing_transaction;
+	spin_unlock(&journal->j_state_lock);
+	if (inode->i_transaction == commit_trans) {
+		ret = filemap_fdatawrite_range(inode->i_vfs_inode->i_mapping,
+			new_size, LLONG_MAX);
+		if (ret)
+			jbd2_journal_abort(journal, ret);
+	}
+out:
+	return ret;
+}
diff --git a/fs/mpage.c b/fs/mpage.c
index 235e4d3..dbcc7af 100644
--- a/fs/mpage.c
+++ b/fs/mpage.c
@@ -82,7 +82,7 @@ static void mpage_end_io_write(struct bio *bio, int err)
 	bio_put(bio);
 }
 
-static struct bio *mpage_bio_submit(int rw, struct bio *bio)
+struct bio *mpage_bio_submit(int rw, struct bio *bio)
 {
 	bio->bi_end_io = mpage_end_io_read;
 	if (rw == WRITE)
@@ -90,6 +90,7 @@ static struct bio *mpage_bio_submit(int rw, struct bio *bio)
 	submit_bio(rw, bio);
 	return NULL;
 }
+EXPORT_SYMBOL(mpage_bio_submit);
 
 static struct bio *
 mpage_alloc(struct block_device *bdev,
@@ -435,15 +436,9 @@ EXPORT_SYMBOL(mpage_readpage);
  * written, so it can intelligently allocate a suitably-sized BIO.  For now,
  * just allocate full-size (16-page) BIOs.
  */
-struct mpage_data {
-	struct bio *bio;
-	sector_t last_block_in_bio;
-	get_block_t *get_block;
-	unsigned use_writepage;
-};
 
-static int __mpage_writepage(struct page *page, struct writeback_control *wbc,
-			     void *data)
+int __mpage_writepage(struct page *page, struct writeback_control *wbc,
+		      void *data)
 {
 	struct mpage_data *mpd = data;
 	struct bio *bio = mpd->bio;
@@ -651,6 +646,7 @@ out:
 	mpd->bio = bio;
 	return ret;
 }
+EXPORT_SYMBOL(__mpage_writepage);
 
 /**
  * mpage_writepages - walk the list of dirty pages of the given address space & writepage() all of them
diff --git a/include/linux/fs.h b/include/linux/fs.h
index d8e2762..97f992a 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -1740,6 +1740,8 @@ extern int wait_on_page_writeback_range(struct address_space *mapping,
 				pgoff_t start, pgoff_t end);
 extern int __filemap_fdatawrite_range(struct address_space *mapping,
 				loff_t start, loff_t end, int sync_mode);
+extern int filemap_fdatawrite_range(struct address_space *mapping,
+				loff_t start, loff_t end);
 
 extern long do_fsync(struct file *file, int datasync);
 extern void sync_supers(void);
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index d147f0f..3dd2090 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -168,6 +168,8 @@ struct commit_header {
 	unsigned char   h_chksum_size;
 	unsigned char 	h_padding[2];
 	__be32 		h_chksum[JBD2_CHECKSUM_BYTES];
+	__be64		h_commit_sec;
+	__be32		h_commit_nsec;
 };
 
 /*
@@ -379,6 +381,38 @@ static inline void jbd_unlock_bh_journal_head(struct buffer_head *bh)
 	bit_spin_unlock(BH_JournalHead, &bh->b_state);
 }
 
+/* Flags in jbd_inode->i_flags */
+#define __JI_COMMIT_RUNNING 0
+/* Commit of the inode data in progress. We use this flag to protect us from
+ * concurrent deletion of inode. We cannot use reference to inode for this
+ * since we cannot afford doing last iput() on behalf of kjournald
+ */
+#define JI_COMMIT_RUNNING (1 << __JI_COMMIT_RUNNING)
+
+/**
+ * struct jbd_inode is the structure linking inodes in ordered mode
+ *   present in a transaction so that we can sync them during commit.
+ */
+struct jbd2_inode {
+	/* Which transaction does this inode belong to? Either the running
+	 * transaction or the committing one. [j_list_lock] */
+	transaction_t *i_transaction;
+
+	/* Pointer to the running transaction modifying inode's data in case
+	 * there is already a committing transaction touching it. [j_list_lock] */
+	transaction_t *i_next_transaction;
+
+	/* List of inodes in the i_transaction [j_list_lock] */
+	struct list_head i_list;
+
+	/* VFS inode this inode belongs to [constant during the lifetime
+	 * of the structure] */
+	struct inode *i_vfs_inode;
+
+	/* Flags of inode [j_list_lock] */
+	unsigned int i_flags;
+};
+
 struct jbd2_revoke_table_s;
 
 /**
@@ -509,24 +543,12 @@ struct transaction_s
 	struct journal_head	*t_reserved_list;
 
 	/*
-	 * Doubly-linked circular list of all buffers under writeout during
-	 * commit [j_list_lock]
-	 */
-	struct journal_head	*t_locked_list;
-
-	/*
 	 * Doubly-linked circular list of all metadata buffers owned by this
 	 * transaction [j_list_lock]
 	 */
 	struct journal_head	*t_buffers;
 
 	/*
-	 * Doubly-linked circular list of all data buffers still to be
-	 * flushed before this transaction can be committed [j_list_lock]
-	 */
-	struct journal_head	*t_sync_datalist;
-
-	/*
 	 * Doubly-linked circular list of all forget buffers (superseded
 	 * buffers which we can un-checkpoint once this transaction commits)
 	 * [j_list_lock]
@@ -565,6 +587,12 @@ struct transaction_s
 	struct journal_head	*t_log_list;
 
 	/*
+	 * List of inodes whose data we've modified in data=ordered mode.
+	 * [j_list_lock]
+	 */
+	struct list_head	t_inode_list;
+
+	/*
 	 * Protects info related to handles
 	 */
 	spinlock_t		t_handle_lock;
@@ -1004,7 +1032,6 @@ extern int	 jbd2_journal_extend (handle_t *, int nblocks);
 extern int	 jbd2_journal_get_write_access(handle_t *, struct buffer_head *);
 extern int	 jbd2_journal_get_create_access (handle_t *, struct buffer_head *);
 extern int	 jbd2_journal_get_undo_access(handle_t *, struct buffer_head *);
-extern int	 jbd2_journal_dirty_data (handle_t *, struct buffer_head *);
 extern int	 jbd2_journal_dirty_metadata (handle_t *, struct buffer_head *);
 extern void	 jbd2_journal_release_buffer (handle_t *, struct buffer_head *);
 extern int	 jbd2_journal_forget (handle_t *, struct buffer_head *);
@@ -1044,6 +1071,10 @@ extern void	   jbd2_journal_ack_err    (journal_t *);
 extern int	   jbd2_journal_clear_err  (journal_t *);
 extern int	   jbd2_journal_bmap(journal_t *, unsigned long, unsigned long long *);
 extern int	   jbd2_journal_force_commit(journal_t *);
+extern int	   jbd2_journal_file_inode(handle_t *handle, struct jbd2_inode *inode);
+extern int	   jbd2_journal_begin_ordered_truncate(struct jbd2_inode *inode, loff_t new_size);
+extern void	   jbd2_journal_init_jbd_inode(struct jbd2_inode *jinode, struct inode *inode);
+extern void	   jbd2_journal_release_jbd_inode(journal_t *journal, struct jbd2_inode *jinode);
 
 /*
  * journal_head management
@@ -1179,15 +1210,13 @@ static inline int jbd_space_needed(journal_t *journal)
 
 /* journaling buffer types */
 #define BJ_None		0	/* Not journaled */
-#define BJ_SyncData	1	/* Normal data: flush before commit */
-#define BJ_Metadata	2	/* Normal journaled metadata */
-#define BJ_Forget	3	/* Buffer superseded by this transaction */
-#define BJ_IO		4	/* Buffer is for temporary IO use */
-#define BJ_Shadow	5	/* Buffer contents being shadowed to the log */
-#define BJ_LogCtl	6	/* Buffer contains log descriptors */
-#define BJ_Reserved	7	/* Buffer is reserved for access by journal */
-#define BJ_Locked	8	/* Locked for I/O during commit */
-#define BJ_Types	9
+#define BJ_Metadata	1	/* Normal journaled metadata */
+#define BJ_Forget	2	/* Buffer superseded by this transaction */
+#define BJ_IO		3	/* Buffer is for temporary IO use */
+#define BJ_Shadow	4	/* Buffer contents being shadowed to the log */
+#define BJ_LogCtl	5	/* Buffer contains log descriptors */
+#define BJ_Reserved	6	/* Buffer is reserved for access by journal */
+#define BJ_Types	7
 
 extern int jbd_blocks_per_page(struct inode *inode);
 
diff --git a/include/linux/mpage.h b/include/linux/mpage.h
index 068a0c9..5c42821 100644
--- a/include/linux/mpage.h
+++ b/include/linux/mpage.h
@@ -11,11 +11,21 @@
  */
 #ifdef CONFIG_BLOCK
 
+struct mpage_data {
+	struct bio *bio;
+	sector_t last_block_in_bio;
+	get_block_t *get_block;
+	unsigned use_writepage;
+};
+
 struct writeback_control;
 
+struct bio *mpage_bio_submit(int rw, struct bio *bio);
 int mpage_readpages(struct address_space *mapping, struct list_head *pages,
 				unsigned nr_pages, get_block_t get_block);
 int mpage_readpage(struct page *page, get_block_t get_block);
+int __mpage_writepage(struct page *page, struct writeback_control *wbc,
+		      void *data);
 int mpage_writepages(struct address_space *mapping,
 		struct writeback_control *wbc, get_block_t get_block);
 int mpage_writepage(struct page *page, get_block_t *get_block,
diff --git a/include/linux/percpu_counter.h b/include/linux/percpu_counter.h
index 9007ccd..2083888 100644
--- a/include/linux/percpu_counter.h
+++ b/include/linux/percpu_counter.h
@@ -35,7 +35,7 @@ int percpu_counter_init_irq(struct percpu_counter *fbc, s64 amount);
 void percpu_counter_destroy(struct percpu_counter *fbc);
 void percpu_counter_set(struct percpu_counter *fbc, s64 amount);
 void __percpu_counter_add(struct percpu_counter *fbc, s64 amount, s32 batch);
-s64 __percpu_counter_sum(struct percpu_counter *fbc);
+s64 __percpu_counter_sum(struct percpu_counter *fbc, int set);
 
 static inline void percpu_counter_add(struct percpu_counter *fbc, s64 amount)
 {
@@ -44,13 +44,19 @@ static inline void percpu_counter_add(struct percpu_counter *fbc, s64 amount)
 
 static inline s64 percpu_counter_sum_positive(struct percpu_counter *fbc)
 {
-	s64 ret = __percpu_counter_sum(fbc);
+	s64 ret = __percpu_counter_sum(fbc, 0);
 	return ret < 0 ? 0 : ret;
 }
 
+static inline s64 percpu_counter_sum_and_set(struct percpu_counter *fbc)
+{
+	return __percpu_counter_sum(fbc, 1);
+}
+
+
 static inline s64 percpu_counter_sum(struct percpu_counter *fbc)
 {
-	return __percpu_counter_sum(fbc);
+	return __percpu_counter_sum(fbc, 0);
 }
 
 static inline s64 percpu_counter_read(struct percpu_counter *fbc)
diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index f462439..0d8573e 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -63,6 +63,7 @@ struct writeback_control {
 	unsigned for_writepages:1;	/* This is a writepages() call */
 	unsigned range_cyclic:1;	/* range_start is cyclic */
 	unsigned more_io:1;		/* more io to be dispatched */
+	unsigned range_cont:1;
 };
 
 /*
diff --git a/lib/percpu_counter.c b/lib/percpu_counter.c
index 1191744..4a8ba4b 100644
--- a/lib/percpu_counter.c
+++ b/lib/percpu_counter.c
@@ -52,7 +52,7 @@ EXPORT_SYMBOL(__percpu_counter_add);
  * Add up all the per-cpu counts, return the result.  This is a more accurate
  * but much slower version of percpu_counter_read_positive()
  */
-s64 __percpu_counter_sum(struct percpu_counter *fbc)
+s64 __percpu_counter_sum(struct percpu_counter *fbc, int set)
 {
 	s64 ret;
 	int cpu;
@@ -62,7 +62,12 @@ s64 __percpu_counter_sum(struct percpu_counter *fbc)
 	for_each_online_cpu(cpu) {
 		s32 *pcount = per_cpu_ptr(fbc->counters, cpu);
 		ret += *pcount;
+		if (set)
+			*pcount = 0;
 	}
+	if (set)
+		fbc->count = ret;
+
 	spin_unlock(&fbc->lock);
 	return ret;
 }
diff --git a/mm/filemap.c b/mm/filemap.c
index 1e6a7d3..65d9d9e 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -236,11 +236,12 @@ int filemap_fdatawrite(struct address_space *mapping)
 }
 EXPORT_SYMBOL(filemap_fdatawrite);
 
-static int filemap_fdatawrite_range(struct address_space *mapping, loff_t start,
+int filemap_fdatawrite_range(struct address_space *mapping, loff_t start,
 				loff_t end)
 {
 	return __filemap_fdatawrite_range(mapping, start, end, WB_SYNC_ALL);
 }
+EXPORT_SYMBOL(filemap_fdatawrite_range);
 
 /**
  * filemap_flush - mostly a non-blocking flush
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 789b6ad..ded57d5 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -956,6 +956,9 @@ retry:
 	}
 	if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
 		mapping->writeback_index = index;
+
+	if (wbc->range_cont)
+		wbc->range_start = index << PAGE_CACHE_SHIFT;
 	return ret;
 }
 EXPORT_SYMBOL(write_cache_pages);