[patch 77/87] ext4: Fix discard of inode prealloc space with delayed allocation.

Greg KH
2009-06-09T10:36:13Z

[-- Attachment #1: ext4-fix-discard-of-inode-prealloc-space-with-delayed-allocation.patch --]
[-- Type: text/plain, Size: 1891 bytes --]

2.6.29-stable review patch. If anyone has any objections, please let us know.

------------------

From: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

(cherry picked from commit d6014301b5599fba395c42a1e96a7fe86f7d0b2d)

With delayed allocation we should not/cannot discard inode prealloc
space during file close. We would still have dirty pages for which we
haven't allocated blocks yet. With this fix after each get_blocks
request we check whether we have zero reserved blocks and if yes and
we don't have any writers on the file we discard inode prealloc space.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
fs/ext4/file.c | 3 ++-
fs/ext4/inode.c | 9 ++++++++-
2 files changed, 10 insertions(+), 2 deletions(-)

--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -39,7 +39,8 @@ static int ext4_release_file(struct inod
}
/* if we are the last writer on the inode, drop the block reservation */
if ((filp->f_mode & FMODE_WRITE) &&
- (atomic_read(&inode->i_writecount) == 1))
+ (atomic_read(&inode->i_writecount) == 1) &&
+ !EXT4_I(inode)->i_reserved_data_blocks)
{
down_write(&EXT4_I(inode)->i_data_sem);
ext4_discard_preallocations(inode);
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1036,8 +1036,15 @@ static void ext4_da_update_reserve_space
/* update per-inode reservations */
BUG_ON(used > EXT4_I(inode)->i_reserved_data_blocks);
EXT4_I(inode)->i_reserved_data_blocks -= used;
-
spin_unlock(&EXT4_I(inode)->i_block_reservation_lock);
+
+ /*
+ * If we have done all the pending block allocations and if
+ * there aren't any writers on the inode, we can discard the
+ * inode's preallocations.
+ */
+ if (!total && (atomic_read(&inode->i_writecount) == 0))
+ ext4_discard_preallocations(inode);
}

/*