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Btrfs: add missing inode item update in fallocate()

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If we fallocate(), without the keep size flag, into an area already covered
by an extent previously fallocated, we were updating the inode's i_size but
we weren't updating the inode item in the fs/subvol tree. A following umount
+ mount would result in a loss of the inode's size (and an fsync would miss
too the fact that the inode changed).

Reproducer:

  $ mkfs.btrfs -f /dev/sdd
  $ mount /dev/sdd /mnt
  $ fallocate -n -l 1M /mnt/foobar
  $ fallocate -l 512K /mnt/foobar
  $ umount /mnt
  $ mount /dev/sdd /mnt
  $ od -t x1 /mnt/foobar
  0000000

The expected result is:

  $ od -t x1 /mnt/foobar
  0000000 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  *
  2000000

A test case for fstests follows soon.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: Chris Mason <clm@fb.com>
This commit is contained in:
Filipe Manana 2015-03-12 23:23:13 +00:00 committed by Chris Mason
parent 5f806c3ae2
commit 3d850dd448
1 changed files with 20 additions and 9 deletions
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29
fs/btrfs/file.c
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@ -2669,23 +2669,34 @@ static long btrfs_fallocate(struct file *file, int mode,
1 << inode->i_blkbits,
offset + len,
&alloc_hint);
if (ret < 0) {
free_extent_map(em);
break;
}
} else if (actual_end > inode->i_size &&
!(mode & FALLOC_FL_KEEP_SIZE)) {
struct btrfs_trans_handle *trans;
/*
* We didn't need to allocate any more space, but we
* still extended the size of the file so we need to
* update i_size.
* update i_size and the inode item.
*/
inode->i_ctime = CURRENT_TIME;
i_size_write(inode, actual_end);
btrfs_ordered_update_i_size(inode, actual_end, NULL);
trans = btrfs_start_transaction(root, 1);
if (IS_ERR(trans)) {
ret = PTR_ERR(trans);
} else {
inode->i_ctime = CURRENT_TIME;
i_size_write(inode, actual_end);
btrfs_ordered_update_i_size(inode, actual_end,
NULL);
ret = btrfs_update_inode(trans, root, inode);
if (ret)
btrfs_end_transaction(trans, root);
else
ret = btrfs_end_transaction(trans,
root);
}
}
free_extent_map(em);
if (ret < 0)
break;
cur_offset = last_byte;
if (cur_offset >= alloc_end) {