Btrfs: fix wrong nbytes information of the inode

If we write some data into the data hole of the file(no preallocation for this
hole), Btrfs will allocate some disk space, and update nbytes of the inode, but
the other element--disk_i_size needn't be updated. At this condition, we must
update inode metadata though disk_i_size is not changed(btrfs_ordered_update_i_size()
return 1).

 # mkfs.btrfs /dev/sdb1
 # mount /dev/sdb1 /mnt
 # touch /mnt/a
 # truncate -s 856002 /mnt/a
 # dd if=/dev/zero of=/mnt/a bs=4K count=1 conv=nocreat,notrunc
 # umount /mnt
 # btrfsck /dev/sdb1
 root 5 inode 257 errors 400
 found 32768 bytes used err is 1

Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index c257af2ce9cb16fdd630cc3834e5640fdf72c748..b94c0da3b43fcfec34c62591bfb450a866c68170 100644 (file)
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -1786,7 +1786,7 @@ static int btrfs_finish_ordered_io(struct inode *inode, u64 start, u64 end)
                          &ordered_extent->list);
 
        ret = btrfs_ordered_update_i_size(inode, 0, ordered_extent);
-       if (!ret) {
+       if (!ret || !test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags)) {
                ret = btrfs_update_inode(trans, root, inode);
                BUG_ON(ret);
        }
@@ -5788,7 +5788,7 @@ again:
 
        add_pending_csums(trans, inode, ordered->file_offset, &ordered->list);
        ret = btrfs_ordered_update_i_size(inode, 0, ordered);
-       if (!ret)
+       if (!ret || !test_bit(BTRFS_ORDERED_PREALLOC, &ordered->flags))
                btrfs_update_inode(trans, root, inode);
        ret = 0;
 out_unlock: