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>
3d850dd448