Btrfs: fix recursive auto-defrag
Follow those steps:
# mount -o autodefrag /dev/sda7 /mnt
# dd if=/dev/urandom of=/mnt/tmp bs=200K count=1
# dd if=/dev/urandom of=/mnt/tmp bs=8K count=1 conv=notrunc
and then it'll go into a loop: writeback -> defrag -> writeback ...
It's because writeback writes [8K, 200K] and then writes [0, 8K].
I tried to make writeback know if the pages are dirtied by defrag,
but the patch was a bit intrusive. Here I simply set writeback_index
when we defrag a file.
Signed-off-by: Li Zefan <firstname.lastname@example.org>
Signed-off-by: Chris Mason <email@example.com>
1 file changed