On Thu, Oct 06, 2011 at 11:39:54AM +0800, Li Zefan wrote: > Follow those steps: > > # mount -o autodefrag /dev/sda7 /mnt > # dd if=/dev/urandom of=/mnt/tmp bs=200K count=1 > # sync > # 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. Really nice and small fix. I'll definitely send this for 3.1 -chris -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
