On Thu, Oct 31, 2019 at 09:39:23AM +0000, misono.tomoh...@fujitsu.com wrote: [..] > > > > Hi Misono, > > > > > > > > Have you tried running pjdfstests. Looks like with the patch applied > > > > I see following tests failing which were passing without the patch. > > > > Can you please have a look. I ran daemon with options "-o > > > cache=always -o writeback" > > > > I see these errors in both with and without this patch but not always. > > Do you always see the failure? > > > > I use: > > Kernel: Fuse's for-next branch > > Qemu: virtio-fs-dev branch > > backend: XFS (relatime) > > > > These tests fail because a/c/m time is not updated as expected. > > So it seems this is related to the failure of xfstest generic/003. > > I will look into the problem more. > > > > Hi, > > So I fugured out the problem. > The failure occurs when guest clock is earlier than host clock in writeback > mode. > > The failure case checks: > 1. get current c/time of file > 2. sleep 1 second > 3. modify file's metadata/data > 4. check if c/mtime is updated > > And the tests fail because: > 1. when file is opened, guest inode's time is initialized by host's inode > information > 2. In writeback mode, guest clock is used for c/mtime update > 3. if guest clock is earlier than host clock, c/mtime could be updated > earlier than current inode time. > > I can reproduce the problem reliably by deliberately setting guest clock > earlier > than host clock. I'm not sure if virtiofs is to be blmaed in this case, but > should > we not update c/mtime in guest if it is earlier then current c/mtime? > > Anyway, I believe this O_APPEND fix patch is irrelevant to the problem, > could you please check it again?
Hi Misono, Thanks for looking into it. I agree that a/c/m time updates with -o writeback is probably a different issue and not related to your patch. So I am fine with your patch. Thanks Vivek
