From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qk0-f182.google.com ([209.85.220.182]:37874 "EHLO mail-qk0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751310AbdIAHDh (ORCPT ); Fri, 1 Sep 2017 03:03:37 -0400 Received: by mail-qk0-f182.google.com with SMTP id k126so7151410qkb.4 for ; Fri, 01 Sep 2017 00:03:36 -0700 (PDT) Date: Fri, 1 Sep 2017 03:03:33 -0400 From: Josef Bacik Subject: Re: [PATCH v2 00/14] Crash consistency xfstest using dm-log-writes Message-ID: <20170901070332.kbklcom7rghvqhri@destiny> References: <20170830152326.vil3fhsrecp2ccql@destiny> <20170830185512.7q5mnh5ja6o4mpds@destiny> <20170831134320.lnyu4jibsm3amuk7@destiny> <20170831205403.2tene34ccvw55yo7@destiny> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: fstests-owner@vger.kernel.org To: Amir Goldstein Cc: Josef Bacik , fstests , Theodore Tso , Eryu Guan List-ID: On Fri, Sep 01, 2017 at 09:52:18AM +0300, Amir Goldstein wrote: > [CC list, Ted] > > On Thu, Aug 31, 2017 at 11:54 PM, Josef Bacik wrote: > > On Thu, Aug 31, 2017 at 05:02:46PM +0300, Amir Goldstein wrote: > >> On Thu, Aug 31, 2017 at 4:43 PM, Josef Bacik wrote: > >> > On Thu, Aug 31, 2017 at 03:48:44PM +0300, Amir Goldstein wrote: > >> >> > >> >> Josef, > >> >> > >> >> I am at lost with these log corruptions. > >> >> I see log entry bios submitted and log_end_io report success, > >> >> but then in the log I see old data on disk where that entry should be. > >> >> This happens quite randomly and I assume it also happens on > >> >> logged data, because tests sometime fail on checksum on ext4. > >> >> > >> >> Mean while I added some more log entry sanity checks and debug > >> >> prints to replay-log to debug the corruption: > >> >> https://github.com/amir73il/xfstests/commit/bb946deb0dc285867be394613ddb19ce281392cc > >> >> > >> >> This only happens to me when running in kvm, so maybe something > >> >> with the virtio devices is fishy. > >> >> > >> >> Anyway, I ran out of time to work on this for now, so if you have > >> >> any ideas and/or time to test this issue, let me know. > >> >> > >> > > ... > >> > > > > Alright I tested it and it's working fine for me. I'm creating three lv's and > > then doing > > > > -drive file=/dev/mapper/whatever,format=raw,cache=none,if=virtio,aio=native > > > > And I get /dev/vd[bcd] which I use for my test/scratch/log dev and it works out > > fine. What is your -drive option line and I'll duplicate what you are doing. > > Thanks, > > > > I am using Ted's kvm-xfstests, so this is the qemu command line: > https://github.com/tytso/xfstests-bld/blob/master/kvm-xfstests/kvm-xfstests#L104 > > The only difference in -drive command is no aio=native. > BINGO! when I add aio-native there are no more log corruptions :) > Please try to use aio=threads to see if you also get log corruptions. > > Thing is we cannot change kvm-xfstests to always use aio=native because > it is not recommended for sparse images: > https://access.redhat.com/articles/41313 > I will try to work something out so that kvm-xfstest will use aio=native > when using the recommended (by not default) LV setup. > > However, why would aio=threads cause log corruption? > Does it indicate a bug in kvm-qemu or in dm-log-writes?? > > Did you try to use kvm-xfstests? its quite convenient to deploy in masses, > so I think it would be ideal to integrate crash tests with. > It also helps unifying the environment between us fs developers > when a bug can not be reproduced on another system. see: > https://github.com/tytso/xfstests-bld/blob/master/Documentation/kvm-xfstests.md > > Anyway, if you do end up using kvm-xfstests, you'l need this > small patch to automatically define the log-writes device: > > --- a/kvm-xfstests/test-appliance/files/root/runtests.sh > +++ b/kvm-xfstests/test-appliance/files/root/runtests.sh > @@ -269,9 +269,11 @@ do > if test "$SIZE" = "large" ; then > export SCRATCH_DEV=$LG_SCR_DEV > export SCRATCH_MNT=$LG_SCR_MNT > + export LOGWRITES_DEV=$SM_SCR_DEV > else > export SCRATCH_DEV=$SM_SCR_DEV > export SCRATCH_MNT=$SM_SCR_MNT > + export LOGWRITES_DEV=$LG_SCR_DEV > fi > fi > > kvm-xfstests defined 2 sets of test/scratch a small and a large set > and uses only one of those sets depending on command line, > so I use the "other" scratch as the log writes device. > Cool I didn't know about kvm-xfstests, I'll give that a whirl. The baby just woke me up but when I get up for real I'll switch my config to use aio=threads and see what happens, but I'm starting to suspect there's a bug in qemu. Thanks, Josef