From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from ipmail07.adl2.internode.on.net ([150.101.137.131]:57686 "EHLO ipmail07.adl2.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752939AbcFTWsp (ORCPT ); Mon, 20 Jun 2016 18:48:45 -0400 Date: Tue, 21 Jun 2016 08:48:39 +1000 From: Dave Chinner Subject: Re: [PATCH v2] xfstests: xfs discontiguous multi-block buffer logging test Message-ID: <20160620224839.GO12670@dastard> References: <1464873001-17508-1-git-send-email-bfoster@redhat.com> <20160616011349.GM12670@dastard> <20160616114525.GA8342@bfoster.bfoster> <5f0d9c6d-3950-7e01-35f8-525cb1b6280f@sandeen.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5f0d9c6d-3950-7e01-35f8-525cb1b6280f@sandeen.net> Sender: fstests-owner@vger.kernel.org To: Eric Sandeen Cc: Brian Foster , fstests@vger.kernel.org List-ID: On Thu, Jun 16, 2016 at 10:10:09AM -0500, Eric Sandeen wrote: > On 6/16/16 6:45 AM, Brian Foster wrote: > > On Thu, Jun 16, 2016 at 11:13:49AM +1000, Dave Chinner wrote: > >> On Thu, Jun 02, 2016 at 09:10:01AM -0400, Brian Foster wrote: > >>> XFS had a bug in the multi-block buffer logging code that caused a NULL > >>> lv panic at log push time due to invalid regions being set in the buffer > >>> log format bitmap. This was demonstrated by modifying a multi-block > >>> directory buffer in a manner that only logs regions beyond the first > >>> FSB-sized mapping of the buffer. > >>> > >>> To recreate these conditions, this test fragments free space and > >>> populates several directories with enough entries to require > >>> discontiguous multi-block buffers. To recreate the problem, we remove > >>> entries from the tail end of the directory and fsync to flush the log. > >>> > >>> Note that this test causes a panic on kernels affected by the bug. As > >>> such, it is included in the 'dangerous' group. The bug is resolved by > >>> kernel commit a3916e528b91 ("xfs: fix broken multi-fsb buffer logging"). > >>> > >>> Signed-off-by: Brian Foster > >> ..... > >>> +# Create a small fs with a large directory block size. We want to fill up the fs > >>> +# quickly and then create multi-fsb dirblocks over fragmented free space. > >>> +_scratch_mkfs_xfs -d size=20m -n size=64k >> $seqres.full 2>&1 > >>> +_scratch_mount > >>> + > >>> +# Fill a source directory with many largish-named files. 1k uuid-named entries > >>> +# sufficiently populates a 64k directory block. > >>> +mkdir $SCRATCH_MNT/src > >>> +for i in $(seq 0 1023); do > >>> + touch $SCRATCH_MNT/src/`uuidgen` > >>> +done > >> > >> What's 'uuidgen'? Not installed on my test systems, so this needs > >> a requires check, I think.... > >> > >> Hmmm - looks like a separate package is needed on debian systems: > >> uuid-runtime. Can you send a followup patch that adds the necesary > >> checks to this test and added the above package to the iniitial list > >> in the README file (for ubunutu, I know, but the package name will > >> be the same). > >> > > > > Eryu pointed this on on v1 of the test but I didn't think it necessary > > as it's part of a standard package on fedora. I guess that's not true > > for other distros. I'll post something to fix it up... > > Yeah, that's surprising, it's been part of util-linux[-ng] on my RHEL & > Fedora distros since 2009. It's to do with dependencies against systemd and ensuring core packages don't have systemd dependencies. i.e. uuid-runtime has a dependency on libsystemd because of the uuidd daemon that is used to generate uuids. Hence it has to be packaged it separately so that linux-util/libuuid packages do not require systemd to be installed on the system. Cheers, Dave. -- Dave Chinner david@fromorbit.com