From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx1.redhat.com ([209.132.183.28]:59293 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753256AbcFPLp1 (ORCPT ); Thu, 16 Jun 2016 07:45:27 -0400 Date: Thu, 16 Jun 2016 07:45:25 -0400 From: Brian Foster Subject: Re: [PATCH v2] xfstests: xfs discontiguous multi-block buffer logging test Message-ID: <20160616114525.GA8342@bfoster.bfoster> References: <1464873001-17508-1-git-send-email-bfoster@redhat.com> <20160616011349.GM12670@dastard> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160616011349.GM12670@dastard> Sender: fstests-owner@vger.kernel.org To: Dave Chinner Cc: fstests@vger.kernel.org List-ID: 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... Brian > Cheers, > > Dave. > -- > Dave Chinner > david@fromorbit.com > -- > To unsubscribe from this list: send the line "unsubscribe fstests" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html