From: Jan Kara <jack@suse.cz>
To: Dave Chinner <david@fromorbit.com>
Cc: Ben Myers <bpm@sgi.com>, Jan Kara <jack@suse.cz>, xfs@oss.sgi.com
Subject: Re: [PATCH] xfs: Fix WARN_ON(delalloc) in xfs_vm_releasepage()
Date: Tue, 19 Mar 2013 16:42:29 +0100 [thread overview]
Message-ID: <20130319154229.GB5222@quack.suse.cz> (raw)
In-Reply-To: <20130319034759.GZ6369@dastard>
On Tue 19-03-13 14:47:59, Dave Chinner wrote:
> On Mon, Mar 18, 2013 at 05:05:52PM +0100, Jan Kara wrote:
> > On Fri 15-03-13 15:52:14, Ben Myers wrote:
> > > Hi Jan,
> > >
> > > On Thu, Mar 14, 2013 at 02:30:54PM +0100, Jan Kara wrote:
> > > > When a dirty page is truncated from a file but reclaim gets to it before
> > > > truncate_inode_pages(), we hit WARN_ON(delalloc) in
> > > > xfs_vm_releasepage(). This is because reclaim tries to write the page,
> > > > xfs_vm_writepage() just bails out (leaving page clean) and thus reclaim
> > > > thinks it can continue and calls xfs_vm_releasepage() on page with dirty
> > > > buffers.
> > > >
> > > > Fix the issue by redirtying the page in xfs_vm_writepage(). This makes
> > > > reclaim stop reclaiming the page and also logically it keeps page in a
> > > > more consistent state where page with dirty buffers has PageDirty set.
> > >
> > > Was there an easy way to reproduce this? I'm testing and reviewing this now
> > > and it might help.
> > I used scripts/run-bash-shared-mapping.sh from the attached tarball - it
> > fires up several processes beating a file with mmap accesses while
> > truncating the file and memory stressing the machine. I presume fsx with
> > some memhog could trigger the issue as well.
>
> I have seen fsx trip this occasionally. The problem is that it was
> never reliable because of the fact that other memory pressure had to
> be generated at the same time....
>
> Is the above script something you could turn into an xfstest (I
> haven't looked at the script yet)?
Yes, that should be doable. I'll try combining fsx and usemem whether
that will be enough to trigger the race.
Honza
--
Jan Kara <jack@suse.cz>
SUSE Labs, CR
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next prev parent reply other threads:[~2013-03-19 15:42 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-14 13:30 [PATCH] xfs: Fix WARN_ON(delalloc) in xfs_vm_releasepage() Jan Kara
2013-03-14 20:21 ` Carlos Maiolino
2013-03-15 20:52 ` Ben Myers
2013-03-18 16:05 ` Jan Kara
2013-03-19 3:47 ` Dave Chinner
2013-03-19 15:42 ` Jan Kara [this message]
2013-03-21 1:37 ` Dave Chinner
2013-03-22 21:12 ` Ben Myers
2013-03-16 7:35 ` Dave Chinner
2013-03-22 23:18 ` Ben Myers
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