Re: [Bisected] Corruption of root fs during git bisect of drm system hang

From: Dave Chinner <david@fromorbit.com>
To: Markus Trippelsdorf <markus@trippelsdorf.de>
Cc: Ben Myers <bpm@sgi.com>, Mark Tinguely <tinguely@sgi.com>,
	Stan Hoeppner <stan@hardwarefreak.com>,
	xfs@oss.sgi.com
Subject: Re: [Bisected] Corruption of root fs during git bisect of drm system hang
Date: Tue, 23 Jul 2013 08:54:45 +1000	[thread overview]
Message-ID: <20130722225445.GA19986@dastard> (raw)
In-Reply-To: <20130722104743.GA361@x4>

On Mon, Jul 22, 2013 at 12:47:43PM +0200, Markus Trippelsdorf wrote:
> On 2013.07.22 at 20:22 +1000, Dave Chinner wrote:
> > On Sat, Jul 20, 2013 at 11:48:36AM +1000, Dave Chinner wrote:
> > > On Fri, Jul 19, 2013 at 02:22:35PM +0200, Markus Trippelsdorf wrote:
> > > > On 2013.07.15 at 08:47 +0200, Markus Trippelsdorf wrote:
> > > > I've bisected this issue to the following commit:
> > > > 
> > > >  commit cca9f93a52d2ead50b5da59ca83d5f469ee4be5f
> > > >  Author: Dave Chinner <dchinner@redhat.com>
> > > >  Date:   Thu Jun 27 16:04:49 2013 +1000
> > > > 
> > > >      xfs: don't do IO when creating an new inode
> > > >          
> > > > Reverting this commit on top of the Linus tree "solves" all problems for
> > > > me. IOW I no longer loose my KDE and LibreOffice config files during a
> > > > crash. Log recovery now works fine and xfs_repair shows no issues.
> > > 
> > > Thanks for bisecting this, Marcus.
> > > 
> > > I'll admit, right now it doesn't make a lot of sense to me - I don't
> > > immediately see a connection between not reading an inode during the
> > > create phase and unlinked list and directory corruption after a
> > > crash. But now you've identified a change that might be the cause,
> > > I have an avenue of investigation I can follow.
> > > 
> > > Indeed, in the time I've taken to write this mail I've thought of
> > > 2-3 possible causes that I need to investigate....
> > 
> > Hi Markus, can you test the patch I just posted to the list titled
> > "xfs: di_flushiter considered harmful" and see if it fixes your
> > problem? Archive link here:
> > 
> > http://oss.sgi.com/pipermail/xfs/2013-July/028331.html
> 
> Unfortunately no. I still get the same corruption with this patch
> applied.

Umm, really? can you please put together a simple reproducer then?
Because it definitely fixes the problem that Mark reproduced...

> (It's embarrassing to mention, but please add:
> Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de>
> to the next iteration of this patch.
> Thanks.)

The reason I asked you to test it was so I could confirm that it was
fixing the problem you've reported and so I could added reported-by
and tested-by tags to it.

Indeed, if it doesn't fix your problem, then it's not fixing the bug
you reported, and so adding such tags is wrong.... ;)

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

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