From: Kasparek Tomas <kasparek@fit.vutbr.cz>
Subject: Re: NFS corruption in 2.6.18.2?
Date: Sat, 25 Nov 2006 19:26:00 +0100
Message-ID: <20061125182600.GA74811@fit.vutbr.cz>
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	<20061123213311.GH40079@fit.vutbr.cz>
	<20061124064752.GI40079@fit.vutbr.cz>
	<1164395516.5702.53.camel@lade.trondhjem.org>
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To: Trond Myklebust <trond.myklebust@fys.uio.no>
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On Fri, Nov 24, 2006 at 02:11:55PM -0500, Trond Myklebust wrote:
> > > > On Thu, Nov 23, 2006 at 05:17:38PM +0100, Kasparek Tomas wrote:
> > > > Just update: 2.6.17.14 is ok
> > > 
> > > did git bisect between 2.6.17 and 2.6.18 and found that the commit is:
> > > 
> > > 44b11874ff583b6e766a05856b04f3c492c32b84
> > >  NFS: Separate metadata and page cache revalidation mechanisms
> > > 
> > > will verify (with and without patch) tomorrow.
> > 
> > 2.6.18.3 with reversed 44b11874ff583b6e766a05856b04f3c492c32b84 is OK.
> > 
> > exact patch used included.
> 
> If you are not using any form of synchronisation, then your test would
> appear to be violating the close-to-open cache consistency rules (see
> http://nfs.sourceforge.net/#faq_a8).

Yes, I understand this, but with no synchronization I should get old or
somewhat 'not current' data at worst, I don't expect to get some data
generated by the kernel. The test is synthetic, it was constructed to be
as easy as possible, but this one works well on 2.6.16 (mean no zeros, data
are sometimes overwriten or mixed from several clients as a result of no
locking, but that's ok for my application).

I think the real bug/problem/misbehaving is somwhere else than in the patch
itself I mention, this patch just enables different behaviour that ends
with the real bad code having the possibility to show up.

I will try to find this bad code next week.

Regards

--   

  Tomas Kasparek, PhD student  E-mail: kasparek@fit.vutbr.cz
  CVT FIT VUT Brno, BI/140a    Web:    http://www.fit.vutbr.cz/~kasparek
  Bozetechova 2, 612 66        Fax:    +420 54114-1270
  Brno, Czech Republic         Phone:  +420 54114-1220

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