Subject: Re: [BUG] 2.6.0-test4-mm1: NFS+XFS=data corruption
From: Steve Lord <lord@sgi.com>
To: Andrew Morton <akpm@osdl.org>
Cc: "Barry K. Nathan" <barryn@pobox.com>,
       Linux Kernel <linux-kernel@vger.kernel.org>, linux-mm@kvack.org,
       linux-xfs@oss.sgi.com
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Date: 25 Aug 2003 17:54:11 -0500
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On Mon, 2003-08-25 at 14:45, Andrew Morton wrote:
> "Barry K. Nathan" <barryn@pobox.com> wrote:
> >
> > I'm really short on time right now, so this bug report might be vague,
> > but it's important enough for me to try:
> > 
> > I have an NFS fileserver (running 2.6.0-test4-mm1) exporting stuff from
> > three filesystems: ReiserFS, ext3, and XFS. I'm seeing no problems with
> > my ReiserFS and ext3 filesystems. XFS is a different story.
> > 
> > My client machine is running 2.4.21bkn1 (my own kernel, not released to
> > the public; the differences from vanilla 2.4.21 are XFS and Win4Lin). 
> > 
> > If I use my client machine to sign RPM packages (rpm --addsign ...),
> > using rpm-4.2-16mdk, and the packages are on the XFS partition on the
> > NFS server, about half of the packages are truncated by a couple hundred
> > bytes afterwards (and GPG sig verification fails on those packages).
> > 
> > It's always the same packages that get truncated by the same amounts of
> > data. This is 100% reproducible. It doesn't matter whether I compile the
> > kernel with gcc 2.95.3 or 3.1.1. If I perform the operation on my non-XFS
> > filesystem the problem doesn't happen. If I run 2.6.0-test4-bk2 instead of
> > test4-mm1 on the NFS server, the problem goes away. (I have never run
> > any previous -mm kernels on this server.)
> > 
> > Hmmm... If I sign the packages on the NFS server itself, even with
> > test4-mm1 on the XFS partition, I can't reproduce the problem.
> > *However*, that's a different version of RPM (4.0.4).
> > 
> > Is this enough information to help find the cause of the bug? If not,
> > it might be several days (if I'm unlucky, maybe even a week or two)
> > before I have time to do anything more...
> > 
> 
> -mm kernels have O_DIRECT-for-NFS patches in them.  And some versions of
> RPM use O_DIRECT.  Whether O_DIRECT makes any difference at the server end
> I do not know, but it would be useful if you could repeat the test on stock
> 2.6.0-test4.
> 
> Alternatively, run
> 
> 	export LD_ASSUME_KERNEL=2.2.5
> 
> before running RPM.  I think that should tell RPM to not try O_DIRECT.

I doubt the NFS client is O_DIRECT capable here, I have run some rpm
builds over nfs to 2.6.0-test4 and an xfs filesystem, everything is
behaving so far. I will try mm1 tomorrow.

Do we know if this NFS V3 or V2 by the way?

Steve

-- 

Steve Lord                                      voice: +1-651-683-3511
Principal Engineer, Filesystem Software         email: lord@sgi.com
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