linux-kernel - Re: [2.6.34-rc2 NFS4 oops] open error path failure...

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Date:	Mon, 29 Mar 2010 20:21:57 +0100
From:	Daniel J Blueman <daniel.blueman@...il.com>
To:	Al Viro <viro@...iv.linux.org.uk>
Cc:	Trond Myklebust <trond.myklebust@....uio.no>,
	linux-nfs@...r.kernel.org,
	Linux Kernel <linux-kernel@...r.kernel.org>
Subject: Re: [2.6.34-rc2 NFS4 oops] open error path failure...

Hi Al,

On Mon, Mar 29, 2010 at 8:03 PM, Al Viro <viro@...iv.linux.org.uk> wrote:
> On Mon, Mar 29, 2010 at 07:36:45PM +0100, Daniel J Blueman wrote:
>> Hi Trond,
>>
>> When open fails and should return EPERM [1], instead we see an oops
>> [2]. I see this on 2.6.34-rc1 and -rc2 mainline; NFS4 server is
>> mainline 2.6.33.1.
>>
>> Let me know if you can't reproduce it and I'll provide some analysis
>> from this end.
>
> Joy...  ERR_PTR(-EPERM) in nd.intent.file, and whoever had called
> lookup_instantiate_filp() hadn't bothered to check the return value.
>
> OK, I think I see what's going on.  Replace
>                                lookup_instantiate_filp(nd, (struct dentry *)state, NULL);
>                                return 1;
> with
>                                lookup_instantiate_filp(nd, (struct dentry *)state, NULL);
>                                return state;
> in fs/nfs/nfs4proc.c:nfs4_open_revalidate() and see if everything works
> properly (or just lose the lookup_instantiate_filp() in there and simply
> return state).

That did the trick!

Looks like I should have reported this when I first encountered it,
but I guess it goes to show there needs to be some NFS validation
(LTP?). I'm still trying to chase down a rare NFSv4 dentry "Stale NFS
file handle" issue I've seen.

Thanks,
  Daniel
-- 
Daniel J Blueman
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