Date: Fri, 20 May 2011 13:26:39 -0400
From: "Dr. J. Bruce Fields" <bfields@fieldses.org>
To: Harry Edmon <harry@uw.edu>
Cc: Trond Myklebust <Trond.Myklebust@netapp.com>,
        Chuck Lever <chuck.lever@oracle.com>, linux-nfs@vger.kernel.org
Subject: Re: 2.6.38.6 - state manager constantly respawns
Message-ID: <20110520172639.GA11670@fieldses.org>
References: <05D08339-888C-4A64-BDC5-8667B3901E7A@oracle.com>
 <4DD1772E.9010609@uw.edu>
 <6A6FB1C3-D4C3-40BE-810A-B4551FA9E591@oracle.com>
 <4DD17CB5.7010009@uw.edu>
 <1305575007.19725.3.camel@lade.trondhjem.org>
 <4DD17F79.305@uw.edu>
 <1305575656.19725.9.camel@lade.trondhjem.org>
 <20110516202059.GC1680@fieldses.org>
 <20110516205351.GD1680@fieldses.org>
 <4DD694DF.2060302@uw.edu>
Content-Type: text/plain; charset=us-ascii
In-Reply-To: <4DD694DF.2060302@uw.edu>
Sender: linux-nfs-owner@vger.kernel.org
MIME-Version: 1.0

On Fri, May 20, 2011 at 09:20:47AM -0700, Harry Edmon wrote:
> On 05/16/11 13:53, Dr. J. Bruce Fields wrote:
> >Hm, so the renews all have clid 465ccc4d09000000, and the reads all have
> >a stateid (0, 465ccc4dc24c0a0000000000).
> >
> >So the first 4 bytes matching just tells me both were handed out by the
> >same server instance (so there was no server reboot in between); there's
> >no way for me to tell whether they really belong to the same client.
> >
> >The server does assume that any stateid from the current server instance
> >that no longer exists in its table is expired.  I believe that's
> >correct, given a correctly functioning client, but perhaps I'm missing a
> >case.
> >
> >--b.
> I am very appreciative of the quick initial comments I receive from
> all of you on my NFS problem.   I notice that there has been silence
> on the problem since the 16th, so I assume that either this is a
> hard bug to track down or you have been busy with higher priority
> tasks.  Is there anything I can do to help develop a solution to
> this problem?

Well, the only candidate explanation for the problem is that my
assumption--that any time the server gets a stateid from the current
boot instance that it doesn't recognize as an active stateid, it is safe
for the server to return EXPIRED--is wrong.

I don't immediately see why it's wrong, and based on the silence nobody
else does either, but I'm not 100% convinced I'm right either.

So one approach might be to add server code that makes a better effort
to return EXPIRED only when we're sure it's a stateid from an expired
client, and see if that solves your problem.

Remind me, did you have an easy way to reproduce your problem?

--b.