Date: Tue, 5 May 2015 13:24:03 -0400 (EDT)
From: Benjamin Coddington <bcodding@redhat.com>
To: Joschi Brauchle <joschi.brauchle@tum.de>
cc: "linux-nfs@vger.kernel.org" <linux-nfs@vger.kernel.org>
Subject: Re: NFS Client looping with STALE_STATE_ID error - 100% load on one
 CPU core
In-Reply-To: <5538C66A.1020302@tum.de>
Message-ID: <alpine.OSX.2.19.9992.1505051301510.946@planck.local>
References: <5538C66A.1020302@tum.de>
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Sender: linux-nfs-owner@vger.kernel.org

Hi J Brauchle,

Are you producing this on a kernel that has "8faaa6d Fixing lease renewal"?
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=8faaa6d5d48b2015

If not, I think that might be what you need.

Ben

On Thu, 23 Apr 2015, Joschi Brauchle wrote:

> Hello everyone,
>
> I am posting to this list as suggested by Neil F Brown in this OpenSUSE
> bugzilla: https://bugzilla.novell.com/show_bug.cgi?id=909634
>
>
> We are mounting user homes and other shares using 'sec=krb' and NFSv4. With
> kernel 3.16.7+ (includes latest NFS patches, please see BZ link for details)
> we are seeing 100% CPU core usage by a kernel process on some machine
> connected to a 'NetApp FAS 3140 with ONTAP 8.1.4P1 7-mode' NFSv3/4 Server. It
> looks like the problem is triggered when the NFS server is unavailable for a
> short period of time or was rebooted.
>
> Neil F Brown has come to the following conclusion so far:
> ------------- QUOTE -------------
> What I see happening here is that a WRITE or LOCK request gets
> NFS4ERR_STALE_STATEID, and then the client sends a "RENEW" request.
>
> If the stateid is really stale, that should fail, but it doesn't. So the
> client assumes everything is OK and keeps sending requests .... which fail
> with NFS4ERR_STALE_STATEID.
>
> STALE_STATEID means:
>
>       A stateid generated by an earlier server instance was used.
>
> which means that the server must have restarted since that stateid was issued.
>
> So there seem to be two possible explanations:
>
> 1/ The server is lying.  The stateid isn't really 'stale'.  Maybe it is 'bad'.
> 2/ The client has previously handled a STALE_STATEID error and created a new
> "client" handle, but hasn't refreshed all of the stateids that it was holding.
> So it is trying to use old stateid even though it has established a new
> client.
>
> The client code looks OK, though it is sufficiently complex that I cannot be
> certain.  There are no patches in more recent versions.
> -------------  END  -------------
>
> We have some RPC/NFS debug logs available here:
> https://bugzilla.novell.com/attachment.cgi?id=631962
> And a wireshark trace here:
> https://bugzilla.novell.com/attachment.cgi?id=632104
>
>
> What I cannot do:
> - Trigger or reproduce the problem reliably. It comes up every once in a
> while. Around 2-3 times a month on a handful of ~50 machines.
> - Provide logs from with the latest kernel (because I cannot trigger the
> problem by any means. Updating all ~50 machines is not an option)
>
>
> What I can do:
> - Provide logs from or possibly even access to the machine in the 'broken'
> state for the next couple of days. I will have to reboot it at some time to
> take the load of the NFS server.
>
>
>
> I would be grateful for any help or comments.
>
> -J Brauchle