Return-Path: Received: from mail-pv0-f174.google.com ([74.125.83.174]:37733 "EHLO mail-pv0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935701Ab1ETT3J (ORCPT ); Fri, 20 May 2011 15:29:09 -0400 Received: by pvg12 with SMTP id 12so1800250pvg.19 for ; Fri, 20 May 2011 12:29:09 -0700 (PDT) Message-ID: <4DD6C103.7090302@uw.edu> Date: Fri, 20 May 2011 12:29:07 -0700 From: Harry Edmon To: Trond Myklebust CC: "Dr. J. Bruce Fields" , Chuck Lever , linux-nfs@vger.kernel.org Subject: Re: 2.6.38.6 - state manager constantly respawns 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> <20110520172639.GA11670@fieldses.org> <1305913963.12712.6.camel@lade.trondhjem.org> In-Reply-To: <1305913963.12712.6.camel@lade.trondhjem.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Sender: linux-nfs-owner@vger.kernel.org List-ID: MIME-Version: 1.0 On 05/20/11 10:52, Trond Myklebust wrote: > On Fri, 2011-05-20 at 13:26 -0400, Dr. J. Bruce Fields wrote: > >> 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? >> > My silence is simply because I'm mystified as to how this can happen. > Patching for it is trivial (see below). > > When the server tells us that our lease is expired, the normal behaviour > for the client is to re-establish the lease, and then proceed to recover > all known stateids. I don't see how we can 'miss' a stateid that then > needs to be recovered afterwards... > > Cheers > Trond > > 8<---------------------------------------------------------------------------- > From 920ddb153f28717be363f6e87dde24ef2a8d0ce2 Mon Sep 17 00:00:00 2001 > From: Trond Myklebust > Date: Fri, 20 May 2011 13:44:02 -0400 > Subject: [PATCH] NFSv4: Handle expired stateids when the lease is still valid > > Currently, if the server returns NFS4ERR_EXPIRED in reply to a READ or > WRITE, but the RENEW test determines that the lease is still active, we > fail to recover and end up looping forever in a READ/WRITE + RENEW death > spiral. > > Signed-off-by: Trond Myklebust > --- > fs/nfs/nfs4proc.c | 9 +++++++-- > 1 files changed, 7 insertions(+), 2 deletions(-) > > diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c > index cf1b339..d0e15db 100644 > --- a/fs/nfs/nfs4proc.c > +++ b/fs/nfs/nfs4proc.c > @@ -267,9 +267,11 @@ static int nfs4_handle_exception(struct nfs_server *server, int errorcode, struc > break; > nfs4_schedule_stateid_recovery(server, state); > goto wait_on_recovery; > + case -NFS4ERR_EXPIRED: > + if (state != NULL) > + nfs4_schedule_stateid_recovery(server, state); > case -NFS4ERR_STALE_STATEID: > case -NFS4ERR_STALE_CLIENTID: > - case -NFS4ERR_EXPIRED: > nfs4_schedule_lease_recovery(clp); > goto wait_on_recovery; > #if defined(CONFIG_NFS_V4_1) > @@ -3670,9 +3672,11 @@ nfs4_async_handle_error(struct rpc_task *task, const struct nfs_server *server, > break; > nfs4_schedule_stateid_recovery(server, state); > goto wait_on_recovery; > + case -NFS4ERR_EXPIRED: > + if (state != NULL) > + nfs4_schedule_stateid_recovery(server, state); > case -NFS4ERR_STALE_STATEID: > case -NFS4ERR_STALE_CLIENTID: > - case -NFS4ERR_EXPIRED: > nfs4_schedule_lease_recovery(clp); > goto wait_on_recovery; > #if defined(CONFIG_NFS_V4_1) > @@ -4543,6 +4547,7 @@ int nfs4_lock_delegation_recall(struct nfs4_state *state, struct file_lock *fl) > case -ESTALE: > goto out; > case -NFS4ERR_EXPIRED: > + nfs4_schedule_stateid_recovery(server, state); > case -NFS4ERR_STALE_CLIENTID: > case -NFS4ERR_STALE_STATEID: > nfs4_schedule_lease_recovery(server->nfs_client); > I installed this patch on my client, and now I am seeing the state manager appear in the process accounting file about once a minute rather that the constant respawning I saw earlier. Is once a minute normal, or is there still a problem? -- Dr. Harry Edmon E-MAIL: harry@uw.edu 206-543-0547 FAX: 206-543-0308 harry@atmos.washington.edu Director of IT, College of the Environment and Director of Computing, Dept of Atmospheric Sciences University of Washington, Box 351640, Seattle, WA 98195-1640