Return-Path: linux-nfs-owner@vger.kernel.org Received: from mail-wi0-f170.google.com ([209.85.212.170]:51262 "EHLO mail-wi0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751269AbaKESiP (ORCPT ); Wed, 5 Nov 2014 13:38:15 -0500 Received: by mail-wi0-f170.google.com with SMTP id r20so868165wiv.5 for ; Wed, 05 Nov 2014 10:38:13 -0800 (PST) MIME-Version: 1.0 In-Reply-To: References: <1415025403-31914-1-git-send-email-kolga@netapp.com> Date: Wed, 5 Nov 2014 13:38:13 -0500 Message-ID: Subject: Re: [PATCH 1/1] Fixing infinite state recovery loop due to failed delegation return From: Trond Myklebust To: Olga Kornievskaia Cc: linux-nfs Content-Type: text/plain; charset=UTF-8 Sender: linux-nfs-owner@vger.kernel.org List-ID: On Wed, Nov 5, 2014 at 12:53 PM, Olga Kornievskaia wrote: > Thank you for looking into this! > > On Tue, Nov 4, 2014 at 7:14 PM, Trond Myklebust > wrote: >> On Tue, Nov 4, 2014 at 6:22 PM, Olga Kornievskaia wrote: >>> Trond, can you please respond to the patch? >>> >>> As per earlier conversation, in this solution, state recovery is >>> initiated which marks the locks lost. >>> >>> Please either accept this patch or let me know what needs to be fixed. >>> >> >> Please see the 3 fixes I just sent out concerning delegation recovery >> w.r.t. NFSv4+NFSv4.1. In addition, we need to handle the case you >> patch attempts to address (however see the question I have below). >> >>> Thank you. >>> >>> On Mon, Nov 3, 2014 at 9:36 AM, Olga Kornievskaia wrote: >>>> If we get a bad-stateid-type of error when we send OPEN with delegate_cur >>>> to return currently held delegation, we shouldn't be trying to reclaim locks >>>> associated with that delegation state_id because we don't have an >>>> open_stateid to be used for the LOCK operation. Thus, we should >>>> return an error from the nfs4_open_delegation_recall() in that case. >>>> >>>> Furthermore, if an error occurs the delegation code will call >>>> nfs_abort_delegation_return() which sets again the NFS4CLNT_DELEGRETURN >>>> flags in the state and it leads the state manager to into an infinite loop >>>> for trying to reclaim the delegated state. >>>> >>>> Signed-off-by: Olga Kornievskaia >>>> --- >>>> fs/nfs/delegation.c | 5 +++-- >>>> fs/nfs/nfs4proc.c | 2 +- >>>> 2 files changed, 4 insertions(+), 3 deletions(-) >>>> >>>> diff --git a/fs/nfs/delegation.c b/fs/nfs/delegation.c >>>> index 5853f53..8016d89 100644 >>>> --- a/fs/nfs/delegation.c >>>> +++ b/fs/nfs/delegation.c >>>> @@ -394,7 +394,7 @@ static int nfs_end_delegation_return(struct inode *inode, struct nfs_delegation >>>> err = nfs4_wait_clnt_recover(clp); >>>> } while (err == 0); >>>> >>>> - if (err) { >>>> + if (err && err != -EIO) { >>>> nfs_abort_delegation_return(delegation, clp); >> >> This exception for EIO now has me worried. If we detach the >> delegation, then it looks to me as if we will never send a >> FREE_STATEID, as required for the case of NFSv4.1. > > I'd need to brush up on the FREE_STATEID op to confidently answer > that. But can't this be taken care of in state_recovery when locks are > marked lost? No, because in the case of EIO we now fall through to nfs_detach_delegation() and nfs_do_return_delegation(). What we really want to do is call TEST_STATEID + FREE_STATEID (see RFC5661 sections 8.2.4, 8.5 and 18.38.3), which will now be done as part of state recovery. -- Trond Myklebust Linux NFS client maintainer, PrimaryData trond.myklebust@primarydata.com