Return-Path: Received: from mx2.netapp.com ([216.240.18.37]:5713 "EHLO mx2.netapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754816Ab1HDSRz convert rfc822-to-8bit (ORCPT ); Thu, 4 Aug 2011 14:17:55 -0400 Subject: Re: [NLM] fcntl(F_SETLKW) yields -ENOLCK when grace period expires. From: Trond Myklebust To: Frank van Maarseveen Cc: "J. Bruce Fields" , Linux NFS mailing list Date: Thu, 04 Aug 2011 14:17:35 -0400 In-Reply-To: <20110804172710.GB18087@janus> References: <20110804103018.GA11727@janus> <20110804163452.GE12445@fieldses.org> <20110804164313.GA17572@janus> <20110804164913.GG12445@fieldses.org> <1312477820.8919.5.camel@lade.trondhjem.org> <20110804172710.GB18087@janus> Content-Type: text/plain; charset="UTF-8" Message-ID: <1312481855.8919.20.camel@lade.trondhjem.org> Sender: linux-nfs-owner@vger.kernel.org List-ID: MIME-Version: 1.0 On Thu, 2011-08-04 at 19:27 +0200, Frank van Maarseveen wrote: > On Thu, Aug 04, 2011 at 01:10:20PM -0400, Trond Myklebust wrote: > > On Thu, 2011-08-04 at 12:49 -0400, J. Bruce Fields wrote: > > > On Thu, Aug 04, 2011 at 06:43:13PM +0200, Frank van Maarseveen wrote: > > > > On Thu, Aug 04, 2011 at 12:34:52PM -0400, J. Bruce Fields wrote: > > > > > On Thu, Aug 04, 2011 at 12:30:19PM +0200, Frank van Maarseveen wrote: > > > > > > Both client- and server run 2.6.39.3, NFSv3 over UDP (without the > > > > > > relock_filesystem patch proposed earlier). > > > > > > > > > > > > A second client has an exclusive lock on a file on the server. The > > > > > > client under test calls fcntl(F_SETLKW) to wait for the same exclusive > > > > > > lock. Wireshark sees NLM V4 LOCK calls resulting in NLM_BLOCKED. > > > > > > > > > > > > Next the server is rebooted. The second client recovers the lock > > > > > > correctly. The client under test now receives NLM_DENIED_GRACE_PERIOD for > > > > > > every NLM V4 LOCK request resulting from the waiting fcntl(F_SETLKW). When > > > > > > this changes to NLM_BLOCKED after grace period expiration the fcntl > > > > > > returns -ENOLCK ("No locks available.") instead of continuing to wait. > > > > > > > > > > So that sounds like a client bug, and correct behavior from the server > > > > > (assuming the second client was still holding the lock throughout). > > > > > > > > yes. > > > > Is the client actually asking for a blocking lock after the grace period > > expires? > > yes, according to my interpretation of that of wireshark, see reply to Bruce. > OK... Does the following patch help? Cheers Trond --- diff --git a/fs/lockd/clntproc.c b/fs/lockd/clntproc.c index 8392cb8..40c0d88 100644 --- a/fs/lockd/clntproc.c +++ b/fs/lockd/clntproc.c @@ -270,6 +270,9 @@ nlmclnt_call(struct rpc_cred *cred, struct nlm_rqst *req, u32 proc) return -ENOLCK; msg.rpc_proc = &clnt->cl_procinfo[proc]; + /* Reset the reply status */ + if (argp->block) + resp->status = nlm_lck_blocked; /* Perform the RPC call. If an error occurs, try again */ if ((status = rpc_call_sync(clnt, &msg, 0)) < 0) { dprintk("lockd: rpc_call returned error %d\n", -status); -- Trond Myklebust Linux NFS client maintainer NetApp Trond.Myklebust@netapp.com www.netapp.com