Return-Path: linux-nfs-owner@vger.kernel.org Received: from mail-lpp01m010-f46.google.com ([209.85.215.46]:63333 "EHLO mail-lpp01m010-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754216Ab2CHV1j (ORCPT ); Thu, 8 Mar 2012 16:27:39 -0500 MIME-Version: 1.0 In-Reply-To: <1331239814.11759.1.camel@lade.trondhjem.org> References: <87k42yjb0c.fsf@tucsk.pomaz.szeredi.hu> <1331160049-3842-1-git-send-email-Trond.Myklebust@netapp.com> <1331160049-3842-2-git-send-email-Trond.Myklebust@netapp.com> <1331160049-3842-3-git-send-email-Trond.Myklebust@netapp.com> <1331230525.2472.39.camel@lade.trondhjem.org> <20120308204205.GB9273@fieldses.org> <1331239814.11759.1.camel@lade.trondhjem.org> Date: Thu, 8 Mar 2012 16:27:37 -0500 Message-ID: Subject: Re: [PATCH 2/2] NFSv4: Return the delegation if the server returns NFS4ERR_OPENMODE From: Olga Kornievskaia To: "Myklebust, Trond" Cc: "J. Bruce Fields" , Miklos Szeredi , "linux-nfs@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" , "linux-kernel@vger.kernel.org" Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-nfs-owner@vger.kernel.org List-ID: On Thu, Mar 8, 2012 at 3:50 PM, Myklebust, Trond wrote: > On Thu, 2012-03-08 at 15:42 -0500, J. Bruce Fields wrote: >> On Thu, Mar 08, 2012 at 03:23:34PM -0500, Olga Kornievskaia wrote: >> > On Thu, Mar 8, 2012 at 1:15 PM, Myklebust, Trond >> > wrote: >> > > On Thu, 2012-03-08 at 12:52 -0500, Olga Kornievskaia wrote: >> > >> wouldn't it be better for you to proactively return a read delegation >> > >> then unnecessarily erroring? >> > > >> > > If nobody else holds a delegation, then the NFS client is actually >> > > allowed to keep its read delegation while writing to the file. It does >> > > admittedly need to request an OPEN stateid for write in that case... >> > > (See section 10.4 of RFC3530bis draft 16) >> > >> > If we both agree that there has to be a request for an open stateid for >> > a write, then instead of returning the read delegation if the client receives >> > err_openmode (when it send the request with read delegation stateid >> > as you said per 3560bis), can't the client resend the setattr with the open >> > stateid? The ordering of the stateid usage is a "should" and not a "must". >> > >> > In rfc5661, it really doesn't make sense to ever send a setattr with >> > a read delegation stateid. According to 9.1.2, the server "MUST" return >> > err_open_mode" error in that case. >> > >> > I gather you are in this case dealing with 4.0 delegations. But I wonder >> > if you'll do something else for 4.1 delegation then? >> >> 3530bis has the same language ("...must verify that the access mode >> allows writing and return an NFS4ERR_OPENMODE error if it does not"). > > OK, so we shouldn't send the delegation stateid either for v4 or v4.1. > However should we pre-emptively return the delegation? I've been > assuming not. It would be nice not to pre-emptively return delegations but for that we need server implementors to get on board with the idea.