From mboxrd@z Thu Jan 1 00:00:00 1970 From: Neil Brown Date: Sat, 28 Apr 2007 08:22:55 +1000 Subject: [NFS] [Cluster-devel] [PATCH 0/4 Revised] NLM - lock failover In-Reply-To: References: <46302C01.2060500@redhat.com> <17968.15370.88587.653447@notabene.brown> <46315EED.9020103@redhat.com> <17969.37229.250000.895316@notabene.brown> <20070427111513.GA25126@salusa.poochiereds.net> <17969.61232.323762.29003@notabene.brown> <20070427134248.GB25126@salusa.poochiereds.net> <20070427141710.GA11484@infradead.org> <20070427154259.GF32278@fieldses.org> <46321870.7000607@redhat.com> <20070427163129.GI32278@fieldses.org> Message-ID: <17970.30655.854497.849900@notabene.brown> List-Id: To: cluster-devel.redhat.com MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit On Friday April 27, bfields at fieldses.org wrote: > On Fri, Apr 27, 2007 at 11:36:16AM -0400, Wendy Cheng wrote: > > J. Bruce Fields wrote: > > >On Fri, Apr 27, 2007 at 03:17:10PM +0100, Christoph Hellwig wrote: > > > > > >>In fact couldn't this be treated as a reexport with a NFSEXP_ flag > > >>meaning drop all locks to avoid creating new interfaces? > > >> > > > > > >Off hand, I can't see any reason why that wouldn't work. The code to > > >handle it would probably go in fs/nfsd/export.c:svc_export_parse(). > > > > > > > > Sign :( ... folks, we go back to the loop again. That *was* my first > > proposal ... Yes, I grinned when I saw it too. Your first proposal was actually a flag to "unexport", where as Christoph seems to be a flag to "export". So there is at least a subtle difference. A flag to unexport cannot work because we don't call unexport - we just flush a kernel cache. A flag to export is just .... weird. All the other export flags are state flags. This would be an action flag. They are quite different things. Setting a state flag again is a no-op. Setting an action flag again has a very real effect. Also, each filesystem is potentially exported multiple times for different sets of clients. If such a flag (whether on 'export' or 'unexport') just said "remove locks from this set of clients" it wouldn't meet the needs, and if it said "remove all locks" it would be a very irregular interface. > > So you're talking about this and followups?: > > http://marc.info/?l=linux-nfs&m=115009204513790&w=2 > > I just took a look and couldn't find any complaints about that > approach. Were they elsewhere? https://www.redhat.com/archives/linux-cluster/2006-June/msg00101.html Is where I said that I don't like the unexport flag. NeilBrown