From: Wendy Cheng Subject: Re: [NFS] [RFC] NLM lock failover admin interface Date: Tue, 13 Jun 2006 03:00:11 -0400 Message-ID: <1150182012.27203.42.camel@localhost.localdomain> References: <1150089943.26019.18.camel@localhost.localdomain> <17550.11870.186706.36949@cse.unsw.edu.au> Reply-To: linux clustering Mime-Version: 1.0 Content-Type: text/plain Cc: linux-cluster@redhat.com, nfs@lists.sourceforge.net Return-path: To: Neil Brown In-Reply-To: <17550.11870.186706.36949@cse.unsw.edu.au> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-cluster-bounces@redhat.com Errors-To: linux-cluster-bounces@redhat.com List-ID: On Tue, 2006-06-13 at 13:17 +1000, Neil Brown wrote: > So: > I think if we really want to "remove all NFS locks on a filesystem", > we could probably tie it into umount - maybe have lockd register some > callback which gets called just before s_op->umount_begin. The "umount_begin" idea was one time on my list but got discarded. The thought was that nfsd was not a filesystem, neither was lockd. How to register something with VFS umount for non-filesystem kernel modules ? Invent another autofs-like pseudo filesystem ? Mostly, not every filesystem would like to get un-mounted upon failover (GFS, for example, does not get un-mounted by our cluster suite upon failover). > If we want to remove all locks that arrived on a particular > interface, then we should arrange to do exactly that. There are a > number of different options here. > One is the multiple-lockd-threads idea. Certainly a good option. To make it happen, we still need admin interface. How to pass IP address from user mode into kernel - care to give this some suggestions if you have them handy ? Should socket ports get dynamics assigned ? Will we have scalibility issues ? > One is to register a callback when an interface is shut down. > Another (possibly the best) is to arrange a new signal for lockd > which say "Drop any locks which were sent to IP addresses that are > no longer valid local addresses". These, again, give individual filesystem no freedom to adjust what they need upon failover. But I'll check them out this week - maybe there are good socket layer hooks that I overlook. > > So those are my thoughts. Do any of them seem reasonable to you? > The comments are greatly appreciated. And hopefully we can reach agreement soon. -- Wendy