Return-Path: Received: from fieldses.org ([173.255.197.46]:52222 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932086AbcGBA6W (ORCPT ); Fri, 1 Jul 2016 20:58:22 -0400 Date: Fri, 1 Jul 2016 20:58:20 -0400 From: Bruce Fields To: Marc Eshel Cc: linux-nfs@vger.kernel.org, Tomer Perry Subject: Re: grace period Message-ID: <20160702005820.GA27063@fieldses.org> References: <1465939516-44769-1-git-send-email-trond.myklebust@primarydata.com> <20160701160857.GB20327@fieldses.org> <20160701200742.GA24269@fieldses.org> <20160701210151.GE24269@fieldses.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: Sender: linux-nfs-owner@vger.kernel.org List-ID: On Fri, Jul 01, 2016 at 03:42:43PM -0700, Marc Eshel wrote: > Yes, the locks are requested from another node, what fs are you using, I > don't think it should make any difference, but I can try it with the same > fs. > Make sure you are using v3, it does work for v4. I tested v3 on upstream.--b. > Marc. > > > > From: Bruce Fields > To: Marc Eshel/Almaden/IBM@IBMUS > Cc: linux-nfs@vger.kernel.org, Tomer Perry > Date: 07/01/2016 02:01 PM > Subject: Re: grace period > > > > On Fri, Jul 01, 2016 at 01:46:42PM -0700, Marc Eshel wrote: > > This is my v3 test that show the lock still there after echo 0 > > > /proc/fs/nfsd/threads > > > > [root@sonascl21 ~]# cat /etc/redhat-release > > Red Hat Enterprise Linux Server release 7.2 (Maipo) > > > > [root@sonascl21 ~]# uname -a > > Linux sonascl21.sonasad.almaden.ibm.com 3.10.0-327.el7.x86_64 #1 SMP Thu > > > Oct 29 17:29:29 EDT 2015 x86_64 x86_64 x86_64 GNU/Linux > > > > [root@sonascl21 ~]# cat /proc/locks | grep 999 > > 3: POSIX ADVISORY WRITE 2349 00:2a:489486 0 999 > > > > [root@sonascl21 ~]# echo 0 > /proc/fs/nfsd/threads > > [root@sonascl21 ~]# cat /proc/fs/nfsd/threads > > 0 > > > > [root@sonascl21 ~]# cat /proc/locks | grep 999 > > 3: POSIX ADVISORY WRITE 2349 00:2a:489486 0 999 > > Huh, that's not what I see. Are you positive that's the lock on the > backend filesystem and not the client-side lock (in case you're doing a > loopback mount?) > > --b. > > > > > > > > > > > From: Bruce Fields > > To: Marc Eshel/Almaden/IBM@IBMUS > > Cc: linux-nfs@vger.kernel.org > > Date: 07/01/2016 01:07 PM > > Subject: Re: grace period > > > > > > > > On Fri, Jul 01, 2016 at 10:31:55AM -0700, Marc Eshel wrote: > > > It used to be that sending KILL signal to lockd would free locks and > > start > > > Grace period, and when setting nfsd threads to zero, > nfsd_last_thread() > > > calls nfsd_shutdown that called lockd_down that I believe was causing > > both > > > freeing of locks and starting grace period or maybe it was setting it > > back > > > to a value > 0 that started the grace period. > > > > OK, apologies, I didn't know (or forgot) that. > > > > > Any way starting with the kernels that are in RHEL7.1 and up echo 0 > > > > /proc/fs/nfsd/threads doesn't do it anymore, I assume going to common > > > grace period for NLM and NFSv4 changed things. > > > The question is how to do IP fail-over, so when a node fails and the > IP > > is > > > moving to another node, we need to go into grace period on all the > nodes > > > > > in the cluster so the locks of the failed node are not given to anyone > > > > other than the client that is reclaiming his locks. Restarting NFS > > server > > > is to distractive. > > > > What's the difference? Just that clients don't have to reestablish tcp > > connections? > > > > --b. > > > > > For NFSv3 KILL signal to lockd still works but for > > > NFSv4 have no way to do it for v4. > > > Marc. > > > > > > > > > > > > From: Bruce Fields > > > To: Marc Eshel/Almaden/IBM@IBMUS > > > Cc: linux-nfs@vger.kernel.org > > > Date: 07/01/2016 09:09 AM > > > Subject: Re: grace period > > > > > > > > > > > > On Thu, Jun 30, 2016 at 02:46:19PM -0700, Marc Eshel wrote: > > > > I see that setting the number of nfsd threads to 0 (echo 0 > > > > > /proc/fs/nfsd/threads) is not releasing the locks and putting the > > server > > > > > > > in grace mode. > > > > > > Writing 0 to /proc/fs/nfsd/threads shuts down knfsd. So it should > > > certainly drop locks. If that's not happening, there's a bug, but > we'd > > > need to know more details (version numbers, etc.) to help. > > > > > > That alone has never been enough to start a grace period--you'd have > to > > > start knfsd again to do that. > > > > > > > What is the best way to go into grace period, in new version of the > > > > kernel, without restarting the nfs server? > > > > > > Restarting the nfs server is the only way. That's true on older > kernels > > > true, as far as I know. (OK, you can apparently make lockd do > something > > > like this with a signal, I don't know if that's used much, and I doubt > > > it works outside an NFSv3-only environment.) > > > > > > So if you want locks dropped and a new grace period, then you should > run > > > "systemctl restart nfs-server", or your distro's equivalent. > > > > > > But you're probably doing something more complicated than that. I'm > not > > > sure I understand the question.... > > > > > > --b. > > > > > > > > > > > > > > > > > > > > > > > >