echo 0 > /proc/fs/nfsd/threads does delete the locks for v4 but not for v3 Marc. From: Marc Eshel/Almaden/IBM To: Bruce Fields <bfields@xxxxxxxxxxxx> Cc: linux-nfs@xxxxxxxxxxxxxxx, Tomer Perry/Israel/IBM@IBMIL Date: 07/01/2016 01:46 PM Subject: Re: grace period 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 From: Bruce Fields <bfields@xxxxxxxxxxxx> To: Marc Eshel/Almaden/IBM@IBMUS Cc: linux-nfs@xxxxxxxxxxxxxxx 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 <bfields@xxxxxxxxxxxx> > To: Marc Eshel/Almaden/IBM@IBMUS > Cc: linux-nfs@xxxxxxxxxxxxxxx > 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. > > > > -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
