Hi Chuck,
Chuck Lever 写道:
> On 01/13/2010 07:51 AM, Jeff Layton wrote:
>> On Wed, 13 Jan 2010 17:51:25 +0800
>> Mi Jinlong<mijinlong@xxxxxxxxxxxxxx> wrote:
>>
>> Assuming you're using a RH-derived distro like Fedora or RHEL, then no.
>> statd is controlled by a separate init script (nfslock) and when you
>> run "service nfs restart" you're not restarting it. NSM notifications
>> are not sent and clients generally won't reclaim their locks.
>>
>> IOW, "you're doing it wrong". If you want locks to be reclaimed then
>> you probably need to restart the nfslock service too.
>
> Mi Jinlong is exercising another case we know doesn't work right, but we
> don't expect admins will ever perform this kind of "down-up" on a normal
> production server. In other words, we expect it to work this way, and
> it's been good enough, so far.
>
> As Jeff points out, the "nfs" and the "nfslock" services are separate.
> This is because "nfslock" is required for both client and server side
> NFS, but "nfs" is required only on the server. This split also dictates
> the way sm-notify works, since it has to behave differently on NFS
> clients and servers.
>
> Two other points:
>
> + lockd would not restart itself in this case if there happened to be
> NFS mounts on that system
When testing, i find nfs restart will cause lockd restart.
I find some codes which cause the lock stop when nfs stop.
At kernel 2.6.18, fs/lockd/svc.c
...
354 if (nlmsvc_users) {
355 if (--nlmsvc_users)
356 goto out;
357 } else
358 printk(KERN_WARNING "lockd_down: no users! pid=%d\n", nlmsvc_pid);
...
366
367 kill_proc(nlmsvc_pid, SIGKILL, 1);
...
At kernel 2.6.18, fs/lockd/svc.c
...
344 if (nlmsvc_users) {
345 if (--nlmsvc_users)
346 goto out;
347 } else {
348 printk(KERN_ERR "lockd_down: no users! task=%p\n",
349 nlmsvc_task);
350 BUG();
351 }
....
357 kthread_stop(nlmsvc_task);
358 svc_exit_thread(nlmsvc_rqst);
...
As above, when nlmsvc_users <= 1, the lockd will be killed.
>
> + lockd doesn't currently poke statd when it restarts to tell it to
> send reboot notifications, but it probably should
Yes, I agree with you. But now, when some reason cause lockd restart but
statd not restart, locks which hold before will lost.
Maybe, the kernel should fix this.
>
> We know that lockd will start up when someone mounts the first NFS
> share, or when the NFS server is started. If lockd sent statd an
> SM_SIMU_CRASH (or something like it) every time it cold started, statd
> could send reboot notifications at the right time on both servers and
> clients without extra logic in the init scripts, and we wouldn't need
> that kludge in sm-notify to know when a machine has rebooted.
What's the meaning of cold start?? System reboot? Or statd reboot?
I want to know when using cammond "service nfslock restart" restart the
nfslock service(means restart statd and lockd), will the statd call sm-notify
to notify other client? Or don't?
At RHEL5 and Fedora, the sm-notify will be call and send SM-NOTIFY every time
when nfslock restart.
thanks,
Mi Jinlong
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