NFS locking question

Rong-en Fan grafan at gmail.com
Tue Aug 15 11:49:12 UTC 2006


On 8/15/06, Kris Kennaway <kris at obsecurity.org> wrote:
> On Tue, Aug 15, 2006 at 11:59:50AM +0200, Morten A. Middelthon wrote:
> > On Tue, Feb 28, 2006 at 05:21:50AM -0500, Kris Kennaway wrote:
> > > On Tue, Feb 28, 2006 at 11:14:53AM +0100, Patrick M. Hausen wrote:
> > > > Hi, all!
> > > >
> > > > In our local office network we have a rather old FreeBSD 5.2.1
> > > > server acting as an NFS server for several other systems, mostly
> > > > running 6.0.
> > > >
> > > > >From time to time we experience processes on the NFS clients
> > > > hanging in statd "D" with wchan "lockd" when accessing files
> > > > over NFS.
> > >
> > > Try the attached patch on the 6.0 machines:
> > >
> > > Index: usr.sbin/rpc.lockd/lock_proc.c
> > <snip>
> >
> > Hi,
> >
> > I have been plagued with this NFS lockd issue for quite some time now. It has
> > kept me from installing FreeBSD 6.x on our workstations at work. I just tried
> > applying your patch to my own 6.1-RELEASE-p3 workstation, and so far it has
> > been working nicely. Has anyone else had the same experience? If so, maybe it
> > should go into production?
>
> I was unable to obtain confirmation from anyone else (including the
> submitter who previously claimed it was necessary, and my own testing)
> that the patch actually solved a problem.  Since it involves reverting
> useful functionality, someone would need to obtain further debugging
> from your system (tcpdump traces before/after, etc) to determine what
> it's actually solving.
>
> Kris

In my experiences, rpc.lockd dies automatically on both server and
client. If this happens, then all processes that want to lock a file, they
will be stuck in lockd (top will tell). In my case, rpc.lockd dies because
write failed, and then a SIGPIPE generated. Two months ago, bin/97768
is sent and rodrigc@ committed (also MFC'ed in RELENG_6). That PR
ignores SIGPIPE (since the code in server/client already takes care of
write failed case). After I applied this PR, I'm quite happy with nfs locking.

Regards,
Rong-En Fan


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