NFS deadlock (unkillable nfsd and no mounts work)

[Josh Carroll]

>> I'm having a problem with nfsd hanging and not serving mount points,
>> during which time it can not not be killed. This problem started
>> happening sometime after November 2nd, since kernel from 11/2 sources
>> does not exhibit this problem.
>
> Please try the attached patch, rick

Thanks! I had to manually patch for some reason, but I can confirmed
that nfsd is now well-behaved with your patch applied. I tested a
couple of different mounts and played two separate files on the
Popcorn Hour (one lower bitrate, the other higher bitrate) and both
played without a hiccup. While those were playing I also was able to
automount my home directory on the macbook and move around my home
directory.

So it looks like this patch did the trick. Thanks Rick, really
appreciate the fast response. Is there a reason why this doesn't seem
to be getting reported a lot? What is particular in my setup that
broke it?

> ps: Starting about Monday I won't be able to do commits for about 3 weeks
>    so, if this patch works, could someone else please commit it, thanks,
>    rick
>

If someone can commit this, I'd really appreciate it. I will report
back if I notice any problems, but I imagine this would probably get
fixed in HEAD first, then MFC'd anyway, right? Unless this is already
fixed in HEAD.

Anyway, thanks again Rick! I appreciate it.

Regards,
Josh
As far as I can tell, there have been no adverse effects or
regressions with the kernel built with this patch (I had t