vkernel stuck in umtxsl state when booting from a NFS root mount

[Rumko]

Matthew Dillon wrote:

> 
> :When booting a vkernel with '-n 1' I'm not sure when was the last time that
> :it got stuck, while booting with '-n 2' fails in most if not all cases.
> 
>     Ok, all the NFS issues with vkernels should now be fixed.  There were
>     several problems but the ones causing the permanent stalls were
> 
>     (1) NFS was running the kernel out of mbufs, and
> 
>     (2) The NFS root mount was NFSv2 instead of NFSv3, and there appears
> to be bugs with large write()s on NFSv2 mounts.
> 
>     I also changed the default mount type from UDP to TCP which will improve
>     performance.
> 
>     I have not figured out what the problem with NFSv2 write()'s is yet.
>     I'm still working on that one.  But the vkernel should now mount w/
>     NFSv3 and thus work around that issue.
> 
> -Matt

Can't seem to be able to reproduce any more hangs.

Thank you
-- 
Regards,
Rumko