nfsv4 FreeBSD server vs. Linux client I/O error

[Rick Macklem]

On Thu, 12 Nov 2009, Gerrit Kühn wrote:

> Hi all,
>
> ist this the right place to talk about nfsv4 issues, or does this better
> go to -net (or even somewhere else)?
>
> Anyways, I'll start here and now:
> I have a FreeBSD8-RC2 server which I set up for nfsv4 serving according
> to nfsv4(4). I have a Linux client (Kernel 2.6.25) trying to do
> "mount.nfs4 / /mnt -v". This takes *exactly* 30s. (looks like running into
> some kind of timeout). After that, the mount is there. It is displayed by
> "mount" and gives the right sizes with "du -h".
> However, as soon as I try to access /mnt with "cd /mnt" or "ls /mnt" I get
> an Input/Output Error on the client side.
>
One more thing that came to mind. If your root fs in NFS mounted, it can't
be exported, so you have to use the version (assuming /exports is a local
on-disk file system that is exported):
V4: /export
and not
V4: /

and then the mount needs to look like:
 	mount -t nfs4 <server>:/export /mnt

I tried a relatively recent Ubuntu client here and it seemed to mount ok.
(There are many variants of the mount utilities and patch versions of the
nfs4 client for Linux, so your mileage definitely may vary.)

I'll be happy to look at a tcpdump capture, if you get one, rick