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.
>
A few things to check on the server:
- Did you add a "V4:" line to your /etc/exports and what did you set as
   the root path in it? If you used "V4: /" then the root file system
   would need to be exported by another line in /etc/exports for it to
   work.

- If you are only exporting another filesystem, lets say "/exports",
   then your mount command would have to look like:
 	mount -t nfs4 <server>/exports /mnt
   (assuming "V4: /" was used)

- If you used "V4: /exports", then "mount -t nfs4 <server>:/ /mnt"
   would work and you would see /exports at /mnt.

Beyond something like the above, if you capture packets using
"tcpdump -s 0 -w <file> host <server>" on the server and then
email me "<file>", I can take a look at it. (tcpdump doesn't know
diddly about NFSv4, but wireshark does and can handle tcpdump captures.)

> Googleing around I found only very few information about nfsv4 and FreeBSD
> (ok, it's a new feature after all :-). Does anyone here already have some
> experiences to share? Anyone already using FreeBSD servers against Linux
> clients? Any suggestions how to debug and solve the problem above?
>
I don't usually test against Linux, but I'll try a quick mount here,
in case something is obviously broken.

rick