On Wed, Nov 17, 2004 at 07:07:16AM -0800, Greg Earle wrote:
> I tried my first-ever NFS mount, mounting a directory from my
> Ultra 60 running Solaris 9 onto my SPARCserver 20 running NetBSD 1.6.2.
> 
> It mounted OK, but accesses to the mount point hang:
> 
> isolar# mount
> /dev/sd2a on / type ffs (local)
> /dev/sd2d on /var type ffs (local)
> /dev/sd2g on /usr type ffs (local)
> /dev/sd2f on /home type ffs (local)
> /dev/cd0a on /cdrom type cd9660 (read-only, local)
> mfs:129 on /tmp type mfs (synchronous, local)
> procfs on /proc type procfs (read-only, local)
> solaris9box:/export/home/earle/Maildir/.SPAM/cur on /mnt type nfs 
> (read-only)
> 
> [7:00] isolar:~ % /bin/ls /mnt
> [... hangs ...]
> 
> Even more worrisome, I can't unmount it:
> 
> isolar# umount /mnt
> umount: /mnt: Permission denied
> isolar# umount -f /mnt
> umount: /mnt: Permission denied
> isolar#
> 
> The mounted directory is only readable by me on the other end:
> 
> isolar# ls -l / | grep mnt
> drwx------   2 earle  10      293376 Nov 17 06:43 mnt
> 
> But still, I should be able to "ls" it, and certainly no matter
> what, "root" should be able to unmount it.  I have to reboot to
> clear the mount.
> 
> WTF?

AFICT it nfs request stalled by any reason (network failure, NIC driver error, etc)
then you won't be able to unmount and probably everything else will stall too.
I'd start collecting tcpdump.

	Andrey