On Mon, Apr 04, 2005 at 02:35:46PM -0400, Christos Zoulas scribed:
> On Apr 4,  6:29pm, dlagno@rambler.ru (Denis Lagno) wrote:
> -- Subject: kern/29881: umount stale NFS volume blocks deadly
> 
> | # umount -fv /flam/stuffy
> | /stuffy: unmount from /flam/stuffy
> | umount: /flam/stuffy: Invalid argument
> 
> does adding -R help?

no, it does not work.  At least it was so in the middle of February:

# mount | grep stuffy
flam:/stuffy on /flam/stuffy type nfs (read-only, nosuid, nodev)
# umount -R flam:/stuffy
umount: flam:/stuffy: No such file or directory
# umount -fRv flam:/stuffy
flam:/stuffy: unmount from flam:/stuffy
umount: flam:/stuffy: No such file or directory
# umount -fRv /flam/stuffy
/flam/stuffy: unmount from /flam/stuffy
umount: /flam/stuffy: Invalid argument

I asked about this second problem on current-users, there are some details:
http://mail-index.NetBSD.org/current-users/2005/02/13/0000.html
http://mail-index.NetBSD.org/current-users/2005/02/13/0013.html