Problem in a nutshell: [root@redhat-11 cthon04]# mount -t nfs -o vers=3 redhat-2:/server /mnt/cthon/ [root@redhat-11 cthon04]# umount -v /mnt/cthon umount.nfs: Server failed to unmount '172.16.16.2:/server' redhat-2:/server umounted ...but... [root@redhat-11 cthon04]# mount -t nfs redhat-2:/server /mnt/cthon/ [root@redhat-11 cthon04]# umount -v /mnt/cthon umount.nfs: trying 172.16.16.2 prog 100005 vers 3 prot UDP port 797 redhat-2:/server umounted ...so we get an error message when unmounting if the mount was done with vers= option set. If it's not set, then we don't get an error.
This bug appears to have been reported against 'rawhide' during the Fedora 11 development cycle. Changing version to '11'. More information and reason for this action is here: http://fedoraproject.org/wiki/BugZappers/HouseKeeping
This has been fixed in nfs-utils-1.2.0-3