root@override:~# cat /etc/fstab|grep backup
UUID=5f6f1a3f-8d3b-491a-82e3-56a08292753a /backup ext3 defaults 0 2
root@override:~# mount /backup/
mount: /dev/sdb1 already mounted or /backup busy
root@override:~# fuser /backup/
root@override:~# fuser /dev/sdb1
root@override:~# umount /dev/sdb1
umount: /dev/sdb1: not mounted
root@override:~# rmdir /backup/
root@override:~# mkdir /backup
root@override:~# mount /dev/sdb1
mount: /dev/sdb1 already mounted or /backup busy