Recovering from "uncleanly unmounted" loop devices

Hi, I had mounted ccd1 and cd2.iso files onto cd1dir and cd2dir directories manually, using -o loop option. While doing 'umount' I did not give the -d option. (I did this twice!) How can I clean them up and reclaim thedev-loop* devices?

myhostdev % foreach i ( 0 1 6 7 ) ioctl: LOOPCLRFD: Device or resource busy ioctl: LOOPCLRFD: Device or resource busy ioctl: LOOPCLRFD: Device or resource busy ioctl: LOOPCLRFD: Device or resource busy myhost ~ % ps -ef grep loop root 16340 1 0 Jul19 ? 00:00:03 loop0 root 16342 1 0 Jul19 ? 00:00:03 loop1 root 3606 1 0 12:13 ? 00:00:00 loop6 root 3608 1 0 12:13 ? 00:00:00 loop7 naren 9375 4082 0 13:58 pts-7 00:00:00 grep loop myhost ~ % foreach i (0 1 6 7)dev-loop0: 0010:116752640 (cd1.iso) offset 0, no encryptiondev-loop1: 0010:116752641 (cd2.iso) offset 0, no encryptiondev-loop6: 0010:116752640 (cd1.iso) offset 0, no encryptiondev-loop7: 0010:116752641 (cd2.iso) offset 0, no encryption myhost ~ % mount grep cd1 myhost ~ % mount grep cd2 myhost ~ % cd dir myhost ~-dir % sudo umount -f -d cd1dir umount2: Invalid argument umount: cd1dir: not mounted myhost ~-dir % sudo umount -f -d cd2dir umount2: Invalid argument umount: cd2dir: not mounted myhost ~-dir % sudo kill -9 16340 16342 3606 3608 # does not work!!! myhost ~-dir % ps -ef grep loop root 16340 1 0 Jul19 ? 00:00:03 loop0 root 16342 1 0 Jul19 ? 00:00:03 loop1 root 3606 1 0 12:13 ? 00:00:00 loop6 root 3608 1 0 12:13 ? 00:00:00 loop7 naren 9405 4082 0 14:00 pts-7 00:00:00 grep loop