Comment 26 for bug 533493

I'm experiencing the same problem, looping the lvremove statement doesn't succeed, the snapshot can only be removed after a reboot. I notice also a similar problem with fsck on logical volumes - once the volume has been mounted once, and unmounted, it cannot be checked with fsck (e2fsck).

# fsck /dev/mapper/Backup-Home--backup
fsck from util-linux 2.20.1
e2fsck 1.41.14 (22-Dec-2010)
fsck.ext4: Device or resource busy while trying to open /dev/mapper/Backup-Home--backup
Filesystem mounted or opened exclusively by another program?

# mount | grep Backup | wc -l
0

Could this be a clue?