LVM snapshot fails to be removed for some unknown reason.

Issue

• LVM snapshot fails to be removed for some uknown reason.

• I am running the follwing bash script to remove the lvm snapshot volume on a daily basis:

[..]
 /bin/umount -l /data_snap
 /sbin/lvremove -f /dev/Volume00/snap
[..]

• To find the cause of the issue I added some option strings to get more verbose logging in removing the snapshot:

[..]
 /bin/umount -l /data_snap
/sbin/lvremove -fvvv /dev/Volume00/snap > lvremove.out 2>&1
[..]

• Looking at lvremove.out I found lvremove -fvvv showed the snapshot volume was in use:

[..]
        Getting device info for Volume00-snap [LVM-MTOzwX254vVyUNyoxDBoBdVo7Dv9bBqUhNKPINp1kSUgOHM2BduKWpad2nXzKSIB]
        dm info  LVM-MTOzwX254vVyUNyoxDBoBdVo7Dv9bBqUhNKPINp1kSUgOHM2BduKWpad2nXzKSIB OF   [16384] (*1)
  Logical volume Volume00/snap contains a filesystem in use.
        Unlock: Memlock counters: locked:0 critical:0 daemon:0 suspended:0
        Syncing device names
      Unlocking /var/lock/lvm/V_Volume00
        _undo_flock /var/lock/lvm/V_Volume00
        Closed /dev/mapper/mpathbp1
        Freeing VG Volume00 at 0x1aed1a0.