dmsetup remove <device name>
on the LV device?
#dmsetup remove /dev/vgTEST/lvTEST
dm_task_set_name: Device /dev/vgTEST/lvTEST not found
Command failed
on the mpath device?
# dmsetup remove /dev/mpath/mpath1
device-mapper: remove ioctl failed: Device or resource busy
Command failed