You can use the lsblk command. If the disk is already unlocked, it will display two lines: the device and the mapped device, where the mapped device should be of type crypt. # lsblk -l -n /dev/sdaX sdaX 253:11 0 2G 0 part sdaX_crypt (dm-6) 253:11 0 2G 0 crypt If the disk is not yet unlocked, it will only show the device. # lsblk -l -n /dev/sdaX sdaX 253:11 0 2G 0 part

Yes, this happens when luks encrypted device was not cleanly deactivated with cryptsetup close. You can try to remove the mapping using dmsetup remove /dev/mapper/luks-... if you want to avoid rebooting.