I see that LVM1 (/dev/mapper/lvm1--vg-lvm1--lv) fails to umount during the shutdown, when I cannot run one of the many options to find out which process or user is holding up the mountpoint.
It also seems that there is no log kept which I could look into.
How do I log or at least display which process is locking the disk during a shutdown?
PS: Ubuntu 18.04.1