Can't remove lv with dmsetup - "Device or resource busy"
 

I am trying to remove a volume group on a single drive that contains a single logical volume. This is on openfiler which I believe is CentOS based.

dmsetup info vg2-backup shows an open count of 1.

Try running dmsetup remove vg2-backup but it fails because it says device or resource busy.

How do I find the process that is tying this up so I can kill it and remove the lv and then volume group?

Figured it out on my own but wanted to share the solution for anyone that happens across this with the same problem.

Ran cat /proc/mounts and saw /dev/vg2/backup was mounted. Did umount /dev/vg2/backup and then ran dmsetup info vg2-backup. Open count was now 0 and I was able to successfully run dmsetup remove command. Followed that up with lvremove and vgremove.