Tue, 2016-11-01
umount: /mnt/tmp: device is busy permalink
If you are trying to unmount a device, you get the error "device is busy", but lsof/fuser don't show any process holding the device open, it could be that a file on the device is associated with a loop device.
try
# losetup -a /dev/loop/0: [0821]:25280514 (image) offset=55273881600 # losetup -d /dev/loop0 # umount /mnt/tmp(updated, 2016-11-01)
dmsetup info | grep loop dmsetup remove loop0p2 dmsetup remove loop0p3may help too