I've mounted a block device (internal hard disk) to say
~/HD, and I'm trying,
~# umount ~/HD
umount: device is busy.
Now I kill all processes manually by examining
~# fuser -m ~/HD
I also make sure that really no process is accessing the
~# lsof | grep HD
umount ~/HD says
device is busy even with
PS: I don't want to use the
-l option of
umount, since the mounted device is actually an encrypted mapper device, which in turn won't get unmounted unless mapper device is clearly unmounted.
So basically my question is how to really force
umount to unmount a device OR How can a device still be marked as busy while no processes are accessing it (or at least
lsof don't report it) and what can I do about it?
I'm on Ubuntu 9.10 x64.