tree 43d68c6d3174e1ae8a778acd834665c122f8b2a4
parent c2ade42dd35466d90aa6fc7cc717f396e165492f
author Alasdair G Kergon <agk@redhat.com> 1151306854 -0700
committer Linus Torvalds <torvalds@g5.osdl.org> 1151341116 -0700

[PATCH] dm: prevent removal if open

If you misuse the device-mapper interface (or there's a bug in your userspace
tools) it's possible to end up with 'unlinked' mapped devices that cannot be
removed until you reboot (along with uninterruptible processes).

This patch prevents you from removing a device that is still open.

It introduces dm_lock_for_deletion() which is called when a device is about to
be removed to ensure that nothing has it open and nothing further can open it.
 It uses a private open_count for this which also lets us remove one of the
problematic bdget_disk() calls elsewhere.

Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>