When closing and freeing the source device we could end up doing our
final blkdev_put() on the bdev, which will grab the bd_mutex.  As such
we want to be holding as few locks as possible, so move this call
outside of the dev_replace->lock_finishing_cancel_unmount lock.  Since
we're modifying the fs_devices we need to make sure we're holding the
uuid_mutex here, so take that as well.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>