Use blk_unref to drop the last reference, which will close the block
backend and flush all caches and outstanding writes.
This is especially important for restoring to Ceph, as the userspace
librbd caches will not be flushed if the application exits immediately,
leading to potentially incomplete restores.
Reported-by: Eneko Lacunza <elacunza@binovo.es>
Signed-off-by: Stefan Reiter <s.reiter@proxmox.com>
4194124719
