Comment 37 for bug 1578036

Hi weiguo,

Volume should not be attached to two different nodes at the same time, so for a 'in-use' original volume, a temp snapshot/clone would be attached to backup service node as we see from change https://review.openstack.org/#/c/262395. Because of temp snapshot/clone, it is impossiable to success to do an incremental/differential backup if the source volume is an RBD, considering it needs a 'from-snap'(recently created snapshot for backup).

In rbd backup driver, maybe it need a check to skip attempting incremental backup when the temp snapshot/clone was found.