Before this update, the internal temporary snapshot, created during async migration when creating a volume from a snapshot, was not being deleted from the VNX storage. For example, if we create a new volume, V2, from snapshot S1, which we created from volume V1, an internal temporary snapshot, S2, is created from copying S1. V1 now has two snapshots, S1 and S2. Although we delete V1, V2 and S1 from OpenStack Block Storage (cinder), S2 is not deleted. This causes both V1 and S2 to remain on the VNX storage. With this update, the temporary snapshot, S2, is deleted, and V1 can be successfully deleted.