Ceph » rbd

When the non-primary snapshot is created, it will also create an object-map by copying the contents from the HEAD revision object-map. This should therefore start off as consistent with the previous non-primary snapshot object-map. However, the deep-copy object-copy state machine assumes that the object-map is already set to NONEXISTENT so it will not properly update the non-primary snapshot's object map.

The non-primary snapshot's object map either needs to be default-initialized to NONEXISTENT and updated in the deep-copy object-copy state machine (currently not handled) or the object-map creation should be deferred and then created after deep-copy image-copy completes (which will properly copy the data from the HEAD revision snapshot).

This doesn't affect data correctness from a mirroring point-of-view, however, since that non-primary snapshot object map is not used for replication and user snapshot and the HEAD revision object-map will be correct.