rbd: fix snapshot deletion by resolving image names correctly

When creating a Snapshot with the new NewSnapshotByID() function, the
name of the RBD-image that is created is the same as the name of the
Snapshot. The `RbdImageName` points to the name of parent image, which
causes deleting the Snapshot to delete the parent image instead.

Correcting the `RbdImageName` and setting it to the `RbdSnapName` makes
sure that upon deletion, the Snapshot RBD-image is removed, and not the
parent image.

Signed-off-by: Niels de Vos <[email protected]>

internal/rbd/manager.go

@@ -212,6 +212,11 @@ func (mgr *rbdManager) GetSnapshotByID(ctx context.Context, id string) (types.Sn
 		}
 	}
 
+	// FIXME: The snapshot will have RbdImageName set to the image that was
+	// used as source. This is not correct for group snapshots images, and
+	// need to be fixed. See rbdVolume.NewSnapshotByID() for more details.
+	snapshot.RbdImageName = snapshot.RbdSnapName
+
 	return snapshot, nil
 }
 

internal/rbd/snapshot.go

@@ -221,7 +221,12 @@ func (rv *rbdVolume) NewSnapshotByID(
 		}
 	}()
 
-	// a new snapshot image will be created, needs to have a unique name
+	// A new snapshot image will be created, and needs to have a unique
+	// name.
+	// FIXME: the journal contains rv.RbdImageName as SourceName. When
+	// resolving the snapshot image, snap.RbdImageName will be set to the
+	// original RbdImageName/SourceName (incorrect). This is fixed-up in
+	// rbdManager.GetSnapshotByID(), this needs to be done cleaner.
 	snap.RbdImageName = snap.RbdSnapName
 
 	err = rv.Connect(cr)