rbd: add new image features for dummy image

The dummy image will be created with 1Mib size.
during the snapshot transfer operation the 1Mib
will be transferred even if the dummy image doesnot
contains any data. adding the new image features
`fast-diff,layering,obj-map,exclusive-lock`on the
dummy image will ensure that only the diff is
transferred to the remote cluster.

Signed-off-by: Madhu Rajanna <madhupr007@gmail.com>

internal/rbd/replicationcontrollerserver.go

@@ -311,6 +311,14 @@ func createDummyImage(ctx context.Context, rbdVol *rbdVolume) error {
 		}
 		dummyVol := *rbdVol
 		dummyVol.RbdImageName = imgName
+		f := []string{
+			librbd.FeatureNameLayering,
+			librbd.FeatureNameObjectMap,
+			librbd.FeatureNameExclusiveLock,
+			librbd.FeatureNameFastDiff,
+		}
+		featues := librbd.FeatureSetFromNames(f)
+		dummyVol.imageFeatureSet = featues
 		// create 1MiB dummy image. 1MiB=1048576 bytes
 		dummyVol.VolSize = 1048576
 		err = createImage(ctx, &dummyVol, dummyVol.conn.Creds)
@@ -330,6 +338,10 @@ func createDummyImage(ctx context.Context, rbdVol *rbdVolume) error {
 
 // repairDummyImage deletes and recreates the dummy image.
 func repairDummyImage(ctx context.Context, dummyVol *rbdVolume) error {
+	// instead of checking the images features and than adding missing image
+	// features, updating the image size to 1Mib. We will delete the image
+	// and recreate it.
+
 	// deleting and recreating the dummy image will not impact anything as its
 	// a workaround to fix the scheduling problem.
 	err := deleteImage(ctx, dummyVol, dummyVol.conn.Creds)