rbd: consider lastSyncTimeNotFound as image not syncing

This commit modifies code to consider image as not syncing
when the lastSyncTime is not found.

Currently replication's Resync call fails if the
lastSyncTime of an image is not found.
Instead, we should treat missing lastSyncTime as
the image not being in Syncing state.

Signed-off-by: Rakshith R <rar@redhat.com>

Author: Rakshith-R

internal/csi-addons/rbd/replication.go

@@ -716,19 +716,32 @@ func (rs *ReplicationServer) ResyncVolume(ctx context.Context,
 			err.Error())
 	}
 
+	// If the savedImageTime is not empty,
+	// then the image might be in need of resync.
 	if savedImageTime != "" {
 		st, sErr := timestampFromString(savedImageTime)
 		if sErr != nil {
 			return nil, status.Errorf(codes.Internal, "failed to parse image creation time: %s", sErr.Error())
 		}
 		log.DebugLog(ctx, "image %s, savedImageTime=%v, currentImageTime=%v", rbdVol, st, creationTime)
 
+		// Fetch the last sync info from the local status in order
+		// to determine if the image is syncing or not.
 		syncInfo, sErr := localStatus.GetLastSyncInfo(ctx)
-		if sErr != nil {
+		if sErr != nil && !errors.Is(sErr, rbderrors.ErrLastSyncTimeNotFound) {
 			return nil, status.Errorf(codes.Internal, "failed to get last sync info: %s", sErr.Error())
 		}
-
-		if req.GetForce() && st.Equal(*creationTime) && !syncInfo.IsSyncing() {
+		// consider the image to be not syncing if either
+		// - the last sync time was not found
+		// or
+		// - the sync info indicates the image is not syncing
+		isNotSyncing := errors.Is(sErr, rbderrors.ErrLastSyncTimeNotFound) || !syncInfo.IsSyncing()
+
+		// image needs to be resynced if
+		// - force option is set
+		// - image creation time is equal to the saved image creation time
+		// - image is not already in syncing state
+		if req.GetForce() && st.Equal(*creationTime) && isNotSyncing {
 			err = mirror.Resync(ctx)
 			if err != nil {
 				return nil, getGRPCError(err)