rbd: make use of both listSnapshots and listChildren

Currently, CephCSI only uses listSnaps to determine
number of snapshots on a RBD image and uses snapshot
names as child image names to flatten them.
But child images may have different name(in case of
group snapshot) or they maybe in trash
(deleted k8s VolSnapshot with alive restored PVC).

The above problems are avoid by making use of both
snap and child image lists.

Signed-off-by: Rakshith R <[email protected]>

internal/rbd/controllerserver.go

@@ -573,7 +573,7 @@ func (cs *ControllerServer) repairExistingVolume(ctx context.Context, req *csi.C
 // are more than the `minSnapshotOnImage` Add a task to flatten all the
 // temporary cloned images.
 func flattenTemporaryClonedImages(ctx context.Context, rbdVol *rbdVolume, cr *util.Credentials) error {
-	snaps, err := rbdVol.listSnapshots()
+	snaps, children, err := rbdVol.ListSnapAndChildren()
 	if err != nil {
 		if errors.Is(err, ErrImageNotFound) {
 			return status.Error(codes.InvalidArgument, err.Error())
@@ -589,9 +589,17 @@ func flattenTemporaryClonedImages(ctx context.Context, rbdVol *rbdVolume, cr *ut
 			len(snaps),
 			rbdVol,
 			maxSnapshotsOnImage)
+
+		if len(children) == 0 {
+			// if none of the child images(are in trash) exist, we can't flatten them.
+			// return ResourceExhausted error message as we have reached the hard limit.
+			log.DebugLog(ctx, "child images of image %q cannot be flatten", rbdVol)
+
+			return status.Errorf(codes.ResourceExhausted, "rbd image %q has %d snapshots but child images cannot be flattened", rbdVol, len(snaps))
+		}
 		err = flattenClonedRbdImages(
 			ctx,
-			snaps,
+			children,
 			rbdVol.Pool,
 			rbdVol.Monitors,
 			rbdVol.RbdImageName,
@@ -610,13 +618,20 @@ func flattenTemporaryClonedImages(ctx context.Context, rbdVol *rbdVolume, cr *ut
 			len(snaps),
 			rbdVol,
 			minSnapshotsOnImageToStartFlatten)
+		if len(children) == 0 {
+			// if none of the child images(are in trash) exist, we can't flatten them.
+			// return nil since we have only reach the soft limit.
+			log.DebugLog(ctx, "child images of image %q cannot be flatten", rbdVol)
+
+			return nil
+		}
 		// If we start flattening all the snapshots at one shot the volume
 		// creation time will be affected,so we will flatten only the extra
 		// snapshots.
-		snaps = snaps[minSnapshotsOnImageToStartFlatten-1:]
+		children = children[:minSnapshotsOnImageToStartFlatten]
 		err = flattenClonedRbdImages(
 			ctx,
-			snaps,
+			children,
 			rbdVol.Pool,
 			rbdVol.Monitors,
 			rbdVol.RbdImageName,

internal/rbd/group_controllerserver.go

@@ -134,12 +134,16 @@ func (cs *ControllerServer) CreateVolumeGroupSnapshot(
 	if err != nil {
 		return nil, status.Error(codes.Internal, err.Error())
 	}
+	errList := make([]error, 0)
 	for _, volume := range volumes {
 		err = volume.PrepareVolumeForSnapshot(ctx, creds)
 		if err != nil {
-			return nil, status.Error(codes.Aborted, err.Error())
+			errList = append(errList, err)
 		}
 	}
+	if err != nil {
+		return nil, status.Errorf(codes.Aborted, "failed to prepare volumes for snapshot: %v", errList)
+	}
 
 	// create a temporary VolumeGroup with a different name
 	vg, err = mgr.CreateVolumeGroup(ctx, vgName)

internal/rbd/rbd_util.go

@@ -787,7 +787,7 @@ type trashSnapInfo struct {
 
 func flattenClonedRbdImages(
 	ctx context.Context,
-	snaps []librbd.SnapInfo,
+	children []string,
 	pool, monitors, rbdImageName string,
 	cr *util.Credentials,
 ) error {
@@ -803,26 +803,9 @@ func flattenClonedRbdImages(
 
 		return err
 	}
-	var origNameList []trashSnapInfo
-	for _, snapInfo := range snaps {
-		// check if the snapshot belongs to trash namespace.
-		isTrash, retErr := rv.isTrashSnap(snapInfo.Id)
-		if retErr != nil {
-			return retErr
-		}
-
-		if isTrash {
-			// get original snap name for the snapshot in trash namespace
-			origSnapName, retErr := rv.getOrigSnapName(snapInfo.Id)
-			if retErr != nil {
-				return retErr
-			}
-			origNameList = append(origNameList, trashSnapInfo{origSnapName})
-		}
-	}
 
-	for _, snapName := range origNameList {
-		rv.RbdImageName = snapName.origSnapName
+	for _, childName := range children {
+		rv.RbdImageName = childName
 		err = rv.flattenRbdImage(ctx, true, rbdHardMaxCloneDepth, rbdSoftMaxCloneDepth)
 		if err != nil {
 			log.ErrorLog(ctx, "failed to flatten %s; err %v", rv, err)
@@ -2048,19 +2031,26 @@ func (ri *rbdImage) DisableDeepFlatten() error {
 	return image.UpdateFeatures(librbd.FeatureDeepFlatten, false)
 }
 
-func (ri *rbdImage) listSnapshots() ([]librbd.SnapInfo, error) {
+// ListSnapAndChildren returns list of names of snapshots and child images.
+func (ri *rbdImage) ListSnapAndChildren() ([]librbd.SnapInfo, []string, error) {
 	image, err := ri.open()
 	if err != nil {
-		return nil, err
+		return nil, nil, err
 	}
 	defer image.Close()
 
-	snapInfoList, err := image.GetSnapshotNames()
+	snaps, err := image.GetSnapshotNames()
 	if err != nil {
-		return nil, err
+		return nil, nil, err
+	}
+
+	// ListChildren() returns pools, images, err.
+	_, children, err := image.ListChildren()
+	if err != nil {
+		return nil, nil, err
 	}
 
-	return snapInfoList, nil
+	return snaps, children, nil
 }
 
 // isTrashSnap returns true if the snapshot belongs to trash namespace.