rbd: use DeepCopy to create a thick-provisioned clone

To create a full-allocated RBD image from a snapshot/clone DeepCopy()
can be used. This is needed when the parent of the new volume is
thick-provisioner, so that the new volume is independent of the parent
and thick-provisioned as well.

Signed-off-by: Niels de Vos <ndevos@redhat.com>

internal/rbd/clone.go

@@ -152,6 +152,8 @@ func (rv *rbdVolume) createCloneFromImage(ctx context.Context, parentVol *rbdVol
 	}
 	defer j.Destroy()
 
+	// TODO: if rv exists, delete the image and start over?
+
 	err = rv.doSnapClone(ctx, parentVol)
 	if err != nil {
 		return status.Error(codes.Internal, err.Error())
@@ -170,6 +172,19 @@ func (rv *rbdVolume) createCloneFromImage(ctx context.Context, parentVol *rbdVol
 		}
 	}
 
+	// TODO: copy thick provision config
+	thick, err := parentVol.isThickProvisioned()
+	if err != nil {
+		return fmt.Errorf("failed checking thick-provisioning of %q: %w", parentVol, err)
+	}
+
+	if thick {
+		err = rv.setThickProvisioned()
+		if err != nil {
+			return fmt.Errorf("failed mark %q thick-provisioned: %w", rv, err)
+		}
+	}
+
 	err = j.StoreImageID(ctx, rv.JournalPool, rv.ReservedID, rv.ImageID)
 	if err != nil {
 		util.ErrorLog(ctx, "failed to store volume %s: %v", rv, err)
@@ -221,19 +236,28 @@ func (rv *rbdVolume) doSnapClone(ctx context.Context, parentVol *rbdVolume) erro
 			}
 		}
 	}()
-	// flatten clone
+
-	errFlatten = tempClone.flattenRbdImage(ctx, rv.conn.Creds, false, rbdHardMaxCloneDepth, rbdSoftMaxCloneDepth)
+	if rv.ThickProvision {
-	if errFlatten != nil {
+		err = tempClone.DeepCopy(rv)
-		return errFlatten
+		if err != nil {
-	}
+			return fmt.Errorf("failed to deep copy %q into %q: %w", parentVol, rv, err)
-	// create snap of temp clone from temporary cloned image
+		}
-	// create final clone
+	} else {
-	// delete snap of temp clone
+		// flatten clone
-	errClone = createRBDClone(ctx, tempClone, rv, cloneSnap, rv.conn.Creds)
+		errFlatten = tempClone.flattenRbdImage(ctx, rv.conn.Creds, false, rbdHardMaxCloneDepth, rbdSoftMaxCloneDepth)
-	if errClone != nil {
+		if errFlatten != nil {
-		// set errFlatten error to cleanup temporary snapshot and temporary clone
+			return errFlatten
-		errFlatten = errors.New("failed to create user requested cloned image")
+		}
-		return errClone
+
+		// create snap of temp clone from temporary cloned image
+		// create final clone
+		// delete snap of temp clone
+		errClone = createRBDClone(ctx, tempClone, rv, cloneSnap, rv.conn.Creds)
+		if errClone != nil {
+			// set errFlatten error to cleanup temporary snapshot and temporary clone
+			errFlatten = errors.New("failed to create user requested cloned image")
+			return errClone
+		}
 	}
 
 	return nil

internal/rbd/rbd_util.go

@@ -1508,6 +1508,32 @@ func (rv *rbdVolume) RepairThickProvision() error {
 	return nil
 }
 
+// DeepCopy creates an independent image (dest) from the source image. This
+// process may take some time when the image is large.
+func (rv *rbdVolume) DeepCopy(dest *rbdVolume) error {
+	opts := librbd.NewRbdImageOptions()
+	defer opts.Destroy()
+
+	// when doing DeepCopy, also flatten the new image
+	err := opts.SetUint64(librbd.ImageOptionFlatten, 1)
+	if err != nil {
+		return err
+	}
+
+	err = dest.openIoctx()
+	if err != nil {
+		return err
+	}
+
+	image, err := rv.open()
+	if err != nil {
+		return err
+	}
+	defer image.Close()
+
+	return image.DeepCopy(dest.ioctx, dest.RbdImageName, opts)
+}
+
 func (rv *rbdVolume) listSnapshots() ([]librbd.SnapInfo, error) {
 	image, err := rv.open()
 	if err != nil {