rbd: do not return an error when deleting a non-existing image

Deleting an image that has been already remove, should not be reported
as a failure. This improves the idempotency of the `rbdImage.Delete()`
function, making it easier for callers to detect real errors.

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

internal/rbd/rbd_util.go

@@ -671,7 +671,7 @@ func (ri *rbdImage) Delete(ctx context.Context) error {
 
 	rbdImage := librbd.GetImage(ri.ioctx, image)
 	err = rbdImage.Trash(0)
-	if err != nil {
+	if err != nil && !errors.Is(err, librbd.ErrNotFound) {
 		log.ErrorLog(ctx, "failed to delete rbd image: %s, error: %v", ri, err)
 
 		return err
@@ -694,7 +694,7 @@ func (ri *rbdImage) trashRemoveImage(ctx context.Context) error {
 	_, err = ta.AddTrashRemove(admin.NewImageSpec(ri.Pool, ri.RadosNamespace, ri.ImageID))
 
 	rbdCephMgrSupported := isCephMgrSupported(ctx, ri.ClusterID, err)
-	if rbdCephMgrSupported && err != nil {
+	if rbdCephMgrSupported && err != nil && !errors.Is(err, librbd.ErrNotFound) {
 		log.ErrorLog(ctx, "failed to add task to delete rbd image: %s, %v", ri, err)
 
 		return err