e2e: pvc mounting when snap and parent pvc is deleted

Added an E2E test to test below case

* Create PVC
* Create Snapshot from PVC
* Delete PVC
* Create Clone from Snapshot
* Delete Snapshot
* Mount clone to Application
* Delete Application and PVC Clone

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

e2e/rbd.go

@@ -1088,6 +1088,112 @@ var _ = Describe("RBD", func() {
 				}
 			})
 
+			By("validate PVC mounting if snapshot and parent PVC are deleted", func() {
+				// snapshot beta is only supported from v1.17+
+				if !k8sVersionGreaterEquals(f.ClientSet, 1, 17) {
+					Skip("pvc restore is only supported from v1.17+")
+				}
+				err := createRBDSnapshotClass(f)
+				if err != nil {
+					e2elog.Failf("failed to create storageclass with error %v", err)
+				}
+				defer func() {
+					err = deleteRBDSnapshotClass()
+					if err != nil {
+						e2elog.Failf("failed to delete VolumeSnapshotClass: %v", err)
+					}
+				}()
+
+				// create PVC and bind it to an app
+				pvc, err := loadPVC(pvcPath)
+				if err != nil {
+					e2elog.Failf("failed to load PVC with error %v", err)
+				}
+
+				pvc.Namespace = f.UniqueName
+				app, err := loadApp(appPath)
+				if err != nil {
+					e2elog.Failf("failed to load application with error %v", err)
+				}
+				app.Namespace = f.UniqueName
+				err = createPVCAndApp("", f, pvc, app, deployTimeout)
+				if err != nil {
+					e2elog.Failf("failed to create PVC and application with error %v", err)
+				}
+				// validate created backend rbd images
+				validateRBDImageCount(f, 1)
+
+				snap := getSnapshot(snapshotPath)
+				snap.Namespace = f.UniqueName
+				snap.Spec.Source.PersistentVolumeClaimName = &pvc.Name
+
+				err = createSnapshot(&snap, deployTimeout)
+				if err != nil {
+					e2elog.Failf("failed to create snapshot with error %v", err)
+				}
+				// validate created backend rbd images
+				// parent PVC + snapshot
+				totalImages := 2
+				validateRBDImageCount(f, totalImages)
+				pvcClone, err := loadPVC(pvcClonePath)
+				if err != nil {
+					e2elog.Failf("failed to load PVC with error %v", err)
+				}
+
+				// delete parent PVC
+				err = deletePVCAndApp("", f, pvc, app)
+				if err != nil {
+					e2elog.Failf("failed to delete PVC and application with error %v", err)
+				}
+				// validate created backend rbd images
+				validateRBDImageCount(f, 1)
+
+				// create clone PVC
+				pvcClone.Namespace = f.UniqueName
+				err = createPVCAndvalidatePV(f.ClientSet, pvcClone, deployTimeout)
+				if err != nil {
+					e2elog.Failf("failed to create PVC with error %v", err)
+				}
+				// validate created backend rbd images = snapshot + clone
+				totalImages = 2
+				validateRBDImageCount(f, totalImages)
+
+				// delete snapshot
+				err = deleteSnapshot(&snap, deployTimeout)
+				if err != nil {
+					e2elog.Failf("failed to delete snapshot with error %v", err)
+				}
+
+				// validate created backend rbd images = clone
+				totalImages = 1
+				validateRBDImageCount(f, totalImages)
+
+				appClone, err := loadApp(appClonePath)
+				if err != nil {
+					e2elog.Failf("failed to load application with error %v", err)
+				}
+				appClone.Namespace = f.UniqueName
+				appClone.Spec.Volumes[0].PersistentVolumeClaim.ClaimName = pvcClone.Name
+
+				// create application
+				err = createApp(f.ClientSet, appClone, deployTimeout)
+				if err != nil {
+					e2elog.Failf("failed to create application with error %v", err)
+				}
+
+				err = deletePod(appClone.Name, appClone.Namespace, f.ClientSet, deployTimeout)
+				if err != nil {
+					e2elog.Failf("failed to delete application with error %v", err)
+				}
+				// delete PVC clone
+				err = deletePVCAndValidatePV(f.ClientSet, pvcClone, deployTimeout)
+				if err != nil {
+					e2elog.Failf("failed to delete PVC with error %v", err)
+				}
+				// validate created backend rbd images
+				validateRBDImageCount(f, 0)
+			})
+
 			By("ensuring all operations will work within a rados namespace", func() {
 				updateConfigMap := func(radosNS string) {
 					radosNamespace = radosNS