e2e: add test for cephfs snapshot-backed volumes

Signed-off-by: Robert Vasek <robert.vasek@cern.ch>

e2e/cephfs.go

@@ -1209,6 +1209,142 @@ var _ = Describe(cephfsType, func() {
 				validateSubvolumeCount(f, 0, fileSystemName, subvolumegroup)
 				validateOmapCount(f, 0, cephfsType, metadataPool, volumesType)
 				validateOmapCount(f, 0, cephfsType, metadataPool, snapsType)
+
+				err = deleteResource(cephFSExamplePath + "snapshotclass.yaml")
+				if err != nil {
+					e2elog.Failf("failed to delete CephFS snapshotclass: %v", err)
+				}
+			})
+
+			By("checking snapshot-backed volume", func() {
+				err := createCephFSSnapshotClass(f)
+				if err != nil {
+					e2elog.Failf("failed to delete CephFS storageclass: %v", err)
+				}
+
+				pvc, err := loadPVC(pvcPath)
+				if err != nil {
+					e2elog.Failf("failed to load PVC: %v", err)
+				}
+				pvc.Namespace = f.UniqueName
+				err = createPVCAndvalidatePV(f.ClientSet, pvc, deployTimeout)
+				if err != nil {
+					e2elog.Failf("failed to create PVC: %v", err)
+				}
+
+				app, err := loadApp(appPath)
+				if err != nil {
+					e2elog.Failf("failed to load application: %v", err)
+				}
+				app.Namespace = f.UniqueName
+				app.Spec.Volumes[0].PersistentVolumeClaim.ClaimName = pvc.Name
+				appLabels := map[string]string{
+					appKey: appLabel,
+				}
+				app.Labels = appLabels
+				optApp := metav1.ListOptions{
+					LabelSelector: fmt.Sprintf("%s=%s", appKey, appLabels[appKey]),
+				}
+				err = writeDataInPod(app, &optApp, f)
+				if err != nil {
+					e2elog.Failf("failed to write data: %v", err)
+				}
+
+				appTestFilePath := app.Spec.Containers[0].VolumeMounts[0].MountPath + "/test"
+
+				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: %v", err)
+				}
+
+				err = appendToFileInContainer(f, app, appTestFilePath, "hello", &optApp)
+				if err != nil {
+					e2elog.Failf("failed to append data: %v", err)
+				}
+
+				parentFileSum, err := calculateSHA512sum(f, app, appTestFilePath, &optApp)
+				if err != nil {
+					e2elog.Failf("failed to get SHA512 sum for file: %v", err)
+				}
+
+				err = deleteResource(cephFSExamplePath + "storageclass.yaml")
+				if err != nil {
+					e2elog.Failf("failed to delete CephFS storageclass: %v", err)
+				}
+				err = createCephfsStorageClass(f.ClientSet, f, false, map[string]string{
+					"backingSnapshot": "true",
+				})
+				if err != nil {
+					e2elog.Failf("failed to create CephFS storageclass: %v", err)
+				}
+
+				pvcClone, err := loadPVC(pvcClonePath)
+				if err != nil {
+					e2elog.Failf("failed to load PVC: %v", err)
+				}
+				// Snapshot-backed volumes support read-only access modes only.
+				pvcClone.Spec.AccessModes = []v1.PersistentVolumeAccessMode{v1.ReadOnlyMany}
+				appClone, err := loadApp(appClonePath)
+				if err != nil {
+					e2elog.Failf("failed to load application: %v", err)
+				}
+				appCloneLabels := map[string]string{
+					appKey: appCloneLabel,
+				}
+				appClone.Labels = appCloneLabels
+				optAppClone := metav1.ListOptions{
+					LabelSelector: fmt.Sprintf("%s=%s", appKey, appCloneLabels[appKey]),
+				}
+				pvcClone.Namespace = f.UniqueName
+				appClone.Namespace = f.UniqueName
+				err = createPVCAndApp("", f, pvcClone, appClone, deployTimeout)
+				if err != nil {
+					e2elog.Failf("failed to create PVC and app: %v", err)
+				}
+
+				// Snapshot-backed volume shouldn't contribute to total subvolume count.
+				validateSubvolumeCount(f, 1, fileSystemName, subvolumegroup)
+
+				// Deleting snapshot before deleting pvcClone should succeed. It will be
+				// deleted once all volumes that are backed by this snapshot are gone.
+				err = deleteSnapshot(&snap, deployTimeout)
+				if err != nil {
+					e2elog.Failf("failed to delete snapshot: %v", err)
+				}
+
+				appCloneTestFilePath := appClone.Spec.Containers[0].VolumeMounts[0].MountPath + "/test"
+
+				snapFileSum, err := calculateSHA512sum(f, appClone, appCloneTestFilePath, &optAppClone)
+				if err != nil {
+					e2elog.Failf("failed to get SHA512 sum for file: %v", err)
+				}
+
+				if parentFileSum == snapFileSum {
+					e2elog.Failf("SHA512 sums of files in parent subvol and snapshot should differ")
+				}
+
+				err = deletePVCAndApp("", f, pvcClone, appClone)
+				if err != nil {
+					e2elog.Failf("failed to delete PVC or application: %v", err)
+				}
+
+				err = deletePVCAndApp("", f, pvc, app)
+				if err != nil {
+					e2elog.Failf("failed to delete PVC or application: %v", err)
+				}
+
+				err = deleteResource(cephFSExamplePath + "storageclass.yaml")
+				if err != nil {
+					e2elog.Failf("failed to delete CephFS storageclass: %v", err)
+				}
+
+				err = createCephfsStorageClass(f.ClientSet, f, false, nil)
+				if err != nil {
+					e2elog.Failf("failed to create CephFS storageclass: %v", err)
+				}
 			})
 
 			By("create a PVC-PVC clone and bind it to an app", func() {