Assert NodePublishVolume behavior for single node single writer volumes

Ensure that a single node single writer volume cannot be mounted at two
different target paths on the same node.

See the second table in the NodePublishVolume section of the CSI spec
for more details:
https://github.com/container-storage-interface/spec/blob/v1.7.0/spec.md#nodepublishvolume

pkg/sanity/node.go

@@ -183,12 +183,13 @@ var _ = DescribeSanity("Node Service", func(sc *TestContext) {
 	var (
 		r *Resources
 
-		providesControllerService    bool
-		controllerPublishSupported   bool
-		nodeStageSupported           bool
-		nodeVolumeStatsSupported     bool
-		nodeExpansionSupported       bool
-		controllerExpansionSupported bool
+		providesControllerService      bool
+		controllerPublishSupported     bool
+		nodeStageSupported             bool
+		nodeVolumeStatsSupported       bool
+		nodeExpansionSupported         bool
+		controllerExpansionSupported   bool
+		singleNodeMultiWriterSupported bool
 	)
 
 	createVolumeWithCapability := func(volumeName string, cap *csi.VolumeCapability) *csi.CreateVolumeResponse {
@@ -319,6 +320,8 @@ var _ = DescribeSanity("Node Service", func(sc *TestContext) {
 		nodeVolumeStatsSupported = isNodeCapabilitySupported(n, csi.NodeServiceCapability_RPC_GET_VOLUME_STATS)
 		nodeExpansionSupported = isNodeCapabilitySupported(n, csi.NodeServiceCapability_RPC_EXPAND_VOLUME)
 		controllerExpansionSupported = isControllerCapabilitySupported(cl, csi.ControllerServiceCapability_RPC_EXPAND_VOLUME)
+		singleNodeMultiWriterSupported = isNodeCapabilitySupported(n, csi.NodeServiceCapability_RPC_SINGLE_NODE_MULTI_WRITER)
+
 		r = &Resources{
 			Context:          sc,
 			ControllerClient: cl,
@@ -431,6 +434,55 @@ var _ = DescribeSanity("Node Service", func(sc *TestContext) {
 			Expect(ok).To(BeTrue())
 			Expect(serverError.Code()).To(Equal(codes.InvalidArgument), "unexpected error: %s", serverError.Message())
 		})
+
+		Describe("with single node multi writer capability", func() {
+			BeforeEach(func() {
+				if !singleNodeMultiWriterSupported {
+					Skip("Service does not have single node multi writer capability")
+				}
+			})
+
+			It("should fail when volume with single node single writer access mode is already mounted at a different target path", func() {
+				By("creating a single node single writer volume")
+				name := UniqueString("sanity-node-publish-single-node-single-writer")
+				cap := TestVolumeCapabilityWithAccessType(sc, csi.VolumeCapability_AccessMode_SINGLE_NODE_SINGLE_WRITER)
+				vol := createVolumeWithCapability(name, cap)
+
+				By("Getting a node id")
+				nid, err := r.NodeGetInfo(
+					context.Background(),
+					&csi.NodeGetInfoRequest{})
+				Expect(err).NotTo(HaveOccurred())
+				Expect(nid).NotTo(BeNil())
+				Expect(nid.GetNodeId()).NotTo(BeEmpty())
+
+				By("Staging and publishing a volume")
+				conpubvol := controllerPublishVolumeWithCapability(name, vol, nid, cap)
+				_ = nodeStageVolumeWithCapability(name, vol, conpubvol, cap)
+				_ = nodePublishVolumeWithCapability(name, vol, conpubvol, cap)
+
+				var stagingPath string
+				if nodeStageSupported {
+					stagingPath = sc.StagingPath
+				}
+				_, err = r.NodePublishVolume(
+					context.Background(),
+					&csi.NodePublishVolumeRequest{
+						VolumeId:          vol.GetVolume().GetVolumeId(),
+						TargetPath:        sc.TargetPath + "/other_target",
+						StagingTargetPath: stagingPath,
+						VolumeCapability:  cap,
+						VolumeContext:     vol.GetVolume().GetVolumeContext(),
+						Secrets:           sc.Secrets.NodePublishVolumeSecret,
+					},
+				)
+				Expect(err).To(HaveOccurred())
+
+				serverError, ok := status.FromError(err)
+				Expect(ok).To(BeTrue())
+				Expect(serverError.Code()).To(Equal(codes.FailedPrecondition), "unexpected error: %s", serverError.Message())
+			})
+		})
 	})
 
 	Describe("NodeUnpublishVolume", func() {