Summary of block volume related CSI driver's methods are as follows:
 - GetGlobalMapPath returns a global map path,
 - GetPodDeviceMapPath returns a pod device map path and filename,
 - SetUpDevice calls CSI's NodeStageVolume and stage a volume to its staging path,
 - MapPodDevice calls CSI's NodePublishVolume and publish a volume to its publish path,
 - UnmapPodDevice calls CSI's NodeUnpublishVolume and unpublish a volume from its publish path,

	if err != nil {
		t.Fatalf("mapper failed to SetupDevice: %v", err)
	}

	// Check if NodeStageVolume staged to the right path
	svols := csiMapper.csiClient.(*fakeCsiDriverClient).nodeClient.GetNodeStagedVolumes()
	svol, ok := svols[csiMapper.volumeID]
	if !ok {
		t.Error("csi server may not have received NodeStageVolume call")
	}
	if svol.Path != stagingPath {

	return err
}

func (c *csiDriverClient) NodeStageVolume(ctx context.Context,
	volID string,
	publishContext map[string]string,
	stagingTargetPath string,
	fsType string,
	accessMode api.PersistentVolumeAccessMode,
	secrets map[string]string,
	volumeContext map[string]string,
	mountOptions []string,
	fsGroup *int64,
) error {

	return err
}

func (c *fakeCsiDriverClient) NodeStageVolume(ctx context.Context,
	volID string,
	publishContext map[string]string,
	stagingTargetPath string,
	fsType string,
	accessMode api.PersistentVolumeAccessMode,
	secrets map[string]string,
	volumeContext map[string]string,
	mountOptions []string,
	fsGroup *int64,
) error {
	c.t.Log("calling fake.NodeStageVolume...")
	req := &csipbv1.NodeStageVolumeRequest{

		return nil, fmt.Errorf("failed to remove publish path %s: %s", req.TargetPath, err)
	}

	return &csipb.NodeUnpublishVolumeResponse{}, nil
}

// NodeStagevolume implements csi method
func (f *NodeClient) NodeStageVolume(ctx context.Context, req *csipb.NodeStageVolumeRequest, opts ...grpc.CallOption) (*csipb.NodeStageVolumeResponse, error) {
	if f.nextErr != nil {
		return nil, f.nextErr
	}

		klog.V(3).Infof("Driver %s supports applying FSGroup (has VOLUME_MOUNT_GROUP node capability). Delegating FSGroup application to the driver through NodeStageVolume.", csiSource.Driver)
		nodeStageFSGroupArg = deviceMounterArgs.FsGroup
	}

	fsType := csiSource.FSType
	err = csi.NodeStageVolume(ctx,
		csiSource.VolumeHandle,
		publishContext,
		deviceMountPath,
		fsType,
		accessMode,
		nodeStageSecrets,

		},
		{
			testName:                       "fsgroup provided, driver supports volume mount group; expect fsgroup to be passed to NodeStageVolume",
			volName:                        "test-vol1",
			devicePath:                     "path1",
			deviceMountPath:                "path2",
			fsGroup:                        &testFSGroup,

- For raw block CSI volumes on Kubernetes, kubelet was incorrectly calling CSI NodeStageVolume for every single "map" (i.e. raw block "mount") operation for a volume already attached to the node. This PR ensures it is only called once per volume per node. ([#112403](https://github.com/kubernetes/kubernetes/pull/112403), [@akankshakumar...

  optional SecretReference controllerPublishSecretRef = 6;

  // nodeStageSecretRef is a reference to the secret object containing sensitive
  // information to pass to the CSI driver to complete the CSI NodeStageVolume
  // and NodeStageVolume and NodeUnstageVolume calls.
  // This field is optional, and may be empty if no secret is required. If the
  // secret object contains more than one secret, all secrets are passed.
  // +optional

	// +optional
	ControllerPublishSecretRef *SecretReference

	// NodeStageSecretRef is a reference to the secret object containing sensitive
	// information to pass to the CSI driver to complete the CSI NodeStageVolume
	// and NodeStageVolume and NodeUnstageVolume calls.
	// This field is optional, and may be empty if no secret is required. If the
	// secret object contains more than one secret, all secrets are passed.
	// +optional