disk: re-implement StagingTargetPath cleanup logic

We should unlink the file we created for volumeDevice.

We should check targetPath is not mounted before we check for volumeDevice, in case the user has a file with the same name.

And the overall complexity is greatly reduced. We do not call stat() on the mounted path now, so no need to worry about EIO or similar.

Author: huww98

pkg/disk/nodeserver.go

@@ -95,8 +95,6 @@ const (
 	RundSocketDir = "/host/etc/kubernetes/volumes/rund/"
 	// VolumeDirRemove volume dir remove
 	VolumeDirRemove = "/host/etc/kubernetes/volumes/disk/remove"
-	// InputOutputErr tag
-	InputOutputErr = "input/output error"
 	// CreateDiskARN ARN parameter of the CreateDisk interface
 	CreateDiskARN = "alibabacloud.com/createdisk-arn"
 	// PVC annotation key of KMS key ID, override the storage class parameter kmsKeyId
@@ -708,9 +706,44 @@ func addDiskXattr(diskID string) (err error) {
 	return unix.Setxattr(device, DiskXattrName, []byte(diskID), 0)
 }
 
-// target format: /var/lib/kubelet/plugins/kubernetes.io/csi/pv/pv-disk-1e7001e0-c54a-11e9-8f89-00163e0e78a0/globalmount
+func ensureUnmounted(mounter k8smount.Interface, target string) error {
+	notmounted, err := mounter.IsLikelyNotMountPoint(target)
+	if err != nil {
+		return fmt.Errorf("failed to check if %s is not a mount point after unmount: %w", target, err)
+	}
+	if !notmounted {
+		return fmt.Errorf("path %s is still mounted after unmount", target)
+	}
+	return nil
+}
+
+func cleanupVolumeDeviceMount(path string) error {
+	err := unix.Unmount(path, 0)
+	if err != nil {
+		switch {
+		case errors.Is(err, unix.ENOENT):
+			return nil
+		case errors.Is(err, unix.EINVAL):
+			// Maybe not mounted, proceed to remove it. If not, unlink will report error.
+		default:
+			return err
+		}
+	}
+
+	errUnlink := unix.Unlink(path)
+	if errUnlink == nil {
+		return nil
+	}
+	if err != nil {
+		return fmt.Errorf("failed to unlink %s: %w", path, errUnlink)
+	} else {
+		return fmt.Errorf("failed to unmount %s: %w; then failed to unlink: %w", path, err, errUnlink)
+	}
+}
+
 func (ns *nodeServer) NodeUnstageVolume(ctx context.Context, req *csi.NodeUnstageVolumeRequest) (*csi.NodeUnstageVolumeResponse, error) {
-	klog.Infof("NodeUnstageVolume:: Starting to Unmount volume, volumeId: %s, target: %v", req.VolumeId, req.StagingTargetPath)
+	logger := klog.FromContext(ctx)
+	logger.Info("Starting to Unmount volume", "target", req.StagingTargetPath)
 
 	if !ns.locks.TryAcquire(req.VolumeId) {
 		return nil, status.Errorf(codes.Aborted, "There is already an operation for %s", req.VolumeId)
@@ -719,66 +752,35 @@ func (ns *nodeServer) NodeUnstageVolume(ctx context.Context, req *csi.NodeUnstag
 
 	// check block device mountpoint
 	targetPath := req.GetStagingTargetPath()
-	tmpPath := filepath.Join(req.GetStagingTargetPath(), req.VolumeId)
-	if IsFileExisting(tmpPath) {
-		fileInfo, err := os.Lstat(tmpPath)
-		if err != nil {
-			if strings.Contains(strings.ToLower(err.Error()), InputOutputErr) {
-				if err = isPathAvailable(targetPath); err != nil {
-					if err = ns.k8smounter.Unmount(targetPath); err != nil {
-						klog.Errorf("NodeUnstageVolume: umount target %s(input/output error) with error: %v", targetPath, err)
-						return nil, status.Errorf(codes.InvalidArgument, "NodeUnstageVolume umount target %s with error: %v", targetPath, err)
-					}
-					klog.Warningf("NodeUnstageVolume: target path %s show input/output error: %v, umount it.", targetPath, err)
-				}
-			} else {
-				klog.Errorf("NodeUnstageVolume: lstat mountpoint: %s with error: %s", tmpPath, err.Error())
-				return nil, status.Error(codes.InvalidArgument, "NodeUnstageVolume: stat mountpoint error: "+err.Error())
-			}
-		} else {
-			if (fileInfo.Mode() & os.ModeDevice) != 0 {
-				klog.Infof("NodeUnstageVolume: mountpoint %s, is block device", tmpPath)
+	err := unix.Unmount(targetPath, 0)
+	if err != nil {
+		switch {
+		case errors.Is(err, unix.ENOENT):
+			logger.Info("targetPath not exist, continue to detach")
+		case errors.Is(err, unix.EINVAL):
+			// Maybe unmounted, lets check
+			if errCheck := ensureUnmounted(ns.k8smounter, targetPath); errCheck != nil {
+				return nil, status.Errorf(codes.Internal, "failed to unmount %s: %v. %v", targetPath, err, errCheck)
 			}
-			// if mountpoint not a block device, maybe something wrong happened in VolumeStageVolume.
-			// when pod deleted, the volume should be detached
-			targetPath = tmpPath
-		}
-	}
 
-	// Step 1: check folder exists and umount
-	msgLog := ""
-	if IsFileExisting(targetPath) {
-		notmounted, err := ns.k8smounter.IsLikelyNotMountPoint(targetPath)
-		if err != nil {
-			klog.Errorf("NodeUnstageVolume: VolumeId: %s, check mountPoint: %s error: %v", req.VolumeId, targetPath, err)
-			return nil, status.Error(codes.Internal, err.Error())
-		}
-		if !notmounted {
-			err = ns.k8smounter.Unmount(targetPath)
+			// really umounted, check volumeDevice
+			// Note: we remove the blockPath, but not targetPath, because the former is created by us, while the latter is created by CO.
+			blockPath := filepath.Join(targetPath, req.VolumeId)
+			logger.Info("targetPath may not be a mountpoint, checking volumeDevice")
+			err := cleanupVolumeDeviceMount(blockPath)
 			if err != nil {
-				klog.Errorf("NodeUnstageVolume: VolumeId: %s, umount path: %s failed with: %v", req.VolumeId, targetPath, err)
-				return nil, status.Error(codes.Internal, err.Error())
-			}
-			notmounted, err = ns.k8smounter.IsLikelyNotMountPoint(targetPath)
-			if err != nil {
-				return nil, status.Errorf(codes.Internal, "failed to check if %s is not a mount point after umount: %v", targetPath, err)
+				return nil, status.Errorf(codes.Internal, "failed to cleanup volumeDevice path %s: %v", blockPath, err)
 			}
-			if !notmounted {
-				klog.Errorf("NodeUnstageVolume: TargetPath mounted yet, volumeId: %s, Target: %s", req.VolumeId, targetPath)
-				return nil, status.Error(codes.Internal, "NodeUnstageVolume: TargetPath mounted yet with target"+targetPath)
-			}
-		} else {
-			msgLog = fmt.Sprintf("NodeUnstageVolume: VolumeId: %s, mountpoint: %s not mounted, skipping and continue to detach", req.VolumeId, targetPath)
+		default:
+			return nil, status.Errorf(codes.Internal, "failed to unmount %s: %v", targetPath, err)
 		}
 	} else {
-		msgLog = fmt.Sprintf("NodeUnstageVolume: VolumeId: %s, Path %s doesn't exist, continue to detach", req.VolumeId, targetPath)
-	}
-
-	if msgLog == "" {
-		klog.Infof("NodeUnstageVolume: Unmount TargetPath successful, target %v, volumeId: %s", targetPath, req.VolumeId)
-	} else {
-		klog.Info(msgLog)
+		err := ensureUnmounted(ns.k8smounter, targetPath)
+		if err != nil {
+			return nil, status.Error(codes.Internal, err.Error())
+		}
 	}
+	logger.V(2).Info("targetPath cleaned up")
 
 	if IsVFNode() {
 		if err := unbindBdfDisk(req.VolumeId); err != nil {
@@ -797,7 +799,7 @@ func (ns *nodeServer) NodeUnstageVolume(ctx context.Context, req *csi.NodeUnstag
 		}
 	}
 
-	err := addDiskXattr(req.VolumeId)
+	err = addDiskXattr(req.VolumeId)
 	if err != nil {
 		klog.Errorf("NodeUnstageVolume: addDiskXattr %s failed: %v", req.VolumeId, err)
 	}

pkg/disk/utils.go

@@ -845,20 +845,6 @@ func GetVolumeDeviceName(diskID string) (string, error) {
 	return device, err
 }
 
-// isPathAvailable
-func isPathAvailable(path string) error {
-	f, err := os.Open(path)
-	if err != nil {
-		return fmt.Errorf("Open Path (%s) with error: %v ", path, err)
-	}
-	defer f.Close()
-	_, err = f.Readdirnames(1)
-	if err != nil && err != io.EOF {
-		return fmt.Errorf("Read Path (%s) with error: %v ", path, err)
-	}
-	return nil
-}
-
 func getBlockDeviceCapacity(devicePath string) int64 {
 
 	file, err := os.Open(devicePath)