Node Publish Mount Idempotent

pkg/cloud/aws_metrics.go

@@ -1,3 +1,4 @@
+//go:build !providerless
 // +build !providerless
 
 /*

pkg/driver/mount.go

@@ -32,7 +32,7 @@ type Mounter interface {
 	mountInterface
 
 	FormatAndMount(source string, target string, fstype string, options []string) error
-
+	IsCorruptedMnt(err error) bool
 	GetDeviceNameFromMount(mountPath string) (string, int, error)
 	MakeFile(path string) error
 	MakeDir(path string) error

pkg/driver/mount_linux.go

@@ -1,3 +1,4 @@
+//go:build linux
 // +build linux
 
 /*
@@ -33,6 +34,11 @@ func (m NodeMounter) GetDeviceNameFromMount(mountPath string) (string, int, erro
 	return mountutils.GetDeviceNameFromMount(m, mountPath)
 }
 
+// IsCorruptedMnt return true if err is about corrupted mount point
+func (m NodeMounter) IsCorruptedMnt(err error) bool {
+	return mountutils.IsCorruptedMnt(err)
+}
+
 // This function is mirrored in ./sanity_test.go to make sure sanity test covered this block of code
 // Please mirror the change to func MakeFile in ./sanity_test.go
 func (m *NodeMounter) MakeFile(path string) error {

pkg/driver/mount_windows.go

@@ -1,3 +1,4 @@
+//go:build windows
 // +build windows
 
 /*

pkg/driver/node.go

@@ -586,17 +586,57 @@ func (d *nodeService) nodePublishVolumeForBlock(req *csi.NodePublishVolumeReques
 		return status.Errorf(codes.Internal, "Could not create file %q: %v", target, err)
 	}
 
-	klog.V(4).Infof("NodePublishVolume [block]: mounting %s at %s", source, target)
-	if err := d.mounter.Mount(source, target, "", mountOptions); err != nil {
-		if removeErr := os.Remove(target); removeErr != nil {
-			return status.Errorf(codes.Internal, "Could not remove mount target %q: %v", target, removeErr)
-		}
+	//Checking if the target file is already mounted with a device.
+	mounted, err := d.isMounted(source, target)
+	if err != nil {
 		return status.Errorf(codes.Internal, "Could not mount %q at %q: %v", source, target, err)
 	}
 
+	if !mounted {
+		klog.V(4).Infof("NodePublishVolume [block]: mounting %s at %s", source, target)
+		if err := d.mounter.Mount(source, target, "", mountOptions); err != nil {
+			if removeErr := os.Remove(target); removeErr != nil {
+				return status.Errorf(codes.Internal, "Could not remove mount target %q: %v", target, removeErr)
+			}
+			return status.Errorf(codes.Internal, "Could not mount %q at %q: %v", source, target, err)
+		}
+	} else {
+		klog.V(4).Infof("NodePublishVolume [block]: Target path %q is already mounted", target)
+	}
+
 	return nil
 }
 
+func (d *nodeService) isMounted(source string, target string) (bool, error) {
+	/*
+		Checking if it's a mount point using IsLikelyNotMountPoint. There are three different return values,
+		1. true, err when the directory does not exist or corrupted.
+		2. false, nil when the path is already mounted with a device.
+		3. true, nil when the path is not mounted with any device.
+	*/
+	notMnt, err := d.mounter.IsLikelyNotMountPoint(target)
+	if err != nil && !os.IsNotExist(err) {
+		//Checking if the path exists and error is related to Corrupted Mount, in that case, the system could unmount and mount.
+		_, pathErr := d.mounter.PathExists(target)
+		if pathErr != nil && d.mounter.IsCorruptedMnt(pathErr) {
+			klog.V(4).Infof("NodePublishVolume: Target path %q is a corrupted mount. Trying to unmount.", target)
+			if mntErr := d.mounter.Unmount(target); mntErr != nil {
+				return !notMnt, status.Errorf(codes.Internal, "Unable to unmount the target %q : %v", target, mntErr)
+			}
+			//After successful unmount, the device is ready to be mounted.
+			return !notMnt, nil
+		}
+		return !notMnt, status.Errorf(codes.Internal, "Could not mount %q at %q: %v", source, target, err)
+	}
+
+	if !notMnt {
+		klog.V(4).Infof("NodePublishVolume: Target path %q is already mounted", target)
+		return !notMnt, nil
+	}
+
+	return !notMnt, err
+}
+
 func (d *nodeService) nodePublishVolumeForFileSystem(req *csi.NodePublishVolumeRequest, mountOptions []string, mode *csi.VolumeCapability_Mount) error {
 	target := req.GetTargetPath()
 	source := req.GetStagingTargetPath()
@@ -620,13 +660,20 @@ func (d *nodeService) nodePublishVolumeForFileSystem(req *csi.NodePublishVolumeR
 	mountOptions = collectMountOptions(fsType, mountOptions)
 
 	klog.V(4).Infof("NodePublishVolume: mounting %s at %s with option %s as fstype %s", source, target, mountOptions, fsType)
-	if err := d.mounter.Mount(source, target, fsType, mountOptions); err != nil {
-		if removeErr := os.Remove(target); removeErr != nil {
-			return status.Errorf(codes.Internal, "Could not remove mount target %q: %v", target, err)
-		}
+
+	//Checking if the target directory is already mounted with a device.
+	mounted, err := d.isMounted(source, target)
+
+	if err != nil {
 		return status.Errorf(codes.Internal, "Could not mount %q at %q: %v", source, target, err)
 	}
 
+	if !mounted {
+		if err := d.mounter.Mount(source, target, fsType, mountOptions); err != nil {
+			return status.Errorf(codes.Internal, "Could not mount %q at %q: %v", source, target, err)
+		}
+	}
+
 	return nil
 }
 

pkg/driver/node_linux.go

@@ -1,3 +1,4 @@
+//go:build linux
 // +build linux
 
 /*