When remove ephemeral csi failed, force remove it.

Dockerfile

@@ -1,10 +1,10 @@
-FROM golang:1.15.6 AS builder
+FROM golang:1.15.6@sha256:9a3218c894d35d855c819fb6ec52333920fea69f90a793b6570620a128643363 AS builder
 
 WORKDIR /go/src/github.com/alibaba/open-local
 COPY . .
 RUN make build && chmod +x bin/open-local
 
-FROM alpine:3.9
+FROM alpine:3.9@sha256:65b3a80ebe7471beecbc090c5b2cdd0aafeaefa0715f8f12e40dc918a3a70e32
 LABEL maintainers="Alibaba Cloud Authors"
 LABEL description="open-local is a local disk management system"
 RUN apk update && apk upgrade && apk add util-linux coreutils e2fsprogs e2fsprogs-extra xfsprogs xfsprogs-extra blkid file open-iscsi jq

pkg/csi/nodeserver.go

@@ -19,6 +19,7 @@ package csi
 import (
 	"encoding/json"
 	"fmt"
+	"io/fs"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -224,13 +225,22 @@ func (ns *nodeServer) NodeUnpublishVolume(ctx context.Context, req *csi.NodeUnpu
 		}
 	}
 
+	ephemeralDevice, exist := ns.ephemeralVolumeStore.GetDevice(volumeID)
+
 	if err := ns.osTool.CleanupMountPoint(targetPath, ns.k8smounter, true /*extensiveMountPointCheck*/); err != nil {
-		return nil, status.Errorf(codes.Internal, "NodeUnpublishVolume: fail to umount volume %s for path %s: %s", volumeID, targetPath, err.Error())
+		if e1, ok := err.(*fs.PathError); ok && e1.Unwrap().Error() == "directory not empty" &&
+			exist && ephemeralDevice != "" {
+			log.Infof("NodeUnpublishVolume: failed to umount target path %s cause not empty, try to force remove it", targetPath)
+			if e2 := os.RemoveAll(targetPath); e2 != nil {
+				return nil, status.Errorf(codes.Internal, "NodeUnpublishVolume: fail to umount volume %s for path %s: %s, and failed to force remove it: %s", volumeID, targetPath, err.Error(), e2.Error())
+			}
+		} else {
+			return nil, status.Errorf(codes.Internal, "NodeUnpublishVolume: fail to umount volume %s for path %s: %s", volumeID, targetPath, err.Error())
+		}
 	}
 
 	// Step 3: delete ephemeral device
 	var err error
-	ephemeralDevice, exist := ns.ephemeralVolumeStore.GetDevice(volumeID)
 	if exist && ephemeralDevice != "" {
 		// /dev/mapper/yoda--pool0-yoda--5c523416--7288--4138--95e0--f9392995959f
 		if ns.spdkSupported {