fix: user forceUmounter and lazy umount

Author: andyzhangx

pkg/mounter/safe_mounter_unix.go

@@ -20,13 +20,20 @@ limitations under the License.
 package mounter
 
 import (
+	"runtime"
+
 	mount "k8s.io/mount-utils"
 	utilexec "k8s.io/utils/exec"
 )
 
 func NewSafeMounter(removeSMBMappingDuringUnmount bool) (*mount.SafeFormatAndMount, error) {
+	mounter := mount.New("")
+	if runtime.GOOS == "linux" {
+		// MounterForceUnmounter is only implemented on Linux now
+		mounter = mounter.(mount.MounterForceUnmounter)
+	}
 	return &mount.SafeFormatAndMount{
-		Interface: mount.New(""),
+		Interface: mounter,
 		Exec:      utilexec.New(),
 	}, nil
 }

pkg/smb/smb_common_linux.go

@@ -20,8 +20,13 @@ limitations under the License.
 package smb
 
 import (
+	"fmt"
 	"os"
+	"os/exec"
+	"strings"
+	"time"
 
+	"k8s.io/klog/v2"
 	mount "k8s.io/mount-utils"
 )
 
@@ -34,7 +39,21 @@ func CleanupSMBMountPoint(m *mount.SafeFormatAndMount, target string, extensiveM
 }
 
 func CleanupMountPoint(m *mount.SafeFormatAndMount, target string, extensiveMountCheck bool) error {
-	return mount.CleanupMountPoint(target, m, extensiveMountCheck)
+	var err error
+	extensiveMountPointCheck := true
+	forceUnmounter, ok := m.Interface.(mount.MounterForceUnmounter)
+	if ok {
+		klog.V(2).Infof("force unmount on %s", target)
+		err = mount.CleanupMountWithForce(target, forceUnmounter, extensiveMountPointCheck, 30*time.Second)
+	} else {
+		err = mount.CleanupMountPoint(target, m.Interface, extensiveMountPointCheck)
+	}
+
+	if err != nil && strings.Contains(err.Error(), "target is busy") {
+		klog.Warningf("unmount on %s failed with %v, try lazy unmount", target, err)
+		err = forceUmount(target)
+	}
+	return err
 }
 
 func preparePublishPath(path string, m *mount.SafeFormatAndMount) error {
@@ -48,3 +67,12 @@ func prepareStagePath(path string, m *mount.SafeFormatAndMount) error {
 func Mkdir(m *mount.SafeFormatAndMount, name string, perm os.FileMode) error {
 	return os.Mkdir(name, perm)
 }
+
+func forceUmount(path string) error {
+	cmd := exec.Command("umount", "-lf", path)
+	out, cmderr := cmd.CombinedOutput()
+	if cmderr != nil {
+		return fmt.Errorf("lazy unmount on %s failed with %v, output: %s", path, cmderr, string(out))
+	}
+	return nil
+}