Merge pull request #52401 from andyzhangx/azuredisk-getdevfunc

Automatic merge from submit-queue. If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

fix warning messages due to GetMountRefs func not implemented in windows

**What this PR does / why we need it**:
This PR completes the windows implementation of GetMountRefs in mount.go. In linux, the GetMountRefs implementaion is: read `/proc/mounts` and find all mount points, while in Windows, there is no such `/proc/mounts` place which shows all mounting points. 
There is another way in windows, **we could walk through(by `getAllParentLinks` func) the mount path(symbolic link) and get all symlinks until we got the final device, which is actually a drive**.

**Which issue this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close that issue when PR gets merged)*: fixes #54670
This PR fixed the warnning issue mentioned in https://github.com/kubernetes/kubernetes/pull/51252

**Special notes for your reviewer**:
Some values in the code would be like follwoing:
```
GetMountRefs: mountPath ("\\var\\lib\\kubelet\\pods/4c74b128-92ca-11e7-b86b-000d3a36d70c/volumes/kubernetes.io~azure-disk/pvc-1cc91c70-92ca-11e7-b86b-000d3a36d70c")
getAllParentLinks: refs (["" "" "c:\\var\\lib\\kubelet\\plugins\\kubernetes.io\\azure-disk\\mounts\\b1246717734" "G:\\"])
basemountPath c:\var\lib\kubelet\plugins\kubernetes.io\azure-disk\mounts
got volumeID b1246717734
```

**Release note**:

```
fix warning messages due to GetMountRefs func not implemented in windows
```

pkg/util/mount/mount.go

@@ -19,12 +19,7 @@ limitations under the License.
 package mount
 
 import (
-	"fmt"
-	"path"
 	"path/filepath"
-	"strings"
-
-	"github.com/golang/glog"
 )
 
 type FileType string
@@ -138,41 +133,6 @@ func (mounter *SafeFormatAndMount) FormatAndMount(source string, target string,
 	return mounter.formatAndMount(source, target, fstype, options)
 }
 
-// GetMountRefs finds all other references to the device referenced
-// by mountPath; returns a list of paths.
-func GetMountRefs(mounter Interface, mountPath string) ([]string, error) {
-	mps, err := mounter.List()
-	if err != nil {
-		return nil, err
-	}
-	// Find the device name.
-	deviceName := ""
-	// If mountPath is symlink, need get its target path.
-	slTarget, err := filepath.EvalSymlinks(mountPath)
-	if err != nil {
-		slTarget = mountPath
-	}
-	for i := range mps {
-		if mps[i].Path == slTarget {
-			deviceName = mps[i].Device
-			break
-		}
-	}
-
-	// Find all references to the device.
-	var refs []string
-	if deviceName == "" {
-		glog.Warningf("could not determine device for path: %q", mountPath)
-	} else {
-		for i := range mps {
-			if mps[i].Device == deviceName && mps[i].Path != slTarget {
-				refs = append(refs, mps[i].Path)
-			}
-		}
-	}
-	return refs, nil
-}
-
 // GetMountRefsByDev finds all references to the device provided
 // by mountPath; returns a list of paths.
 func GetMountRefsByDev(mounter Interface, mountPath string) ([]string, error) {
@@ -239,34 +199,6 @@ func GetDeviceNameFromMount(mounter Interface, mountPath string) (string, int, e
 	return device, refCount, nil
 }
 
-// getDeviceNameFromMount find the device name from /proc/mounts in which
-// the mount path reference should match the given plugin directory. In case no mount path reference
-// matches, returns the volume name taken from its given mountPath
-func getDeviceNameFromMount(mounter Interface, mountPath, pluginDir string) (string, error) {
-	refs, err := GetMountRefs(mounter, mountPath)
-	if err != nil {
-		glog.V(4).Infof("GetMountRefs failed for mount path %q: %v", mountPath, err)
-		return "", err
-	}
-	if len(refs) == 0 {
-		glog.V(4).Infof("Directory %s is not mounted", mountPath)
-		return "", fmt.Errorf("directory %s is not mounted", mountPath)
-	}
-	basemountPath := path.Join(pluginDir, MountsInGlobalPDPath)
-	for _, ref := range refs {
-		if strings.HasPrefix(ref, basemountPath) {
-			volumeID, err := filepath.Rel(basemountPath, ref)
-			if err != nil {
-				glog.Errorf("Failed to get volume id from mount %s - %v", mountPath, err)
-				return "", err
-			}
-			return volumeID, nil
-		}
-	}
-
-	return path.Base(mountPath), nil
-}
-
 // IsNotMountPoint determines if a directory is a mountpoint.
 // It should return ErrNotExist when the directory does not exist.
 // This method uses the List() of all mountpoints

pkg/util/mount/mount_linux.go

@@ -22,6 +22,8 @@ import (
 	"fmt"
 	"os"
 	"os/exec"
+	"path"
+	"path/filepath"
 	"strconv"
 	"strings"
 	"syscall"
@@ -141,6 +143,41 @@ func (m *Mounter) doMount(mounterPath string, mountCmd string, source string, ta
 	return err
 }
 
+// GetMountRefs finds all other references to the device referenced
+// by mountPath; returns a list of paths.
+func GetMountRefs(mounter Interface, mountPath string) ([]string, error) {
+	mps, err := mounter.List()
+	if err != nil {
+		return nil, err
+	}
+	// Find the device name.
+	deviceName := ""
+	// If mountPath is symlink, need get its target path.
+	slTarget, err := filepath.EvalSymlinks(mountPath)
+	if err != nil {
+		slTarget = mountPath
+	}
+	for i := range mps {
+		if mps[i].Path == slTarget {
+			deviceName = mps[i].Device
+			break
+		}
+	}
+
+	// Find all references to the device.
+	var refs []string
+	if deviceName == "" {
+		glog.Warningf("could not determine device for path: %q", mountPath)
+	} else {
+		for i := range mps {
+			if mps[i].Device == deviceName && mps[i].Path != slTarget {
+				refs = append(refs, mps[i].Path)
+			}
+		}
+	}
+	return refs, nil
+}
+
 // detectSystemd returns true if OS runs with systemd as init. When not sure
 // (permission errors, ...), it returns false.
 // There may be different ways how to detect systemd, this one makes sure that
@@ -299,6 +336,34 @@ func (mounter *Mounter) GetDeviceNameFromMount(mountPath, pluginDir string) (str
 	return getDeviceNameFromMount(mounter, mountPath, pluginDir)
 }
 
+// getDeviceNameFromMount find the device name from /proc/mounts in which
+// the mount path reference should match the given plugin directory. In case no mount path reference
+// matches, returns the volume name taken from its given mountPath
+func getDeviceNameFromMount(mounter Interface, mountPath, pluginDir string) (string, error) {
+	refs, err := GetMountRefs(mounter, mountPath)
+	if err != nil {
+		glog.V(4).Infof("GetMountRefs failed for mount path %q: %v", mountPath, err)
+		return "", err
+	}
+	if len(refs) == 0 {
+		glog.V(4).Infof("Directory %s is not mounted", mountPath)
+		return "", fmt.Errorf("directory %s is not mounted", mountPath)
+	}
+	basemountPath := path.Join(pluginDir, MountsInGlobalPDPath)
+	for _, ref := range refs {
+		if strings.HasPrefix(ref, basemountPath) {
+			volumeID, err := filepath.Rel(basemountPath, ref)
+			if err != nil {
+				glog.Errorf("Failed to get volume id from mount %s - %v", mountPath, err)
+				return "", err
+			}
+			return volumeID, nil
+		}
+	}
+
+	return path.Base(mountPath), nil
+}
+
 func listProcMounts(mountFilePath string) ([]MountPoint, error) {
 	content, err := utilio.ConsistentRead(mountFilePath, maxListTries)
 	if err != nil {

pkg/util/mount/mount_unsupported.go

@@ -43,6 +43,12 @@ func (mounter *Mounter) Unmount(target string) error {
 	return nil
 }
 
+// GetMountRefs finds all other references to the device referenced
+// by mountPath; returns a list of paths.
+func GetMountRefs(mounter Interface, mountPath string) ([]string, error) {
+	return []string{}, nil
+}
+
 func (mounter *Mounter) List() ([]MountPoint, error) {
 	return []MountPoint{}, nil
 }
@@ -63,6 +69,10 @@ func (mounter *Mounter) GetDeviceNameFromMount(mountPath, pluginDir string) (str
 	return "", nil
 }
 
+func getDeviceNameFromMount(mounter Interface, mountPath, pluginDir string) (string, error) {
+	return "", nil
+}
+
 func (mounter *Mounter) DeviceOpened(pathname string) (bool, error) {
 	return false, nil
 }

pkg/util/mount/mount_windows.go

@@ -22,6 +22,7 @@ import (
 	"fmt"
 	"os"
 	"os/exec"
+	"path"
 	"path/filepath"
 	"strconv"
 	"strings"
@@ -118,6 +119,16 @@ func (mounter *Mounter) Unmount(target string) error {
 	return nil
 }
 
+// GetMountRefs finds all other references to the device(drive) referenced
+// by mountPath; returns a list of paths.
+func GetMountRefs(mounter Interface, mountPath string) ([]string, error) {
+	refs, err := getAllParentLinks(normalizeWindowsPath(mountPath))
+	if err != nil {
+		return nil, err
+	}
+	return refs, nil
+}
+
 // List returns a list of all mounted filesystems. todo
 func (mounter *Mounter) List() ([]MountPoint, error) {
 	return []MountPoint{}, nil
@@ -152,6 +163,33 @@ func (mounter *Mounter) GetDeviceNameFromMount(mountPath, pluginDir string) (str
 	return getDeviceNameFromMount(mounter, mountPath, pluginDir)
 }
 
+// getDeviceNameFromMount find the device(drive) name in which
+// the mount path reference should match the given plugin directory. In case no mount path reference
+// matches, returns the volume name taken from its given mountPath
+func getDeviceNameFromMount(mounter Interface, mountPath, pluginDir string) (string, error) {
+	refs, err := GetMountRefs(mounter, mountPath)
+	if err != nil {
+		glog.V(4).Infof("GetMountRefs failed for mount path %q: %v", mountPath, err)
+		return "", err
+	}
+	if len(refs) == 0 {
+		return "", fmt.Errorf("directory %s is not mounted", mountPath)
+	}
+	basemountPath := normalizeWindowsPath(path.Join(pluginDir, MountsInGlobalPDPath))
+	for _, ref := range refs {
+		if strings.Contains(ref, basemountPath) {
+			volumeID, err := filepath.Rel(normalizeWindowsPath(basemountPath), ref)
+			if err != nil {
+				glog.Errorf("Failed to get volume id from mount %s - %v", mountPath, err)
+				return "", err
+			}
+			return volumeID, nil
+		}
+	}
+
+	return path.Base(mountPath), nil
+}
+
 // DeviceOpened determines if the device is in use elsewhere
 func (mounter *Mounter) DeviceOpened(pathname string) (bool, error) {
 	return false, nil
@@ -300,3 +338,30 @@ func getDriveLetterByDiskNumber(diskNum string, exec Exec) (string, error) {
 	}
 	return string(output)[:1], nil
 }
+
+// getAllParentLinks walks all symbolic links and return all the parent targets recursively
+func getAllParentLinks(path string) ([]string, error) {
+	const maxIter = 255
+	links := []string{}
+	for {
+		links = append(links, path)
+		if len(links) > maxIter {
+			return links, fmt.Errorf("unexpected length of parent links: %v", links)
+		}
+
+		fi, err := os.Lstat(path)
+		if err != nil {
+			return links, fmt.Errorf("Lstat: %v", err)
+		}
+		if fi.Mode()&os.ModeSymlink == 0 {
+			break
+		}
+
+		path, err = os.Readlink(path)
+		if err != nil {
+			return links, fmt.Errorf("Readlink error: %v", err)
+		}
+	}
+
+	return links, nil
+}

pkg/util/mount/mount_windows_test.go

@@ -19,6 +19,8 @@ limitations under the License.
 package mount
 
 import (
+	"fmt"
+	"os/exec"
 	"testing"
 )
 
@@ -69,3 +71,70 @@ func TestValidateDiskNumber(t *testing.T) {
 		t.Errorf("TestValidateDiskNumber test failed, disk number : %s", diskNum)
 	}
 }
+
+func makeLink(link, target string) error {
+	if output, err := exec.Command("cmd", "/c", "mklink", "/D", link, target).CombinedOutput(); err != nil {
+		return fmt.Errorf("mklink failed: %v, link(%q) target(%q) output: %q", err, link, target, string(output))
+	}
+	return nil
+}
+
+func removeLink(link string) error {
+	if output, err := exec.Command("cmd", "/c", "rmdir", link).CombinedOutput(); err != nil {
+		return fmt.Errorf("rmdir failed: %v, output: %q", err, string(output))
+	}
+	return nil
+}
+
+func setEquivalent(set1, set2 []string) bool {
+	map1 := make(map[string]bool)
+	map2 := make(map[string]bool)
+	for _, s := range set1 {
+		map1[s] = true
+	}
+	for _, s := range set2 {
+		map2[s] = true
+	}
+
+	for s := range map1 {
+		if !map2[s] {
+			return false
+		}
+	}
+	for s := range map2 {
+		if !map1[s] {
+			return false
+		}
+	}
+	return true
+}
+
+// this func must run in admin mode, otherwise it will fail
+func TestGetMountRefs(t *testing.T) {
+	fm := &FakeMounter{MountPoints: []MountPoint{}}
+	mountPath := `c:\secondmountpath`
+	expectedRefs := []string{`c:\`, `c:\firstmountpath`, mountPath}
+
+	// remove symbolic links first
+	for i := 1; i < len(expectedRefs); i++ {
+		removeLink(expectedRefs[i])
+	}
+
+	// create symbolic links
+	for i := 1; i < len(expectedRefs); i++ {
+		if err := makeLink(expectedRefs[i], expectedRefs[i-1]); err != nil {
+			t.Errorf("makeLink failed: %v", err)
+		}
+	}
+
+	if refs, err := GetMountRefs(fm, mountPath); err != nil || !setEquivalent(expectedRefs, refs) {
+		t.Errorf("getMountRefs(%q) = %v, error: %v; expected %v", mountPath, refs, err, expectedRefs)
+	}
+
+	// remove symbolic links
+	for i := 1; i < len(expectedRefs); i++ {
+		if err := removeLink(expectedRefs[i]); err != nil {
+			t.Errorf("removeLink failed: %v", err)
+		}
+	}
+}