Merge pull request #62102 from cofyc/fixlocalvolumefsgroup

Automatic merge from submit-queue (batch tested with PRs 64013, 63896, 64139, 57527, 62102). 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>.

Setup fsGroup for local volumes correctly

**What this PR does / why we need it**:

This pr fixes fsGroup check in local volume in containerized kubelet. Except this, it also fixes fsGroup check when volume source is a normal directory whether kubelet is running on the host or in a container.

**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
Fixes #61741 

**Special notes for your reviewer**:

Bind mounts are detected in `/proc/mounts`, but it does not contain root of mount for bind mounts. So `mount.GetMountRefsByDev()` cannot get all references if source is a normal directory. e.g.

```
# mkdir /tmp/src /mnt/dst
# mount --bind /tmp/src /tmp/src # required by local-volume-provisioner, see https://github.com/kubernetes-incubator/external-storage/pull/499
# mount --bind /tmp/src /mnt/dst
# grep -P 'src|dst' /proc/mounts 
tmpfs /tmp/src tmpfs rw,nosuid,nodev,noatime,size=4194304k 0 0
tmpfs /mnt/dst tmpfs rw,nosuid,nodev,noatime,size=4194304k 0 0
# grep -P 'src|dst' /proc/self/mountinfo 
234 409 0:42 /src /tmp/src rw,nosuid,nodev,noatime shared:30 - tmpfs tmpfs rw,size=4194304k
235 24 0:42 /src /mnt/dst rw,nosuid,nodev,noatime shared:30 - tmpfs tmpfs rw,size=4194304k
```

We need to compare root of mount and device in this case.

**Release note**:

```release-note
NONE
```

pkg/util/mount/mount_linux.go

@@ -42,6 +42,8 @@ const (
 	maxListTries = 3
 	// Number of fields per line in /proc/mounts as per the fstab man page.
 	expectedNumFieldsPerLine = 6
+	// At least number of fields per line in /proc/<pid>/mountinfo.
+	expectedAtLeastNumFieldsPerMountInfo = 10
 	// Location of the mount file to use
 	procMountsPath = "/proc/mounts"
 	// Location of the mountinfo file
@@ -602,7 +604,7 @@ func isShared(mount string, mountInfoPath string) (bool, error) {
 	}
 
 	// parse optional parameters
-	for _, opt := range info.optional {
+	for _, opt := range info.optionalFields {
 		if strings.HasPrefix(opt, "shared:") {
 			return true, nil
 		}
@@ -610,14 +612,27 @@ func isShared(mount string, mountInfoPath string) (bool, error) {
 	return false, nil
 }
 
+// This represents a single line in /proc/<pid>/mountinfo.
 type mountInfo struct {
-	// Path of the mount point
+	// Unique ID for the mount (maybe reused after umount).
+	id int
+	// The ID of the parent mount (or of self for the root of this mount namespace's mount tree).
+	parentID int
+	// The value of `st_dev` for files on this filesystem.
+	majorMinor string
+	// The pathname of the directory in the filesystem which forms the root of this mount.
+	root string
+	// Mount source, filesystem-specific information. e.g. device, tmpfs name.
+	source string
+	// Mount point, the pathname of the mount point.
 	mountPoint string
-	// list of "optional parameters", mount propagation is one of them
+	// Optional fieds, zero or more fields of the form "tag[:value]".
-	optional []string
+	optionalFields []string
-	// mount options
+	// The filesystem type in the form "type[.subtype]".
+	fsType string
+	// Per-mount options.
 	mountOptions []string
-	// super options: per-superblock options.
+	// Per-superblock options.
 	superOptions []string
 }
 
@@ -637,20 +652,38 @@ func parseMountInfo(filename string) ([]mountInfo, error) {
 		}
 		// See `man proc` for authoritative description of format of the file.
 		fields := strings.Fields(line)
-		if len(fields) < 10 {
+		if len(fields) < expectedAtLeastNumFieldsPerMountInfo {
-			return nil, fmt.Errorf("wrong number of fields in (expected %d, got %d): %s", 10, len(fields), line)
+			return nil, fmt.Errorf("wrong number of fields in (expected at least %d, got %d): %s", expectedAtLeastNumFieldsPerMountInfo, len(fields), line)
+		}
+		id, err := strconv.Atoi(fields[0])
+		if err != nil {
+			return nil, err
+		}
+		parentID, err := strconv.Atoi(fields[1])
+		if err != nil {
+			return nil, err
 		}
 		info := mountInfo{
+			id:           id,
+			parentID:     parentID,
+			majorMinor:   fields[2],
+			root:         fields[3],
 			mountPoint:   fields[4],
 			mountOptions: strings.Split(fields[5], ","),
-			optional:     []string{},
 		}
 		// All fields until "-" are "optional fields".
-		for i := 6; i < len(fields) && fields[i] != "-"; i++ {
+		i := 6
-			info.optional = append(info.optional, fields[i])
+		for ; i < len(fields) && fields[i] != "-"; i++ {
+			info.optionalFields = append(info.optionalFields, fields[i])
 		}
-		superOpts := fields[len(fields)-1]
+		// Parse the rest 3 fields.
-		info.superOptions = strings.Split(superOpts, ",")
+		i += 1
+		if len(fields)-i < 3 {
+			return nil, fmt.Errorf("expect 3 fields in %s, got %d", line, len(fields)-i)
+		}
+		info.fsType = fields[i]
+		info.source = fields[i+1]
+		info.superOptions = strings.Split(fields[i+2], ",")
 		infos = append(infos, info)
 	}
 	return infos, nil
@@ -971,7 +1004,7 @@ func (mounter *Mounter) GetMountRefs(pathname string) ([]string, error) {
 	if err != nil {
 		return nil, err
 	}
-	return getMountRefsByDev(mounter, realpath)
+	return searchMountPoints(realpath, procMountInfoPath)
 }
 
 func (mounter *Mounter) GetSELinuxSupport(pathname string) (bool, error) {
@@ -1220,3 +1253,51 @@ func doSafeOpen(pathname string, base string) (int, error) {
 
 	return finalFD, nil
 }
+
+// searchMountPoints finds all mount references to the source, returns a list of
+// mountpoints.
+// This function assumes source cannot be device.
+// Some filesystems may share a source name, e.g. tmpfs. And for bind mounting,
+// it's possible to mount a non-root path of a filesystem, so we need to use
+// root path and major:minor to represent mount source uniquely.
+// This implementation is shared between Linux and NsEnterMounter
+func searchMountPoints(hostSource, mountInfoPath string) ([]string, error) {
+	mis, err := parseMountInfo(mountInfoPath)
+	if err != nil {
+		return nil, err
+	}
+
+	mountID := 0
+	rootPath := ""
+	majorMinor := ""
+
+	// Finding the underlying root path and major:minor if possible.
+	// We need search in backward order because it's possible for later mounts
+	// to overlap earlier mounts.
+	for i := len(mis) - 1; i >= 0; i-- {
+		if hostSource == mis[i].mountPoint || pathWithinBase(hostSource, mis[i].mountPoint) {
+			// If it's a mount point or path under a mount point.
+			mountID = mis[i].id
+			rootPath = filepath.Join(mis[i].root, strings.TrimPrefix(hostSource, mis[i].mountPoint))
+			majorMinor = mis[i].majorMinor
+			break
+		}
+	}
+
+	if rootPath == "" || majorMinor == "" {
+		return nil, fmt.Errorf("failed to get root path and major:minor for %s", hostSource)
+	}
+
+	var refs []string
+	for i := range mis {
+		if mis[i].id == mountID {
+			// Ignore mount entry for mount source itself.
+			continue
+		}
+		if mis[i].root == rootPath && mis[i].majorMinor == majorMinor {
+			refs = append(refs, mis[i].mountPoint)
+		}
+	}
+
+	return refs, nil
+}

pkg/util/mount/mount_linux_test.go

@@ -1383,6 +1383,19 @@ func TestParseMountInfo(t *testing.T) {
 187 23 0:58 / /var/lib/kubelet/pods/1fc5ea21-eff4-11e7-ac80-0e858b8eaf40/volumes/kubernetes.io~nfs/nfs2 rw,relatime shared:96 - nfs4 172.18.4.223:/srv/nfs2 rw,vers=4.0,rsize=524288,wsize=524288,namlen=255,hard,proto=tcp,port=0,timeo=600,retrans=2,sec=sys,clientaddr=172.18.4.223,local_lock=none,addr=172.18.4.223
 188 24 0:58 / /var/lib/kubelet/pods/43219158-e5e1-11e7-a392-0e858b8eaf40/volume-subpaths/nfs1/subpath1/0 rw,relatime shared:89 - nfs4 172.18.4.223:/srv/nfs/foo rw,vers=4.0,rsize=524288,wsize=524288,namlen=255,hard,proto=tcp,port=0,timeo=600,retrans=2,sec=sys,clientaddr=172.18.4.223,local_lock=none,addr=172.18.4.223
 347 60 0:71 / /var/lib/kubelet/pods/13195d46-f9fa-11e7-bbf1-5254007a695a/volumes/kubernetes.io~nfs/vol2 rw,relatime shared:170 - nfs 172.17.0.3:/exports/2 rw,vers=3,rsize=1048576,wsize=1048576,namlen=255,hard,proto=tcp,timeo=600,retrans=2,sec=sys,mountaddr=172.17.0.3,mountvers=3,mountport=20048,mountproto=udp,local_lock=none,addr=172.17.0.3
+222 24 253:0 /tmp/src /mnt/dst rw,relatime shared:1 - ext4 /dev/mapper/vagrant--vg-root rw,errors=remount-ro,data=ordered
+28 18 0:24 / /sys/fs/cgroup ro,nosuid,nodev,noexec shared:9 - tmpfs tmpfs ro,mode=755
+29 28 0:25 / /sys/fs/cgroup/systemd rw,nosuid,nodev,noexec,relatime shared:10 - cgroup cgroup rw,xattr,release_agent=/lib/systemd/systemd-cgroups-agent,name=systemd
+31 28 0:27 / /sys/fs/cgroup/cpuset rw,nosuid,nodev,noexec,relatime shared:13 - cgroup cgroup rw,cpuset
+32 28 0:28 / /sys/fs/cgroup/cpu,cpuacct rw,nosuid,nodev,noexec,relatime shared:14 - cgroup cgroup rw,cpu,cpuacct
+33 28 0:29 / /sys/fs/cgroup/freezer rw,nosuid,nodev,noexec,relatime shared:15 - cgroup cgroup rw,freezer
+34 28 0:30 / /sys/fs/cgroup/net_cls,net_prio rw,nosuid,nodev,noexec,relatime shared:16 - cgroup cgroup rw,net_cls,net_prio
+35 28 0:31 / /sys/fs/cgroup/pids rw,nosuid,nodev,noexec,relatime shared:17 - cgroup cgroup rw,pids
+36 28 0:32 / /sys/fs/cgroup/devices rw,nosuid,nodev,noexec,relatime shared:18 - cgroup cgroup rw,devices
+37 28 0:33 / /sys/fs/cgroup/hugetlb rw,nosuid,nodev,noexec,relatime shared:19 - cgroup cgroup rw,hugetlb
+38 28 0:34 / /sys/fs/cgroup/blkio rw,nosuid,nodev,noexec,relatime shared:20 - cgroup cgroup rw,blkio
+39 28 0:35 / /sys/fs/cgroup/memory rw,nosuid,nodev,noexec,relatime shared:21 - cgroup cgroup rw,memory
+40 28 0:36 / /sys/fs/cgroup/perf_event rw,nosuid,nodev,noexec,relatime shared:22 - cgroup cgroup rw,perf_event
 `
 	tempDir, filename, err := writeFile(info)
 	if err != nil {
@@ -1392,17 +1405,103 @@ func TestParseMountInfo(t *testing.T) {
 
 	tests := []struct {
 		name         string
-		mountPoint   string
+		id           int
 		expectedInfo mountInfo
 	}{
 		{
 			"simple bind mount",
-			"/var/lib/kubelet",
+			189,
 			mountInfo{
-				mountPoint:   "/var/lib/kubelet",
+				id:             189,
-				optional:     []string{"shared:30"},
+				parentID:       80,
-				mountOptions: []string{"rw", "relatime"},
+				majorMinor:     "8:1",
-				superOptions: []string{"rw", "commit=30", "data=ordered"},
+				root:           "/var/lib/kubelet",
+				source:         "/dev/sda1",
+				mountPoint:     "/var/lib/kubelet",
+				optionalFields: []string{"shared:30"},
+				fsType:         "ext4",
+				mountOptions:   []string{"rw", "relatime"},
+				superOptions:   []string{"rw", "commit=30", "data=ordered"},
+			},
+		},
+		{
+			"bind mount a directory",
+			222,
+			mountInfo{
+				id:             222,
+				parentID:       24,
+				majorMinor:     "253:0",
+				root:           "/tmp/src",
+				source:         "/dev/mapper/vagrant--vg-root",
+				mountPoint:     "/mnt/dst",
+				optionalFields: []string{"shared:1"},
+				fsType:         "ext4",
+				mountOptions:   []string{"rw", "relatime"},
+				superOptions:   []string{"rw", "errors=remount-ro", "data=ordered"},
+			},
+		},
+		{
+			"more than one optional fields",
+			224,
+			mountInfo{
+				id:             224,
+				parentID:       62,
+				majorMinor:     "253:0",
+				root:           "/var/lib/docker/devicemapper/test/shared",
+				source:         "/dev/mapper/ssd-root",
+				mountPoint:     "/var/lib/docker/devicemapper/test/shared",
+				optionalFields: []string{"master:1", "shared:44"},
+				fsType:         "ext4",
+				mountOptions:   []string{"rw", "relatime"},
+				superOptions:   []string{"rw", "seclabel", "data=ordered"},
+			},
+		},
+		{
+			"cgroup-mountpoint",
+			28,
+			mountInfo{
+				id:             28,
+				parentID:       18,
+				majorMinor:     "0:24",
+				root:           "/",
+				source:         "tmpfs",
+				mountPoint:     "/sys/fs/cgroup",
+				optionalFields: []string{"shared:9"},
+				fsType:         "tmpfs",
+				mountOptions:   []string{"ro", "nosuid", "nodev", "noexec"},
+				superOptions:   []string{"ro", "mode=755"},
+			},
+		},
+		{
+			"cgroup-subsystem-systemd-mountpoint",
+			29,
+			mountInfo{
+				id:             29,
+				parentID:       28,
+				majorMinor:     "0:25",
+				root:           "/",
+				source:         "cgroup",
+				mountPoint:     "/sys/fs/cgroup/systemd",
+				optionalFields: []string{"shared:10"},
+				fsType:         "cgroup",
+				mountOptions:   []string{"rw", "nosuid", "nodev", "noexec", "relatime"},
+				superOptions:   []string{"rw", "xattr", "release_agent=/lib/systemd/systemd-cgroups-agent", "name=systemd"},
+			},
+		},
+		{
+			"cgroup-subsystem-cpuset-mountpoint",
+			31,
+			mountInfo{
+				id:             31,
+				parentID:       28,
+				majorMinor:     "0:27",
+				root:           "/",
+				source:         "cgroup",
+				mountPoint:     "/sys/fs/cgroup/cpuset",
+				optionalFields: []string{"shared:13"},
+				fsType:         "cgroup",
+				mountOptions:   []string{"rw", "nosuid", "nodev", "noexec", "relatime"},
+				superOptions:   []string{"rw", "cpuset"},
 			},
 		},
 	}
@@ -1415,7 +1514,7 @@ func TestParseMountInfo(t *testing.T) {
 	for _, test := range tests {
 		found := false
 		for _, info := range infos {
-			if info.mountPoint == test.mountPoint {
+			if info.id == test.id {
 				found = true
 				if !reflect.DeepEqual(info, test.expectedInfo) {
 					t.Errorf("Test case %q:\n expected: %+v\n got:      %+v", test.name, test.expectedInfo, info)
@@ -1424,7 +1523,7 @@ func TestParseMountInfo(t *testing.T) {
 			}
 		}
 		if !found {
-			t.Errorf("Test case %q: mountPoint %s not found", test.name, test.mountPoint)
+			t.Errorf("Test case %q: mountPoint %d not found", test.name, test.id)
 		}
 	}
 }
@@ -1917,3 +2016,153 @@ func isOperationNotPermittedError(err error) bool {
 	}
 	return false
 }
+
+func TestSearchMountPoints(t *testing.T) {
+	base := `
+19 25 0:18 / /sys rw,nosuid,nodev,noexec,relatime shared:7 - sysfs sysfs rw
+20 25 0:4 / /proc rw,nosuid,nodev,noexec,relatime shared:12 - proc proc rw
+21 25 0:6 / /dev rw,nosuid,relatime shared:2 - devtmpfs udev rw,size=4058156k,nr_inodes=1014539,mode=755
+22 21 0:14 / /dev/pts rw,nosuid,noexec,relatime shared:3 - devpts devpts rw,gid=5,mode=620,ptmxmode=000
+23 25 0:19 / /run rw,nosuid,noexec,relatime shared:5 - tmpfs tmpfs rw,size=815692k,mode=755
+25 0 252:0 / / rw,relatime shared:1 - ext4 /dev/mapper/ubuntu--vg-root rw,errors=remount-ro,data=ordered
+26 19 0:12 / /sys/kernel/security rw,nosuid,nodev,noexec,relatime shared:8 - securityfs securityfs rw
+27 21 0:21 / /dev/shm rw,nosuid,nodev shared:4 - tmpfs tmpfs rw
+28 23 0:22 / /run/lock rw,nosuid,nodev,noexec,relatime shared:6 - tmpfs tmpfs rw,size=5120k
+29 19 0:23 / /sys/fs/cgroup ro,nosuid,nodev,noexec shared:9 - tmpfs tmpfs ro,mode=755
+30 29 0:24 / /sys/fs/cgroup/systemd rw,nosuid,nodev,noexec,relatime shared:10 - cgroup cgroup rw,xattr,release_agent=/lib/systemd/systemd-cgroups-agent,name=systemd
+31 19 0:25 / /sys/fs/pstore rw,nosuid,nodev,noexec,relatime shared:11 - pstore pstore rw
+32 29 0:26 / /sys/fs/cgroup/devices rw,nosuid,nodev,noexec,relatime shared:13 - cgroup cgroup rw,devices
+33 29 0:27 / /sys/fs/cgroup/freezer rw,nosuid,nodev,noexec,relatime shared:14 - cgroup cgroup rw,freezer
+34 29 0:28 / /sys/fs/cgroup/pids rw,nosuid,nodev,noexec,relatime shared:15 - cgroup cgroup rw,pids
+35 29 0:29 / /sys/fs/cgroup/blkio rw,nosuid,nodev,noexec,relatime shared:16 - cgroup cgroup rw,blkio
+36 29 0:30 / /sys/fs/cgroup/memory rw,nosuid,nodev,noexec,relatime shared:17 - cgroup cgroup rw,memory
+37 29 0:31 / /sys/fs/cgroup/perf_event rw,nosuid,nodev,noexec,relatime shared:18 - cgroup cgroup rw,perf_event
+38 29 0:32 / /sys/fs/cgroup/hugetlb rw,nosuid,nodev,noexec,relatime shared:19 - cgroup cgroup rw,hugetlb
+39 29 0:33 / /sys/fs/cgroup/cpu,cpuacct rw,nosuid,nodev,noexec,relatime shared:20 - cgroup cgroup rw,cpu,cpuacct
+40 29 0:34 / /sys/fs/cgroup/cpuset rw,nosuid,nodev,noexec,relatime shared:21 - cgroup cgroup rw,cpuset
+41 29 0:35 / /sys/fs/cgroup/net_cls,net_prio rw,nosuid,nodev,noexec,relatime shared:22 - cgroup cgroup rw,net_cls,net_prio
+58 25 7:1 / /mnt/disks/blkvol1 rw,relatime shared:38 - ext4 /dev/loop1 rw,data=ordere
+`
+
+	testcases := []struct {
+		name         string
+		source       string
+		mountInfos   string
+		expectedRefs []string
+		expectedErr  error
+	}{
+		{
+			"dir",
+			"/mnt/disks/vol1",
+			base,
+			nil,
+			nil,
+		},
+		{
+			"dir-used",
+			"/mnt/disks/vol1",
+			base + `
+56 25 252:0 /mnt/disks/vol1 /var/lib/kubelet/pods/1890aef5-5a60-11e8-962f-000c29bb0377/volumes/kubernetes.io~local-volume/local-pv-test rw,relatime shared:1 - ext4 /dev/mapper/ubuntu--vg-root rw,errors=remount-ro,data=ordered
+57 25 0:45 / /mnt/disks/vol rw,relatime shared:36 - tmpfs tmpfs rw
+`,
+			[]string{"/var/lib/kubelet/pods/1890aef5-5a60-11e8-962f-000c29bb0377/volumes/kubernetes.io~local-volume/local-pv-test"},
+			nil,
+		},
+		{
+			"tmpfs-vol",
+			"/mnt/disks/vol1",
+			base + `120 25 0:76 / /mnt/disks/vol1 rw,relatime shared:41 - tmpfs vol1 rw,size=10000k
+`,
+			nil,
+			nil,
+		},
+		{
+			"tmpfs-vol-used-by-two-pods",
+			"/mnt/disks/vol1",
+			base + `120 25 0:76 / /mnt/disks/vol1 rw,relatime shared:41 - tmpfs vol1 rw,size=10000k
+196 25 0:76 / /var/lib/kubelet/pods/ade3ac21-5a5b-11e8-8559-000c29bb0377/volumes/kubernetes.io~local-volume/local-pv-8f263585 rw,relatime shared:41 - tmpfs vol1 rw,size=10000k
+228 25 0:76 / /var/lib/kubelet/pods/ac60532d-5a5b-11e8-8559-000c29bb0377/volumes/kubernetes.io~local-volume/local-pv-8f263585 rw,relatime shared:41 - tmpfs vol1 rw,size=10000k
+`,
+			[]string{
+				"/var/lib/kubelet/pods/ade3ac21-5a5b-11e8-8559-000c29bb0377/volumes/kubernetes.io~local-volume/local-pv-8f263585",
+				"/var/lib/kubelet/pods/ac60532d-5a5b-11e8-8559-000c29bb0377/volumes/kubernetes.io~local-volume/local-pv-8f263585",
+			},
+			nil,
+		},
+		{
+			"tmpfs-subdir-used-indirectly-via-bindmount-dir-by-one-pod",
+			"/mnt/vol1/foo",
+			base + `177 25 0:46 / /mnt/data rw,relatime shared:37 - tmpfs data rw
+190 25 0:46 /vol1 /mnt/vol1 rw,relatime shared:37 - tmpfs data rw
+191 25 0:46 /vol2 /mnt/vol2 rw,relatime shared:37 - tmpfs data rw
+62 25 0:46 /vol1/foo /var/lib/kubelet/pods/e25f2f01-5b06-11e8-8694-000c29bb0377/volumes/kubernetes.io~local-volume/local-pv-test rw,relatime shared:37 - tmpfs data rw
+`,
+			[]string{"/var/lib/kubelet/pods/e25f2f01-5b06-11e8-8694-000c29bb0377/volumes/kubernetes.io~local-volume/local-pv-test"},
+			nil,
+		},
+		{
+			"dir-bindmounted",
+			"/mnt/disks/vol2",
+			base + `342 25 252:0 /mnt/disks/vol2 /mnt/disks/vol2 rw,relatime shared:1 - ext4 /dev/mapper/ubuntu--vg-root rw,errors=remount-ro,data=ordered
+`,
+			nil,
+			nil,
+		},
+		{
+			"dir-bindmounted-used-by-one-pod",
+			"/mnt/disks/vol2",
+			base + `342 25 252:0 /mnt/disks/vol2 /mnt/disks/vol2 rw,relatime shared:1 - ext4 /dev/mapper/ubuntu--vg-root rw,errors=remount-ro,data=ordered
+77 25 252:0 /mnt/disks/vol2 /var/lib/kubelet/pods/f30dc360-5a5d-11e8-962f-000c29bb0377/volumes/kubernetes.io~local-volume/local-pv-1fb30a1c rw,relatime shared:1 - ext4 /dev/mapper/ubuntu--vg-root rw,errors=remount-ro,data=ordered
+`,
+			[]string{"/var/lib/kubelet/pods/f30dc360-5a5d-11e8-962f-000c29bb0377/volumes/kubernetes.io~local-volume/local-pv-1fb30a1c"},
+			nil,
+		},
+		{
+			"blockfs",
+			"/mnt/disks/blkvol1",
+			base + `58 25 7:1 / /mnt/disks/blkvol1 rw,relatime shared:38 - ext4 /dev/loop1 rw,data=ordered
+`,
+			nil,
+			nil,
+		},
+		{
+			"blockfs-used-by-one-pod",
+			"/mnt/disks/blkvol1",
+			base + `58 25 7:1 / /mnt/disks/blkvol1 rw,relatime shared:38 - ext4 /dev/loop1 rw,data=ordered
+62 25 7:1 / /var/lib/kubelet/pods/f19fe4e2-5a63-11e8-962f-000c29bb0377/volumes/kubernetes.io~local-volume/local-pv-test rw,relatime shared:38 - ext4 /dev/loop1 rw,data=ordered
+`,
+			[]string{"/var/lib/kubelet/pods/f19fe4e2-5a63-11e8-962f-000c29bb0377/volumes/kubernetes.io~local-volume/local-pv-test"},
+			nil,
+		},
+		{
+			"blockfs-used-by-two-pods",
+			"/mnt/disks/blkvol1",
+			base + `58 25 7:1 / /mnt/disks/blkvol1 rw,relatime shared:38 - ext4 /dev/loop1 rw,data=ordered
+62 25 7:1 / /var/lib/kubelet/pods/f19fe4e2-5a63-11e8-962f-000c29bb0377/volumes/kubernetes.io~local-volume/local-pv-test rw,relatime shared:38 - ext4 /dev/loop1 rw,data=ordered
+95 25 7:1 / /var/lib/kubelet/pods/4854a48b-5a64-11e8-962f-000c29bb0377/volumes/kubernetes.io~local-volume/local-pv-test rw,relatime shared:38 - ext4 /dev/loop1 rw,data=ordered
+`,
+			[]string{"/var/lib/kubelet/pods/f19fe4e2-5a63-11e8-962f-000c29bb0377/volumes/kubernetes.io~local-volume/local-pv-test",
+				"/var/lib/kubelet/pods/4854a48b-5a64-11e8-962f-000c29bb0377/volumes/kubernetes.io~local-volume/local-pv-test"},
+			nil,
+		},
+	}
+	tmpFile, err := ioutil.TempFile("", "test-get-filetype")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer os.Remove(tmpFile.Name())
+	defer tmpFile.Close()
+	for _, v := range testcases {
+		tmpFile.Truncate(0)
+		tmpFile.Seek(0, 0)
+		tmpFile.WriteString(v.mountInfos)
+		tmpFile.Sync()
+		refs, err := searchMountPoints(v.source, tmpFile.Name())
+		if !reflect.DeepEqual(refs, v.expectedRefs) {
+			t.Errorf("test %q: expected Refs: %#v, got %#v", v.name, v.expectedRefs, refs)
+		}
+		if !reflect.DeepEqual(err, v.expectedErr) {
+			t.Errorf("test %q: expected err: %v, got %v", v.name, v.expectedErr, err)
+		}
+	}
+}

pkg/util/mount/nsenter_mount.go

@@ -333,7 +333,7 @@ func (mounter *NsenterMounter) GetMountRefs(pathname string) ([]string, error) {
 	if err != nil {
 		return nil, err
 	}
-	return getMountRefsByDev(mounter, hostpath)
+	return searchMountPoints(hostpath, procMountInfoPath)
 }
 
 func (mounter *NsenterMounter) GetFSGroup(pathname string) (int64, error) {

test/e2e/storage/persistent_volumes-local.go

@@ -290,14 +290,6 @@ var _ = utils.SIGDescribe("PersistentVolumes-local ", func() {
 				})
 
 				It("should set fsGroup for one pod", func() {
-					skipTypes := sets.NewString(
-						string(DirectoryBindMountedLocalVolumeType),
-						string(DirectoryLinkBindMountedLocalVolumeType),
-					)
-					if skipTypes.Has(string(testVolType)) {
-						// TODO(cofyc): Test it when bug is fixed.
-						framework.Skipf("Skipped when volume type is %v", testVolType)
-					}
 					By("Checking fsGroup is set")
 					pod := createPodWithFsGroupTest(config, testVol, 1234, 1234)
 					By("Deleting pod")
@@ -305,14 +297,6 @@ var _ = utils.SIGDescribe("PersistentVolumes-local ", func() {
 				})
 
 				It("should set same fsGroup for two pods simultaneously", func() {
-					skipTypes := sets.NewString(
-						string(DirectoryBindMountedLocalVolumeType),
-						string(DirectoryLinkBindMountedLocalVolumeType),
-					)
-					if skipTypes.Has(string(testVolType)) {
-						// TODO(cofyc): Test it when bug is fixed.
-						framework.Skipf("Skipped when volume type is %v", testVolType)
-					}
 					fsGroup := int64(1234)
 					By("Create first pod and check fsGroup is set")
 					pod1 := createPodWithFsGroupTest(config, testVol, fsGroup, fsGroup)
@@ -325,14 +309,6 @@ var _ = utils.SIGDescribe("PersistentVolumes-local ", func() {
 				})
 
 				It("should set different fsGroup for second pod if first pod is deleted", func() {
-					skipTypes := sets.NewString(
-						string(DirectoryBindMountedLocalVolumeType),
-						string(DirectoryLinkBindMountedLocalVolumeType),
-					)
-					if skipTypes.Has(string(testVolType)) {
-						// TODO(cofyc): Test it when bug is fixed.
-						framework.Skipf("Skipped when volume type is %v", testVolType)
-					}
 					fsGroup1, fsGroup2 := int64(1234), int64(4321)
 					By("Create first pod and check fsGroup is set")
 					pod1 := createPodWithFsGroupTest(config, testVol, fsGroup1, fsGroup1)
@@ -346,16 +322,6 @@ var _ = utils.SIGDescribe("PersistentVolumes-local ", func() {
 				})
 
 				It("should not set different fsGroups for two pods simultaneously", func() {
-					skipTypes := sets.NewString(
-						string(DirectoryLocalVolumeType),
-						string(DirectoryLinkLocalVolumeType),
-						string(DirectoryBindMountedLocalVolumeType),
-						string(DirectoryLinkBindMountedLocalVolumeType),
-					)
-					if skipTypes.Has(string(testVolType)) {
-						// TODO(cofyc): Test it when bug is fixed.
-						framework.Skipf("Skipped when volume type is %v", testVolType)
-					}
 					fsGroup1, fsGroup2 := int64(1234), int64(4321)
 					By("Create first pod and check fsGroup is set")
 					pod1 := createPodWithFsGroupTest(config, testVol, fsGroup1, fsGroup1)