fs: evaluate labels from all mount points

fs/fs.go

@@ -76,6 +76,10 @@ func NewFsInfo(context Context) (FsInfo, error) {
 		labels:     make(map[string]string, 0),
 		dmsetup:    &defaultDmsetupClient{},
 	}
+
+	fsInfo.addSystemRootLabel(mounts)
+	fsInfo.addDockerImagesLabel(context, mounts)
+
 	supportedFsType := map[string]bool{
 		// all ext systems are checked through prefix.
 		"btrfs": true,
@@ -102,12 +106,7 @@ func NewFsInfo(context Context) (FsInfo, error) {
 		}
 	}
 
-	// need to call this before the log line below printing out the partitions, as this function may
-	// add a "partition" for devicemapper to fsInfo.partitions
-	fsInfo.addDockerImagesLabel(context)
-
 	glog.Infof("Filesystem partitions: %+v", fsInfo.partitions)
-	fsInfo.addSystemRootLabel()
 	return fsInfo, nil
 }
 
@@ -144,18 +143,23 @@ func (self *RealFsInfo) getDockerDeviceMapperInfo(dockerInfo map[string]string)
 }
 
 // addSystemRootLabel attempts to determine which device contains the mount for /.
-func (self *RealFsInfo) addSystemRootLabel() {
+func (self *RealFsInfo) addSystemRootLabel(mounts []*mount.Info) {
-	for src, p := range self.partitions {
+	for _, m := range mounts {
-		if p.mountpoint == "/" {
+		if m.Mountpoint == "/" {
-			if _, ok := self.labels[LabelSystemRoot]; !ok {
+			self.partitions[m.Source] = partition{
-				self.labels[LabelSystemRoot] = src
+				fsType:     m.Fstype,
+				mountpoint: m.Mountpoint,
+				major:      uint(m.Major),
+				minor:      uint(m.Minor),
 			}
+			self.labels[LabelSystemRoot] = m.Source
+			return
 		}
 	}
 }
 
 // addDockerImagesLabel attempts to determine which device contains the mount for docker images.
-func (self *RealFsInfo) addDockerImagesLabel(context Context) {
+func (self *RealFsInfo) addDockerImagesLabel(context Context, mounts []*mount.Info) {
 	dockerDev, dockerPartition, err := self.getDockerDeviceMapperInfo(context.DockerInfo)
 	if err != nil {
 		glog.Warningf("Could not get Docker devicemapper device: %v", err)
@@ -164,11 +168,7 @@ func (self *RealFsInfo) addDockerImagesLabel(context Context) {
 		self.partitions[dockerDev] = *dockerPartition
 		self.labels[LabelDockerImages] = dockerDev
 	} else {
-		dockerPaths := getDockerImagePaths(context)
+		self.updateDockerImagesPath(mounts, getDockerImagePaths(context))
-
-		for src, p := range self.partitions {
-			self.updateDockerImagesPath(src, p.mountpoint, dockerPaths)
-		}
 	}
 }
 
@@ -190,22 +190,30 @@ func getDockerImagePaths(context Context) []string {
 	return dockerImagePaths
 }
 
-// This method compares the mountpoint with possible docker image mount points. If a match is found,
+// This method compares the mountpoints with possible docker image mount points. If a match is found,
 // docker images label is added to the partition.
-func (self *RealFsInfo) updateDockerImagesPath(source string, mountpoint string, dockerImagePaths []string) {
+func (self *RealFsInfo) updateDockerImagesPath(mounts []*mount.Info, dockerImagePaths []string) {
-	for _, v := range dockerImagePaths {
+	var useMount *mount.Info
-		if v == mountpoint {
+	for _, m := range mounts {
-			if i, ok := self.labels[LabelDockerImages]; ok {
+		for _, p := range dockerImagePaths {
-				// pick the innermost mountpoint.
+			if p != m.Mountpoint {
-				mnt := self.partitions[i].mountpoint
+				continue
-				if len(mnt) < len(mountpoint) {
+			}
-					self.labels[LabelDockerImages] = source
+			// pick the innermost mountpoint
-				}
+			if useMount == nil || (len(useMount.Mountpoint) < len(m.Mountpoint)) {
-			} else {
+				useMount = m
-				self.labels[LabelDockerImages] = source
 			}
 		}
 	}
+	if useMount != nil {
+		self.partitions[useMount.Source] = partition{
+			fsType:     useMount.Fstype,
+			mountpoint: useMount.Mountpoint,
+			major:      uint(useMount.Major),
+			minor:      uint(useMount.Minor),
+		}
+		self.labels[LabelDockerImages] = useMount.Source
+	}
 }
 
 func (self *RealFsInfo) GetDeviceForLabel(label string) (string, error) {

fs/fs_test.go

@@ -22,6 +22,7 @@ import (
 	"testing"
 	"time"
 
+	"github.com/docker/docker/pkg/mount"
 	"github.com/stretchr/testify/assert"
 )
 
@@ -161,22 +162,29 @@ func TestParseDMTable(t *testing.T) {
 }
 
 func TestAddSystemRootLabel(t *testing.T) {
-	fsInfo := &RealFsInfo{
+	tests := []struct {
-		labels: map[string]string{},
+		mounts   []*mount.Info
-		partitions: map[string]partition{
+		expected string
-			"/dev/mapper/vg_vagrant-lv_root": {
+	}{
-				mountpoint: "/",
+		{
-			},
+			mounts: []*mount.Info{
-			"vg_vagrant-docker--pool": {
+				{Source: "/dev/sda1", Mountpoint: "/foo"},
-				mountpoint: "",
+				{Source: "/dev/sdb1", Mountpoint: "/"},
-				fsType:     "devicemapper",
 			},
+			expected: "/dev/sdb1",
 		},
 	}
 
-	fsInfo.addSystemRootLabel()
+	for i, tt := range tests {
-	if e, a := "/dev/mapper/vg_vagrant-lv_root", fsInfo.labels[LabelSystemRoot]; e != a {
+		fsInfo := &RealFsInfo{
-		t.Errorf("expected %q, got %q", e, a)
+			labels:     map[string]string{},
+			partitions: map[string]partition{},
+		}
+		fsInfo.addSystemRootLabel(tt.mounts)
+
+		if source, ok := fsInfo.labels[LabelSystemRoot]; !ok || source != tt.expected {
+			t.Errorf("case %d: expected mount source '%s', got '%s'", i, tt.expected, source)
+		}
 	}
 }
 
@@ -305,7 +313,7 @@ func TestAddDockerImagesLabel(t *testing.T) {
 		driverStatus                   string
 		dmsetupTable                   string
 		getDockerDeviceMapperInfoError error
-		partitions                     map[string]partition
+		mounts                         []*mount.Info
 		expectedDockerDevice           string
 		expectedPartition              *partition
 	}{
@@ -314,10 +322,11 @@ func TestAddDockerImagesLabel(t *testing.T) {
 			driver:       "devicemapper",
 			driverStatus: `[["Pool Name", "vg_vagrant-docker--pool"]]`,
 			dmsetupTable: "0 53870592 thin-pool 253:2 253:3 1024 0 1 skip_block_zeroing",
-			partitions: map[string]partition{
+			mounts: []*mount.Info{
-				"/dev/mapper/vg_vagrant-lv_root": {
+				{
-					mountpoint: "/",
+					Source:     "/dev/mapper/vg_vagrant-lv_root",
-					fsType:     "devicemapper",
+					Mountpoint: "/",
+					Fstype:     "devicemapper",
 				},
 			},
 			expectedDockerDevice: "vg_vagrant-docker--pool",
@@ -332,41 +341,62 @@ func TestAddDockerImagesLabel(t *testing.T) {
 			name:         "devicemapper, loopback on non-root partition",
 			driver:       "devicemapper",
 			driverStatus: `[["Data loop file","/var/lib/docker/devicemapper/devicemapper/data"]]`,
-			partitions: map[string]partition{
+			mounts: []*mount.Info{
-				"/dev/mapper/vg_vagrant-lv_root": {
+				{
-					mountpoint: "/",
+					Source:     "/dev/mapper/vg_vagrant-lv_root",
-					fsType:     "devicemapper",
+					Mountpoint: "/",
+					Fstype:     "devicemapper",
 				},
-				"/dev/sdb1": {
+				{
-					mountpoint: "/var/lib/docker/devicemapper",
+					Source:     "/dev/sdb1",
+					Mountpoint: "/var/lib/docker/devicemapper",
 				},
 			},
 			expectedDockerDevice: "/dev/sdb1",
 		},
 		{
 			name: "multiple mounts - innermost check",
-			partitions: map[string]partition{
+			mounts: []*mount.Info{
-				"/dev/sda1": {
+				{
-					mountpoint: "/",
+					Source:     "/dev/sda1",
-					fsType:     "ext4",
+					Mountpoint: "/",
+					Fstype:     "ext4",
 				},
-				"/dev/sdb1": {
+				{
-					mountpoint: "/var/lib/docker",
+					Source:     "/dev/sdb1",
-					fsType:     "ext4",
+					Mountpoint: "/var/lib/docker",
+					Fstype:     "ext4",
 				},
-				"/dev/sdb2": {
+				{
-					mountpoint: "/var/lib/docker/btrfs",
+					Source:     "/dev/sdb2",
-					fsType:     "btrfs",
+					Mountpoint: "/var/lib/docker/btrfs",
+					Fstype:     "btrfs",
 				},
 			},
 			expectedDockerDevice: "/dev/sdb2",
 		},
+		{
+			name: "root fs inside container, docker-images bindmount",
+			mounts: []*mount.Info{
+				{
+					Source:     "overlay",
+					Mountpoint: "/",
+					Fstype:     "overlay",
+				},
+				{
+					Source:     "/dev/sda1",
+					Mountpoint: "/var/lib/docker",
+					Fstype:     "ext4",
+				},
+			},
+			expectedDockerDevice: "/dev/sda1",
+		},
 	}
 
 	for _, tt := range tests {
 		fsInfo := &RealFsInfo{
 			labels:     map[string]string{},
-			partitions: tt.partitions,
+			partitions: map[string]partition{},
 			dmsetup: &testDmsetup{
 				data: []byte(tt.dmsetupTable),
 			},
@@ -380,7 +410,7 @@ func TestAddDockerImagesLabel(t *testing.T) {
 			},
 		}
 
-		fsInfo.addDockerImagesLabel(context)
+		fsInfo.addDockerImagesLabel(context, tt.mounts)
 
 		if e, a := tt.expectedDockerDevice, fsInfo.labels[LabelDockerImages]; e != a {
 			t.Errorf("%s: docker device: expected %q, got %q", tt.name, e, a)