Merge pull request #2487 from moricho:fix/bindmount

PiperOrigin-RevId: 309082540

runsc/boot/fs.go

@@ -219,6 +219,9 @@ func mountFlags(opts []string) fs.MountSourceFlags {
 			mf.NoAtime = true
 		case "noexec":
 			mf.NoExec = true
+		case "bind", "rbind":
+			// When options include either "bind" or "rbind",
+			// it's converted to a 9P mount.
 		default:
 			log.Warningf("ignoring unknown mount option %q", o)
 		}
@@ -765,6 +768,16 @@ func (c *containerMounter) getMountNameAndOptions(conf *Config, m specs.Mount) (
 		useOverlay bool
 	)
 
+	for _, opt := range m.Options {
+		// When options include either "bind" or "rbind", this behaves as
+		// bind mount even if the mount type is equal to a filesystem supported
+		// on runsc.
+		if opt == "bind" || opt == "rbind" {
+			m.Type = bind
+			break
+		}
+	}
+
 	switch m.Type {
 	case devpts, devtmpfs, proc, sysfs:
 		fsName = m.Type

runsc/container/container_test.go

@@ -1535,6 +1535,28 @@ func TestReadonlyMount(t *testing.T) {
 	}
 }
 
+func TestBindMountByOption(t *testing.T) {
+	for _, conf := range configs(t, overlay) {
+		t.Logf("Running test with conf: %+v", conf)
+
+		dir, err := ioutil.TempDir(testutil.TmpDir(), "bind-mount")
+		spec := testutil.NewSpecWithArgs("/bin/touch", path.Join(dir, "file"))
+		if err != nil {
+			t.Fatalf("ioutil.TempDir() failed: %v", err)
+		}
+		spec.Mounts = append(spec.Mounts, specs.Mount{
+			Destination: dir,
+			Source:      dir,
+			Type:        "none",
+			Options:     []string{"rw", "bind"},
+		})
+
+		if err := run(spec, conf); err != nil {
+			t.Fatalf("error running sandbox: %v", err)
+		}
+	}
+}
+
 // TestAbbreviatedIDs checks that runsc supports using abbreviated container
 // IDs in place of full IDs.
 func TestAbbreviatedIDs(t *testing.T) {

runsc/container/multi_container_test.go

@@ -1394,7 +1394,7 @@ func TestMultiContainerSharedMountUnsupportedOptions(t *testing.T) {
 		Destination: "/mydir/test",
 		Source:      "/some/dir",
 		Type:        "tmpfs",
-		Options:     []string{"rw", "rbind", "relatime"},
+		Options:     []string{"rw", "relatime"},
 	}
 	podSpec[0].Mounts = append(podSpec[0].Mounts, mnt0)
 

runsc/specutils/specutils.go

@@ -311,7 +311,19 @@ func capsFromNames(names []string, skipSet map[linux.Capability]struct{}) (auth.
 
 // Is9PMount returns true if the given mount can be mounted as an external gofer.
 func Is9PMount(m specs.Mount) bool {
-	return m.Type == "bind" && m.Source != "" && IsSupportedDevMount(m)
+	var isBind bool
+	switch m.Type {
+	case "bind":
+		isBind = true
+	default:
+		for _, opt := range m.Options {
+			if opt == "bind" || opt == "rbind" {
+				isBind = true
+				break
+			}
+		}
+	}
+	return isBind && m.Source != "" && IsSupportedDevMount(m)
 }
 
 // IsSupportedDevMount returns true if the mount is a supported /dev mount.