refactor ListSubvolumes

btrfs.go

@@ -201,6 +201,25 @@ func (f *FS) ReceiveTo(r io.Reader, mount string) error {
 	return Receive(r, filepath.Join(f.f.Name(), mount))
 }
 
+func (f *FS) ListSubvolumes(filter func(Subvolume) bool) ([]Subvolume, error) {
+	//root, err := getPathRootID(f)
+	//if err != nil {
+	//	return nil, fmt.Errorf("can't get rootid for '%s': %v", path, err)
+	//}
+	m, err := listSubVolumes(f.f)
+	if err != nil {
+		return nil, err
+	}
+	out := make([]Subvolume, 0, len(m))
+	for _, v := range m {
+		if filter != nil && !filter(v) {
+			continue
+		}
+		out = append(out, v)
+	}
+	return out, nil
+}
+
 type Compression string
 
 const (

cmd/gbtrfs.go

@@ -74,7 +74,12 @@ var SubvolumeListCmd = &cobra.Command{
 		if len(args) != 1 {
 			return fmt.Errorf("expected one destination argument")
 		}
-		list, err := btrfs.ListSubVolumes(args[0])
+		fs, err := btrfs.Open(args[0], true)
+		if err != nil {
+			return err
+		}
+		defer fs.Close()
+		list, err := fs.ListSubvolumes(nil)
 		if err == nil {
 			for _, v := range list {
 				fmt.Printf("%+v\n", v)

subvolume.go

@@ -146,27 +146,6 @@ func SnapshotSubVolume(subvol, dst string, ro bool) error {
 	return nil
 }
 
-func ListSubVolumes(path string) ([]Subvolume, error) {
-	f, err := openDir(path)
-	if err != nil {
-		return nil, err
-	}
-	defer f.Close()
-	//root, err := getPathRootID(f)
-	//if err != nil {
-	//	return nil, fmt.Errorf("can't get rootid for '%s': %v", path, err)
-	//}
-	m, err := listSubVolumes(f)
-	if err != nil {
-		return nil, err
-	}
-	out := make([]Subvolume, 0, len(m))
-	for _, v := range m {
-		out = append(out, v)
-	}
-	return out, nil
-}
-
 type Subvolume struct {
 	ObjectID     uint64
 	TransID      uint64