@@ -11,22 +11,29 @@ import (

 	"github.com/docker/docker/pkg/archive"

 )

+// FsMagic unsigned id of the filesystem in use.

 type FsMagic uint32

 const (

+	// FsMagicUnsupported is a predifined contant value other than a valid filesystem id.

 	FsMagicUnsupported = FsMagic(0x00000000)

 )

 var (

+	// DefaultDriver if a storage driver is not specified.

 	DefaultDriver string

 	// All registred drivers

 	drivers map[string]InitFunc

-	ErrNotSupported   = errors.New("driver not supported")

-	ErrPrerequisites  = errors.New("prerequisites for driver not satisfied (wrong filesystem?)")

+	// ErrNotSupported returned when driver is not supported.

+	ErrNotSupported = errors.New("driver not supported")

+	// ErrPrerequisites retuned when driver does not meet prerequisites.

+	ErrPrerequisites = errors.New("prerequisites for driver not satisfied (wrong filesystem?)")

+	// ErrIncompatibleFS returned when file system is not supported.

 	ErrIncompatibleFS = fmt.Errorf("backing file system is unsupported for this graph driver")

 )

+// InitFunc initializes the storage driver.

 type InitFunc func(root string, options []string) (Driver, error)

 // ProtoDriver defines the basic capabilities of a driver.

@@ -89,6 +96,7 @@ func init() {

 	drivers = make(map[string]InitFunc)

 }

+// Register registers a InitFunc for the driver.

 func Register(name string, initFunc InitFunc) error {

 	if _, exists := drivers[name]; exists {

 		return fmt.Errorf("Name already registered %s", name)

@@ -98,6 +106,7 @@ func Register(name string, initFunc InitFunc) error {

 	return nil

 }

+// GetDriver initializes and returns the registered driver

 func GetDriver(name, home string, options []string) (Driver, error) {

 	if initFunc, exists := drivers[name]; exists {

 		return initFunc(filepath.Join(home, name), options)

@@ -106,6 +115,7 @@ func GetDriver(name, home string, options []string) (Driver, error) {

 	return nil, ErrNotSupported

 }

+// New creates the driver and initializes it at the specified root.

 func New(root string, options []string) (driver Driver, err error) {

 	for _, name := range []string{os.Getenv("DOCKER_DRIVER"), DefaultDriver} {

 		if name != "" {

@@ -192,7 +202,7 @@ func checkPriorDriver(name, root string) error {

 	if len(priorDrivers) > 0 {

-		return errors.New(fmt.Sprintf("%q contains other graphdrivers: %s; Please cleanup or explicitly choose storage driver (-s <DRIVER>)", root, strings.Join(priorDrivers, ",")))

+		return fmt.Errorf("%q contains other graphdrivers: %s; Please cleanup or explicitly choose storage driver (-s <DRIVER>)", root, strings.Join(priorDrivers, ","))

 	}

 	return nil

 }

@@ -8,22 +8,38 @@ import (

 )

 const (

-	FsMagicAufs     = FsMagic(0x61756673)

-	FsMagicBtrfs    = FsMagic(0x9123683E)

-	FsMagicCramfs   = FsMagic(0x28cd3d45)

-	FsMagicExtfs    = FsMagic(0x0000EF53)

-	FsMagicF2fs     = FsMagic(0xF2F52010)

-	FsMagicJffs2Fs  = FsMagic(0x000072b6)

-	FsMagicJfs      = FsMagic(0x3153464a)

-	FsMagicNfsFs    = FsMagic(0x00006969)

-	FsMagicRamFs    = FsMagic(0x858458f6)

+	// FsMagicAufs filesystem id for Aufs

+	FsMagicAufs = FsMagic(0x61756673)

+	// FsMagicBtrfs filesystem id for Btrfs

+	FsMagicBtrfs = FsMagic(0x9123683E)

+	// FsMagicCramfs filesystem id for Cramfs

+	FsMagicCramfs = FsMagic(0x28cd3d45)

+	// FsMagicExtfs filesystem id for Extfs

+	FsMagicExtfs = FsMagic(0x0000EF53)

+	// FsMagicF2fs filesystem id for F2fs

+	FsMagicF2fs = FsMagic(0xF2F52010)

+	// FsMagicJffs2Fs filesystem if for Jffs2Fs

+	FsMagicJffs2Fs = FsMagic(0x000072b6)

+	// FsMagicJfs filesystem id for Jfs

+	FsMagicJfs = FsMagic(0x3153464a)

+	// FsMagicNfsFs filesystem id for NfsFs

+	FsMagicNfsFs = FsMagic(0x00006969)

+	// FsMagicRAMFs filesystem id for RamFs

+	FsMagicRAMFs = FsMagic(0x858458f6)

+	// FsMagicReiserFs filesystem id for ReiserFs

 	FsMagicReiserFs = FsMagic(0x52654973)

-	FsMagicSmbFs    = FsMagic(0x0000517B)

+	// FsMagicSmbFs filesystem id for SmbFs

+	FsMagicSmbFs = FsMagic(0x0000517B)

+	// FsMagicSquashFs filesystem id for SquashFs

 	FsMagicSquashFs = FsMagic(0x73717368)

-	FsMagicTmpFs    = FsMagic(0x01021994)

-	FsMagicVxFS     = FsMagic(0xa501fcf5)

-	FsMagicXfs      = FsMagic(0x58465342)

-	FsMagicZfs      = FsMagic(0x2fc12fc1)

+	// FsMagicTmpFs filesystem id for TmpFs

+	FsMagicTmpFs = FsMagic(0x01021994)

+	// FsMagicVxFS filesystem id for VxFs

+	FsMagicVxFS = FsMagic(0xa501fcf5)

+	// FsMagicXfs filesystem id for Xfs

+	FsMagicXfs = FsMagic(0x58465342)

+	// FsMagicZfs filesystem id for Zfs

+	FsMagicZfs = FsMagic(0x2fc12fc1)

 )

 var (

@@ -37,6 +53,7 @@ var (

 		"vfs",

 	}

+	// FsNames maps filesystem id to name of the filesystem.

 	FsNames = map[FsMagic]string{

 		FsMagicAufs:        "aufs",

 		FsMagicBtrfs:       "btrfs",

@@ -46,7 +63,7 @@ var (

 		FsMagicJffs2Fs:     "jffs2",

 		FsMagicJfs:         "jfs",

 		FsMagicNfsFs:       "nfs",

-		FsMagicRamFs:       "ramfs",

+		FsMagicRAMFs:       "ramfs",

 		FsMagicReiserFs:    "reiserfs",

 		FsMagicSmbFs:       "smb",

 		FsMagicSquashFs:    "squashfs",

@@ -58,6 +75,7 @@ var (

 	}

 )

+// GetFSMagic returns the filesystem id given the path.

 func GetFSMagic(rootpath string) (FsMagic, error) {

 	var buf syscall.Statfs_t

 	if err := syscall.Statfs(filepath.Dir(rootpath), &buf); err != nil {

@@ -9,6 +9,7 @@ var (

 	}

 )

+// GetFSMagic returns the filesystem id given the path.

 func GetFSMagic(rootpath string) (FsMagic, error) {

 	return FsMagicUnsupported, nil

 }

@@ -9,6 +9,7 @@ var (

 	}

 )

+// GetFSMagic returns the filesystem id given the path.

 func GetFSMagic(rootpath string) (FsMagic, error) {

 	// Note it is OK to return FsMagicUnsupported on Windows.

 	return FsMagicUnsupported, nil

@@ -25,6 +25,7 @@ packages=(

 	daemon/execdriver/native

 	daemon/execdriver/native/template

 	daemon/execdriver/windows

+	daemon/graphdriver

 	daemon/graphdriver/aufs

 	daemon/graphdriver/devmapper

 	daemon/graphdriver/overlay