daemon/graphdriver fix lint errors/warnings

Addresses #14756

Signed-off-by: Srini Brahmaroutu <srbrahma@us.ibm.com>

daemon/graphdriver/driver.go

@@ -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
 }

daemon/graphdriver/driver_linux.go

@@ -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 {

daemon/graphdriver/driver_unsupported.go

@@ -9,6 +9,7 @@ var (
 	}
 )
 
+// GetFSMagic returns the filesystem id given the path.
 func GetFSMagic(rootpath string) (FsMagic, error) {
 	return FsMagicUnsupported, nil
 }

daemon/graphdriver/driver_windows.go

@@ -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

hack/make/validate-lint

@@ -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