Fix pkg/volume/util/nsenter linting errors

cmd/kubelet/app/server.go

@@ -374,7 +374,7 @@ func UnsecuredDependencies(s *options.KubeletServer) (*kubelet.Dependencies, err
 		if err != nil {
 			return nil, err
 		}
-		mounter = nsutil.NewNsenterMounter(s.RootDirectory, ne)
+		mounter = nsutil.NewMounter(s.RootDirectory, ne)
 		// NSenter only valid on Linux
 		subpather = subpath.NewNSEnter(mounter, ne, s.RootDirectory)
 		// an exec interface which can use nsenter for flex plugin calls

pkg/volume/util/nsenter/nsenter_mount.go

@@ -37,29 +37,30 @@ const (
 	hostProcMountinfoPath = "/rootfs/proc/1/mountinfo"
 )
 
+// Mounter implements mount.Interface
 // Currently, all docker containers receive their own mount namespaces.
-// NsenterMounter works by executing nsenter to run commands in
+// Mounter works by executing nsenter to run commands in
 // the host's mount namespace.
-type NsenterMounter struct {
+type Mounter struct {
 	ne *nsenter.Nsenter
 	// rootDir is location of /var/lib/kubelet directory.
 	rootDir string
 }
 
-// NewNsenterMounter creates a new mounter for kubelet that runs as a container.
+// NewMounter creates a new mounter for kubelet that runs as a container.
-func NewNsenterMounter(rootDir string, ne *nsenter.Nsenter) *NsenterMounter {
+func NewMounter(rootDir string, ne *nsenter.Nsenter) *Mounter {
-	return &NsenterMounter{
+	return &Mounter{
 		rootDir: rootDir,
 		ne:      ne,
 	}
 }
 
-// NsenterMounter implements mount.Interface
+// Mounter implements mount.Interface
-var _ = mount.Interface(&NsenterMounter{})
+var _ = mount.Interface(&Mounter{})
 
 // Mount runs mount(8) in the host's root mount namespace.  Aside from this
 // aspect, Mount has the same semantics as the mounter returned by mount.New()
-func (n *NsenterMounter) Mount(source string, target string, fstype string, options []string) error {
+func (n *Mounter) Mount(source string, target string, fstype string, options []string) error {
 	bind, bindOpts, bindRemountOpts := mount.IsBind(options)
 
 	if bind {
@@ -75,7 +76,7 @@ func (n *NsenterMounter) Mount(source string, target string, fstype string, opti
 
 // doNsenterMount nsenters the host's mount namespace and performs the
 // requested mount.
-func (n *NsenterMounter) doNsenterMount(source, target, fstype string, options []string) error {
+func (n *Mounter) doNsenterMount(source, target, fstype string, options []string) error {
 	klog.V(5).Infof("nsenter mount %s %s %s %v", source, target, fstype, options)
 	cmd, args := n.makeNsenterArgs(source, target, fstype, options)
 	outputBytes, err := n.ne.Exec(cmd, args).CombinedOutput()
@@ -87,7 +88,7 @@ func (n *NsenterMounter) doNsenterMount(source, target, fstype string, options [
 
 // makeNsenterArgs makes a list of argument to nsenter in order to do the
 // requested mount.
-func (n *NsenterMounter) makeNsenterArgs(source, target, fstype string, options []string) (string, []string) {
+func (n *Mounter) makeNsenterArgs(source, target, fstype string, options []string) (string, []string) {
 	mountCmd := n.ne.AbsHostPath("mount")
 	mountArgs := mount.MakeMountArgs(source, target, fstype, options)
 
@@ -125,7 +126,7 @@ func (n *NsenterMounter) makeNsenterArgs(source, target, fstype string, options
 }
 
 // Unmount runs umount(8) in the host's mount namespace.
-func (n *NsenterMounter) Unmount(target string) error {
+func (n *Mounter) Unmount(target string) error {
 	args := []string{target}
 	// No need to execute systemd-run here, it's enough that unmount is executed
 	// in the host's mount namespace. It will finish appropriate fuse daemon(s)
@@ -139,18 +140,19 @@ func (n *NsenterMounter) Unmount(target string) error {
 }
 
 // List returns a list of all mounted filesystems in the host's mount namespace.
-func (*NsenterMounter) List() ([]mount.MountPoint, error) {
+func (*Mounter) List() ([]mount.MountPoint, error) {
 	return mount.ListProcMounts(hostProcMountsPath)
 }
 
-func (*NsenterMounter) IsMountPointMatch(mp mount.MountPoint, dir string) bool {
+// IsMountPointMatch tests if dir and mp are the same path
+func (*Mounter) IsMountPointMatch(mp mount.MountPoint, dir string) bool {
 	deletedDir := fmt.Sprintf("%s\\040(deleted)", dir)
 	return (mp.Path == dir) || (mp.Path == deletedDir)
 }
 
 // IsLikelyNotMountPoint determines whether a path is a mountpoint by calling findmnt
 // in the host's root mount namespace.
-func (n *NsenterMounter) IsLikelyNotMountPoint(file string) (bool, error) {
+func (n *Mounter) IsLikelyNotMountPoint(file string) (bool, error) {
 	file, err := filepath.Abs(file)
 	if err != nil {
 		return true, err
@@ -213,30 +215,32 @@ func parseFindMnt(out string) (string, error) {
 // Returns true if open returns errno EBUSY, and false if errno is nil.
 // Returns an error if errno is any error other than EBUSY.
 // Returns with error if pathname is not a device.
-func (n *NsenterMounter) DeviceOpened(pathname string) (bool, error) {
+func (n *Mounter) DeviceOpened(pathname string) (bool, error) {
 	return mount.ExclusiveOpenFailsOnDevice(pathname)
 }
 
 // PathIsDevice uses FileInfo returned from os.Stat to check if path refers
 // to a device.
-func (n *NsenterMounter) PathIsDevice(pathname string) (bool, error) {
+func (n *Mounter) PathIsDevice(pathname string) (bool, error) {
 	pathType, err := n.GetFileType(pathname)
 	isDevice := pathType == mount.FileTypeCharDev || pathType == mount.FileTypeBlockDev
 	return isDevice, err
 }
 
 //GetDeviceNameFromMount given a mount point, find the volume id from checking /proc/mounts
-func (n *NsenterMounter) GetDeviceNameFromMount(mountPath, pluginDir string) (string, error) {
+func (n *Mounter) GetDeviceNameFromMount(mountPath, pluginDir string) (string, error) {
 	return mount.GetDeviceNameFromMountLinux(n, mountPath, pluginDir)
 }
 
-func (n *NsenterMounter) MakeRShared(path string) error {
+// MakeRShared checks if path is shared and bind-mounts it as rshared if needed.
+func (n *Mounter) MakeRShared(path string) error {
 	return mount.DoMakeRShared(path, hostProcMountinfoPath)
 }
 
-func (mounter *NsenterMounter) GetFileType(pathname string) (mount.FileType, error) {
+// GetFileType checks for file/directory/socket/block/character devices.
+func (n *Mounter) GetFileType(pathname string) (mount.FileType, error) {
 	var pathType mount.FileType
-	outputBytes, err := mounter.ne.Exec("stat", []string{"-L", "--printf=%F", pathname}).CombinedOutput()
+	outputBytes, err := n.ne.Exec("stat", []string{"-L", "--printf=%F", pathname}).CombinedOutput()
 	if err != nil {
 		if strings.Contains(string(outputBytes), "No such file") {
 			err = fmt.Errorf("%s does not exist", pathname)
@@ -262,69 +266,80 @@ func (mounter *NsenterMounter) GetFileType(pathname string) (mount.FileType, err
 	return pathType, fmt.Errorf("only recognise file, directory, socket, block device and character device")
 }
 
-func (mounter *NsenterMounter) MakeDir(pathname string) error {
+// MakeDir creates a new directory.
+func (n *Mounter) MakeDir(pathname string) error {
 	args := []string{"-p", pathname}
-	if _, err := mounter.ne.Exec("mkdir", args).CombinedOutput(); err != nil {
+	if _, err := n.ne.Exec("mkdir", args).CombinedOutput(); err != nil {
 		return err
 	}
 	return nil
 }
 
-func (mounter *NsenterMounter) MakeFile(pathname string) error {
+// MakeFile creates an empty file.
+func (n *Mounter) MakeFile(pathname string) error {
 	args := []string{pathname}
-	if _, err := mounter.ne.Exec("touch", args).CombinedOutput(); err != nil {
+	if _, err := n.ne.Exec("touch", args).CombinedOutput(); err != nil {
 		return err
 	}
 	return nil
 }
 
-func (mounter *NsenterMounter) ExistsPath(pathname string) (bool, error) {
+// ExistsPath checks if pathname exists.
+// Error is returned on any other error than "file not found".
+func (n *Mounter) ExistsPath(pathname string) (bool, error) {
 	// Resolve the symlinks but allow the target not to exist. EvalSymlinks
 	// would return an generic error when the target does not exist.
-	hostPath, err := mounter.ne.EvalSymlinks(pathname, false /* mustExist */)
+	hostPath, err := n.ne.EvalSymlinks(pathname, false /* mustExist */)
 	if err != nil {
 		return false, err
 	}
-	kubeletpath := mounter.ne.KubeletPath(hostPath)
+	kubeletpath := n.ne.KubeletPath(hostPath)
 	return utilpath.Exists(utilpath.CheckFollowSymlink, kubeletpath)
 }
 
-func (mounter *NsenterMounter) EvalHostSymlinks(pathname string) (string, error) {
+// EvalHostSymlinks returns the path name after evaluating symlinks.
-	return mounter.ne.EvalSymlinks(pathname, true)
+func (n *Mounter) EvalHostSymlinks(pathname string) (string, error) {
+	return n.ne.EvalSymlinks(pathname, true)
 }
 
-func (mounter *NsenterMounter) GetMountRefs(pathname string) ([]string, error) {
+// GetMountRefs finds all mount references to the path, returns a
+// list of paths. Path could be a mountpoint path, device or a normal
+// directory (for bind mount).
+func (n *Mounter) GetMountRefs(pathname string) ([]string, error) {
 	pathExists, pathErr := mount.PathExists(pathname)
 	if !pathExists || mount.IsCorruptedMnt(pathErr) {
 		return []string{}, nil
 	} else if pathErr != nil {
 		return nil, fmt.Errorf("Error checking path %s: %v", pathname, pathErr)
 	}
-	hostpath, err := mounter.ne.EvalSymlinks(pathname, true /* mustExist */)
+	hostpath, err := n.ne.EvalSymlinks(pathname, true /* mustExist */)
 	if err != nil {
 		return nil, err
 	}
 	return mount.SearchMountPoints(hostpath, hostProcMountinfoPath)
 }
 
-func (mounter *NsenterMounter) GetFSGroup(pathname string) (int64, error) {
+// GetFSGroup returns FSGroup of pathname.
-	hostPath, err := mounter.ne.EvalSymlinks(pathname, true /* mustExist */)
+func (n *Mounter) GetFSGroup(pathname string) (int64, error) {
+	hostPath, err := n.ne.EvalSymlinks(pathname, true /* mustExist */)
 	if err != nil {
 		return -1, err
 	}
-	kubeletpath := mounter.ne.KubeletPath(hostPath)
+	kubeletpath := n.ne.KubeletPath(hostPath)
 	return mount.GetFSGroupLinux(kubeletpath)
 }
 
-func (mounter *NsenterMounter) GetSELinuxSupport(pathname string) (bool, error) {
+// GetSELinuxSupport tests if pathname is on a mount that supports SELinux.
+func (n *Mounter) GetSELinuxSupport(pathname string) (bool, error) {
 	return mount.GetSELinux(pathname, hostProcMountsPath)
 }
 
-func (mounter *NsenterMounter) GetMode(pathname string) (os.FileMode, error) {
+// GetMode returns permissions of pathname.
-	hostPath, err := mounter.ne.EvalSymlinks(pathname, true /* mustExist */)
+func (n *Mounter) GetMode(pathname string) (os.FileMode, error) {
+	hostPath, err := n.ne.EvalSymlinks(pathname, true /* mustExist */)
 	if err != nil {
 		return 0, err
 	}
-	kubeletpath := mounter.ne.KubeletPath(hostPath)
+	kubeletpath := n.ne.KubeletPath(hostPath)
 	return mount.GetModeLinux(kubeletpath)
 }

pkg/volume/util/nsenter/nsenter_mount_test.go

@@ -74,7 +74,7 @@ func TestParseFindMnt(t *testing.T) {
 	}
 }
 
-func newFakeNsenterMounter(tmpdir string, t *testing.T) (mounter *NsenterMounter, rootfsPath string, varlibPath string, err error) {
+func newFakeNsenterMounter(tmpdir string, t *testing.T) (mounter *Mounter, rootfsPath string, varlibPath string, err error) {
 	rootfsPath = filepath.Join(tmpdir, "rootfs")
 	if err := os.Mkdir(rootfsPath, 0755); err != nil {
 		return nil, "", "", err
@@ -89,7 +89,7 @@ func newFakeNsenterMounter(tmpdir string, t *testing.T) (mounter *NsenterMounter
 		return nil, "", "", err
 	}
 
-	return NewNsenterMounter(varlibPath, ne), rootfsPath, varlibPath, nil
+	return NewMounter(varlibPath, ne), rootfsPath, varlibPath, nil
 }
 
 func TestNsenterExistsFile(t *testing.T) {

pkg/volume/util/nsenter/nsenter_mount_unsupported.go

@@ -27,82 +27,113 @@ import (
 	"k8s.io/kubernetes/pkg/util/mount"
 )
 
-type NsenterMounter struct{}
+// Mounter provides the mount.Interface implementation for unsupported
+// platforms.
+type Mounter struct{}
 
-func NewNsenterMounter(rootDir string, ne *nsenter.Nsenter) *NsenterMounter {
+// NewMounter returns a new Mounter for the current system
-	return &NsenterMounter{}
+func NewMounter(rootDir string, ne *nsenter.Nsenter) *Mounter {
+	return &Mounter{}
 }
 
-var _ = mount.Interface(&NsenterMounter{})
+var _ = mount.Interface(&Mounter{})
 
-func (*NsenterMounter) Mount(source string, target string, fstype string, options []string) error {
+// Mount mounts the source to the target. It is a noop for unsupported systems
+func (*Mounter) Mount(source string, target string, fstype string, options []string) error {
 	return nil
 }
 
-func (*NsenterMounter) Unmount(target string) error {
+// Unmount unmounts the target path from the system. it is a noop for unsupported
+// systems
+func (*Mounter) Unmount(target string) error {
 	return nil
 }
 
-func (*NsenterMounter) List() ([]mount.MountPoint, error) {
+// List returns a list of all mounted filesystems. It is a noop for unsupported systems
+func (*Mounter) List() ([]mount.MountPoint, error) {
 	return []mount.MountPoint{}, nil
 }
 
-func (*NsenterMounter) IsMountPointMatch(mp mount.MountPoint, dir string) bool {
+// IsMountPointMatch tests if dir and mp are the same path
+func (*Mounter) IsMountPointMatch(mp mount.MountPoint, dir string) bool {
 	return (mp.Path == dir)
 }
 
-func (*NsenterMounter) IsLikelyNotMountPoint(file string) (bool, error) {
+// IsLikelyNotMountPoint determines if a directory is not a mountpoint.
+// It is a noop on unsupported systems
+func (*Mounter) IsLikelyNotMountPoint(file string) (bool, error) {
 	return true, nil
 }
 
-func (*NsenterMounter) DeviceOpened(pathname string) (bool, error) {
+// DeviceOpened checks if block device in use. I tis a noop for unsupported systems
+func (*Mounter) DeviceOpened(pathname string) (bool, error) {
 	return false, nil
 }
 
-func (*NsenterMounter) PathIsDevice(pathname string) (bool, error) {
+// PathIsDevice checks if pathname refers to a device. It is a noop for unsupported
+// systems
+func (*Mounter) PathIsDevice(pathname string) (bool, error) {
 	return true, nil
 }
 
-func (*NsenterMounter) GetDeviceNameFromMount(mountPath, pluginDir string) (string, error) {
+// GetDeviceNameFromMount finds the device name from its global mount point using the
+// given mountpath and plugin location. It is a noop of unsupported platforms
+func (*Mounter) GetDeviceNameFromMount(mountPath, pluginDir string) (string, error) {
 	return "", nil
 }
 
-func (*NsenterMounter) MakeRShared(path string) error {
+// MakeRShared checks if path is shared and bind-mounts it as rshared if needed.
+// It is a noop on unsupported platforms
+func (*Mounter) MakeRShared(path string) error {
 	return nil
 }
 
-func (*NsenterMounter) GetFileType(_ string) (mount.FileType, error) {
+// GetFileType checks for file/directory/socket/block/character devices.
+// Always returns an error and "fake" filetype on unsupported platforms
+func (*Mounter) GetFileType(_ string) (mount.FileType, error) {
 	return mount.FileType("fake"), errors.New("not implemented")
 }
 
-func (*NsenterMounter) MakeDir(pathname string) error {
+// MakeDir creates a new directory. Noop on unsupported platforms
+func (*Mounter) MakeDir(pathname string) error {
 	return nil
 }
 
-func (*NsenterMounter) MakeFile(pathname string) error {
+// MakeFile creats an empty file. Noop on unsupported platforms
+func (*Mounter) MakeFile(pathname string) error {
 	return nil
 }
 
-func (*NsenterMounter) ExistsPath(pathname string) (bool, error) {
+// ExistsPath checks if pathname exists. Always returns an error on unsupported
+// platforms
+func (*Mounter) ExistsPath(pathname string) (bool, error) {
 	return true, errors.New("not implemented")
 }
 
-func (*NsenterMounter) EvalHostSymlinks(pathname string) (string, error) {
+// EvalHostSymlinks returns the path name after evaluating symlinks. Always
+// returns an error on unsupported platforms
+func (*Mounter) EvalHostSymlinks(pathname string) (string, error) {
 	return "", errors.New("not implemented")
 }
 
-func (*NsenterMounter) GetMountRefs(pathname string) ([]string, error) {
+// GetMountRefs finds all mount references to the path, returns a
+// list of paths. Always returns an error on unsupported platforms
+func (*Mounter) GetMountRefs(pathname string) ([]string, error) {
 	return nil, errors.New("not implemented")
 }
 
-func (*NsenterMounter) GetFSGroup(pathname string) (int64, error) {
+// GetFSGroup returns FSGroup of pathname. Always returns an error on unsupported platforms
+func (*Mounter) GetFSGroup(pathname string) (int64, error) {
 	return -1, errors.New("not implemented")
 }
 
-func (*NsenterMounter) GetSELinuxSupport(pathname string) (bool, error) {
+// GetSELinuxSupport tests if pathname is on a mount that supports SELinux.
+// Always returns an error on unsupported platforms
+func (*Mounter) GetSELinuxSupport(pathname string) (bool, error) {
 	return false, errors.New("not implemented")
 }
 
-func (*NsenterMounter) GetMode(pathname string) (os.FileMode, error) {
+// GetMode returns permissions of pathname. Always returns an error on unsupported platforms
+func (*Mounter) GetMode(pathname string) (os.FileMode, error) {
 	return 0, errors.New("not implemented")
 }

pkg/volume/util/subpath/subpath_nsenter_test.go

@@ -106,7 +106,7 @@ func TestCheckDeviceInode(t *testing.T) {
 	}
 }
 
-func newFakeNsenterMounter(tmpdir string, t *testing.T) (*nsutil.NsenterMounter, string, string, *nsenter.Nsenter, error) {
+func newFakeNsenterMounter(tmpdir string, t *testing.T) (*nsutil.Mounter, string, string, *nsenter.Nsenter, error) {
 	rootfsPath := filepath.Join(tmpdir, "rootfs")
 	if err := os.Mkdir(rootfsPath, 0755); err != nil {
 		return nil, "", "", nil, err
@@ -121,7 +121,7 @@ func newFakeNsenterMounter(tmpdir string, t *testing.T) (*nsutil.NsenterMounter,
 		return nil, "", "", nil, err
 	}
 
-	return nsutil.NewNsenterMounter(varlibPath, ne), rootfsPath, varlibPath, ne, nil
+	return nsutil.NewMounter(varlibPath, ne), rootfsPath, varlibPath, ne, nil
 }
 
 func TestNsenterSafeMakeDir(t *testing.T) {