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- /*
- Copyright 2018 The Kubernetes Authors.
- Licensed under the Apache License, Version 2.0 (the "License");
- you may not use this file except in compliance with the License.
- You may obtain a copy of the License at
- http://www.apache.org/licenses/LICENSE-2.0
- Unless required by applicable law or agreed to in writing, software
- distributed under the License is distributed on an "AS IS" BASIS,
- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- See the License for the specific language governing permissions and
- limitations under the License.
- */
- package volumepathhandler
- import (
- "fmt"
- "io/ioutil"
- "os"
- "path/filepath"
- "k8s.io/klog"
- utilexec "k8s.io/utils/exec"
- "k8s.io/utils/mount"
- "k8s.io/apimachinery/pkg/types"
- )
- const (
- losetupPath = "losetup"
- statPath = "stat"
- ErrDeviceNotFound = "device not found"
- ErrDeviceNotSupported = "device not supported"
- )
- // BlockVolumePathHandler defines a set of operations for handling block volume-related operations
- type BlockVolumePathHandler interface {
- // MapDevice creates a symbolic link to block device under specified map path
- MapDevice(devicePath string, mapPath string, linkName string, bindMount bool) error
- // UnmapDevice removes a symbolic link to block device under specified map path
- UnmapDevice(mapPath string, linkName string, bindMount bool) error
- // RemovePath removes a file or directory on specified map path
- RemoveMapPath(mapPath string) error
- // IsSymlinkExist retruns true if specified symbolic link exists
- IsSymlinkExist(mapPath string) (bool, error)
- // IsDeviceBindMountExist retruns true if specified bind mount exists
- IsDeviceBindMountExist(mapPath string) (bool, error)
- // GetDeviceBindMountRefs searches bind mounts under global map path
- GetDeviceBindMountRefs(devPath string, mapPath string) ([]string, error)
- // FindGlobalMapPathUUIDFromPod finds {pod uuid} symbolic link under globalMapPath
- // corresponding to map path symlink, and then return global map path with pod uuid.
- FindGlobalMapPathUUIDFromPod(pluginDir, mapPath string, podUID types.UID) (string, error)
- // AttachFileDevice takes a path to a regular file and makes it available as an
- // attached block device.
- AttachFileDevice(path string) (string, error)
- // DetachFileDevice takes a path to the attached block device and
- // detach it from block device.
- DetachFileDevice(path string) error
- // GetLoopDevice returns the full path to the loop device associated with the given path.
- GetLoopDevice(path string) (string, error)
- }
- // NewBlockVolumePathHandler returns a new instance of BlockVolumeHandler.
- func NewBlockVolumePathHandler() BlockVolumePathHandler {
- var volumePathHandler VolumePathHandler
- return volumePathHandler
- }
- // VolumePathHandler is path related operation handlers for block volume
- type VolumePathHandler struct {
- }
- // MapDevice creates a symbolic link to block device under specified map path
- func (v VolumePathHandler) MapDevice(devicePath string, mapPath string, linkName string, bindMount bool) error {
- // Example of global map path:
- // globalMapPath/linkName: plugins/kubernetes.io/{PluginName}/{DefaultKubeletVolumeDevicesDirName}/{volumePluginDependentPath}/{podUid}
- // linkName: {podUid}
- //
- // Example of pod device map path:
- // podDeviceMapPath/linkName: pods/{podUid}/{DefaultKubeletVolumeDevicesDirName}/{escapeQualifiedPluginName}/{volumeName}
- // linkName: {volumeName}
- if len(devicePath) == 0 {
- return fmt.Errorf("failed to map device to map path. devicePath is empty")
- }
- if len(mapPath) == 0 {
- return fmt.Errorf("failed to map device to map path. mapPath is empty")
- }
- if !filepath.IsAbs(mapPath) {
- return fmt.Errorf("the map path should be absolute: map path: %s", mapPath)
- }
- klog.V(5).Infof("MapDevice: devicePath %s", devicePath)
- klog.V(5).Infof("MapDevice: mapPath %s", mapPath)
- klog.V(5).Infof("MapDevice: linkName %s", linkName)
- // Check and create mapPath
- _, err := os.Stat(mapPath)
- if err != nil && !os.IsNotExist(err) {
- return fmt.Errorf("cannot validate map path: %s: %v", mapPath, err)
- }
- if err = os.MkdirAll(mapPath, 0750); err != nil {
- return fmt.Errorf("failed to mkdir %s: %v", mapPath, err)
- }
- if bindMount {
- return mapBindMountDevice(v, devicePath, mapPath, linkName)
- }
- return mapSymlinkDevice(v, devicePath, mapPath, linkName)
- }
- func mapBindMountDevice(v VolumePathHandler, devicePath string, mapPath string, linkName string) error {
- // Check bind mount exists
- linkPath := filepath.Join(mapPath, string(linkName))
- file, err := os.Stat(linkPath)
- if err != nil {
- if !os.IsNotExist(err) {
- return fmt.Errorf("failed to stat file %s: %v", linkPath, err)
- }
- // Create file
- newFile, err := os.OpenFile(linkPath, os.O_CREATE|os.O_RDWR, 0750)
- if err != nil {
- return fmt.Errorf("failed to open file %s: %v", linkPath, err)
- }
- if err := newFile.Close(); err != nil {
- return fmt.Errorf("failed to close file %s: %v", linkPath, err)
- }
- } else {
- // Check if device file
- // TODO: Need to check if this device file is actually the expected bind mount
- if file.Mode()&os.ModeDevice == os.ModeDevice {
- klog.Warningf("Warning: Map skipped because bind mount already exist on the path: %v", linkPath)
- return nil
- }
- klog.Warningf("Warning: file %s is already exist but not mounted, skip creating file", linkPath)
- }
- // Bind mount file
- mounter := &mount.SafeFormatAndMount{Interface: mount.New(""), Exec: utilexec.New()}
- if err := mounter.Mount(devicePath, linkPath, "" /* fsType */, []string{"bind"}); err != nil {
- return fmt.Errorf("failed to bind mount devicePath: %s to linkPath %s: %v", devicePath, linkPath, err)
- }
- return nil
- }
- func mapSymlinkDevice(v VolumePathHandler, devicePath string, mapPath string, linkName string) error {
- // Remove old symbolic link(or file) then create new one.
- // This should be done because current symbolic link is
- // stale across node reboot.
- linkPath := filepath.Join(mapPath, string(linkName))
- if err := os.Remove(linkPath); err != nil && !os.IsNotExist(err) {
- return fmt.Errorf("failed to remove file %s: %v", linkPath, err)
- }
- return os.Symlink(devicePath, linkPath)
- }
- // UnmapDevice removes a symbolic link associated to block device under specified map path
- func (v VolumePathHandler) UnmapDevice(mapPath string, linkName string, bindMount bool) error {
- if len(mapPath) == 0 {
- return fmt.Errorf("failed to unmap device from map path. mapPath is empty")
- }
- klog.V(5).Infof("UnmapDevice: mapPath %s", mapPath)
- klog.V(5).Infof("UnmapDevice: linkName %s", linkName)
- if bindMount {
- return unmapBindMountDevice(v, mapPath, linkName)
- }
- return unmapSymlinkDevice(v, mapPath, linkName)
- }
- func unmapBindMountDevice(v VolumePathHandler, mapPath string, linkName string) error {
- // Check bind mount exists
- linkPath := filepath.Join(mapPath, string(linkName))
- if isMountExist, checkErr := v.IsDeviceBindMountExist(linkPath); checkErr != nil {
- return checkErr
- } else if !isMountExist {
- klog.Warningf("Warning: Unmap skipped because bind mount does not exist on the path: %v", linkPath)
- // Check if linkPath still exists
- if _, err := os.Stat(linkPath); err != nil {
- if !os.IsNotExist(err) {
- return fmt.Errorf("failed to check if path %s exists: %v", linkPath, err)
- }
- // linkPath has already been removed
- return nil
- }
- // Remove file
- if err := os.Remove(linkPath); err != nil && !os.IsNotExist(err) {
- return fmt.Errorf("failed to remove file %s: %v", linkPath, err)
- }
- return nil
- }
- // Unmount file
- mounter := &mount.SafeFormatAndMount{Interface: mount.New(""), Exec: utilexec.New()}
- if err := mounter.Unmount(linkPath); err != nil {
- return fmt.Errorf("failed to unmount linkPath %s: %v", linkPath, err)
- }
- // Remove file
- if err := os.Remove(linkPath); err != nil && !os.IsNotExist(err) {
- return fmt.Errorf("failed to remove file %s: %v", linkPath, err)
- }
- return nil
- }
- func unmapSymlinkDevice(v VolumePathHandler, mapPath string, linkName string) error {
- // Check symbolic link exists
- linkPath := filepath.Join(mapPath, string(linkName))
- if islinkExist, checkErr := v.IsSymlinkExist(linkPath); checkErr != nil {
- return checkErr
- } else if !islinkExist {
- klog.Warningf("Warning: Unmap skipped because symlink does not exist on the path: %v", linkPath)
- return nil
- }
- return os.Remove(linkPath)
- }
- // RemoveMapPath removes a file or directory on specified map path
- func (v VolumePathHandler) RemoveMapPath(mapPath string) error {
- if len(mapPath) == 0 {
- return fmt.Errorf("failed to remove map path. mapPath is empty")
- }
- klog.V(5).Infof("RemoveMapPath: mapPath %s", mapPath)
- err := os.RemoveAll(mapPath)
- if err != nil && !os.IsNotExist(err) {
- return fmt.Errorf("failed to remove directory %s: %v", mapPath, err)
- }
- return nil
- }
- // IsSymlinkExist returns true if specified file exists and the type is symbolik link.
- // If file doesn't exist, or file exists but not symbolic link, return false with no error.
- // On other cases, return false with error from Lstat().
- func (v VolumePathHandler) IsSymlinkExist(mapPath string) (bool, error) {
- fi, err := os.Lstat(mapPath)
- if err != nil {
- // If file doesn't exist, return false and no error
- if os.IsNotExist(err) {
- return false, nil
- }
- // Return error from Lstat()
- return false, fmt.Errorf("failed to Lstat file %s: %v", mapPath, err)
- }
- // If file exits and it's symbolic link, return true and no error
- if fi.Mode()&os.ModeSymlink == os.ModeSymlink {
- return true, nil
- }
- // If file exits but it's not symbolic link, return false and no error
- return false, nil
- }
- // IsDeviceBindMountExist returns true if specified file exists and the type is device.
- // If file doesn't exist, or file exists but not device, return false with no error.
- // On other cases, return false with error from Lstat().
- func (v VolumePathHandler) IsDeviceBindMountExist(mapPath string) (bool, error) {
- fi, err := os.Lstat(mapPath)
- if err != nil {
- // If file doesn't exist, return false and no error
- if os.IsNotExist(err) {
- return false, nil
- }
- // Return error from Lstat()
- return false, fmt.Errorf("failed to Lstat file %s: %v", mapPath, err)
- }
- // If file exits and it's device, return true and no error
- if fi.Mode()&os.ModeDevice == os.ModeDevice {
- return true, nil
- }
- // If file exits but it's not device, return false and no error
- return false, nil
- }
- // GetDeviceBindMountRefs searches bind mounts under global map path
- func (v VolumePathHandler) GetDeviceBindMountRefs(devPath string, mapPath string) ([]string, error) {
- var refs []string
- files, err := ioutil.ReadDir(mapPath)
- if err != nil {
- return nil, fmt.Errorf("directory cannot read %v", err)
- }
- for _, file := range files {
- if file.Mode()&os.ModeDevice != os.ModeDevice {
- continue
- }
- filename := file.Name()
- // TODO: Might need to check if the file is actually linked to devPath
- refs = append(refs, filepath.Join(mapPath, filename))
- }
- klog.V(5).Infof("GetDeviceBindMountRefs: refs %v", refs)
- return refs, nil
- }
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