297 lines
11 KiB
Go
297 lines
11 KiB
Go
/*
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Copyright 2018 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package volumepathhandler
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import (
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"fmt"
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"io/ioutil"
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"os"
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"path/filepath"
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"k8s.io/klog/v2"
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"k8s.io/mount-utils"
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utilexec "k8s.io/utils/exec"
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"k8s.io/apimachinery/pkg/types"
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)
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const (
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losetupPath = "losetup"
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ErrDeviceNotFound = "device not found"
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)
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// BlockVolumePathHandler defines a set of operations for handling block volume-related operations
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type BlockVolumePathHandler interface {
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// MapDevice creates a symbolic link to block device under specified map path
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MapDevice(devicePath string, mapPath string, linkName string, bindMount bool) error
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// UnmapDevice removes a symbolic link to block device under specified map path
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UnmapDevice(mapPath string, linkName string, bindMount bool) error
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// RemovePath removes a file or directory on specified map path
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RemoveMapPath(mapPath string) error
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// IsSymlinkExist returns true if specified symbolic link exists
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IsSymlinkExist(mapPath string) (bool, error)
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// IsDeviceBindMountExist returns true if specified bind mount exists
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IsDeviceBindMountExist(mapPath string) (bool, error)
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// GetDeviceBindMountRefs searches bind mounts under global map path
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GetDeviceBindMountRefs(devPath string, mapPath string) ([]string, error)
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// FindGlobalMapPathUUIDFromPod finds {pod uuid} symbolic link under globalMapPath
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// corresponding to map path symlink, and then return global map path with pod uuid.
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FindGlobalMapPathUUIDFromPod(pluginDir, mapPath string, podUID types.UID) (string, error)
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// AttachFileDevice takes a path to a regular file and makes it available as an
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// attached block device.
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AttachFileDevice(path string) (string, error)
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// DetachFileDevice takes a path to the attached block device and
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// detach it from block device.
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DetachFileDevice(path string) error
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// GetLoopDevice returns the full path to the loop device associated with the given path.
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GetLoopDevice(path string) (string, error)
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}
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// NewBlockVolumePathHandler returns a new instance of BlockVolumeHandler.
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func NewBlockVolumePathHandler() BlockVolumePathHandler {
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var volumePathHandler VolumePathHandler
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return volumePathHandler
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}
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// VolumePathHandler is path related operation handlers for block volume
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type VolumePathHandler struct {
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}
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// MapDevice creates a symbolic link to block device under specified map path
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func (v VolumePathHandler) MapDevice(devicePath string, mapPath string, linkName string, bindMount bool) error {
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// Example of global map path:
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// globalMapPath/linkName: plugins/kubernetes.io/{PluginName}/{DefaultKubeletVolumeDevicesDirName}/{volumePluginDependentPath}/{podUid}
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// linkName: {podUid}
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//
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// Example of pod device map path:
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// podDeviceMapPath/linkName: pods/{podUid}/{DefaultKubeletVolumeDevicesDirName}/{escapeQualifiedPluginName}/{volumeName}
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// linkName: {volumeName}
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if len(devicePath) == 0 {
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return fmt.Errorf("failed to map device to map path. devicePath is empty")
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}
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if len(mapPath) == 0 {
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return fmt.Errorf("failed to map device to map path. mapPath is empty")
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}
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if !filepath.IsAbs(mapPath) {
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return fmt.Errorf("the map path should be absolute: map path: %s", mapPath)
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}
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klog.V(5).Infof("MapDevice: devicePath %s", devicePath)
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klog.V(5).Infof("MapDevice: mapPath %s", mapPath)
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klog.V(5).Infof("MapDevice: linkName %s", linkName)
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// Check and create mapPath
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_, err := os.Stat(mapPath)
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if err != nil && !os.IsNotExist(err) {
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return fmt.Errorf("cannot validate map path: %s: %v", mapPath, err)
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}
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if err = os.MkdirAll(mapPath, 0750); err != nil {
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return fmt.Errorf("failed to mkdir %s: %v", mapPath, err)
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}
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if bindMount {
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return mapBindMountDevice(v, devicePath, mapPath, linkName)
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}
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return mapSymlinkDevice(v, devicePath, mapPath, linkName)
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}
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func mapBindMountDevice(v VolumePathHandler, devicePath string, mapPath string, linkName string) error {
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// Check bind mount exists
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linkPath := filepath.Join(mapPath, string(linkName))
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file, err := os.Stat(linkPath)
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if err != nil {
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if !os.IsNotExist(err) {
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return fmt.Errorf("failed to stat file %s: %v", linkPath, err)
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}
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// Create file
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newFile, err := os.OpenFile(linkPath, os.O_CREATE|os.O_RDWR, 0750)
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if err != nil {
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return fmt.Errorf("failed to open file %s: %v", linkPath, err)
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}
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if err := newFile.Close(); err != nil {
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return fmt.Errorf("failed to close file %s: %v", linkPath, err)
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}
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} else {
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// Check if device file
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// TODO: Need to check if this device file is actually the expected bind mount
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if file.Mode()&os.ModeDevice == os.ModeDevice {
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klog.Warningf("Warning: Map skipped because bind mount already exist on the path: %v", linkPath)
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return nil
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}
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klog.Warningf("Warning: file %s is already exist but not mounted, skip creating file", linkPath)
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}
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// Bind mount file
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mounter := &mount.SafeFormatAndMount{Interface: mount.New(""), Exec: utilexec.New()}
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if err := mounter.MountSensitiveWithoutSystemd(devicePath, linkPath, "" /* fsType */, []string{"bind"}, nil); err != nil {
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return fmt.Errorf("failed to bind mount devicePath: %s to linkPath %s: %v", devicePath, linkPath, err)
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}
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return nil
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}
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func mapSymlinkDevice(v VolumePathHandler, devicePath string, mapPath string, linkName string) error {
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// Remove old symbolic link(or file) then create new one.
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// This should be done because current symbolic link is
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// stale across node reboot.
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linkPath := filepath.Join(mapPath, string(linkName))
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if err := os.Remove(linkPath); err != nil && !os.IsNotExist(err) {
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return fmt.Errorf("failed to remove file %s: %v", linkPath, err)
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}
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return os.Symlink(devicePath, linkPath)
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}
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// UnmapDevice removes a symbolic link associated to block device under specified map path
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func (v VolumePathHandler) UnmapDevice(mapPath string, linkName string, bindMount bool) error {
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if len(mapPath) == 0 {
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return fmt.Errorf("failed to unmap device from map path. mapPath is empty")
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}
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klog.V(5).Infof("UnmapDevice: mapPath %s", mapPath)
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klog.V(5).Infof("UnmapDevice: linkName %s", linkName)
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if bindMount {
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return unmapBindMountDevice(v, mapPath, linkName)
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}
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return unmapSymlinkDevice(v, mapPath, linkName)
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}
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func unmapBindMountDevice(v VolumePathHandler, mapPath string, linkName string) error {
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// Check bind mount exists
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linkPath := filepath.Join(mapPath, string(linkName))
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if isMountExist, checkErr := v.IsDeviceBindMountExist(linkPath); checkErr != nil {
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return checkErr
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} else if !isMountExist {
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klog.Warningf("Warning: Unmap skipped because bind mount does not exist on the path: %v", linkPath)
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// Check if linkPath still exists
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if _, err := os.Stat(linkPath); err != nil {
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if !os.IsNotExist(err) {
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return fmt.Errorf("failed to check if path %s exists: %v", linkPath, err)
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}
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// linkPath has already been removed
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return nil
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}
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// Remove file
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if err := os.Remove(linkPath); err != nil && !os.IsNotExist(err) {
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return fmt.Errorf("failed to remove file %s: %v", linkPath, err)
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}
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return nil
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}
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// Unmount file
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mounter := &mount.SafeFormatAndMount{Interface: mount.New(""), Exec: utilexec.New()}
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if err := mounter.Unmount(linkPath); err != nil {
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return fmt.Errorf("failed to unmount linkPath %s: %v", linkPath, err)
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}
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// Remove file
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if err := os.Remove(linkPath); err != nil && !os.IsNotExist(err) {
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return fmt.Errorf("failed to remove file %s: %v", linkPath, err)
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}
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return nil
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}
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func unmapSymlinkDevice(v VolumePathHandler, mapPath string, linkName string) error {
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// Check symbolic link exists
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linkPath := filepath.Join(mapPath, string(linkName))
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if islinkExist, checkErr := v.IsSymlinkExist(linkPath); checkErr != nil {
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return checkErr
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} else if !islinkExist {
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klog.Warningf("Warning: Unmap skipped because symlink does not exist on the path: %v", linkPath)
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return nil
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}
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return os.Remove(linkPath)
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}
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// RemoveMapPath removes a file or directory on specified map path
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func (v VolumePathHandler) RemoveMapPath(mapPath string) error {
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if len(mapPath) == 0 {
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return fmt.Errorf("failed to remove map path. mapPath is empty")
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}
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klog.V(5).Infof("RemoveMapPath: mapPath %s", mapPath)
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err := os.RemoveAll(mapPath)
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if err != nil && !os.IsNotExist(err) {
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return fmt.Errorf("failed to remove directory %s: %v", mapPath, err)
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}
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return nil
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}
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// IsSymlinkExist returns true if specified file exists and the type is symbolik link.
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// If file doesn't exist, or file exists but not symbolic link, return false with no error.
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// On other cases, return false with error from Lstat().
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func (v VolumePathHandler) IsSymlinkExist(mapPath string) (bool, error) {
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fi, err := os.Lstat(mapPath)
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if err != nil {
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// If file doesn't exist, return false and no error
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if os.IsNotExist(err) {
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return false, nil
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}
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// Return error from Lstat()
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return false, fmt.Errorf("failed to Lstat file %s: %v", mapPath, err)
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}
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// If file exits and it's symbolic link, return true and no error
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if fi.Mode()&os.ModeSymlink == os.ModeSymlink {
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return true, nil
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}
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// If file exits but it's not symbolic link, return false and no error
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return false, nil
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}
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// IsDeviceBindMountExist returns true if specified file exists and the type is device.
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// If file doesn't exist, or file exists but not device, return false with no error.
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// On other cases, return false with error from Lstat().
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func (v VolumePathHandler) IsDeviceBindMountExist(mapPath string) (bool, error) {
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fi, err := os.Lstat(mapPath)
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if err != nil {
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// If file doesn't exist, return false and no error
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if os.IsNotExist(err) {
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return false, nil
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}
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// Return error from Lstat()
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return false, fmt.Errorf("failed to Lstat file %s: %v", mapPath, err)
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}
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// If file exits and it's device, return true and no error
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if fi.Mode()&os.ModeDevice == os.ModeDevice {
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return true, nil
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}
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// If file exits but it's not device, return false and no error
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return false, nil
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}
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// GetDeviceBindMountRefs searches bind mounts under global map path
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func (v VolumePathHandler) GetDeviceBindMountRefs(devPath string, mapPath string) ([]string, error) {
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var refs []string
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files, err := ioutil.ReadDir(mapPath)
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if err != nil {
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return nil, err
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}
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for _, file := range files {
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if file.Mode()&os.ModeDevice != os.ModeDevice {
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continue
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}
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filename := file.Name()
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// TODO: Might need to check if the file is actually linked to devPath
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refs = append(refs, filepath.Join(mapPath, filename))
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}
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klog.V(5).Infof("GetDeviceBindMountRefs: refs %v", refs)
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return refs, nil
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}
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