201 lines
6.3 KiB
Go
201 lines
6.3 KiB
Go
/*
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Copyright 2014 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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// TODO(thockin): This whole pkg is pretty linux-centric. As soon as we have
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// an alternate platform, we will need to abstract further.
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package mount
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import (
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"fmt"
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"path"
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"path/filepath"
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"strings"
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"github.com/golang/glog"
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"k8s.io/kubernetes/pkg/util/exec"
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)
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const (
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// Default mount command if mounter path is not specified
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defaultMountCommand = "mount"
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MountsInGlobalPDPath = "mounts"
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)
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type Interface interface {
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// Mount mounts source to target as fstype with given options.
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Mount(source string, target string, fstype string, options []string) error
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// Unmount unmounts given target.
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Unmount(target string) error
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// List returns a list of all mounted filesystems. This can be large.
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// On some platforms, reading mounts is not guaranteed consistent (i.e.
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// it could change between chunked reads). This is guaranteed to be
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// consistent.
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List() ([]MountPoint, error)
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// IsLikelyNotMountPoint determines if a directory is a mountpoint.
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// It should return ErrNotExist when the directory does not exist.
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IsLikelyNotMountPoint(file string) (bool, error)
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// DeviceOpened determines if the device is in use elsewhere
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// on the system, i.e. still mounted.
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DeviceOpened(pathname string) (bool, error)
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// PathIsDevice determines if a path is a device.
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PathIsDevice(pathname string) (bool, error)
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// GetDeviceNameFromMount finds the device name by checking the mount path
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// to get the global mount path which matches its plugin directory
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GetDeviceNameFromMount(mountPath, pluginDir string) (string, error)
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}
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// Compile-time check to ensure all Mounter implementations satisfy
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// the mount interface
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var _ Interface = &Mounter{}
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// This represents a single line in /proc/mounts or /etc/fstab.
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type MountPoint struct {
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Device string
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Path string
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Type string
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Opts []string
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Freq int
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Pass int
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}
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// SafeFormatAndMount probes a device to see if it is formatted.
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// Namely it checks to see if a file system is present. If so it
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// mounts it otherwise the device is formatted first then mounted.
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type SafeFormatAndMount struct {
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Interface
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Runner exec.Interface
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}
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// FormatAndMount formats the given disk, if needed, and mounts it.
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// That is if the disk is not formatted and it is not being mounted as
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// read-only it will format it first then mount it. Otherwise, if the
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// disk is already formatted or it is being mounted as read-only, it
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// will be mounted without formatting.
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func (mounter *SafeFormatAndMount) FormatAndMount(source string, target string, fstype string, options []string) error {
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// Don't attempt to format if mounting as readonly. Go straight to mounting.
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for _, option := range options {
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if option == "ro" {
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return mounter.Interface.Mount(source, target, fstype, options)
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}
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}
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return mounter.formatAndMount(source, target, fstype, options)
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}
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// New returns a mount.Interface for the current system.
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// It provides options to override the default mounter behavior.
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// mounterPath allows using an alternative to `/bin/mount` for mounting.
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func New(mounterPath string) Interface {
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return &Mounter{
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mounterPath: mounterPath,
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}
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}
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// GetMountRefs finds all other references to the device referenced
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// by mountPath; returns a list of paths.
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func GetMountRefs(mounter Interface, mountPath string) ([]string, error) {
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mps, err := mounter.List()
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if err != nil {
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return nil, err
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}
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// Find the device name.
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deviceName := ""
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// If mountPath is symlink, need get its target path.
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slTarget, err := filepath.EvalSymlinks(mountPath)
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if err != nil {
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slTarget = mountPath
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}
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for i := range mps {
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if mps[i].Path == slTarget {
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deviceName = mps[i].Device
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break
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}
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}
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// Find all references to the device.
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var refs []string
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if deviceName == "" {
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glog.Warningf("could not determine device for path: %q", mountPath)
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} else {
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for i := range mps {
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if mps[i].Device == deviceName && mps[i].Path != slTarget {
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refs = append(refs, mps[i].Path)
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}
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}
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}
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return refs, nil
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}
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// GetDeviceNameFromMount: given a mnt point, find the device from /proc/mounts
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// returns the device name, reference count, and error code
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func GetDeviceNameFromMount(mounter Interface, mountPath string) (string, int, error) {
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mps, err := mounter.List()
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if err != nil {
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return "", 0, err
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}
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// Find the device name.
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// FIXME if multiple devices mounted on the same mount path, only the first one is returned
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device := ""
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// If mountPath is symlink, need get its target path.
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slTarget, err := filepath.EvalSymlinks(mountPath)
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if err != nil {
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slTarget = mountPath
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}
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for i := range mps {
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if mps[i].Path == slTarget {
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device = mps[i].Device
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break
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}
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}
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// Find all references to the device.
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refCount := 0
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for i := range mps {
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if mps[i].Device == device {
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refCount++
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}
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}
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return device, refCount, nil
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}
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// getDeviceNameFromMount find the device name from /proc/mounts in which
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// the mount path reference should match the given plugin directory. In case no mount path reference
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// matches, returns the volume name taken from its given mountPath
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func getDeviceNameFromMount(mounter Interface, mountPath, pluginDir string) (string, error) {
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refs, err := GetMountRefs(mounter, mountPath)
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if err != nil {
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glog.V(4).Infof("GetMountRefs failed for mount path %q: %v", mountPath, err)
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return "", err
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}
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if len(refs) == 0 {
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glog.V(4).Infof("Directory %s is not mounted", mountPath)
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return "", fmt.Errorf("directory %s is not mounted", mountPath)
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}
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basemountPath := path.Join(pluginDir, MountsInGlobalPDPath)
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for _, ref := range refs {
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if strings.HasPrefix(ref, basemountPath) {
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volumeID, err := filepath.Rel(basemountPath, ref)
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if err != nil {
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glog.Errorf("Failed to get volume id from mount %s - %v", mountPath, err)
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return "", err
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}
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return volumeID, nil
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}
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}
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return path.Base(mountPath), nil
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}
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