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volumes.go
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volumes.go
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package daemon
import (
"fmt"
"io/ioutil"
"os"
"path/filepath"
"strings"
"github.com/Sirupsen/logrus"
"github.com/docker/docker/pkg/chrootarchive"
"github.com/docker/docker/runconfig"
"github.com/docker/docker/volume"
"github.com/docker/docker/volume/local"
"github.com/docker/libcontainer/label"
)
type mountPoint struct {
Name string
Destination string
Driver string
RW bool
Volume volume.Volume `json:"-"`
Source string
Relabel string
}
func (m *mountPoint) Setup() (string, error) {
if m.Volume != nil {
return m.Volume.Mount()
}
if len(m.Source) > 0 {
if _, err := os.Stat(m.Source); err != nil {
if !os.IsNotExist(err) {
return "", err
}
if err := os.MkdirAll(m.Source, 0755); err != nil {
return "", err
}
}
return m.Source, nil
}
return "", fmt.Errorf("Unable to setup mount point, neither source nor volume defined")
}
func (m *mountPoint) Path() string {
if m.Volume != nil {
return m.Volume.Path()
}
return m.Source
}
// BackwardsCompatible decides whether this mount point can be
// used in old versions of Docker or not.
// Only bind mounts and local volumes can be used in old versions of Docker.
func (m *mountPoint) BackwardsCompatible() bool {
return len(m.Source) > 0 || m.Driver == volume.DefaultDriverName
}
func parseBindMount(spec string, mountLabel string, config *runconfig.Config) (*mountPoint, error) {
bind := &mountPoint{
RW: true,
}
arr := strings.Split(spec, ":")
switch len(arr) {
case 2:
bind.Destination = arr[1]
case 3:
bind.Destination = arr[1]
mode := arr[2]
if !validMountMode(mode) {
return nil, fmt.Errorf("invalid mode for volumes-from: %s", mode)
}
bind.RW = rwModes[mode]
// Relabel will apply a SELinux label, if necessary
bind.Relabel = mode
default:
return nil, fmt.Errorf("Invalid volume specification: %s", spec)
}
name, source, err := parseVolumeSource(arr[0])
if err != nil {
return nil, err
}
if len(source) == 0 {
bind.Driver = config.VolumeDriver
if len(bind.Driver) == 0 {
bind.Driver = volume.DefaultDriverName
}
} else {
bind.Source = filepath.Clean(source)
}
bind.Name = name
bind.Destination = filepath.Clean(bind.Destination)
return bind, nil
}
func parseVolumesFrom(spec string) (string, string, error) {
if len(spec) == 0 {
return "", "", fmt.Errorf("malformed volumes-from specification: %s", spec)
}
specParts := strings.SplitN(spec, ":", 2)
id := specParts[0]
mode := "rw"
if len(specParts) == 2 {
mode = specParts[1]
if !validMountMode(mode) {
return "", "", fmt.Errorf("invalid mode for volumes-from: %s", mode)
}
}
return id, mode, nil
}
// read-write modes
var rwModes = map[string]bool{
"rw": true,
"rw,Z": true,
"rw,z": true,
"z,rw": true,
"Z,rw": true,
"Z": true,
"z": true,
}
// read-only modes
var roModes = map[string]bool{
"ro": true,
"ro,Z": true,
"ro,z": true,
"z,ro": true,
"Z,ro": true,
}
func validMountMode(mode string) bool {
return roModes[mode] || rwModes[mode]
}
func copyExistingContents(source, destination string) error {
volList, err := ioutil.ReadDir(source)
if err != nil {
return err
}
if len(volList) > 0 {
srcList, err := ioutil.ReadDir(destination)
if err != nil {
return err
}
if len(srcList) == 0 {
// If the source volume is empty copy files from the root into the volume
if err := chrootarchive.CopyWithTar(source, destination); err != nil {
return err
}
}
}
return copyOwnership(source, destination)
}
// registerMountPoints initializes the container mount points with the configured volumes and bind mounts.
// It follows the next sequence to decide what to mount in each final destination:
//
// 1. Select the previously configured mount points for the containers, if any.
// 2. Select the volumes mounted from another containers. Overrides previously configured mount point destination.
// 3. Select the bind mounts set by the client. Overrides previously configured mount point destinations.
func (daemon *Daemon) registerMountPoints(container *Container, hostConfig *runconfig.HostConfig) error {
binds := map[string]bool{}
mountPoints := map[string]*mountPoint{}
// 1. Read already configured mount points.
for name, point := range container.MountPoints {
mountPoints[name] = point
}
// 2. Read volumes from other containers.
for _, v := range hostConfig.VolumesFrom {
containerID, mode, err := parseVolumesFrom(v)
if err != nil {
return err
}
c, err := daemon.Get(containerID)
if err != nil {
return err
}
for _, m := range c.MountPoints {
cp := m
cp.RW = m.RW && mode != "ro"
if len(m.Source) == 0 {
v, err := createVolume(m.Name, m.Driver)
if err != nil {
return err
}
cp.Volume = v
}
mountPoints[cp.Destination] = cp
}
}
// 3. Read bind mounts
for _, b := range hostConfig.Binds {
// #10618
bind, err := parseBindMount(b, container.MountLabel, container.Config)
if err != nil {
return err
}
if binds[bind.Destination] {
return fmt.Errorf("Duplicate bind mount %s", bind.Destination)
}
if len(bind.Name) > 0 && len(bind.Driver) > 0 {
// create the volume
v, err := createVolume(bind.Name, bind.Driver)
if err != nil {
return err
}
bind.Volume = v
bind.Source = v.Path()
// Since this is just a named volume and not a typical bind, set to shared mode `z`
if bind.Relabel == "" {
bind.Relabel = "z"
}
}
if err := label.Relabel(bind.Source, container.MountLabel, bind.Relabel); err != nil {
return err
}
binds[bind.Destination] = true
mountPoints[bind.Destination] = bind
}
// Keep backwards compatible structures
bcVolumes := map[string]string{}
bcVolumesRW := map[string]bool{}
for _, m := range mountPoints {
if m.BackwardsCompatible() {
bcVolumes[m.Destination] = m.Path()
bcVolumesRW[m.Destination] = m.RW
}
}
container.Lock()
container.MountPoints = mountPoints
container.Volumes = bcVolumes
container.VolumesRW = bcVolumesRW
container.Unlock()
return nil
}
// verifyVolumesInfo ports volumes configured for the containers pre docker 1.7.
// It reads the container configuration and creates valid mount points for the old volumes.
func (daemon *Daemon) verifyVolumesInfo(container *Container) error {
// Inspect old structures only when we're upgrading from old versions
// to versions >= 1.7 and the MountPoints has not been populated with volumes data.
if len(container.MountPoints) == 0 && len(container.Volumes) > 0 {
for destination, hostPath := range container.Volumes {
vfsPath := filepath.Join(daemon.root, "vfs", "dir")
rw := container.VolumesRW != nil && container.VolumesRW[destination]
if strings.HasPrefix(hostPath, vfsPath) {
id := filepath.Base(hostPath)
if err := migrateVolume(id, hostPath); err != nil {
return err
}
container.addLocalMountPoint(id, destination, rw)
} else { // Bind mount
id, source, err := parseVolumeSource(hostPath)
// We should not find an error here coming
// from the old configuration, but who knows.
if err != nil {
return err
}
container.addBindMountPoint(id, source, destination, rw)
}
}
} else if len(container.MountPoints) > 0 {
// Volumes created with a Docker version >= 1.7. We verify integrity in case of data created
// with Docker 1.7 RC versions that put the information in
// DOCKER_ROOT/volumes/VOLUME_ID rather than DOCKER_ROOT/volumes/VOLUME_ID/_container_data.
l, err := getVolumeDriver(volume.DefaultDriverName)
if err != nil {
return err
}
for _, m := range container.MountPoints {
if m.Driver != volume.DefaultDriverName {
continue
}
dataPath := l.(*local.Root).DataPath(m.Name)
volumePath := filepath.Dir(dataPath)
d, err := ioutil.ReadDir(volumePath)
if err != nil {
// If the volume directory doesn't exist yet it will be recreated,
// so we only return the error when there is a different issue.
if !os.IsNotExist(err) {
return err
}
// Do not check when the volume directory does not exist.
continue
}
if validVolumeLayout(d) {
continue
}
if err := os.Mkdir(dataPath, 0755); err != nil {
return err
}
// Move data inside the data directory
for _, f := range d {
oldp := filepath.Join(volumePath, f.Name())
newp := filepath.Join(dataPath, f.Name())
if err := os.Rename(oldp, newp); err != nil {
logrus.Errorf("Unable to move %s to %s\n", oldp, newp)
}
}
}
return container.ToDisk()
}
return nil
}
func createVolume(name, driverName string) (volume.Volume, error) {
vd, err := getVolumeDriver(driverName)
if err != nil {
return nil, err
}
return vd.Create(name)
}
func removeVolume(v volume.Volume) error {
vd, err := getVolumeDriver(v.DriverName())
if err != nil {
return nil
}
return vd.Remove(v)
}