moby/daemon/volumes.go
Jess Frazelle 828e4ac45a Merge pull request #16355 from duglin/DaemonErrors
Convert some "daemon" static error strings to the new errocode package format
2015-09-17 11:48:37 -07:00

258 lines
6.5 KiB
Go

package daemon
import (
"errors"
"fmt"
"io/ioutil"
"os"
"path/filepath"
"strings"
"sync"
"github.com/Sirupsen/logrus"
derr "github.com/docker/docker/api/errors"
"github.com/docker/docker/api/types"
"github.com/docker/docker/pkg/chrootarchive"
"github.com/docker/docker/pkg/system"
"github.com/docker/docker/volume"
"github.com/docker/docker/volume/drivers"
)
var (
// ErrVolumeReadonly is used to signal an error when trying to copy data into
// a volume mount that is not writable.
ErrVolumeReadonly = errors.New("mounted volume is marked read-only")
// ErrVolumeInUse is a typed error returned when trying to remove a volume that is currently in use by a container
ErrVolumeInUse = errors.New("volume is in use")
// ErrNoSuchVolume is a typed error returned if the requested volume doesn't exist in the volume store
ErrNoSuchVolume = errors.New("no such volume")
)
// mountPoint is the intersection point between a volume and a container. It
// specifies which volume is to be used and where inside a container it should
// be mounted.
type mountPoint struct {
Name string
Destination string
Driver string
RW bool
Volume volume.Volume `json:"-"`
Source string
Mode string `json:"Relabel"` // Originally field was `Relabel`"
}
// Setup sets up a mount point by either mounting the volume if it is
// configured, or creating the source directory if supplied.
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 := system.MkdirAll(m.Source, 0755); err != nil {
return "", err
}
}
return m.Source, nil
}
return "", derr.ErrorCodeMountSetup
}
// hasResource checks whether the given absolute path for a container is in
// this mount point. If the relative path starts with `../` then the resource
// is outside of this mount point, but we can't simply check for this prefix
// because it misses `..` which is also outside of the mount, so check both.
func (m *mountPoint) hasResource(absolutePath string) bool {
relPath, err := filepath.Rel(m.Destination, absolutePath)
return err == nil && relPath != ".." && !strings.HasPrefix(relPath, fmt.Sprintf("..%c", filepath.Separator))
}
// Path returns the path of a volume in a mount point.
func (m *mountPoint) Path() string {
if m.Volume != nil {
return m.Volume.Path()
}
return m.Source
}
// copyExistingContents copies from the source to the destination and
// ensures the ownership is appropriately set.
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)
}
func newVolumeStore(vols []volume.Volume) *volumeStore {
store := &volumeStore{
vols: make(map[string]*volumeCounter),
}
for _, v := range vols {
store.vols[v.Name()] = &volumeCounter{v, 0}
}
return store
}
// volumeStore is a struct that stores the list of volumes available and keeps track of their usage counts
type volumeStore struct {
vols map[string]*volumeCounter
mu sync.Mutex
}
type volumeCounter struct {
volume.Volume
count int
}
func getVolumeDriver(name string) (volume.Driver, error) {
if name == "" {
name = volume.DefaultDriverName
}
return volumedrivers.Lookup(name)
}
// Create tries to find an existing volume with the given name or create a new one from the passed in driver
func (s *volumeStore) Create(name, driverName string, opts map[string]string) (volume.Volume, error) {
s.mu.Lock()
if vc, exists := s.vols[name]; exists {
v := vc.Volume
s.mu.Unlock()
return v, nil
}
s.mu.Unlock()
logrus.Debugf("Registering new volume reference: driver %s, name %s", driverName, name)
vd, err := getVolumeDriver(driverName)
if err != nil {
return nil, err
}
v, err := vd.Create(name, opts)
if err != nil {
return nil, err
}
s.mu.Lock()
s.vols[v.Name()] = &volumeCounter{v, 0}
s.mu.Unlock()
return v, nil
}
// Get looks if a volume with the given name exists and returns it if so
func (s *volumeStore) Get(name string) (volume.Volume, error) {
s.mu.Lock()
defer s.mu.Unlock()
vc, exists := s.vols[name]
if !exists {
return nil, ErrNoSuchVolume
}
return vc.Volume, nil
}
// Remove removes the requested volume. A volume is not removed if the usage count is > 0
func (s *volumeStore) Remove(v volume.Volume) error {
s.mu.Lock()
defer s.mu.Unlock()
name := v.Name()
logrus.Debugf("Removing volume reference: driver %s, name %s", v.DriverName(), name)
vc, exists := s.vols[name]
if !exists {
return ErrNoSuchVolume
}
if vc.count != 0 {
return ErrVolumeInUse
}
vd, err := getVolumeDriver(vc.DriverName())
if err != nil {
return err
}
if err := vd.Remove(vc.Volume); err != nil {
return err
}
delete(s.vols, name)
return nil
}
// Increment increments the usage count of the passed in volume by 1
func (s *volumeStore) Increment(v volume.Volume) {
s.mu.Lock()
defer s.mu.Unlock()
logrus.Debugf("Incrementing volume reference: driver %s, name %s", v.DriverName(), v.Name())
vc, exists := s.vols[v.Name()]
if !exists {
s.vols[v.Name()] = &volumeCounter{v, 1}
return
}
vc.count++
return
}
// Decrement decrements the usage count of the passed in volume by 1
func (s *volumeStore) Decrement(v volume.Volume) {
s.mu.Lock()
defer s.mu.Unlock()
logrus.Debugf("Decrementing volume reference: driver %s, name %s", v.DriverName(), v.Name())
vc, exists := s.vols[v.Name()]
if !exists {
return
}
vc.count--
return
}
// Count returns the usage count of the passed in volume
func (s *volumeStore) Count(v volume.Volume) int {
s.mu.Lock()
defer s.mu.Unlock()
vc, exists := s.vols[v.Name()]
if !exists {
return 0
}
return vc.count
}
// List returns all the available volumes
func (s *volumeStore) List() []volume.Volume {
s.mu.Lock()
defer s.mu.Unlock()
var ls []volume.Volume
for _, vc := range s.vols {
ls = append(ls, vc.Volume)
}
return ls
}
// volumeToAPIType converts a volume.Volume to the type used by the remote API
func volumeToAPIType(v volume.Volume) *types.Volume {
return &types.Volume{
Name: v.Name(),
Driver: v.DriverName(),
Mountpoint: v.Path(),
}
}