mirror of
https://github.com/moby/moby.git
synced 2022-11-09 12:21:53 -05:00
553 lines
13 KiB
Go
553 lines
13 KiB
Go
// +build linux
|
|
|
|
/*
|
|
|
|
aufs driver directory structure
|
|
|
|
.
|
|
├── layers // Metadata of layers
|
|
│ ├── 1
|
|
│ ├── 2
|
|
│ └── 3
|
|
├── diff // Content of the layer
|
|
│ ├── 1 // Contains layers that need to be mounted for the id
|
|
│ ├── 2
|
|
│ └── 3
|
|
└── mnt // Mount points for the rw layers to be mounted
|
|
├── 1
|
|
├── 2
|
|
└── 3
|
|
|
|
*/
|
|
|
|
package aufs
|
|
|
|
import (
|
|
"bufio"
|
|
"fmt"
|
|
"io/ioutil"
|
|
"os"
|
|
"os/exec"
|
|
"path"
|
|
"strings"
|
|
"sync"
|
|
"syscall"
|
|
|
|
"github.com/Sirupsen/logrus"
|
|
|
|
"github.com/docker/docker/daemon/graphdriver"
|
|
"github.com/docker/docker/pkg/archive"
|
|
"github.com/docker/docker/pkg/chrootarchive"
|
|
"github.com/docker/docker/pkg/directory"
|
|
"github.com/docker/docker/pkg/idtools"
|
|
mountpk "github.com/docker/docker/pkg/mount"
|
|
"github.com/docker/docker/pkg/stringid"
|
|
|
|
"github.com/opencontainers/runc/libcontainer/label"
|
|
)
|
|
|
|
var (
|
|
// ErrAufsNotSupported is returned if aufs is not supported by the host.
|
|
ErrAufsNotSupported = fmt.Errorf("AUFS was not found in /proc/filesystems")
|
|
incompatibleFsMagic = []graphdriver.FsMagic{
|
|
graphdriver.FsMagicBtrfs,
|
|
graphdriver.FsMagicAufs,
|
|
}
|
|
backingFs = "<unknown>"
|
|
|
|
enableDirpermLock sync.Once
|
|
enableDirperm bool
|
|
)
|
|
|
|
func init() {
|
|
graphdriver.Register("aufs", Init)
|
|
}
|
|
|
|
type data struct {
|
|
referenceCount int
|
|
path string
|
|
}
|
|
|
|
// Driver contains information about the filesystem mounted.
|
|
// root of the filesystem
|
|
// sync.Mutex to protect against concurrent modifications
|
|
// active maps mount id to the count
|
|
type Driver struct {
|
|
root string
|
|
uidMaps []idtools.IDMap
|
|
gidMaps []idtools.IDMap
|
|
sync.Mutex // Protects concurrent modification to active
|
|
active map[string]*data
|
|
}
|
|
|
|
// Init returns a new AUFS driver.
|
|
// An error is returned if AUFS is not supported.
|
|
func Init(root string, options []string, uidMaps, gidMaps []idtools.IDMap) (graphdriver.Driver, error) {
|
|
|
|
// Try to load the aufs kernel module
|
|
if err := supportsAufs(); err != nil {
|
|
return nil, graphdriver.ErrNotSupported
|
|
}
|
|
|
|
fsMagic, err := graphdriver.GetFSMagic(root)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
if fsName, ok := graphdriver.FsNames[fsMagic]; ok {
|
|
backingFs = fsName
|
|
}
|
|
|
|
for _, magic := range incompatibleFsMagic {
|
|
if fsMagic == magic {
|
|
return nil, graphdriver.ErrIncompatibleFS
|
|
}
|
|
}
|
|
|
|
paths := []string{
|
|
"mnt",
|
|
"diff",
|
|
"layers",
|
|
}
|
|
|
|
a := &Driver{
|
|
root: root,
|
|
active: make(map[string]*data),
|
|
uidMaps: uidMaps,
|
|
gidMaps: gidMaps,
|
|
}
|
|
|
|
rootUID, rootGID, err := idtools.GetRootUIDGID(uidMaps, gidMaps)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
// Create the root aufs driver dir and return
|
|
// if it already exists
|
|
// If not populate the dir structure
|
|
if err := idtools.MkdirAllAs(root, 0755, rootUID, rootGID); err != nil {
|
|
if os.IsExist(err) {
|
|
return a, nil
|
|
}
|
|
return nil, err
|
|
}
|
|
|
|
if err := mountpk.MakePrivate(root); err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
// Populate the dir structure
|
|
for _, p := range paths {
|
|
if err := idtools.MkdirAllAs(path.Join(root, p), 0755, rootUID, rootGID); err != nil {
|
|
return nil, err
|
|
}
|
|
}
|
|
return a, nil
|
|
}
|
|
|
|
// Return a nil error if the kernel supports aufs
|
|
// We cannot modprobe because inside dind modprobe fails
|
|
// to run
|
|
func supportsAufs() error {
|
|
// We can try to modprobe aufs first before looking at
|
|
// proc/filesystems for when aufs is supported
|
|
exec.Command("modprobe", "aufs").Run()
|
|
|
|
f, err := os.Open("/proc/filesystems")
|
|
if err != nil {
|
|
return err
|
|
}
|
|
defer f.Close()
|
|
|
|
s := bufio.NewScanner(f)
|
|
for s.Scan() {
|
|
if strings.Contains(s.Text(), "aufs") {
|
|
return nil
|
|
}
|
|
}
|
|
return ErrAufsNotSupported
|
|
}
|
|
|
|
func (a *Driver) rootPath() string {
|
|
return a.root
|
|
}
|
|
|
|
func (*Driver) String() string {
|
|
return "aufs"
|
|
}
|
|
|
|
// Status returns current information about the filesystem such as root directory, number of directories mounted, etc.
|
|
func (a *Driver) Status() [][2]string {
|
|
ids, _ := loadIds(path.Join(a.rootPath(), "layers"))
|
|
return [][2]string{
|
|
{"Root Dir", a.rootPath()},
|
|
{"Backing Filesystem", backingFs},
|
|
{"Dirs", fmt.Sprintf("%d", len(ids))},
|
|
{"Dirperm1 Supported", fmt.Sprintf("%v", useDirperm())},
|
|
}
|
|
}
|
|
|
|
// GetMetadata not implemented
|
|
func (a *Driver) GetMetadata(id string) (map[string]string, error) {
|
|
return nil, nil
|
|
}
|
|
|
|
// Exists returns true if the given id is registered with
|
|
// this driver
|
|
func (a *Driver) Exists(id string) bool {
|
|
if _, err := os.Lstat(path.Join(a.rootPath(), "layers", id)); err != nil {
|
|
return false
|
|
}
|
|
return true
|
|
}
|
|
|
|
// Create three folders for each id
|
|
// mnt, layers, and diff
|
|
func (a *Driver) Create(id, parent string) error {
|
|
if err := a.createDirsFor(id); err != nil {
|
|
return err
|
|
}
|
|
// Write the layers metadata
|
|
f, err := os.Create(path.Join(a.rootPath(), "layers", id))
|
|
if err != nil {
|
|
return err
|
|
}
|
|
defer f.Close()
|
|
|
|
if parent != "" {
|
|
ids, err := getParentIds(a.rootPath(), parent)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
if _, err := fmt.Fprintln(f, parent); err != nil {
|
|
return err
|
|
}
|
|
for _, i := range ids {
|
|
if _, err := fmt.Fprintln(f, i); err != nil {
|
|
return err
|
|
}
|
|
}
|
|
}
|
|
a.active[id] = &data{}
|
|
return nil
|
|
}
|
|
|
|
func (a *Driver) createDirsFor(id string) error {
|
|
paths := []string{
|
|
"mnt",
|
|
"diff",
|
|
}
|
|
|
|
rootUID, rootGID, err := idtools.GetRootUIDGID(a.uidMaps, a.gidMaps)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
for _, p := range paths {
|
|
if err := idtools.MkdirAllAs(path.Join(a.rootPath(), p, id), 0755, rootUID, rootGID); err != nil {
|
|
return err
|
|
}
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// Remove will unmount and remove the given id.
|
|
func (a *Driver) Remove(id string) error {
|
|
// Protect the a.active from concurrent access
|
|
a.Lock()
|
|
defer a.Unlock()
|
|
|
|
m := a.active[id]
|
|
if m != nil {
|
|
if m.referenceCount > 0 {
|
|
return nil
|
|
}
|
|
// Make sure the dir is umounted first
|
|
if err := a.unmount(m); err != nil {
|
|
return err
|
|
}
|
|
}
|
|
tmpDirs := []string{
|
|
"mnt",
|
|
"diff",
|
|
}
|
|
|
|
// Atomically remove each directory in turn by first moving it out of the
|
|
// way (so that docker doesn't find it anymore) before doing removal of
|
|
// the whole tree.
|
|
for _, p := range tmpDirs {
|
|
realPath := path.Join(a.rootPath(), p, id)
|
|
tmpPath := path.Join(a.rootPath(), p, fmt.Sprintf("%s-removing", id))
|
|
if err := os.Rename(realPath, tmpPath); err != nil && !os.IsNotExist(err) {
|
|
return err
|
|
}
|
|
defer os.RemoveAll(tmpPath)
|
|
}
|
|
// Remove the layers file for the id
|
|
if err := os.Remove(path.Join(a.rootPath(), "layers", id)); err != nil && !os.IsNotExist(err) {
|
|
return err
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// Get returns the rootfs path for the id.
|
|
// This will mount the dir at it's given path
|
|
func (a *Driver) Get(id, mountLabel string) (string, error) {
|
|
ids, err := getParentIds(a.rootPath(), id)
|
|
if err != nil {
|
|
if !os.IsNotExist(err) {
|
|
return "", err
|
|
}
|
|
ids = []string{}
|
|
}
|
|
|
|
// Protect the a.active from concurrent access
|
|
a.Lock()
|
|
defer a.Unlock()
|
|
|
|
m := a.active[id]
|
|
if m == nil {
|
|
m = &data{}
|
|
a.active[id] = m
|
|
}
|
|
|
|
// If a dir does not have a parent ( no layers )do not try to mount
|
|
// just return the diff path to the data
|
|
m.path = path.Join(a.rootPath(), "diff", id)
|
|
if len(ids) > 0 {
|
|
m.path = path.Join(a.rootPath(), "mnt", id)
|
|
if m.referenceCount == 0 {
|
|
if err := a.mount(id, m, mountLabel); err != nil {
|
|
return "", err
|
|
}
|
|
}
|
|
}
|
|
m.referenceCount++
|
|
return m.path, nil
|
|
}
|
|
|
|
// Put unmounts and updates list of active mounts.
|
|
func (a *Driver) Put(id string) error {
|
|
// Protect the a.active from concurrent access
|
|
a.Lock()
|
|
defer a.Unlock()
|
|
|
|
m := a.active[id]
|
|
if m == nil {
|
|
return nil
|
|
}
|
|
if count := m.referenceCount; count > 1 {
|
|
m.referenceCount = count - 1
|
|
} else {
|
|
ids, _ := getParentIds(a.rootPath(), id)
|
|
// We only mounted if there are any parents
|
|
if ids != nil && len(ids) > 0 {
|
|
a.unmount(m)
|
|
}
|
|
delete(a.active, id)
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// Diff produces an archive of the changes between the specified
|
|
// layer and its parent layer which may be "".
|
|
func (a *Driver) Diff(id, parent string) (archive.Archive, error) {
|
|
// AUFS doesn't need the parent layer to produce a diff.
|
|
return archive.TarWithOptions(path.Join(a.rootPath(), "diff", id), &archive.TarOptions{
|
|
Compression: archive.Uncompressed,
|
|
ExcludePatterns: []string{archive.WhiteoutMetaPrefix + "*", "!" + archive.WhiteoutOpaqueDir},
|
|
UIDMaps: a.uidMaps,
|
|
GIDMaps: a.gidMaps,
|
|
})
|
|
}
|
|
|
|
func (a *Driver) applyDiff(id string, diff archive.Reader) error {
|
|
dir := path.Join(a.rootPath(), "diff", id)
|
|
if err := chrootarchive.UntarUncompressed(diff, dir, &archive.TarOptions{
|
|
UIDMaps: a.uidMaps,
|
|
GIDMaps: a.gidMaps,
|
|
}); err != nil {
|
|
return err
|
|
}
|
|
|
|
// show invalid whiteouts warning.
|
|
files, err := ioutil.ReadDir(path.Join(dir, archive.WhiteoutLinkDir))
|
|
if err == nil && len(files) > 0 {
|
|
logrus.Warnf("Archive contains aufs hardlink references that are not supported.")
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// DiffSize calculates the changes between the specified id
|
|
// and its parent and returns the size in bytes of the changes
|
|
// relative to its base filesystem directory.
|
|
func (a *Driver) DiffSize(id, parent string) (size int64, err error) {
|
|
// AUFS doesn't need the parent layer to calculate the diff size.
|
|
return directory.Size(path.Join(a.rootPath(), "diff", id))
|
|
}
|
|
|
|
// ApplyDiff extracts the changeset from the given diff into the
|
|
// layer with the specified id and parent, returning the size of the
|
|
// new layer in bytes.
|
|
func (a *Driver) ApplyDiff(id, parent string, diff archive.Reader) (size int64, err error) {
|
|
// AUFS doesn't need the parent id to apply the diff.
|
|
if err = a.applyDiff(id, diff); err != nil {
|
|
return
|
|
}
|
|
|
|
return a.DiffSize(id, parent)
|
|
}
|
|
|
|
// Changes produces a list of changes between the specified layer
|
|
// and its parent layer. If parent is "", then all changes will be ADD changes.
|
|
func (a *Driver) Changes(id, parent string) ([]archive.Change, error) {
|
|
// AUFS doesn't have snapshots, so we need to get changes from all parent
|
|
// layers.
|
|
layers, err := a.getParentLayerPaths(id)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
return archive.Changes(layers, path.Join(a.rootPath(), "diff", id))
|
|
}
|
|
|
|
func (a *Driver) getParentLayerPaths(id string) ([]string, error) {
|
|
parentIds, err := getParentIds(a.rootPath(), id)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
layers := make([]string, len(parentIds))
|
|
|
|
// Get the diff paths for all the parent ids
|
|
for i, p := range parentIds {
|
|
layers[i] = path.Join(a.rootPath(), "diff", p)
|
|
}
|
|
return layers, nil
|
|
}
|
|
|
|
func (a *Driver) mount(id string, m *data, mountLabel string) error {
|
|
// If the id is mounted or we get an error return
|
|
if mounted, err := a.mounted(m); err != nil || mounted {
|
|
return err
|
|
}
|
|
|
|
var (
|
|
target = m.path
|
|
rw = path.Join(a.rootPath(), "diff", id)
|
|
)
|
|
|
|
layers, err := a.getParentLayerPaths(id)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
if err := a.aufsMount(layers, rw, target, mountLabel); err != nil {
|
|
return fmt.Errorf("error creating aufs mount to %s: %v", target, err)
|
|
}
|
|
return nil
|
|
}
|
|
|
|
func (a *Driver) unmount(m *data) error {
|
|
if mounted, err := a.mounted(m); err != nil || !mounted {
|
|
return err
|
|
}
|
|
return Unmount(m.path)
|
|
}
|
|
|
|
func (a *Driver) mounted(m *data) (bool, error) {
|
|
return mountpk.Mounted(m.path)
|
|
}
|
|
|
|
// Cleanup aufs and unmount all mountpoints
|
|
func (a *Driver) Cleanup() error {
|
|
for id, m := range a.active {
|
|
if err := a.unmount(m); err != nil {
|
|
logrus.Errorf("Unmounting %s: %s", stringid.TruncateID(id), err)
|
|
}
|
|
}
|
|
return mountpk.Unmount(a.root)
|
|
}
|
|
|
|
func (a *Driver) aufsMount(ro []string, rw, target, mountLabel string) (err error) {
|
|
defer func() {
|
|
if err != nil {
|
|
Unmount(target)
|
|
}
|
|
}()
|
|
|
|
// Mount options are clipped to page size(4096 bytes). If there are more
|
|
// layers then these are remounted individually using append.
|
|
|
|
offset := 54
|
|
if useDirperm() {
|
|
offset += len("dirperm1")
|
|
}
|
|
b := make([]byte, syscall.Getpagesize()-len(mountLabel)-offset) // room for xino & mountLabel
|
|
bp := copy(b, fmt.Sprintf("br:%s=rw", rw))
|
|
|
|
firstMount := true
|
|
i := 0
|
|
|
|
for {
|
|
for ; i < len(ro); i++ {
|
|
layer := fmt.Sprintf(":%s=ro+wh", ro[i])
|
|
|
|
if firstMount {
|
|
if bp+len(layer) > len(b) {
|
|
break
|
|
}
|
|
bp += copy(b[bp:], layer)
|
|
} else {
|
|
data := label.FormatMountLabel(fmt.Sprintf("append%s", layer), mountLabel)
|
|
if err = mount("none", target, "aufs", syscall.MS_REMOUNT, data); err != nil {
|
|
return
|
|
}
|
|
}
|
|
}
|
|
|
|
if firstMount {
|
|
opts := "dio,noplink,xino=/dev/shm/aufs.xino"
|
|
if useDirperm() {
|
|
opts += ",dirperm1"
|
|
}
|
|
data := label.FormatMountLabel(fmt.Sprintf("%s,%s", string(b[:bp]), opts), mountLabel)
|
|
if err = mount("none", target, "aufs", 0, data); err != nil {
|
|
return
|
|
}
|
|
firstMount = false
|
|
}
|
|
|
|
if i == len(ro) {
|
|
break
|
|
}
|
|
}
|
|
|
|
return
|
|
}
|
|
|
|
// useDirperm checks dirperm1 mount option can be used with the current
|
|
// version of aufs.
|
|
func useDirperm() bool {
|
|
enableDirpermLock.Do(func() {
|
|
base, err := ioutil.TempDir("", "docker-aufs-base")
|
|
if err != nil {
|
|
logrus.Errorf("error checking dirperm1: %v", err)
|
|
return
|
|
}
|
|
defer os.RemoveAll(base)
|
|
|
|
union, err := ioutil.TempDir("", "docker-aufs-union")
|
|
if err != nil {
|
|
logrus.Errorf("error checking dirperm1: %v", err)
|
|
return
|
|
}
|
|
defer os.RemoveAll(union)
|
|
|
|
opts := fmt.Sprintf("br:%s,dirperm1,xino=/dev/shm/aufs.xino", base)
|
|
if err := mount("none", union, "aufs", 0, opts); err != nil {
|
|
return
|
|
}
|
|
enableDirperm = true
|
|
if err := Unmount(union); err != nil {
|
|
logrus.Errorf("error checking dirperm1: failed to unmount %v", err)
|
|
}
|
|
})
|
|
return enableDirperm
|
|
}
|