Build and install from GOPATH

* Rename 'vendor/src' -> 'vendor'
  * Ignore vendor/ instead of vendor/src/ for lint
* Rename 'cmd/client' -> 'cmd/ocic' to make it 'go install'able
* Rename 'cmd/server' -> 'cmd/ocid' to make it 'go install'able
* Update Makefile to build and install from GOPATH
* Update tests to locate ocid/ocic in GOPATH/bin
* Search for binaries in GOPATH/bin instead of PATH
* Install tools using `go get -u`, so they are updated on each run

Signed-off-by: Jonathan Yu <jawnsy@redhat.com>

vendor/github.com/containers/storage/drivers/aufs/aufs.go

@@ -0,0 +1,586 @@
+// +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"
+	"path/filepath"
+	"strings"
+	"sync"
+	"syscall"
+
+	"github.com/Sirupsen/logrus"
+	"github.com/vbatts/tar-split/tar/storage"
+
+	"github.com/containers/storage/drivers"
+	"github.com/containers/storage/pkg/archive"
+	"github.com/containers/storage/pkg/chrootarchive"
+	"github.com/containers/storage/pkg/directory"
+	"github.com/containers/storage/pkg/idtools"
+	mountpk "github.com/containers/storage/pkg/mount"
+	"github.com/containers/storage/pkg/stringid"
+
+	"github.com/opencontainers/runc/libcontainer/label"
+	rsystem "github.com/opencontainers/runc/libcontainer/system"
+)
+
+var (
+	// ErrAufsNotSupported is returned if aufs is not supported by the host.
+	ErrAufsNotSupported = fmt.Errorf("AUFS was not found in /proc/filesystems")
+	// ErrAufsNested means aufs cannot be used bc we are in a user namespace
+	ErrAufsNested = fmt.Errorf("AUFS cannot be used in non-init user namespace")
+	backingFs     = "<unknown>"
+
+	enableDirpermLock sync.Once
+	enableDirperm     bool
+)
+
+func init() {
+	graphdriver.Register("aufs", Init)
+}
+
+// Driver contains information about the filesystem mounted.
+type Driver struct {
+	sync.Mutex
+	root          string
+	uidMaps       []idtools.IDMap
+	gidMaps       []idtools.IDMap
+	ctr           *graphdriver.RefCounter
+	pathCacheLock sync.Mutex
+	pathCache     map[string]string
+}
+
+// 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
+	}
+
+	switch fsMagic {
+	case graphdriver.FsMagicAufs, graphdriver.FsMagicBtrfs, graphdriver.FsMagicEcryptfs:
+		logrus.Errorf("AUFS is not supported over %s", backingFs)
+		return nil, graphdriver.ErrIncompatibleFS
+	}
+
+	paths := []string{
+		"mnt",
+		"diff",
+		"layers",
+	}
+
+	a := &Driver{
+		root:      root,
+		uidMaps:   uidMaps,
+		gidMaps:   gidMaps,
+		pathCache: make(map[string]string),
+		ctr:       graphdriver.NewRefCounter(graphdriver.NewFsChecker(graphdriver.FsMagicAufs)),
+	}
+
+	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, 0700, 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), 0700, 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()
+
+	if rsystem.RunningInUserNS() {
+		return ErrAufsNested
+	}
+
+	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
+}
+
+// CreateReadWrite creates a layer that is writable for use as a container
+// file system.
+func (a *Driver) CreateReadWrite(id, parent, mountLabel string, storageOpt map[string]string) error {
+	return a.Create(id, parent, mountLabel, storageOpt)
+}
+
+// Create three folders for each id
+// mnt, layers, and diff
+func (a *Driver) Create(id, parent, mountLabel string, storageOpt map[string]string) error {
+
+	if len(storageOpt) != 0 {
+		return fmt.Errorf("--storage-opt is not supported for aufs")
+	}
+
+	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
+			}
+		}
+	}
+
+	return nil
+}
+
+// createDirsFor creates two directories for the given id.
+// mnt and diff
+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
+	}
+	// Directory permission is 0755.
+	// The path of directories are <aufs_root_path>/mnt/<image_id>
+	// and <aufs_root_path>/diff/<image_id>
+	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 {
+	a.pathCacheLock.Lock()
+	mountpoint, exists := a.pathCache[id]
+	a.pathCacheLock.Unlock()
+	if !exists {
+		mountpoint = a.getMountpoint(id)
+	}
+	if err := a.unmount(mountpoint); err != nil {
+		// no need to return here, we can still try to remove since the `Rename` will fail below if still mounted
+		logrus.Debugf("aufs: error while unmounting %s: %v", mountpoint, err)
+	}
+
+	// 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.
+	tmpMntPath := path.Join(a.mntPath(), fmt.Sprintf("%s-removing", id))
+	if err := os.Rename(mountpoint, tmpMntPath); err != nil && !os.IsNotExist(err) {
+		return err
+	}
+	defer os.RemoveAll(tmpMntPath)
+
+	tmpDiffpath := path.Join(a.diffPath(), fmt.Sprintf("%s-removing", id))
+	if err := os.Rename(a.getDiffPath(id), tmpDiffpath); err != nil && !os.IsNotExist(err) {
+		return err
+	}
+	defer os.RemoveAll(tmpDiffpath)
+
+	// Remove the layers file for the id
+	if err := os.Remove(path.Join(a.rootPath(), "layers", id)); err != nil && !os.IsNotExist(err) {
+		return err
+	}
+
+	a.pathCacheLock.Lock()
+	delete(a.pathCache, id)
+	a.pathCacheLock.Unlock()
+	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) {
+	parents, err := a.getParentLayerPaths(id)
+	if err != nil && !os.IsNotExist(err) {
+		return "", err
+	}
+
+	a.pathCacheLock.Lock()
+	m, exists := a.pathCache[id]
+	a.pathCacheLock.Unlock()
+
+	if !exists {
+		m = a.getDiffPath(id)
+		if len(parents) > 0 {
+			m = a.getMountpoint(id)
+		}
+	}
+	if count := a.ctr.Increment(m); count > 1 {
+		return m, nil
+	}
+
+	// If a dir does not have a parent ( no layers )do not try to mount
+	// just return the diff path to the data
+	if len(parents) > 0 {
+		if err := a.mount(id, m, mountLabel, parents); err != nil {
+			return "", err
+		}
+	}
+
+	a.pathCacheLock.Lock()
+	a.pathCache[id] = m
+	a.pathCacheLock.Unlock()
+	return m, nil
+}
+
+// Put unmounts and updates list of active mounts.
+func (a *Driver) Put(id string) error {
+	a.pathCacheLock.Lock()
+	m, exists := a.pathCache[id]
+	if !exists {
+		m = a.getMountpoint(id)
+		a.pathCache[id] = m
+	}
+	a.pathCacheLock.Unlock()
+	if count := a.ctr.Decrement(m); count > 0 {
+		return nil
+	}
+
+	err := a.unmount(m)
+	if err != nil {
+		logrus.Debugf("Failed to unmount %s aufs: %v", id, err)
+	}
+	return err
+}
+
+// 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,
+	})
+}
+
+type fileGetNilCloser struct {
+	storage.FileGetter
+}
+
+func (f fileGetNilCloser) Close() error {
+	return nil
+}
+
+// DiffGetter returns a FileGetCloser that can read files from the directory that
+// contains files for the layer differences. Used for direct access for tar-split.
+func (a *Driver) DiffGetter(id string) (graphdriver.FileGetCloser, error) {
+	p := path.Join(a.rootPath(), "diff", id)
+	return fileGetNilCloser{storage.NewPathFileGetter(p)}, nil
+}
+
+func (a *Driver) applyDiff(id string, diff archive.Reader) error {
+	return chrootarchive.UntarUncompressed(diff, path.Join(a.rootPath(), "diff", id), &archive.TarOptions{
+		UIDMaps: a.uidMaps,
+		GIDMaps: a.gidMaps,
+	})
+}
+
+// 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, target string, mountLabel string, layers []string) error {
+	a.Lock()
+	defer a.Unlock()
+
+	// If the id is mounted or we get an error return
+	if mounted, err := a.mounted(target); err != nil || mounted {
+		return err
+	}
+
+	rw := a.getDiffPath(id)
+
+	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(mountPath string) error {
+	a.Lock()
+	defer a.Unlock()
+
+	if mounted, err := a.mounted(mountPath); err != nil || !mounted {
+		return err
+	}
+	if err := Unmount(mountPath); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (a *Driver) mounted(mountpoint string) (bool, error) {
+	return graphdriver.Mounted(graphdriver.FsMagicAufs, mountpoint)
+}
+
+// Cleanup aufs and unmount all mountpoints
+func (a *Driver) Cleanup() error {
+	var dirs []string
+	if err := filepath.Walk(a.mntPath(), func(path string, info os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+		if !info.IsDir() {
+			return nil
+		}
+		dirs = append(dirs, path)
+		return nil
+	}); err != nil {
+		return err
+	}
+
+	for _, m := range dirs {
+		if err := a.unmount(m); err != nil {
+			logrus.Debugf("aufs error unmounting %s: %s", stringid.TruncateID(m), 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,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
+}

vendor/github.com/containers/storage/drivers/aufs/dirs.go

@@ -0,0 +1,64 @@
+// +build linux
+
+package aufs
+
+import (
+	"bufio"
+	"io/ioutil"
+	"os"
+	"path"
+)
+
+// Return all the directories
+func loadIds(root string) ([]string, error) {
+	dirs, err := ioutil.ReadDir(root)
+	if err != nil {
+		return nil, err
+	}
+	out := []string{}
+	for _, d := range dirs {
+		if !d.IsDir() {
+			out = append(out, d.Name())
+		}
+	}
+	return out, nil
+}
+
+// Read the layers file for the current id and return all the
+// layers represented by new lines in the file
+//
+// If there are no lines in the file then the id has no parent
+// and an empty slice is returned.
+func getParentIds(root, id string) ([]string, error) {
+	f, err := os.Open(path.Join(root, "layers", id))
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+
+	out := []string{}
+	s := bufio.NewScanner(f)
+
+	for s.Scan() {
+		if t := s.Text(); t != "" {
+			out = append(out, s.Text())
+		}
+	}
+	return out, s.Err()
+}
+
+func (a *Driver) getMountpoint(id string) string {
+	return path.Join(a.mntPath(), id)
+}
+
+func (a *Driver) mntPath() string {
+	return path.Join(a.rootPath(), "mnt")
+}
+
+func (a *Driver) getDiffPath(id string) string {
+	return path.Join(a.diffPath(), id)
+}
+
+func (a *Driver) diffPath() string {
+	return path.Join(a.rootPath(), "diff")
+}

vendor/github.com/containers/storage/drivers/aufs/mount.go

@@ -0,0 +1,21 @@
+// +build linux
+
+package aufs
+
+import (
+	"os/exec"
+	"syscall"
+
+	"github.com/Sirupsen/logrus"
+)
+
+// Unmount the target specified.
+func Unmount(target string) error {
+	if err := exec.Command("auplink", target, "flush").Run(); err != nil {
+		logrus.Warnf("Couldn't run auplink before unmount %s: %s", target, err)
+	}
+	if err := syscall.Unmount(target, 0); err != nil {
+		return err
+	}
+	return nil
+}

vendor/github.com/containers/storage/drivers/aufs/mount_linux.go

@@ -0,0 +1,7 @@
+package aufs
+
+import "syscall"
+
+func mount(source string, target string, fstype string, flags uintptr, data string) error {
+	return syscall.Mount(source, target, fstype, flags, data)
+}

vendor/github.com/containers/storage/drivers/aufs/mount_unsupported.go

@@ -0,0 +1,12 @@
+// +build !linux
+
+package aufs
+
+import "errors"
+
+// MsRemount declared to specify a non-linux system mount.
+const MsRemount = 0
+
+func mount(source string, target string, fstype string, flags uintptr, data string) (err error) {
+	return errors.New("mount is not implemented on this platform")
+}

vendor/github.com/containers/storage/drivers/btrfs/btrfs.go

@@ -0,0 +1,520 @@
+// +build linux
+
+package btrfs
+
+/*
+#include <stdlib.h>
+#include <dirent.h>
+#include <btrfs/ioctl.h>
+#include <btrfs/ctree.h>
+
+static void set_name_btrfs_ioctl_vol_args_v2(struct btrfs_ioctl_vol_args_v2* btrfs_struct, const char* value) {
+    snprintf(btrfs_struct->name, BTRFS_SUBVOL_NAME_MAX, "%s", value);
+}
+*/
+import "C"
+
+import (
+	"fmt"
+	"os"
+	"path"
+	"path/filepath"
+	"strings"
+	"syscall"
+	"unsafe"
+
+	"github.com/containers/storage/drivers"
+	"github.com/containers/storage/pkg/idtools"
+	"github.com/containers/storage/pkg/mount"
+	"github.com/containers/storage/pkg/parsers"
+	"github.com/docker/go-units"
+	"github.com/opencontainers/runc/libcontainer/label"
+)
+
+func init() {
+	graphdriver.Register("btrfs", Init)
+}
+
+var (
+	quotaEnabled  = false
+	userDiskQuota = false
+)
+
+type btrfsOptions struct {
+	minSpace uint64
+	size     uint64
+}
+
+// Init returns a new BTRFS driver.
+// An error is returned if BTRFS is not supported.
+func Init(home string, options []string, uidMaps, gidMaps []idtools.IDMap) (graphdriver.Driver, error) {
+
+	fsMagic, err := graphdriver.GetFSMagic(home)
+	if err != nil {
+		return nil, err
+	}
+
+	if fsMagic != graphdriver.FsMagicBtrfs {
+		return nil, graphdriver.ErrPrerequisites
+	}
+
+	rootUID, rootGID, err := idtools.GetRootUIDGID(uidMaps, gidMaps)
+	if err != nil {
+		return nil, err
+	}
+	if err := idtools.MkdirAllAs(home, 0700, rootUID, rootGID); err != nil {
+		return nil, err
+	}
+
+	if err := mount.MakePrivate(home); err != nil {
+		return nil, err
+	}
+
+	opt, err := parseOptions(options)
+	if err != nil {
+		return nil, err
+	}
+
+	if userDiskQuota {
+		if err := subvolEnableQuota(home); err != nil {
+			return nil, err
+		}
+		quotaEnabled = true
+	}
+
+	driver := &Driver{
+		home:    home,
+		uidMaps: uidMaps,
+		gidMaps: gidMaps,
+		options: opt,
+	}
+
+	return graphdriver.NewNaiveDiffDriver(driver, uidMaps, gidMaps), nil
+}
+
+func parseOptions(opt []string) (btrfsOptions, error) {
+	var options btrfsOptions
+	for _, option := range opt {
+		key, val, err := parsers.ParseKeyValueOpt(option)
+		if err != nil {
+			return options, err
+		}
+		key = strings.ToLower(key)
+		switch key {
+		case "btrfs.min_space":
+			minSpace, err := units.RAMInBytes(val)
+			if err != nil {
+				return options, err
+			}
+			userDiskQuota = true
+			options.minSpace = uint64(minSpace)
+		default:
+			return options, fmt.Errorf("Unknown option %s", key)
+		}
+	}
+	return options, nil
+}
+
+// Driver contains information about the filesystem mounted.
+type Driver struct {
+	//root of the file system
+	home    string
+	uidMaps []idtools.IDMap
+	gidMaps []idtools.IDMap
+	options btrfsOptions
+}
+
+// String prints the name of the driver (btrfs).
+func (d *Driver) String() string {
+	return "btrfs"
+}
+
+// Status returns current driver information in a two dimensional string array.
+// Output contains "Build Version" and "Library Version" of the btrfs libraries used.
+// Version information can be used to check compatibility with your kernel.
+func (d *Driver) Status() [][2]string {
+	status := [][2]string{}
+	if bv := btrfsBuildVersion(); bv != "-" {
+		status = append(status, [2]string{"Build Version", bv})
+	}
+	if lv := btrfsLibVersion(); lv != -1 {
+		status = append(status, [2]string{"Library Version", fmt.Sprintf("%d", lv)})
+	}
+	return status
+}
+
+// GetMetadata returns empty metadata for this driver.
+func (d *Driver) GetMetadata(id string) (map[string]string, error) {
+	return nil, nil
+}
+
+// Cleanup unmounts the home directory.
+func (d *Driver) Cleanup() error {
+	if quotaEnabled {
+		if err := subvolDisableQuota(d.home); err != nil {
+			return err
+		}
+	}
+
+	return mount.Unmount(d.home)
+}
+
+func free(p *C.char) {
+	C.free(unsafe.Pointer(p))
+}
+
+func openDir(path string) (*C.DIR, error) {
+	Cpath := C.CString(path)
+	defer free(Cpath)
+
+	dir := C.opendir(Cpath)
+	if dir == nil {
+		return nil, fmt.Errorf("Can't open dir")
+	}
+	return dir, nil
+}
+
+func closeDir(dir *C.DIR) {
+	if dir != nil {
+		C.closedir(dir)
+	}
+}
+
+func getDirFd(dir *C.DIR) uintptr {
+	return uintptr(C.dirfd(dir))
+}
+
+func subvolCreate(path, name string) error {
+	dir, err := openDir(path)
+	if err != nil {
+		return err
+	}
+	defer closeDir(dir)
+
+	var args C.struct_btrfs_ioctl_vol_args
+	for i, c := range []byte(name) {
+		args.name[i] = C.char(c)
+	}
+
+	_, _, errno := syscall.Syscall(syscall.SYS_IOCTL, getDirFd(dir), C.BTRFS_IOC_SUBVOL_CREATE,
+		uintptr(unsafe.Pointer(&args)))
+	if errno != 0 {
+		return fmt.Errorf("Failed to create btrfs subvolume: %v", errno.Error())
+	}
+	return nil
+}
+
+func subvolSnapshot(src, dest, name string) error {
+	srcDir, err := openDir(src)
+	if err != nil {
+		return err
+	}
+	defer closeDir(srcDir)
+
+	destDir, err := openDir(dest)
+	if err != nil {
+		return err
+	}
+	defer closeDir(destDir)
+
+	var args C.struct_btrfs_ioctl_vol_args_v2
+	args.fd = C.__s64(getDirFd(srcDir))
+
+	var cs = C.CString(name)
+	C.set_name_btrfs_ioctl_vol_args_v2(&args, cs)
+	C.free(unsafe.Pointer(cs))
+
+	_, _, errno := syscall.Syscall(syscall.SYS_IOCTL, getDirFd(destDir), C.BTRFS_IOC_SNAP_CREATE_V2,
+		uintptr(unsafe.Pointer(&args)))
+	if errno != 0 {
+		return fmt.Errorf("Failed to create btrfs snapshot: %v", errno.Error())
+	}
+	return nil
+}
+
+func isSubvolume(p string) (bool, error) {
+	var bufStat syscall.Stat_t
+	if err := syscall.Lstat(p, &bufStat); err != nil {
+		return false, err
+	}
+
+	// return true if it is a btrfs subvolume
+	return bufStat.Ino == C.BTRFS_FIRST_FREE_OBJECTID, nil
+}
+
+func subvolDelete(dirpath, name string) error {
+	dir, err := openDir(dirpath)
+	if err != nil {
+		return err
+	}
+	defer closeDir(dir)
+	fullPath := path.Join(dirpath, name)
+
+	var args C.struct_btrfs_ioctl_vol_args
+
+	// walk the btrfs subvolumes
+	walkSubvolumes := func(p string, f os.FileInfo, err error) error {
+		if err != nil {
+			if os.IsNotExist(err) && p != fullPath {
+				// missing most likely because the path was a subvolume that got removed in the previous iteration
+				// since it's gone anyway, we don't care
+				return nil
+			}
+			return fmt.Errorf("error walking subvolumes: %v", err)
+		}
+		// we want to check children only so skip itself
+		// it will be removed after the filepath walk anyways
+		if f.IsDir() && p != fullPath {
+			sv, err := isSubvolume(p)
+			if err != nil {
+				return fmt.Errorf("Failed to test if %s is a btrfs subvolume: %v", p, err)
+			}
+			if sv {
+				if err := subvolDelete(path.Dir(p), f.Name()); err != nil {
+					return fmt.Errorf("Failed to destroy btrfs child subvolume (%s) of parent (%s): %v", p, dirpath, err)
+				}
+			}
+		}
+		return nil
+	}
+	if err := filepath.Walk(path.Join(dirpath, name), walkSubvolumes); err != nil {
+		return fmt.Errorf("Recursively walking subvolumes for %s failed: %v", dirpath, err)
+	}
+
+	// all subvolumes have been removed
+	// now remove the one originally passed in
+	for i, c := range []byte(name) {
+		args.name[i] = C.char(c)
+	}
+	_, _, errno := syscall.Syscall(syscall.SYS_IOCTL, getDirFd(dir), C.BTRFS_IOC_SNAP_DESTROY,
+		uintptr(unsafe.Pointer(&args)))
+	if errno != 0 {
+		return fmt.Errorf("Failed to destroy btrfs snapshot %s for %s: %v", dirpath, name, errno.Error())
+	}
+	return nil
+}
+
+func subvolEnableQuota(path string) error {
+	dir, err := openDir(path)
+	if err != nil {
+		return err
+	}
+	defer closeDir(dir)
+
+	var args C.struct_btrfs_ioctl_quota_ctl_args
+	args.cmd = C.BTRFS_QUOTA_CTL_ENABLE
+	_, _, errno := syscall.Syscall(syscall.SYS_IOCTL, getDirFd(dir), C.BTRFS_IOC_QUOTA_CTL,
+		uintptr(unsafe.Pointer(&args)))
+	if errno != 0 {
+		return fmt.Errorf("Failed to enable btrfs quota for %s: %v", dir, errno.Error())
+	}
+
+	return nil
+}
+
+func subvolDisableQuota(path string) error {
+	dir, err := openDir(path)
+	if err != nil {
+		return err
+	}
+	defer closeDir(dir)
+
+	var args C.struct_btrfs_ioctl_quota_ctl_args
+	args.cmd = C.BTRFS_QUOTA_CTL_DISABLE
+	_, _, errno := syscall.Syscall(syscall.SYS_IOCTL, getDirFd(dir), C.BTRFS_IOC_QUOTA_CTL,
+		uintptr(unsafe.Pointer(&args)))
+	if errno != 0 {
+		return fmt.Errorf("Failed to disable btrfs quota for %s: %v", dir, errno.Error())
+	}
+
+	return nil
+}
+
+func subvolRescanQuota(path string) error {
+	dir, err := openDir(path)
+	if err != nil {
+		return err
+	}
+	defer closeDir(dir)
+
+	var args C.struct_btrfs_ioctl_quota_rescan_args
+	_, _, errno := syscall.Syscall(syscall.SYS_IOCTL, getDirFd(dir), C.BTRFS_IOC_QUOTA_RESCAN_WAIT,
+		uintptr(unsafe.Pointer(&args)))
+	if errno != 0 {
+		return fmt.Errorf("Failed to rescan btrfs quota for %s: %v", dir, errno.Error())
+	}
+
+	return nil
+}
+
+func subvolLimitQgroup(path string, size uint64) error {
+	dir, err := openDir(path)
+	if err != nil {
+		return err
+	}
+	defer closeDir(dir)
+
+	var args C.struct_btrfs_ioctl_qgroup_limit_args
+	args.lim.max_referenced = C.__u64(size)
+	args.lim.flags = C.BTRFS_QGROUP_LIMIT_MAX_RFER
+	_, _, errno := syscall.Syscall(syscall.SYS_IOCTL, getDirFd(dir), C.BTRFS_IOC_QGROUP_LIMIT,
+		uintptr(unsafe.Pointer(&args)))
+	if errno != 0 {
+		return fmt.Errorf("Failed to limit qgroup for %s: %v", dir, errno.Error())
+	}
+
+	return nil
+}
+
+func (d *Driver) subvolumesDir() string {
+	return path.Join(d.home, "subvolumes")
+}
+
+func (d *Driver) subvolumesDirID(id string) string {
+	return path.Join(d.subvolumesDir(), id)
+}
+
+// CreateReadWrite creates a layer that is writable for use as a container
+// file system.
+func (d *Driver) CreateReadWrite(id, parent, mountLabel string, storageOpt map[string]string) error {
+	return d.Create(id, parent, mountLabel, storageOpt)
+}
+
+// Create the filesystem with given id.
+func (d *Driver) Create(id, parent, mountLabel string, storageOpt map[string]string) error {
+	subvolumes := path.Join(d.home, "subvolumes")
+	rootUID, rootGID, err := idtools.GetRootUIDGID(d.uidMaps, d.gidMaps)
+	if err != nil {
+		return err
+	}
+	if err := idtools.MkdirAllAs(subvolumes, 0700, rootUID, rootGID); err != nil {
+		return err
+	}
+	if parent == "" {
+		if err := subvolCreate(subvolumes, id); err != nil {
+			return err
+		}
+	} else {
+		parentDir := d.subvolumesDirID(parent)
+		st, err := os.Stat(parentDir)
+		if err != nil {
+			return err
+		}
+		if !st.IsDir() {
+			return fmt.Errorf("%s: not a directory", parentDir)
+		}
+		if err := subvolSnapshot(parentDir, subvolumes, id); err != nil {
+			return err
+		}
+	}
+
+	if _, ok := storageOpt["size"]; ok {
+		driver := &Driver{}
+		if err := d.parseStorageOpt(storageOpt, driver); err != nil {
+			return err
+		}
+		if err := d.setStorageSize(path.Join(subvolumes, id), driver); err != nil {
+			return err
+		}
+	}
+
+	// if we have a remapped root (user namespaces enabled), change the created snapshot
+	// dir ownership to match
+	if rootUID != 0 || rootGID != 0 {
+		if err := os.Chown(path.Join(subvolumes, id), rootUID, rootGID); err != nil {
+			return err
+		}
+	}
+
+	return label.Relabel(path.Join(subvolumes, id), mountLabel, false)
+}
+
+// Parse btrfs storage options
+func (d *Driver) parseStorageOpt(storageOpt map[string]string, driver *Driver) error {
+	// Read size to change the subvolume disk quota per container
+	for key, val := range storageOpt {
+		key := strings.ToLower(key)
+		switch key {
+		case "size":
+			size, err := units.RAMInBytes(val)
+			if err != nil {
+				return err
+			}
+			driver.options.size = uint64(size)
+		default:
+			return fmt.Errorf("Unknown option %s", key)
+		}
+	}
+
+	return nil
+}
+
+// Set btrfs storage size
+func (d *Driver) setStorageSize(dir string, driver *Driver) error {
+	if driver.options.size <= 0 {
+		return fmt.Errorf("btrfs: invalid storage size: %s", units.HumanSize(float64(driver.options.size)))
+	}
+	if d.options.minSpace > 0 && driver.options.size < d.options.minSpace {
+		return fmt.Errorf("btrfs: storage size cannot be less than %s", units.HumanSize(float64(d.options.minSpace)))
+	}
+
+	if !quotaEnabled {
+		if err := subvolEnableQuota(d.home); err != nil {
+			return err
+		}
+		quotaEnabled = true
+	}
+
+	if err := subvolLimitQgroup(dir, driver.options.size); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// Remove the filesystem with given id.
+func (d *Driver) Remove(id string) error {
+	dir := d.subvolumesDirID(id)
+	if _, err := os.Stat(dir); err != nil {
+		return err
+	}
+	if err := subvolDelete(d.subvolumesDir(), id); err != nil {
+		return err
+	}
+	if err := os.RemoveAll(dir); err != nil && !os.IsNotExist(err) {
+		return err
+	}
+	if err := subvolRescanQuota(d.home); err != nil {
+		return err
+	}
+	return nil
+}
+
+// Get the requested filesystem id.
+func (d *Driver) Get(id, mountLabel string) (string, error) {
+	dir := d.subvolumesDirID(id)
+	st, err := os.Stat(dir)
+	if err != nil {
+		return "", err
+	}
+
+	if !st.IsDir() {
+		return "", fmt.Errorf("%s: not a directory", dir)
+	}
+
+	return dir, nil
+}
+
+// Put is not implemented for BTRFS as there is no cleanup required for the id.
+func (d *Driver) Put(id string) error {
+	// Get() creates no runtime resources (like e.g. mounts)
+	// so this doesn't need to do anything.
+	return nil
+}
+
+// Exists checks if the id exists in the filesystem.
+func (d *Driver) Exists(id string) bool {
+	dir := d.subvolumesDirID(id)
+	_, err := os.Stat(dir)
+	return err == nil
+}

vendor/github.com/containers/storage/drivers/btrfs/dummy_unsupported.go

@@ -0,0 +1,3 @@
+// +build !linux !cgo
+
+package btrfs

vendor/github.com/containers/storage/drivers/btrfs/version.go

@@ -0,0 +1,26 @@
+// +build linux,!btrfs_noversion
+
+package btrfs
+
+/*
+#include <btrfs/version.h>
+
+// around version 3.16, they did not define lib version yet
+#ifndef BTRFS_LIB_VERSION
+#define BTRFS_LIB_VERSION -1
+#endif
+
+// upstream had removed it, but now it will be coming back
+#ifndef BTRFS_BUILD_VERSION
+#define BTRFS_BUILD_VERSION "-"
+#endif
+*/
+import "C"
+
+func btrfsBuildVersion() string {
+	return string(C.BTRFS_BUILD_VERSION)
+}
+
+func btrfsLibVersion() int {
+	return int(C.BTRFS_LIB_VERSION)
+}

vendor/github.com/containers/storage/drivers/btrfs/version_none.go

@@ -0,0 +1,14 @@
+// +build linux,btrfs_noversion
+
+package btrfs
+
+// TODO(vbatts) remove this work-around once supported linux distros are on
+// btrfs utilities of >= 3.16.1
+
+func btrfsBuildVersion() string {
+	return "-"
+}
+
+func btrfsLibVersion() int {
+	return -1
+}

vendor/github.com/containers/storage/drivers/counter.go

@@ -0,0 +1,67 @@
+package graphdriver
+
+import "sync"
+
+type minfo struct {
+	check bool
+	count int
+}
+
+// RefCounter is a generic counter for use by graphdriver Get/Put calls
+type RefCounter struct {
+	counts  map[string]*minfo
+	mu      sync.Mutex
+	checker Checker
+}
+
+// NewRefCounter returns a new RefCounter
+func NewRefCounter(c Checker) *RefCounter {
+	return &RefCounter{
+		checker: c,
+		counts:  make(map[string]*minfo),
+	}
+}
+
+// Increment increaes the ref count for the given id and returns the current count
+func (c *RefCounter) Increment(path string) int {
+	c.mu.Lock()
+	m := c.counts[path]
+	if m == nil {
+		m = &minfo{}
+		c.counts[path] = m
+	}
+	// if we are checking this path for the first time check to make sure
+	// if it was already mounted on the system and make sure we have a correct ref
+	// count if it is mounted as it is in use.
+	if !m.check {
+		m.check = true
+		if c.checker.IsMounted(path) {
+			m.count++
+		}
+	}
+	m.count++
+	c.mu.Unlock()
+	return m.count
+}
+
+// Decrement decreases the ref count for the given id and returns the current count
+func (c *RefCounter) Decrement(path string) int {
+	c.mu.Lock()
+	m := c.counts[path]
+	if m == nil {
+		m = &minfo{}
+		c.counts[path] = m
+	}
+	// if we are checking this path for the first time check to make sure
+	// if it was already mounted on the system and make sure we have a correct ref
+	// count if it is mounted as it is in use.
+	if !m.check {
+		m.check = true
+		if c.checker.IsMounted(path) {
+			m.count++
+		}
+	}
+	m.count--
+	c.mu.Unlock()
+	return m.count
+}

vendor/github.com/containers/storage/drivers/devmapper/devmapper_doc.go

@@ -0,0 +1,106 @@
+package devmapper
+
+// Definition of struct dm_task and sub structures (from lvm2)
+//
+// struct dm_ioctl {
+// 	/*
+// 	 * The version number is made up of three parts:
+// 	 * major - no backward or forward compatibility,
+// 	 * minor - only backwards compatible,
+// 	 * patch - both backwards and forwards compatible.
+// 	 *
+// 	 * All clients of the ioctl interface should fill in the
+// 	 * version number of the interface that they were
+// 	 * compiled with.
+// 	 *
+// 	 * All recognized ioctl commands (ie. those that don't
+// 	 * return -ENOTTY) fill out this field, even if the
+// 	 * command failed.
+// 	 */
+// 	uint32_t version[3];	/* in/out */
+// 	uint32_t data_size;	/* total size of data passed in
+// 				 * including this struct */
+
+// 	uint32_t data_start;	/* offset to start of data
+// 				 * relative to start of this struct */
+
+// 	uint32_t target_count;	/* in/out */
+// 	int32_t open_count;	/* out */
+// 	uint32_t flags;		/* in/out */
+
+// 	/*
+// 	 * event_nr holds either the event number (input and output) or the
+// 	 * udev cookie value (input only).
+// 	 * The DM_DEV_WAIT ioctl takes an event number as input.
+// 	 * The DM_SUSPEND, DM_DEV_REMOVE and DM_DEV_RENAME ioctls
+// 	 * use the field as a cookie to return in the DM_COOKIE
+// 	 * variable with the uevents they issue.
+// 	 * For output, the ioctls return the event number, not the cookie.
+// 	 */
+// 	uint32_t event_nr;      	/* in/out */
+// 	uint32_t padding;
+
+// 	uint64_t dev;		/* in/out */
+
+// 	char name[DM_NAME_LEN];	/* device name */
+// 	char uuid[DM_UUID_LEN];	/* unique identifier for
+// 				 * the block device */
+// 	char data[7];		/* padding or data */
+// };
+
+// struct target {
+// 	uint64_t start;
+// 	uint64_t length;
+// 	char *type;
+// 	char *params;
+
+// 	struct target *next;
+// };
+
+// typedef enum {
+// 	DM_ADD_NODE_ON_RESUME, /* add /dev/mapper node with dmsetup resume */
+// 	DM_ADD_NODE_ON_CREATE  /* add /dev/mapper node with dmsetup create */
+// } dm_add_node_t;
+
+// struct dm_task {
+// 	int type;
+// 	char *dev_name;
+// 	char *mangled_dev_name;
+
+// 	struct target *head, *tail;
+
+// 	int read_only;
+// 	uint32_t event_nr;
+// 	int major;
+// 	int minor;
+// 	int allow_default_major_fallback;
+// 	uid_t uid;
+// 	gid_t gid;
+// 	mode_t mode;
+// 	uint32_t read_ahead;
+// 	uint32_t read_ahead_flags;
+// 	union {
+// 		struct dm_ioctl *v4;
+// 	} dmi;
+// 	char *newname;
+// 	char *message;
+// 	char *geometry;
+// 	uint64_t sector;
+// 	int no_flush;
+// 	int no_open_count;
+// 	int skip_lockfs;
+// 	int query_inactive_table;
+// 	int suppress_identical_reload;
+// 	dm_add_node_t add_node;
+// 	uint64_t existing_table_size;
+// 	int cookie_set;
+// 	int new_uuid;
+// 	int secure_data;
+// 	int retry_remove;
+// 	int enable_checks;
+// 	int expected_errno;
+
+// 	char *uuid;
+// 	char *mangled_uuid;
+// };
+//

vendor/github.com/containers/storage/drivers/devmapper/driver.go

@@ -0,0 +1,226 @@
+// +build linux
+
+package devmapper
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path"
+	"strconv"
+
+	"github.com/Sirupsen/logrus"
+
+	"github.com/containers/storage/drivers"
+	"github.com/containers/storage/pkg/devicemapper"
+	"github.com/containers/storage/pkg/idtools"
+	"github.com/containers/storage/pkg/mount"
+	"github.com/docker/go-units"
+)
+
+func init() {
+	graphdriver.Register("devicemapper", Init)
+}
+
+// Driver contains the device set mounted and the home directory
+type Driver struct {
+	*DeviceSet
+	home    string
+	uidMaps []idtools.IDMap
+	gidMaps []idtools.IDMap
+	ctr     *graphdriver.RefCounter
+}
+
+// Init creates a driver with the given home and the set of options.
+func Init(home string, options []string, uidMaps, gidMaps []idtools.IDMap) (graphdriver.Driver, error) {
+	deviceSet, err := NewDeviceSet(home, true, options, uidMaps, gidMaps)
+	if err != nil {
+		return nil, err
+	}
+
+	if err := mount.MakePrivate(home); err != nil {
+		return nil, err
+	}
+
+	d := &Driver{
+		DeviceSet: deviceSet,
+		home:      home,
+		uidMaps:   uidMaps,
+		gidMaps:   gidMaps,
+		ctr:       graphdriver.NewRefCounter(graphdriver.NewDefaultChecker()),
+	}
+
+	return graphdriver.NewNaiveDiffDriver(d, uidMaps, gidMaps), nil
+}
+
+func (d *Driver) String() string {
+	return "devicemapper"
+}
+
+// Status returns the status about the driver in a printable format.
+// Information returned contains Pool Name, Data File, Metadata file, disk usage by
+// the data and metadata, etc.
+func (d *Driver) Status() [][2]string {
+	s := d.DeviceSet.Status()
+
+	status := [][2]string{
+		{"Pool Name", s.PoolName},
+		{"Pool Blocksize", fmt.Sprintf("%s", units.HumanSize(float64(s.SectorSize)))},
+		{"Base Device Size", fmt.Sprintf("%s", units.HumanSize(float64(s.BaseDeviceSize)))},
+		{"Backing Filesystem", s.BaseDeviceFS},
+		{"Data file", s.DataFile},
+		{"Metadata file", s.MetadataFile},
+		{"Data Space Used", fmt.Sprintf("%s", units.HumanSize(float64(s.Data.Used)))},
+		{"Data Space Total", fmt.Sprintf("%s", units.HumanSize(float64(s.Data.Total)))},
+		{"Data Space Available", fmt.Sprintf("%s", units.HumanSize(float64(s.Data.Available)))},
+		{"Metadata Space Used", fmt.Sprintf("%s", units.HumanSize(float64(s.Metadata.Used)))},
+		{"Metadata Space Total", fmt.Sprintf("%s", units.HumanSize(float64(s.Metadata.Total)))},
+		{"Metadata Space Available", fmt.Sprintf("%s", units.HumanSize(float64(s.Metadata.Available)))},
+		{"Thin Pool Minimum Free Space", fmt.Sprintf("%s", units.HumanSize(float64(s.MinFreeSpace)))},
+		{"Udev Sync Supported", fmt.Sprintf("%v", s.UdevSyncSupported)},
+		{"Deferred Removal Enabled", fmt.Sprintf("%v", s.DeferredRemoveEnabled)},
+		{"Deferred Deletion Enabled", fmt.Sprintf("%v", s.DeferredDeleteEnabled)},
+		{"Deferred Deleted Device Count", fmt.Sprintf("%v", s.DeferredDeletedDeviceCount)},
+	}
+	if len(s.DataLoopback) > 0 {
+		status = append(status, [2]string{"Data loop file", s.DataLoopback})
+	}
+	if len(s.MetadataLoopback) > 0 {
+		status = append(status, [2]string{"Metadata loop file", s.MetadataLoopback})
+	}
+	if vStr, err := devicemapper.GetLibraryVersion(); err == nil {
+		status = append(status, [2]string{"Library Version", vStr})
+	}
+	return status
+}
+
+// GetMetadata returns a map of information about the device.
+func (d *Driver) GetMetadata(id string) (map[string]string, error) {
+	m, err := d.DeviceSet.exportDeviceMetadata(id)
+
+	if err != nil {
+		return nil, err
+	}
+
+	metadata := make(map[string]string)
+	metadata["DeviceId"] = strconv.Itoa(m.deviceID)
+	metadata["DeviceSize"] = strconv.FormatUint(m.deviceSize, 10)
+	metadata["DeviceName"] = m.deviceName
+	return metadata, nil
+}
+
+// Cleanup unmounts a device.
+func (d *Driver) Cleanup() error {
+	err := d.DeviceSet.Shutdown(d.home)
+
+	if err2 := mount.Unmount(d.home); err == nil {
+		err = err2
+	}
+
+	return err
+}
+
+// CreateReadWrite creates a layer that is writable for use as a container
+// file system.
+func (d *Driver) CreateReadWrite(id, parent, mountLabel string, storageOpt map[string]string) error {
+	return d.Create(id, parent, mountLabel, storageOpt)
+}
+
+// Create adds a device with a given id and the parent.
+func (d *Driver) Create(id, parent, mountLabel string, storageOpt map[string]string) error {
+	if err := d.DeviceSet.AddDevice(id, parent, storageOpt); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// Remove removes a device with a given id, unmounts the filesystem.
+func (d *Driver) Remove(id string) error {
+	if !d.DeviceSet.HasDevice(id) {
+		// Consider removing a non-existing device a no-op
+		// This is useful to be able to progress on container removal
+		// if the underlying device has gone away due to earlier errors
+		return nil
+	}
+
+	// This assumes the device has been properly Get/Put:ed and thus is unmounted
+	if err := d.DeviceSet.DeleteDevice(id, false); err != nil {
+		return err
+	}
+
+	mp := path.Join(d.home, "mnt", id)
+	if err := os.RemoveAll(mp); err != nil && !os.IsNotExist(err) {
+		return err
+	}
+
+	return nil
+}
+
+// Get mounts a device with given id into the root filesystem
+func (d *Driver) Get(id, mountLabel string) (string, error) {
+	mp := path.Join(d.home, "mnt", id)
+	rootFs := path.Join(mp, "rootfs")
+	if count := d.ctr.Increment(mp); count > 1 {
+		return rootFs, nil
+	}
+
+	uid, gid, err := idtools.GetRootUIDGID(d.uidMaps, d.gidMaps)
+	if err != nil {
+		d.ctr.Decrement(mp)
+		return "", err
+	}
+
+	// Create the target directories if they don't exist
+	if err := idtools.MkdirAllAs(path.Join(d.home, "mnt"), 0755, uid, gid); err != nil && !os.IsExist(err) {
+		d.ctr.Decrement(mp)
+		return "", err
+	}
+	if err := idtools.MkdirAs(mp, 0755, uid, gid); err != nil && !os.IsExist(err) {
+		d.ctr.Decrement(mp)
+		return "", err
+	}
+
+	// Mount the device
+	if err := d.DeviceSet.MountDevice(id, mp, mountLabel); err != nil {
+		d.ctr.Decrement(mp)
+		return "", err
+	}
+
+	if err := idtools.MkdirAllAs(rootFs, 0755, uid, gid); err != nil && !os.IsExist(err) {
+		d.ctr.Decrement(mp)
+		d.DeviceSet.UnmountDevice(id, mp)
+		return "", err
+	}
+
+	idFile := path.Join(mp, "id")
+	if _, err := os.Stat(idFile); err != nil && os.IsNotExist(err) {
+		// Create an "id" file with the container/image id in it to help reconstruct this in case
+		// of later problems
+		if err := ioutil.WriteFile(idFile, []byte(id), 0600); err != nil {
+			d.ctr.Decrement(mp)
+			d.DeviceSet.UnmountDevice(id, mp)
+			return "", err
+		}
+	}
+
+	return rootFs, nil
+}
+
+// Put unmounts a device and removes it.
+func (d *Driver) Put(id string) error {
+	mp := path.Join(d.home, "mnt", id)
+	if count := d.ctr.Decrement(mp); count > 0 {
+		return nil
+	}
+	err := d.DeviceSet.UnmountDevice(id, mp)
+	if err != nil {
+		logrus.Errorf("devmapper: Error unmounting device %s: %s", id, err)
+	}
+	return err
+}
+
+// Exists checks to see if the device exists.
+func (d *Driver) Exists(id string) bool {
+	return d.DeviceSet.HasDevice(id)
+}

vendor/github.com/containers/storage/drivers/devmapper/mount.go

@@ -0,0 +1,89 @@
+// +build linux
+
+package devmapper
+
+import (
+	"bytes"
+	"fmt"
+	"os"
+	"path/filepath"
+	"syscall"
+)
+
+// FIXME: this is copy-pasted from the aufs driver.
+// It should be moved into the core.
+
+// Mounted returns true if a mount point exists.
+func Mounted(mountpoint string) (bool, error) {
+	mntpoint, err := os.Stat(mountpoint)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return false, nil
+		}
+		return false, err
+	}
+	parent, err := os.Stat(filepath.Join(mountpoint, ".."))
+	if err != nil {
+		return false, err
+	}
+	mntpointSt := mntpoint.Sys().(*syscall.Stat_t)
+	parentSt := parent.Sys().(*syscall.Stat_t)
+	return mntpointSt.Dev != parentSt.Dev, nil
+}
+
+type probeData struct {
+	fsName string
+	magic  string
+	offset uint64
+}
+
+// ProbeFsType returns the filesystem name for the given device id.
+func ProbeFsType(device string) (string, error) {
+	probes := []probeData{
+		{"btrfs", "_BHRfS_M", 0x10040},
+		{"ext4", "\123\357", 0x438},
+		{"xfs", "XFSB", 0},
+	}
+
+	maxLen := uint64(0)
+	for _, p := range probes {
+		l := p.offset + uint64(len(p.magic))
+		if l > maxLen {
+			maxLen = l
+		}
+	}
+
+	file, err := os.Open(device)
+	if err != nil {
+		return "", err
+	}
+	defer file.Close()
+
+	buffer := make([]byte, maxLen)
+	l, err := file.Read(buffer)
+	if err != nil {
+		return "", err
+	}
+
+	if uint64(l) != maxLen {
+		return "", fmt.Errorf("devmapper: unable to detect filesystem type of %s, short read", device)
+	}
+
+	for _, p := range probes {
+		if bytes.Equal([]byte(p.magic), buffer[p.offset:p.offset+uint64(len(p.magic))]) {
+			return p.fsName, nil
+		}
+	}
+
+	return "", fmt.Errorf("devmapper: Unknown filesystem type on %s", device)
+}
+
+func joinMountOptions(a, b string) string {
+	if a == "" {
+		return b
+	}
+	if b == "" {
+		return a
+	}
+	return a + "," + b
+}

vendor/github.com/containers/storage/drivers/driver.go

@@ -0,0 +1,243 @@
+package graphdriver
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/Sirupsen/logrus"
+	"github.com/vbatts/tar-split/tar/storage"
+
+	"github.com/containers/storage/pkg/archive"
+	"github.com/containers/storage/pkg/idtools"
+)
+
+// FsMagic unsigned id of the filesystem in use.
+type FsMagic uint32
+
+const (
+	// FsMagicUnsupported is a predefined constant value other than a valid filesystem id.
+	FsMagicUnsupported = FsMagic(0x00000000)
+)
+
+var (
+	// All registered drivers
+	drivers map[string]InitFunc
+
+	// ErrNotSupported returned when driver is not supported.
+	ErrNotSupported = errors.New("driver not supported")
+	// ErrPrerequisites retuned when driver does not meet prerequisites.
+	ErrPrerequisites = errors.New("prerequisites for driver not satisfied (wrong filesystem?)")
+	// ErrIncompatibleFS returned when file system is not supported.
+	ErrIncompatibleFS = fmt.Errorf("backing file system is unsupported for this graph driver")
+)
+
+// InitFunc initializes the storage driver.
+type InitFunc func(root string, options []string, uidMaps, gidMaps []idtools.IDMap) (Driver, error)
+
+// ProtoDriver defines the basic capabilities of a driver.
+// This interface exists solely to be a minimum set of methods
+// for client code which choose not to implement the entire Driver
+// interface and use the NaiveDiffDriver wrapper constructor.
+//
+// Use of ProtoDriver directly by client code is not recommended.
+type ProtoDriver interface {
+	// String returns a string representation of this driver.
+	String() string
+	// CreateReadWrite creates a new, empty filesystem layer that is ready
+	// to be used as the storage for a container.
+	CreateReadWrite(id, parent, mountLabel string, storageOpt map[string]string) error
+	// Create creates a new, empty, filesystem layer with the
+	// specified id and parent and mountLabel. Parent and mountLabel may be "".
+	Create(id, parent, mountLabel string, storageOpt map[string]string) error
+	// Remove attempts to remove the filesystem layer with this id.
+	Remove(id string) error
+	// Get returns the mountpoint for the layered filesystem referred
+	// to by this id. You can optionally specify a mountLabel or "".
+	// Returns the absolute path to the mounted layered filesystem.
+	Get(id, mountLabel string) (dir string, err error)
+	// Put releases the system resources for the specified id,
+	// e.g, unmounting layered filesystem.
+	Put(id string) error
+	// Exists returns whether a filesystem layer with the specified
+	// ID exists on this driver.
+	Exists(id string) bool
+	// Status returns a set of key-value pairs which give low
+	// level diagnostic status about this driver.
+	Status() [][2]string
+	// Returns a set of key-value pairs which give low level information
+	// about the image/container driver is managing.
+	GetMetadata(id string) (map[string]string, error)
+	// Cleanup performs necessary tasks to release resources
+	// held by the driver, e.g., unmounting all layered filesystems
+	// known to this driver.
+	Cleanup() error
+}
+
+// Driver is the interface for layered/snapshot file system drivers.
+type Driver interface {
+	ProtoDriver
+	// Diff produces an archive of the changes between the specified
+	// layer and its parent layer which may be "".
+	Diff(id, parent string) (archive.Archive, error)
+	// Changes produces a list of changes between the specified layer
+	// and its parent layer. If parent is "", then all changes will be ADD changes.
+	Changes(id, parent string) ([]archive.Change, error)
+	// 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.
+	// The archive.Reader must be an uncompressed stream.
+	ApplyDiff(id, parent string, diff archive.Reader) (size int64, err error)
+	// 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.
+	DiffSize(id, parent string) (size int64, err error)
+}
+
+// DiffGetterDriver is the interface for layered file system drivers that
+// provide a specialized function for getting file contents for tar-split.
+type DiffGetterDriver interface {
+	Driver
+	// DiffGetter returns an interface to efficiently retrieve the contents
+	// of files in a layer.
+	DiffGetter(id string) (FileGetCloser, error)
+}
+
+// FileGetCloser extends the storage.FileGetter interface with a Close method
+// for cleaning up.
+type FileGetCloser interface {
+	storage.FileGetter
+	// Close cleans up any resources associated with the FileGetCloser.
+	Close() error
+}
+
+// Checker makes checks on specified filesystems.
+type Checker interface {
+	// IsMounted returns true if the provided path is mounted for the specific checker
+	IsMounted(path string) bool
+}
+
+func init() {
+	drivers = make(map[string]InitFunc)
+}
+
+// Register registers an InitFunc for the driver.
+func Register(name string, initFunc InitFunc) error {
+	if _, exists := drivers[name]; exists {
+		return fmt.Errorf("Name already registered %s", name)
+	}
+	drivers[name] = initFunc
+
+	return nil
+}
+
+// GetDriver initializes and returns the registered driver
+func GetDriver(name, home string, options []string, uidMaps, gidMaps []idtools.IDMap) (Driver, error) {
+	if initFunc, exists := drivers[name]; exists {
+		return initFunc(filepath.Join(home, name), options, uidMaps, gidMaps)
+	}
+	if pluginDriver, err := lookupPlugin(name, home, options); err == nil {
+		return pluginDriver, nil
+	}
+	logrus.Errorf("Failed to GetDriver graph %s %s", name, home)
+	return nil, ErrNotSupported
+}
+
+// getBuiltinDriver initializes and returns the registered driver, but does not try to load from plugins
+func getBuiltinDriver(name, home string, options []string, uidMaps, gidMaps []idtools.IDMap) (Driver, error) {
+	if initFunc, exists := drivers[name]; exists {
+		return initFunc(filepath.Join(home, name), options, uidMaps, gidMaps)
+	}
+	logrus.Errorf("Failed to built-in GetDriver graph %s %s", name, home)
+	return nil, ErrNotSupported
+}
+
+// New creates the driver and initializes it at the specified root.
+func New(root string, name string, options []string, uidMaps, gidMaps []idtools.IDMap) (Driver, error) {
+	if name != "" {
+		logrus.Debugf("[graphdriver] trying provided driver %q", name) // so the logs show specified driver
+		return GetDriver(name, root, options, uidMaps, gidMaps)
+	}
+
+	// Guess for prior driver
+	driversMap := scanPriorDrivers(root)
+	for _, name := range priority {
+		if name == "vfs" {
+			// don't use vfs even if there is state present.
+			continue
+		}
+		if _, prior := driversMap[name]; prior {
+			// of the state found from prior drivers, check in order of our priority
+			// which we would prefer
+			driver, err := getBuiltinDriver(name, root, options, uidMaps, gidMaps)
+			if err != nil {
+				// unlike below, we will return error here, because there is prior
+				// state, and now it is no longer supported/prereq/compatible, so
+				// something changed and needs attention. Otherwise the daemon's
+				// images would just "disappear".
+				logrus.Errorf("[graphdriver] prior storage driver %q failed: %s", name, err)
+				return nil, err
+			}
+
+			// abort starting when there are other prior configured drivers
+			// to ensure the user explicitly selects the driver to load
+			if len(driversMap)-1 > 0 {
+				var driversSlice []string
+				for name := range driversMap {
+					driversSlice = append(driversSlice, name)
+				}
+
+				return nil, fmt.Errorf("%q contains several valid graphdrivers: %s; Please cleanup or explicitly choose storage driver (-s <DRIVER>)", root, strings.Join(driversSlice, ", "))
+			}
+
+			logrus.Infof("[graphdriver] using prior storage driver %q", name)
+			return driver, nil
+		}
+	}
+
+	// Check for priority drivers first
+	for _, name := range priority {
+		driver, err := getBuiltinDriver(name, root, options, uidMaps, gidMaps)
+		if err != nil {
+			if isDriverNotSupported(err) {
+				continue
+			}
+			return nil, err
+		}
+		return driver, nil
+	}
+
+	// Check all registered drivers if no priority driver is found
+	for name, initFunc := range drivers {
+		driver, err := initFunc(filepath.Join(root, name), options, uidMaps, gidMaps)
+		if err != nil {
+			if isDriverNotSupported(err) {
+				continue
+			}
+			return nil, err
+		}
+		return driver, nil
+	}
+	return nil, fmt.Errorf("No supported storage backend found")
+}
+
+// isDriverNotSupported returns true if the error initializing
+// the graph driver is a non-supported error.
+func isDriverNotSupported(err error) bool {
+	return err == ErrNotSupported || err == ErrPrerequisites || err == ErrIncompatibleFS
+}
+
+// scanPriorDrivers returns an un-ordered scan of directories of prior storage drivers
+func scanPriorDrivers(root string) map[string]bool {
+	driversMap := make(map[string]bool)
+
+	for driver := range drivers {
+		p := filepath.Join(root, driver)
+		if _, err := os.Stat(p); err == nil && driver != "vfs" {
+			driversMap[driver] = true
+		}
+	}
+	return driversMap
+}

vendor/github.com/containers/storage/drivers/driver_freebsd.go

@@ -0,0 +1,19 @@
+package graphdriver
+
+import "syscall"
+
+var (
+	// Slice of drivers that should be used in an order
+	priority = []string{
+		"zfs",
+	}
+)
+
+// Mounted checks if the given path is mounted as the fs type
+func Mounted(fsType FsMagic, mountPath string) (bool, error) {
+	var buf syscall.Statfs_t
+	if err := syscall.Statfs(mountPath, &buf); err != nil {
+		return false, err
+	}
+	return FsMagic(buf.Type) == fsType, nil
+}

vendor/github.com/containers/storage/drivers/driver_linux.go

@@ -0,0 +1,133 @@
+// +build linux
+
+package graphdriver
+
+import (
+	"path/filepath"
+	"syscall"
+
+	"github.com/containers/storage/pkg/mount"
+)
+
+const (
+	// FsMagicAufs filesystem id for Aufs
+	FsMagicAufs = FsMagic(0x61756673)
+	// FsMagicBtrfs filesystem id for Btrfs
+	FsMagicBtrfs = FsMagic(0x9123683E)
+	// FsMagicCramfs filesystem id for Cramfs
+	FsMagicCramfs = FsMagic(0x28cd3d45)
+	// FsMagicEcryptfs filesystem id for eCryptfs
+	FsMagicEcryptfs = FsMagic(0xf15f)
+	// FsMagicExtfs filesystem id for Extfs
+	FsMagicExtfs = FsMagic(0x0000EF53)
+	// FsMagicF2fs filesystem id for F2fs
+	FsMagicF2fs = FsMagic(0xF2F52010)
+	// FsMagicGPFS filesystem id for GPFS
+	FsMagicGPFS = FsMagic(0x47504653)
+	// FsMagicJffs2Fs filesystem if for Jffs2Fs
+	FsMagicJffs2Fs = FsMagic(0x000072b6)
+	// FsMagicJfs filesystem id for Jfs
+	FsMagicJfs = FsMagic(0x3153464a)
+	// FsMagicNfsFs filesystem id for NfsFs
+	FsMagicNfsFs = FsMagic(0x00006969)
+	// FsMagicRAMFs filesystem id for RamFs
+	FsMagicRAMFs = FsMagic(0x858458f6)
+	// FsMagicReiserFs filesystem id for ReiserFs
+	FsMagicReiserFs = FsMagic(0x52654973)
+	// FsMagicSmbFs filesystem id for SmbFs
+	FsMagicSmbFs = FsMagic(0x0000517B)
+	// FsMagicSquashFs filesystem id for SquashFs
+	FsMagicSquashFs = FsMagic(0x73717368)
+	// FsMagicTmpFs filesystem id for TmpFs
+	FsMagicTmpFs = FsMagic(0x01021994)
+	// FsMagicVxFS filesystem id for VxFs
+	FsMagicVxFS = FsMagic(0xa501fcf5)
+	// FsMagicXfs filesystem id for Xfs
+	FsMagicXfs = FsMagic(0x58465342)
+	// FsMagicZfs filesystem id for Zfs
+	FsMagicZfs = FsMagic(0x2fc12fc1)
+	// FsMagicOverlay filesystem id for overlay
+	FsMagicOverlay = FsMagic(0x794C7630)
+)
+
+var (
+	// Slice of drivers that should be used in an order
+	priority = []string{
+		"aufs",
+		"btrfs",
+		"zfs",
+		"devicemapper",
+		"overlay",
+		"vfs",
+	}
+
+	// FsNames maps filesystem id to name of the filesystem.
+	FsNames = map[FsMagic]string{
+		FsMagicAufs:        "aufs",
+		FsMagicBtrfs:       "btrfs",
+		FsMagicCramfs:      "cramfs",
+		FsMagicExtfs:       "extfs",
+		FsMagicF2fs:        "f2fs",
+		FsMagicGPFS:        "gpfs",
+		FsMagicJffs2Fs:     "jffs2",
+		FsMagicJfs:         "jfs",
+		FsMagicNfsFs:       "nfs",
+		FsMagicRAMFs:       "ramfs",
+		FsMagicReiserFs:    "reiserfs",
+		FsMagicSmbFs:       "smb",
+		FsMagicSquashFs:    "squashfs",
+		FsMagicTmpFs:       "tmpfs",
+		FsMagicUnsupported: "unsupported",
+		FsMagicVxFS:        "vxfs",
+		FsMagicXfs:         "xfs",
+		FsMagicZfs:         "zfs",
+	}
+)
+
+// GetFSMagic returns the filesystem id given the path.
+func GetFSMagic(rootpath string) (FsMagic, error) {
+	var buf syscall.Statfs_t
+	if err := syscall.Statfs(filepath.Dir(rootpath), &buf); err != nil {
+		return 0, err
+	}
+	return FsMagic(buf.Type), nil
+}
+
+// NewFsChecker returns a checker configured for the provied FsMagic
+func NewFsChecker(t FsMagic) Checker {
+	return &fsChecker{
+		t: t,
+	}
+}
+
+type fsChecker struct {
+	t FsMagic
+}
+
+func (c *fsChecker) IsMounted(path string) bool {
+	m, _ := Mounted(c.t, path)
+	return m
+}
+
+// NewDefaultChecker returns a check that parses /proc/mountinfo to check
+// if the specified path is mounted.
+func NewDefaultChecker() Checker {
+	return &defaultChecker{}
+}
+
+type defaultChecker struct {
+}
+
+func (c *defaultChecker) IsMounted(path string) bool {
+	m, _ := mount.Mounted(path)
+	return m
+}
+
+// Mounted checks if the given path is mounted as the fs type
+func Mounted(fsType FsMagic, mountPath string) (bool, error) {
+	var buf syscall.Statfs_t
+	if err := syscall.Statfs(mountPath, &buf); err != nil {
+		return false, err
+	}
+	return FsMagic(buf.Type) == fsType, nil
+}

vendor/github.com/containers/storage/drivers/driver_solaris.go

@@ -0,0 +1,65 @@
+// +build solaris,cgo
+
+package graphdriver
+
+/*
+#include <sys/statvfs.h>
+#include <stdlib.h>
+
+static inline struct statvfs *getstatfs(char *s) {
+        struct statvfs *buf;
+        int err;
+        buf = (struct statvfs *)malloc(sizeof(struct statvfs));
+        err = statvfs(s, buf);
+        return buf;
+}
+*/
+import "C"
+import (
+	"path/filepath"
+	"unsafe"
+
+	log "github.com/Sirupsen/logrus"
+)
+
+const (
+	// FsMagicZfs filesystem id for Zfs
+	FsMagicZfs = FsMagic(0x2fc12fc1)
+)
+
+var (
+	// Slice of drivers that should be used in an order
+	priority = []string{
+		"zfs",
+	}
+
+	// FsNames maps filesystem id to name of the filesystem.
+	FsNames = map[FsMagic]string{
+		FsMagicZfs: "zfs",
+	}
+)
+
+// GetFSMagic returns the filesystem id given the path.
+func GetFSMagic(rootpath string) (FsMagic, error) {
+	return 0, nil
+}
+
+// Mounted checks if the given path is mounted as the fs type
+//Solaris supports only ZFS for now
+func Mounted(fsType FsMagic, mountPath string) (bool, error) {
+
+	cs := C.CString(filepath.Dir(mountPath))
+	buf := C.getstatfs(cs)
+
+	// on Solaris buf.f_basetype contains ['z', 'f', 's', 0 ... ]
+	if (buf.f_basetype[0] != 122) || (buf.f_basetype[1] != 102) || (buf.f_basetype[2] != 115) ||
+		(buf.f_basetype[3] != 0) {
+		log.Debugf("[zfs] no zfs dataset found for rootdir '%s'", mountPath)
+		C.free(unsafe.Pointer(buf))
+		return false, ErrPrerequisites
+	}
+
+	C.free(unsafe.Pointer(buf))
+	C.free(unsafe.Pointer(cs))
+	return true, nil
+}

vendor/github.com/containers/storage/drivers/driver_unsupported.go

@@ -0,0 +1,15 @@
+// +build !linux,!windows,!freebsd,!solaris
+
+package graphdriver
+
+var (
+	// Slice of drivers that should be used in an order
+	priority = []string{
+		"unsupported",
+	}
+)
+
+// GetFSMagic returns the filesystem id given the path.
+func GetFSMagic(rootpath string) (FsMagic, error) {
+	return FsMagicUnsupported, nil
+}

vendor/github.com/containers/storage/drivers/driver_windows.go

@@ -0,0 +1,14 @@
+package graphdriver
+
+var (
+	// Slice of drivers that should be used in order
+	priority = []string{
+		"windowsfilter",
+	}
+)
+
+// GetFSMagic returns the filesystem id given the path.
+func GetFSMagic(rootpath string) (FsMagic, error) {
+	// Note it is OK to return FsMagicUnsupported on Windows.
+	return FsMagicUnsupported, nil
+}

vendor/github.com/containers/storage/drivers/fsdiff.go

@@ -0,0 +1,157 @@
+package graphdriver
+
+import (
+	"time"
+
+	"github.com/Sirupsen/logrus"
+
+	"github.com/containers/storage/pkg/archive"
+	"github.com/containers/storage/pkg/chrootarchive"
+	"github.com/containers/storage/pkg/idtools"
+	"github.com/containers/storage/pkg/ioutils"
+)
+
+var (
+	// ApplyUncompressedLayer defines the unpack method used by the graph
+	// driver.
+	ApplyUncompressedLayer = chrootarchive.ApplyUncompressedLayer
+)
+
+// NaiveDiffDriver takes a ProtoDriver and adds the
+// capability of the Diffing methods which it may or may not
+// support on its own. See the comment on the exported
+// NewNaiveDiffDriver function below.
+// Notably, the AUFS driver doesn't need to be wrapped like this.
+type NaiveDiffDriver struct {
+	ProtoDriver
+	uidMaps []idtools.IDMap
+	gidMaps []idtools.IDMap
+}
+
+// NewNaiveDiffDriver returns a fully functional driver that wraps the
+// given ProtoDriver and adds the capability of the following methods which
+// it may or may not support on its own:
+//     Diff(id, parent string) (archive.Archive, error)
+//     Changes(id, parent string) ([]archive.Change, error)
+//     ApplyDiff(id, parent string, diff archive.Reader) (size int64, err error)
+//     DiffSize(id, parent string) (size int64, err error)
+func NewNaiveDiffDriver(driver ProtoDriver, uidMaps, gidMaps []idtools.IDMap) Driver {
+	gdw := &NaiveDiffDriver{
+		ProtoDriver: driver,
+		uidMaps:     uidMaps,
+		gidMaps:     gidMaps,
+	}
+	return gdw
+}
+
+// Diff produces an archive of the changes between the specified
+// layer and its parent layer which may be "".
+func (gdw *NaiveDiffDriver) Diff(id, parent string) (arch archive.Archive, err error) {
+	layerFs, err := gdw.Get(id, "")
+	if err != nil {
+		return nil, err
+	}
+
+	defer func() {
+		if err != nil {
+			gdw.Put(id)
+		}
+	}()
+
+	if parent == "" {
+		archive, err := archive.Tar(layerFs, archive.Uncompressed)
+		if err != nil {
+			return nil, err
+		}
+		return ioutils.NewReadCloserWrapper(archive, func() error {
+			err := archive.Close()
+			gdw.Put(id)
+			return err
+		}), nil
+	}
+
+	parentFs, err := gdw.Get(parent, "")
+	if err != nil {
+		return nil, err
+	}
+	defer gdw.Put(parent)
+
+	changes, err := archive.ChangesDirs(layerFs, parentFs)
+	if err != nil {
+		return nil, err
+	}
+
+	archive, err := archive.ExportChanges(layerFs, changes, gdw.uidMaps, gdw.gidMaps)
+	if err != nil {
+		return nil, err
+	}
+
+	return ioutils.NewReadCloserWrapper(archive, func() error {
+		err := archive.Close()
+		gdw.Put(id)
+		return err
+	}), nil
+}
+
+// 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 (gdw *NaiveDiffDriver) Changes(id, parent string) ([]archive.Change, error) {
+	layerFs, err := gdw.Get(id, "")
+	if err != nil {
+		return nil, err
+	}
+	defer gdw.Put(id)
+
+	parentFs := ""
+
+	if parent != "" {
+		parentFs, err = gdw.Get(parent, "")
+		if err != nil {
+			return nil, err
+		}
+		defer gdw.Put(parent)
+	}
+
+	return archive.ChangesDirs(layerFs, parentFs)
+}
+
+// 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 (gdw *NaiveDiffDriver) ApplyDiff(id, parent string, diff archive.Reader) (size int64, err error) {
+	// Mount the root filesystem so we can apply the diff/layer.
+	layerFs, err := gdw.Get(id, "")
+	if err != nil {
+		return
+	}
+	defer gdw.Put(id)
+
+	options := &archive.TarOptions{UIDMaps: gdw.uidMaps,
+		GIDMaps: gdw.gidMaps}
+	start := time.Now().UTC()
+	logrus.Debug("Start untar layer")
+	if size, err = ApplyUncompressedLayer(layerFs, diff, options); err != nil {
+		return
+	}
+	logrus.Debugf("Untar time: %vs", time.Now().UTC().Sub(start).Seconds())
+
+	return
+}
+
+// DiffSize calculates the changes between the specified layer
+// and its parent and returns the size in bytes of the changes
+// relative to its base filesystem directory.
+func (gdw *NaiveDiffDriver) DiffSize(id, parent string) (size int64, err error) {
+	changes, err := gdw.Changes(id, parent)
+	if err != nil {
+		return
+	}
+
+	layerFs, err := gdw.Get(id, "")
+	if err != nil {
+		return
+	}
+	defer gdw.Put(id)
+
+	return archive.ChangesSize(layerFs, changes), nil
+}

vendor/github.com/containers/storage/drivers/overlay/copy.go

@@ -0,0 +1,169 @@
+// +build linux
+
+package overlay
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"syscall"
+	"time"
+
+	"github.com/containers/storage/pkg/pools"
+	"github.com/containers/storage/pkg/system"
+)
+
+type copyFlags int
+
+const (
+	copyHardlink copyFlags = 1 << iota
+)
+
+func copyRegular(srcPath, dstPath string, mode os.FileMode) error {
+	srcFile, err := os.Open(srcPath)
+	if err != nil {
+		return err
+	}
+	defer srcFile.Close()
+
+	dstFile, err := os.OpenFile(dstPath, os.O_WRONLY|os.O_CREATE, mode)
+	if err != nil {
+		return err
+	}
+	defer dstFile.Close()
+
+	_, err = pools.Copy(dstFile, srcFile)
+
+	return err
+}
+
+func copyXattr(srcPath, dstPath, attr string) error {
+	data, err := system.Lgetxattr(srcPath, attr)
+	if err != nil {
+		return err
+	}
+	if data != nil {
+		if err := system.Lsetxattr(dstPath, attr, data, 0); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func copyDir(srcDir, dstDir string, flags copyFlags) error {
+	err := filepath.Walk(srcDir, func(srcPath string, f os.FileInfo, err error) error {
+		if err != nil {
+			return err
+		}
+
+		// Rebase path
+		relPath, err := filepath.Rel(srcDir, srcPath)
+		if err != nil {
+			return err
+		}
+
+		dstPath := filepath.Join(dstDir, relPath)
+		if err != nil {
+			return err
+		}
+
+		stat, ok := f.Sys().(*syscall.Stat_t)
+		if !ok {
+			return fmt.Errorf("Unable to get raw syscall.Stat_t data for %s", srcPath)
+		}
+
+		isHardlink := false
+
+		switch f.Mode() & os.ModeType {
+		case 0: // Regular file
+			if flags&copyHardlink != 0 {
+				isHardlink = true
+				if err := os.Link(srcPath, dstPath); err != nil {
+					return err
+				}
+			} else {
+				if err := copyRegular(srcPath, dstPath, f.Mode()); err != nil {
+					return err
+				}
+			}
+
+		case os.ModeDir:
+			if err := os.Mkdir(dstPath, f.Mode()); err != nil && !os.IsExist(err) {
+				return err
+			}
+
+		case os.ModeSymlink:
+			link, err := os.Readlink(srcPath)
+			if err != nil {
+				return err
+			}
+
+			if err := os.Symlink(link, dstPath); err != nil {
+				return err
+			}
+
+		case os.ModeNamedPipe:
+			fallthrough
+		case os.ModeSocket:
+			if err := syscall.Mkfifo(dstPath, stat.Mode); err != nil {
+				return err
+			}
+
+		case os.ModeDevice:
+			if err := syscall.Mknod(dstPath, stat.Mode, int(stat.Rdev)); err != nil {
+				return err
+			}
+
+		default:
+			return fmt.Errorf("Unknown file type for %s\n", srcPath)
+		}
+
+		// Everything below is copying metadata from src to dst. All this metadata
+		// already shares an inode for hardlinks.
+		if isHardlink {
+			return nil
+		}
+
+		if err := os.Lchown(dstPath, int(stat.Uid), int(stat.Gid)); err != nil {
+			return err
+		}
+
+		if err := copyXattr(srcPath, dstPath, "security.capability"); err != nil {
+			return err
+		}
+
+		// We need to copy this attribute if it appears in an overlay upper layer, as
+		// this function is used to copy those. It is set by overlay if a directory
+		// is removed and then re-created and should not inherit anything from the
+		// same dir in the lower dir.
+		if err := copyXattr(srcPath, dstPath, "trusted.overlay.opaque"); err != nil {
+			return err
+		}
+
+		isSymlink := f.Mode()&os.ModeSymlink != 0
+
+		// There is no LChmod, so ignore mode for symlink. Also, this
+		// must happen after chown, as that can modify the file mode
+		if !isSymlink {
+			if err := os.Chmod(dstPath, f.Mode()); err != nil {
+				return err
+			}
+		}
+
+		// system.Chtimes doesn't support a NOFOLLOW flag atm
+		if !isSymlink {
+			aTime := time.Unix(int64(stat.Atim.Sec), int64(stat.Atim.Nsec))
+			mTime := time.Unix(int64(stat.Mtim.Sec), int64(stat.Mtim.Nsec))
+			if err := system.Chtimes(dstPath, aTime, mTime); err != nil {
+				return err
+			}
+		} else {
+			ts := []syscall.Timespec{stat.Atim, stat.Mtim}
+			if err := system.LUtimesNano(dstPath, ts); err != nil {
+				return err
+			}
+		}
+		return nil
+	})
+	return err
+}

vendor/github.com/containers/storage/drivers/overlay/overlay.go

@@ -0,0 +1,450 @@
+// +build linux
+
+package overlay
+
+import (
+	"bufio"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"path"
+	"syscall"
+
+	"github.com/Sirupsen/logrus"
+
+	"github.com/containers/storage/drivers"
+	"github.com/containers/storage/pkg/archive"
+	"github.com/containers/storage/pkg/idtools"
+
+	"github.com/containers/storage/pkg/mount"
+	"github.com/opencontainers/runc/libcontainer/label"
+)
+
+// This is a small wrapper over the NaiveDiffWriter that lets us have a custom
+// implementation of ApplyDiff()
+
+var (
+	// ErrApplyDiffFallback is returned to indicate that a normal ApplyDiff is applied as a fallback from Naive diff writer.
+	ErrApplyDiffFallback = fmt.Errorf("Fall back to normal ApplyDiff")
+	backingFs            = "<unknown>"
+)
+
+// ApplyDiffProtoDriver wraps the ProtoDriver by extending the interface with ApplyDiff method.
+type ApplyDiffProtoDriver interface {
+	graphdriver.ProtoDriver
+	// ApplyDiff writes the diff to the archive for the given id and parent id.
+	// It returns the size in bytes written if successful, an error ErrApplyDiffFallback is returned otherwise.
+	ApplyDiff(id, parent string, diff archive.Reader) (size int64, err error)
+}
+
+type naiveDiffDriverWithApply struct {
+	graphdriver.Driver
+	applyDiff ApplyDiffProtoDriver
+}
+
+// NaiveDiffDriverWithApply returns a NaiveDiff driver with custom ApplyDiff.
+func NaiveDiffDriverWithApply(driver ApplyDiffProtoDriver, uidMaps, gidMaps []idtools.IDMap) graphdriver.Driver {
+	return &naiveDiffDriverWithApply{
+		Driver:    graphdriver.NewNaiveDiffDriver(driver, uidMaps, gidMaps),
+		applyDiff: driver,
+	}
+}
+
+// ApplyDiff creates a diff layer with either the NaiveDiffDriver or with a fallback.
+func (d *naiveDiffDriverWithApply) ApplyDiff(id, parent string, diff archive.Reader) (int64, error) {
+	b, err := d.applyDiff.ApplyDiff(id, parent, diff)
+	if err == ErrApplyDiffFallback {
+		return d.Driver.ApplyDiff(id, parent, diff)
+	}
+	return b, err
+}
+
+// This backend uses the overlay union filesystem for containers
+// plus hard link file sharing for images.
+
+// Each container/image can have a "root" subdirectory which is a plain
+// filesystem hierarchy, or they can use overlay.
+
+// If they use overlay there is a "upper" directory and a "lower-id"
+// file, as well as "merged" and "work" directories. The "upper"
+// directory has the upper layer of the overlay, and "lower-id" contains
+// the id of the parent whose "root" directory shall be used as the lower
+// layer in the overlay. The overlay itself is mounted in the "merged"
+// directory, and the "work" dir is needed for overlay to work.
+
+// When an overlay layer is created there are two cases, either the
+// parent has a "root" dir, then we start out with an empty "upper"
+// directory overlaid on the parents root. This is typically the
+// case with the init layer of a container which is based on an image.
+// If there is no "root" in the parent, we inherit the lower-id from
+// the parent and start by making a copy in the parent's "upper" dir.
+// This is typically the case for a container layer which copies
+// its parent -init upper layer.
+
+// Additionally we also have a custom implementation of ApplyLayer
+// which makes a recursive copy of the parent "root" layer using
+// hardlinks to share file data, and then applies the layer on top
+// of that. This means all child images share file (but not directory)
+// data with the parent.
+
+// Driver contains information about the home directory and the list of active mounts that are created using this driver.
+type Driver struct {
+	home    string
+	uidMaps []idtools.IDMap
+	gidMaps []idtools.IDMap
+	ctr     *graphdriver.RefCounter
+}
+
+func init() {
+	graphdriver.Register("overlay", Init)
+}
+
+// Init returns the NaiveDiffDriver, a native diff driver for overlay filesystem.
+// If overlay filesystem is not supported on the host, graphdriver.ErrNotSupported is returned as error.
+// If an overlay filesystem is not supported over an existing filesystem then error graphdriver.ErrIncompatibleFS is returned.
+func Init(home string, options []string, uidMaps, gidMaps []idtools.IDMap) (graphdriver.Driver, error) {
+
+	if err := supportsOverlay(); err != nil {
+		return nil, graphdriver.ErrNotSupported
+	}
+
+	fsMagic, err := graphdriver.GetFSMagic(home)
+	if err != nil {
+		return nil, err
+	}
+	if fsName, ok := graphdriver.FsNames[fsMagic]; ok {
+		backingFs = fsName
+	}
+
+	switch fsMagic {
+	case graphdriver.FsMagicAufs, graphdriver.FsMagicBtrfs, graphdriver.FsMagicOverlay, graphdriver.FsMagicZfs, graphdriver.FsMagicEcryptfs:
+		logrus.Errorf("'overlay' is not supported over %s", backingFs)
+		return nil, graphdriver.ErrIncompatibleFS
+	}
+
+	rootUID, rootGID, err := idtools.GetRootUIDGID(uidMaps, gidMaps)
+	if err != nil {
+		return nil, err
+	}
+	// Create the driver home dir
+	if err := idtools.MkdirAllAs(home, 0700, rootUID, rootGID); err != nil && !os.IsExist(err) {
+		return nil, err
+	}
+
+	if err := mount.MakePrivate(home); err != nil {
+		return nil, err
+	}
+
+	d := &Driver{
+		home:    home,
+		uidMaps: uidMaps,
+		gidMaps: gidMaps,
+		ctr:     graphdriver.NewRefCounter(graphdriver.NewFsChecker(graphdriver.FsMagicOverlay)),
+	}
+
+	return NaiveDiffDriverWithApply(d, uidMaps, gidMaps), nil
+}
+
+func supportsOverlay() error {
+	// We can try to modprobe overlay first before looking at
+	// proc/filesystems for when overlay is supported
+	exec.Command("modprobe", "overlay").Run()
+
+	f, err := os.Open("/proc/filesystems")
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	s := bufio.NewScanner(f)
+	for s.Scan() {
+		if s.Text() == "nodev\toverlay" {
+			return nil
+		}
+	}
+	logrus.Error("'overlay' not found as a supported filesystem on this host. Please ensure kernel is new enough and has overlay support loaded.")
+	return graphdriver.ErrNotSupported
+}
+
+func (d *Driver) String() string {
+	return "overlay"
+}
+
+// Status returns current driver information in a two dimensional string array.
+// Output contains "Backing Filesystem" used in this implementation.
+func (d *Driver) Status() [][2]string {
+	return [][2]string{
+		{"Backing Filesystem", backingFs},
+	}
+}
+
+// GetMetadata returns meta data about the overlay driver such as root, LowerDir, UpperDir, WorkDir and MergeDir used to store data.
+func (d *Driver) GetMetadata(id string) (map[string]string, error) {
+	dir := d.dir(id)
+	if _, err := os.Stat(dir); err != nil {
+		return nil, err
+	}
+
+	metadata := make(map[string]string)
+
+	// If id has a root, it is an image
+	rootDir := path.Join(dir, "root")
+	if _, err := os.Stat(rootDir); err == nil {
+		metadata["RootDir"] = rootDir
+		return metadata, nil
+	}
+
+	lowerID, err := ioutil.ReadFile(path.Join(dir, "lower-id"))
+	if err != nil {
+		return nil, err
+	}
+
+	metadata["LowerDir"] = path.Join(d.dir(string(lowerID)), "root")
+	metadata["UpperDir"] = path.Join(dir, "upper")
+	metadata["WorkDir"] = path.Join(dir, "work")
+	metadata["MergedDir"] = path.Join(dir, "merged")
+
+	return metadata, nil
+}
+
+// Cleanup any state created by overlay which should be cleaned when daemon
+// is being shutdown. For now, we just have to unmount the bind mounted
+// we had created.
+func (d *Driver) Cleanup() error {
+	return mount.Unmount(d.home)
+}
+
+// CreateReadWrite creates a layer that is writable for use as a container
+// file system.
+func (d *Driver) CreateReadWrite(id, parent, mountLabel string, storageOpt map[string]string) error {
+	return d.Create(id, parent, mountLabel, storageOpt)
+}
+
+// Create is used to create the upper, lower, and merge directories required for overlay fs for a given id.
+// The parent filesystem is used to configure these directories for the overlay.
+func (d *Driver) Create(id, parent, mountLabel string, storageOpt map[string]string) (retErr error) {
+
+	if len(storageOpt) != 0 {
+		return fmt.Errorf("--storage-opt is not supported for overlay")
+	}
+
+	dir := d.dir(id)
+
+	rootUID, rootGID, err := idtools.GetRootUIDGID(d.uidMaps, d.gidMaps)
+	if err != nil {
+		return err
+	}
+	if err := idtools.MkdirAllAs(path.Dir(dir), 0700, rootUID, rootGID); err != nil {
+		return err
+	}
+	if err := idtools.MkdirAs(dir, 0700, rootUID, rootGID); err != nil {
+		return err
+	}
+
+	defer func() {
+		// Clean up on failure
+		if retErr != nil {
+			os.RemoveAll(dir)
+		}
+	}()
+
+	// Toplevel images are just a "root" dir
+	if parent == "" {
+		if err := idtools.MkdirAs(path.Join(dir, "root"), 0755, rootUID, rootGID); err != nil {
+			return err
+		}
+		return nil
+	}
+
+	parentDir := d.dir(parent)
+
+	// Ensure parent exists
+	if _, err := os.Lstat(parentDir); err != nil {
+		return err
+	}
+
+	// If parent has a root, just do an overlay to it
+	parentRoot := path.Join(parentDir, "root")
+
+	if s, err := os.Lstat(parentRoot); err == nil {
+		if err := idtools.MkdirAs(path.Join(dir, "upper"), s.Mode(), rootUID, rootGID); err != nil {
+			return err
+		}
+		if err := idtools.MkdirAs(path.Join(dir, "work"), 0700, rootUID, rootGID); err != nil {
+			return err
+		}
+		if err := idtools.MkdirAs(path.Join(dir, "merged"), 0700, rootUID, rootGID); err != nil {
+			return err
+		}
+		if err := ioutil.WriteFile(path.Join(dir, "lower-id"), []byte(parent), 0666); err != nil {
+			return err
+		}
+		return nil
+	}
+
+	// Otherwise, copy the upper and the lower-id from the parent
+
+	lowerID, err := ioutil.ReadFile(path.Join(parentDir, "lower-id"))
+	if err != nil {
+		return err
+	}
+
+	if err := ioutil.WriteFile(path.Join(dir, "lower-id"), lowerID, 0666); err != nil {
+		return err
+	}
+
+	parentUpperDir := path.Join(parentDir, "upper")
+	s, err := os.Lstat(parentUpperDir)
+	if err != nil {
+		return err
+	}
+
+	upperDir := path.Join(dir, "upper")
+	if err := idtools.MkdirAs(upperDir, s.Mode(), rootUID, rootGID); err != nil {
+		return err
+	}
+	if err := idtools.MkdirAs(path.Join(dir, "work"), 0700, rootUID, rootGID); err != nil {
+		return err
+	}
+	if err := idtools.MkdirAs(path.Join(dir, "merged"), 0700, rootUID, rootGID); err != nil {
+		return err
+	}
+
+	return copyDir(parentUpperDir, upperDir, 0)
+}
+
+func (d *Driver) dir(id string) string {
+	return path.Join(d.home, id)
+}
+
+// Remove cleans the directories that are created for this id.
+func (d *Driver) Remove(id string) error {
+	if err := os.RemoveAll(d.dir(id)); err != nil && !os.IsNotExist(err) {
+		return err
+	}
+	return nil
+}
+
+// Get creates and mounts the required file system for the given id and returns the mount path.
+func (d *Driver) Get(id string, mountLabel string) (s string, err error) {
+	dir := d.dir(id)
+	if _, err := os.Stat(dir); err != nil {
+		return "", err
+	}
+	// If id has a root, just return it
+	rootDir := path.Join(dir, "root")
+	if _, err := os.Stat(rootDir); err == nil {
+		return rootDir, nil
+	}
+	mergedDir := path.Join(dir, "merged")
+	if count := d.ctr.Increment(mergedDir); count > 1 {
+		return mergedDir, nil
+	}
+	defer func() {
+		if err != nil {
+			if c := d.ctr.Decrement(mergedDir); c <= 0 {
+				syscall.Unmount(mergedDir, 0)
+			}
+		}
+	}()
+	lowerID, err := ioutil.ReadFile(path.Join(dir, "lower-id"))
+	if err != nil {
+		return "", err
+	}
+	var (
+		lowerDir = path.Join(d.dir(string(lowerID)), "root")
+		upperDir = path.Join(dir, "upper")
+		workDir  = path.Join(dir, "work")
+		opts     = fmt.Sprintf("lowerdir=%s,upperdir=%s,workdir=%s", lowerDir, upperDir, workDir)
+	)
+	if err := syscall.Mount("overlay", mergedDir, "overlay", 0, label.FormatMountLabel(opts, mountLabel)); err != nil {
+		return "", fmt.Errorf("error creating overlay mount to %s: %v", mergedDir, err)
+	}
+	// chown "workdir/work" to the remapped root UID/GID. Overlay fs inside a
+	// user namespace requires this to move a directory from lower to upper.
+	rootUID, rootGID, err := idtools.GetRootUIDGID(d.uidMaps, d.gidMaps)
+	if err != nil {
+		return "", err
+	}
+	if err := os.Chown(path.Join(workDir, "work"), rootUID, rootGID); err != nil {
+		return "", err
+	}
+	return mergedDir, nil
+}
+
+// Put unmounts the mount path created for the give id.
+func (d *Driver) Put(id string) error {
+	mountpoint := path.Join(d.dir(id), "merged")
+	if count := d.ctr.Decrement(mountpoint); count > 0 {
+		return nil
+	}
+	err := syscall.Unmount(mountpoint, 0)
+	if err != nil {
+		rootDir := path.Join(d.dir(id), "root")
+		if _, err := os.Stat(rootDir); err == nil {
+			// We weren't mounting a "merged" directory anyway
+			return nil
+		}
+		logrus.Debugf("Failed to unmount %s overlay: %v", id, err)
+	}
+	return err
+}
+
+// ApplyDiff applies the new layer on top of the root, if parent does not exist with will return an ErrApplyDiffFallback error.
+func (d *Driver) ApplyDiff(id string, parent string, diff archive.Reader) (size int64, err error) {
+	dir := d.dir(id)
+
+	if parent == "" {
+		return 0, ErrApplyDiffFallback
+	}
+
+	parentRootDir := path.Join(d.dir(parent), "root")
+	if _, err := os.Stat(parentRootDir); err != nil {
+		return 0, ErrApplyDiffFallback
+	}
+
+	// We now know there is a parent, and it has a "root" directory containing
+	// the full root filesystem. We can just hardlink it and apply the
+	// layer. This relies on two things:
+	// 1) ApplyDiff is only run once on a clean (no writes to upper layer) container
+	// 2) ApplyDiff doesn't do any in-place writes to files (would break hardlinks)
+	// These are all currently true and are not expected to break
+
+	tmpRootDir, err := ioutil.TempDir(dir, "tmproot")
+	if err != nil {
+		return 0, err
+	}
+	defer func() {
+		if err != nil {
+			os.RemoveAll(tmpRootDir)
+		} else {
+			os.RemoveAll(path.Join(dir, "upper"))
+			os.RemoveAll(path.Join(dir, "work"))
+			os.RemoveAll(path.Join(dir, "merged"))
+			os.RemoveAll(path.Join(dir, "lower-id"))
+		}
+	}()
+
+	if err = copyDir(parentRootDir, tmpRootDir, copyHardlink); err != nil {
+		return 0, err
+	}
+
+	options := &archive.TarOptions{UIDMaps: d.uidMaps, GIDMaps: d.gidMaps}
+	if size, err = graphdriver.ApplyUncompressedLayer(tmpRootDir, diff, options); err != nil {
+		return 0, err
+	}
+
+	rootDir := path.Join(dir, "root")
+	if err := os.Rename(tmpRootDir, rootDir); err != nil {
+		return 0, err
+	}
+
+	return
+}
+
+// Exists checks to see if the id is already mounted.
+func (d *Driver) Exists(id string) bool {
+	_, err := os.Stat(d.dir(id))
+	return err == nil
+}

vendor/github.com/containers/storage/drivers/overlay/overlay_unsupported.go

@@ -0,0 +1,3 @@
+// +build !linux
+
+package overlay

vendor/github.com/containers/storage/drivers/overlay2/mount.go

@@ -0,0 +1,88 @@
+// +build linux
+
+package overlay2
+
+import (
+	"bytes"
+	"encoding/json"
+	"flag"
+	"fmt"
+	"os"
+	"runtime"
+	"syscall"
+
+	"github.com/containers/storage/pkg/reexec"
+)
+
+func init() {
+	reexec.Register("docker-mountfrom", mountFromMain)
+}
+
+func fatal(err error) {
+	fmt.Fprint(os.Stderr, err)
+	os.Exit(1)
+}
+
+type mountOptions struct {
+	Device string
+	Target string
+	Type   string
+	Label  string
+	Flag   uint32
+}
+
+func mountFrom(dir, device, target, mType, label string) error {
+	options := &mountOptions{
+		Device: device,
+		Target: target,
+		Type:   mType,
+		Flag:   0,
+		Label:  label,
+	}
+
+	cmd := reexec.Command("docker-mountfrom", dir)
+	w, err := cmd.StdinPipe()
+	if err != nil {
+		return fmt.Errorf("mountfrom error on pipe creation: %v", err)
+	}
+
+	output := bytes.NewBuffer(nil)
+	cmd.Stdout = output
+	cmd.Stderr = output
+
+	if err := cmd.Start(); err != nil {
+		return fmt.Errorf("mountfrom error on re-exec cmd: %v", err)
+	}
+	//write the options to the pipe for the untar exec to read
+	if err := json.NewEncoder(w).Encode(options); err != nil {
+		return fmt.Errorf("mountfrom json encode to pipe failed: %v", err)
+	}
+	w.Close()
+
+	if err := cmd.Wait(); err != nil {
+		return fmt.Errorf("mountfrom re-exec error: %v: output: %s", err, output)
+	}
+	return nil
+}
+
+// mountfromMain is the entry-point for docker-mountfrom on re-exec.
+func mountFromMain() {
+	runtime.LockOSThread()
+	flag.Parse()
+
+	var options *mountOptions
+
+	if err := json.NewDecoder(os.Stdin).Decode(&options); err != nil {
+		fatal(err)
+	}
+
+	if err := os.Chdir(flag.Arg(0)); err != nil {
+		fatal(err)
+	}
+
+	if err := syscall.Mount(options.Device, options.Target, options.Type, uintptr(options.Flag), options.Label); err != nil {
+		fatal(err)
+	}
+
+	os.Exit(0)
+}

vendor/github.com/containers/storage/drivers/overlay2/overlay.go

@@ -0,0 +1,514 @@
+// +build linux
+
+package overlay2
+
+import (
+	"bufio"
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"os/exec"
+	"path"
+	"strconv"
+	"strings"
+	"syscall"
+
+	"github.com/Sirupsen/logrus"
+
+	"github.com/containers/storage/drivers"
+	"github.com/containers/storage/pkg/archive"
+	"github.com/containers/storage/pkg/chrootarchive"
+	"github.com/containers/storage/pkg/directory"
+	"github.com/containers/storage/pkg/idtools"
+	"github.com/containers/storage/pkg/mount"
+	"github.com/containers/storage/pkg/parsers"
+	"github.com/containers/storage/pkg/parsers/kernel"
+
+	"github.com/opencontainers/runc/libcontainer/label"
+)
+
+var (
+	// untar defines the untar method
+	untar = chrootarchive.UntarUncompressed
+)
+
+// This backend uses the overlay union filesystem for containers
+// with diff directories for each layer.
+
+// This version of the overlay driver requires at least kernel
+// 4.0.0 in order to support mounting multiple diff directories.
+
+// Each container/image has at least a "diff" directory and "link" file.
+// If there is also a "lower" file when there are diff layers
+// below  as well as "merged" and "work" directories. The "diff" directory
+// has the upper layer of the overlay and is used to capture any
+// changes to the layer. The "lower" file contains all the lower layer
+// mounts separated by ":" and ordered from uppermost to lowermost
+// layers. The overlay itself is mounted in the "merged" directory,
+// and the "work" dir is needed for overlay to work.
+
+// The "link" file for each layer contains a unique string for the layer.
+// Under the "l" directory at the root there will be a symbolic link
+// with that unique string pointing the "diff" directory for the layer.
+// The symbolic links are used to reference lower layers in the "lower"
+// file and on mount. The links are used to shorten the total length
+// of a layer reference without requiring changes to the layer identifier
+// or root directory. Mounts are always done relative to root and
+// referencing the symbolic links in order to ensure the number of
+// lower directories can fit in a single page for making the mount
+// syscall. A hard upper limit of 128 lower layers is enforced to ensure
+// that mounts do not fail due to length.
+
+const (
+	driverName = "overlay2"
+	linkDir    = "l"
+	lowerFile  = "lower"
+	maxDepth   = 128
+
+	// idLength represents the number of random characters
+	// which can be used to create the unique link identifer
+	// for every layer. If this value is too long then the
+	// page size limit for the mount command may be exceeded.
+	// The idLength should be selected such that following equation
+	// is true (512 is a buffer for label metadata).
+	// ((idLength + len(linkDir) + 1) * maxDepth) <= (pageSize - 512)
+	idLength = 26
+)
+
+// Driver contains information about the home directory and the list of active mounts that are created using this driver.
+type Driver struct {
+	home    string
+	uidMaps []idtools.IDMap
+	gidMaps []idtools.IDMap
+	ctr     *graphdriver.RefCounter
+}
+
+var backingFs = "<unknown>"
+
+func init() {
+	graphdriver.Register(driverName, Init)
+}
+
+// Init returns the a native diff driver for overlay filesystem.
+// If overlay filesystem is not supported on the host, graphdriver.ErrNotSupported is returned as error.
+// If a overlay filesystem is not supported over a existing filesystem then error graphdriver.ErrIncompatibleFS is returned.
+func Init(home string, options []string, uidMaps, gidMaps []idtools.IDMap) (graphdriver.Driver, error) {
+	opts, err := parseOptions(options)
+	if err != nil {
+		return nil, err
+	}
+
+	if err := supportsOverlay(); err != nil {
+		return nil, graphdriver.ErrNotSupported
+	}
+
+	// require kernel 4.0.0 to ensure multiple lower dirs are supported
+	v, err := kernel.GetKernelVersion()
+	if err != nil {
+		return nil, err
+	}
+	if kernel.CompareKernelVersion(*v, kernel.VersionInfo{Kernel: 4, Major: 0, Minor: 0}) < 0 {
+		if !opts.overrideKernelCheck {
+			return nil, graphdriver.ErrNotSupported
+		}
+		logrus.Warnf("Using pre-4.0.0 kernel for overlay2, mount failures may require kernel update")
+	}
+
+	fsMagic, err := graphdriver.GetFSMagic(home)
+	if err != nil {
+		return nil, err
+	}
+	if fsName, ok := graphdriver.FsNames[fsMagic]; ok {
+		backingFs = fsName
+	}
+
+	// check if they are running over btrfs, aufs, zfs, overlay, or ecryptfs
+	switch fsMagic {
+	case graphdriver.FsMagicBtrfs, graphdriver.FsMagicAufs, graphdriver.FsMagicZfs, graphdriver.FsMagicOverlay, graphdriver.FsMagicEcryptfs:
+		logrus.Errorf("'overlay2' is not supported over %s", backingFs)
+		return nil, graphdriver.ErrIncompatibleFS
+	}
+
+	rootUID, rootGID, err := idtools.GetRootUIDGID(uidMaps, gidMaps)
+	if err != nil {
+		return nil, err
+	}
+	// Create the driver home dir
+	if err := idtools.MkdirAllAs(path.Join(home, linkDir), 0700, rootUID, rootGID); err != nil && !os.IsExist(err) {
+		return nil, err
+	}
+
+	if err := mount.MakePrivate(home); err != nil {
+		return nil, err
+	}
+
+	d := &Driver{
+		home:    home,
+		uidMaps: uidMaps,
+		gidMaps: gidMaps,
+		ctr:     graphdriver.NewRefCounter(graphdriver.NewFsChecker(graphdriver.FsMagicOverlay)),
+	}
+
+	return d, nil
+}
+
+type overlayOptions struct {
+	overrideKernelCheck bool
+}
+
+func parseOptions(options []string) (*overlayOptions, error) {
+	o := &overlayOptions{}
+	for _, option := range options {
+		key, val, err := parsers.ParseKeyValueOpt(option)
+		if err != nil {
+			return nil, err
+		}
+		key = strings.ToLower(key)
+		switch key {
+		case "overlay2.override_kernel_check":
+			o.overrideKernelCheck, err = strconv.ParseBool(val)
+			if err != nil {
+				return nil, err
+			}
+		default:
+			return nil, fmt.Errorf("overlay2: Unknown option %s\n", key)
+		}
+	}
+	return o, nil
+}
+
+func supportsOverlay() error {
+	// We can try to modprobe overlay first before looking at
+	// proc/filesystems for when overlay is supported
+	exec.Command("modprobe", "overlay").Run()
+
+	f, err := os.Open("/proc/filesystems")
+	if err != nil {
+		return err
+	}
+	defer f.Close()
+
+	s := bufio.NewScanner(f)
+	for s.Scan() {
+		if s.Text() == "nodev\toverlay" {
+			return nil
+		}
+	}
+	logrus.Error("'overlay' not found as a supported filesystem on this host. Please ensure kernel is new enough and has overlay support loaded.")
+	return graphdriver.ErrNotSupported
+}
+
+func (d *Driver) String() string {
+	return driverName
+}
+
+// Status returns current driver information in a two dimensional string array.
+// Output contains "Backing Filesystem" used in this implementation.
+func (d *Driver) Status() [][2]string {
+	return [][2]string{
+		{"Backing Filesystem", backingFs},
+	}
+}
+
+// GetMetadata returns meta data about the overlay driver such as
+// LowerDir, UpperDir, WorkDir and MergeDir used to store data.
+func (d *Driver) GetMetadata(id string) (map[string]string, error) {
+	dir := d.dir(id)
+	if _, err := os.Stat(dir); err != nil {
+		return nil, err
+	}
+
+	metadata := map[string]string{
+		"WorkDir":   path.Join(dir, "work"),
+		"MergedDir": path.Join(dir, "merged"),
+		"UpperDir":  path.Join(dir, "diff"),
+	}
+
+	lowerDirs, err := d.getLowerDirs(id)
+	if err != nil {
+		return nil, err
+	}
+	if len(lowerDirs) > 0 {
+		metadata["LowerDir"] = strings.Join(lowerDirs, ":")
+	}
+
+	return metadata, nil
+}
+
+// Cleanup any state created by overlay which should be cleaned when daemon
+// is being shutdown. For now, we just have to unmount the bind mounted
+// we had created.
+func (d *Driver) Cleanup() error {
+	return mount.Unmount(d.home)
+}
+
+// CreateReadWrite creates a layer that is writable for use as a container
+// file system.
+func (d *Driver) CreateReadWrite(id, parent, mountLabel string, storageOpt map[string]string) error {
+	return d.Create(id, parent, mountLabel, storageOpt)
+}
+
+// Create is used to create the upper, lower, and merge directories required for overlay fs for a given id.
+// The parent filesystem is used to configure these directories for the overlay.
+func (d *Driver) Create(id, parent, mountLabel string, storageOpt map[string]string) (retErr error) {
+
+	if len(storageOpt) != 0 {
+		return fmt.Errorf("--storage-opt is not supported for overlay")
+	}
+
+	dir := d.dir(id)
+
+	rootUID, rootGID, err := idtools.GetRootUIDGID(d.uidMaps, d.gidMaps)
+	if err != nil {
+		return err
+	}
+	if err := idtools.MkdirAllAs(path.Dir(dir), 0700, rootUID, rootGID); err != nil {
+		return err
+	}
+	if err := idtools.MkdirAs(dir, 0700, rootUID, rootGID); err != nil {
+		return err
+	}
+
+	defer func() {
+		// Clean up on failure
+		if retErr != nil {
+			os.RemoveAll(dir)
+		}
+	}()
+
+	if err := idtools.MkdirAs(path.Join(dir, "diff"), 0755, rootUID, rootGID); err != nil {
+		return err
+	}
+
+	lid := generateID(idLength)
+	if err := os.Symlink(path.Join("..", id, "diff"), path.Join(d.home, linkDir, lid)); err != nil {
+		return err
+	}
+
+	// Write link id to link file
+	if err := ioutil.WriteFile(path.Join(dir, "link"), []byte(lid), 0644); err != nil {
+		return err
+	}
+
+	// if no parent directory, done
+	if parent == "" {
+		return nil
+	}
+
+	if err := idtools.MkdirAs(path.Join(dir, "work"), 0700, rootUID, rootGID); err != nil {
+		return err
+	}
+	if err := idtools.MkdirAs(path.Join(dir, "merged"), 0700, rootUID, rootGID); err != nil {
+		return err
+	}
+
+	lower, err := d.getLower(parent)
+	if err != nil {
+		return err
+	}
+	if lower != "" {
+		if err := ioutil.WriteFile(path.Join(dir, lowerFile), []byte(lower), 0666); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func (d *Driver) getLower(parent string) (string, error) {
+	parentDir := d.dir(parent)
+
+	// Ensure parent exists
+	if _, err := os.Lstat(parentDir); err != nil {
+		return "", err
+	}
+
+	// Read Parent link fileA
+	parentLink, err := ioutil.ReadFile(path.Join(parentDir, "link"))
+	if err != nil {
+		return "", err
+	}
+	lowers := []string{path.Join(linkDir, string(parentLink))}
+
+	parentLower, err := ioutil.ReadFile(path.Join(parentDir, lowerFile))
+	if err == nil {
+		parentLowers := strings.Split(string(parentLower), ":")
+		lowers = append(lowers, parentLowers...)
+	}
+	if len(lowers) > maxDepth {
+		return "", errors.New("max depth exceeded")
+	}
+	return strings.Join(lowers, ":"), nil
+}
+
+func (d *Driver) dir(id string) string {
+	return path.Join(d.home, id)
+}
+
+func (d *Driver) getLowerDirs(id string) ([]string, error) {
+	var lowersArray []string
+	lowers, err := ioutil.ReadFile(path.Join(d.dir(id), lowerFile))
+	if err == nil {
+		for _, s := range strings.Split(string(lowers), ":") {
+			lp, err := os.Readlink(path.Join(d.home, s))
+			if err != nil {
+				return nil, err
+			}
+			lowersArray = append(lowersArray, path.Clean(path.Join(d.home, "link", lp)))
+		}
+	} else if !os.IsNotExist(err) {
+		return nil, err
+	}
+	return lowersArray, nil
+}
+
+// Remove cleans the directories that are created for this id.
+func (d *Driver) Remove(id string) error {
+	dir := d.dir(id)
+	lid, err := ioutil.ReadFile(path.Join(dir, "link"))
+	if err == nil {
+		if err := os.RemoveAll(path.Join(d.home, linkDir, string(lid))); err != nil {
+			logrus.Debugf("Failed to remove link: %v", err)
+		}
+	}
+
+	if err := os.RemoveAll(dir); err != nil && !os.IsNotExist(err) {
+		return err
+	}
+	return nil
+}
+
+// Get creates and mounts the required file system for the given id and returns the mount path.
+func (d *Driver) Get(id string, mountLabel string) (s string, err error) {
+	dir := d.dir(id)
+	if _, err := os.Stat(dir); err != nil {
+		return "", err
+	}
+
+	diffDir := path.Join(dir, "diff")
+	lowers, err := ioutil.ReadFile(path.Join(dir, lowerFile))
+	if err != nil {
+		// If no lower, just return diff directory
+		if os.IsNotExist(err) {
+			return diffDir, nil
+		}
+		return "", err
+	}
+
+	mergedDir := path.Join(dir, "merged")
+	if count := d.ctr.Increment(mergedDir); count > 1 {
+		return mergedDir, nil
+	}
+	defer func() {
+		if err != nil {
+			if c := d.ctr.Decrement(mergedDir); c <= 0 {
+				syscall.Unmount(mergedDir, 0)
+			}
+		}
+	}()
+
+	workDir := path.Join(dir, "work")
+	opts := fmt.Sprintf("lowerdir=%s,upperdir=%s,workdir=%s", string(lowers), path.Join(id, "diff"), path.Join(id, "work"))
+	mountLabel = label.FormatMountLabel(opts, mountLabel)
+	if len(mountLabel) > syscall.Getpagesize() {
+		return "", fmt.Errorf("cannot mount layer, mount label too large %d", len(mountLabel))
+	}
+
+	if err := mountFrom(d.home, "overlay", path.Join(id, "merged"), "overlay", mountLabel); err != nil {
+		return "", fmt.Errorf("error creating overlay mount to %s: %v", mergedDir, err)
+	}
+
+	// chown "workdir/work" to the remapped root UID/GID. Overlay fs inside a
+	// user namespace requires this to move a directory from lower to upper.
+	rootUID, rootGID, err := idtools.GetRootUIDGID(d.uidMaps, d.gidMaps)
+	if err != nil {
+		return "", err
+	}
+
+	if err := os.Chown(path.Join(workDir, "work"), rootUID, rootGID); err != nil {
+		return "", err
+	}
+
+	return mergedDir, nil
+}
+
+// Put unmounts the mount path created for the give id.
+func (d *Driver) Put(id string) error {
+	mountpoint := path.Join(d.dir(id), "merged")
+	if count := d.ctr.Decrement(mountpoint); count > 0 {
+		return nil
+	}
+	err := syscall.Unmount(mountpoint, 0)
+	if err != nil {
+		if _, err := ioutil.ReadFile(path.Join(d.dir(id), lowerFile)); err != nil {
+			// We didn't have a "lower" directory, so we weren't mounting a "merged" directory anyway
+			return nil
+		}
+		logrus.Debugf("Failed to unmount %s overlay: %v", id, err)
+	}
+	return err
+}
+
+// Exists checks to see if the id is already mounted.
+func (d *Driver) Exists(id string) bool {
+	_, err := os.Stat(d.dir(id))
+	return err == nil
+}
+
+// ApplyDiff applies the new layer into a root
+func (d *Driver) ApplyDiff(id string, parent string, diff archive.Reader) (size int64, err error) {
+	applyDir := d.getDiffPath(id)
+
+	logrus.Debugf("Applying tar in %s", applyDir)
+	// Overlay doesn't need the parent id to apply the diff
+	if err := untar(diff, applyDir, &archive.TarOptions{
+		UIDMaps:        d.uidMaps,
+		GIDMaps:        d.gidMaps,
+		WhiteoutFormat: archive.OverlayWhiteoutFormat,
+	}); err != nil {
+		return 0, err
+	}
+
+	return d.DiffSize(id, parent)
+}
+
+func (d *Driver) getDiffPath(id string) string {
+	dir := d.dir(id)
+
+	return path.Join(dir, "diff")
+}
+
+// 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 (d *Driver) DiffSize(id, parent string) (size int64, err error) {
+	return directory.Size(d.getDiffPath(id))
+}
+
+// Diff produces an archive of the changes between the specified
+// layer and its parent layer which may be "".
+func (d *Driver) Diff(id, parent string) (archive.Archive, error) {
+	diffPath := d.getDiffPath(id)
+	logrus.Debugf("Tar with options on %s", diffPath)
+	return archive.TarWithOptions(diffPath, &archive.TarOptions{
+		Compression:    archive.Uncompressed,
+		UIDMaps:        d.uidMaps,
+		GIDMaps:        d.gidMaps,
+		WhiteoutFormat: archive.OverlayWhiteoutFormat,
+	})
+}
+
+// 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 (d *Driver) Changes(id, parent string) ([]archive.Change, error) {
+	// Overlay doesn't have snapshots, so we need to get changes from all parent
+	// layers.
+	diffPath := d.getDiffPath(id)
+	layers, err := d.getLowerDirs(id)
+	if err != nil {
+		return nil, err
+	}
+
+	return archive.OverlayChanges(layers, diffPath)
+}

vendor/github.com/containers/storage/drivers/overlay2/overlay_unsupported.go

@@ -0,0 +1,3 @@
+// +build !linux
+
+package overlay2

vendor/github.com/containers/storage/drivers/overlay2/randomid.go

@@ -0,0 +1,80 @@
+// +build linux
+
+package overlay2
+
+import (
+	"crypto/rand"
+	"encoding/base32"
+	"fmt"
+	"io"
+	"os"
+	"syscall"
+	"time"
+
+	"github.com/Sirupsen/logrus"
+)
+
+// generateID creates a new random string identifier with the given length
+func generateID(l int) string {
+	const (
+		// ensures we backoff for less than 450ms total. Use the following to
+		// select new value, in units of 10ms:
+		// 	n*(n+1)/2 = d -> n^2 + n - 2d -> n = (sqrt(8d + 1) - 1)/2
+		maxretries = 9
+		backoff    = time.Millisecond * 10
+	)
+
+	var (
+		totalBackoff time.Duration
+		count        int
+		retries      int
+		size         = (l*5 + 7) / 8
+		u            = make([]byte, size)
+	)
+	// TODO: Include time component, counter component, random component
+
+	for {
+		// This should never block but the read may fail. Because of this,
+		// we just try to read the random number generator until we get
+		// something. This is a very rare condition but may happen.
+		b := time.Duration(retries) * backoff
+		time.Sleep(b)
+		totalBackoff += b
+
+		n, err := io.ReadFull(rand.Reader, u[count:])
+		if err != nil {
+			if retryOnError(err) && retries < maxretries {
+				count += n
+				retries++
+				logrus.Errorf("error generating version 4 uuid, retrying: %v", err)
+				continue
+			}
+
+			// Any other errors represent a system problem. What did someone
+			// do to /dev/urandom?
+			panic(fmt.Errorf("error reading random number generator, retried for %v: %v", totalBackoff.String(), err))
+		}
+
+		break
+	}
+
+	s := base32.StdEncoding.EncodeToString(u)
+
+	return s[:l]
+}
+
+// retryOnError tries to detect whether or not retrying would be fruitful.
+func retryOnError(err error) bool {
+	switch err := err.(type) {
+	case *os.PathError:
+		return retryOnError(err.Err) // unpack the target error
+	case syscall.Errno:
+		if err == syscall.EPERM {
+			// EPERM represents an entropy pool exhaustion, a condition under
+			// which we backoff and retry.
+			return true
+		}
+	}
+
+	return false
+}

vendor/github.com/containers/storage/drivers/plugin.go

@@ -0,0 +1,32 @@
+// +build experimental
+
+package graphdriver
+
+import (
+	"fmt"
+	"io"
+
+	"github.com/containers/storage/pkg/plugins"
+)
+
+type pluginClient interface {
+	// Call calls the specified method with the specified arguments for the plugin.
+	Call(string, interface{}, interface{}) error
+	// Stream calls the specified method with the specified arguments for the plugin and returns the response IO stream
+	Stream(string, interface{}) (io.ReadCloser, error)
+	// SendFile calls the specified method, and passes through the IO stream
+	SendFile(string, io.Reader, interface{}) error
+}
+
+func lookupPlugin(name, home string, opts []string) (Driver, error) {
+	pl, err := plugins.Get(name, "GraphDriver")
+	if err != nil {
+		return nil, fmt.Errorf("Error looking up graphdriver plugin %s: %v", name, err)
+	}
+	return newPluginDriver(name, home, opts, pl.Client())
+}
+
+func newPluginDriver(name, home string, opts []string, c pluginClient) (Driver, error) {
+	proxy := &graphDriverProxy{name, c}
+	return proxy, proxy.Init(home, opts)
+}

vendor/github.com/containers/storage/drivers/plugin_unsupported.go

@@ -0,0 +1,7 @@
+// +build !experimental
+
+package graphdriver
+
+func lookupPlugin(name, home string, opts []string) (Driver, error) {
+	return nil, ErrNotSupported
+}

vendor/github.com/containers/storage/drivers/proxy.go

@@ -0,0 +1,225 @@
+// +build experimental
+
+package graphdriver
+
+import (
+	"errors"
+	"fmt"
+
+	"github.com/containers/storage/pkg/archive"
+)
+
+type graphDriverProxy struct {
+	name   string
+	client pluginClient
+}
+
+type graphDriverRequest struct {
+	ID         string `json:",omitempty"`
+	Parent     string `json:",omitempty"`
+	MountLabel string `json:",omitempty"`
+}
+
+type graphDriverResponse struct {
+	Err      string            `json:",omitempty"`
+	Dir      string            `json:",omitempty"`
+	Exists   bool              `json:",omitempty"`
+	Status   [][2]string       `json:",omitempty"`
+	Changes  []archive.Change  `json:",omitempty"`
+	Size     int64             `json:",omitempty"`
+	Metadata map[string]string `json:",omitempty"`
+}
+
+type graphDriverInitRequest struct {
+	Home string
+	Opts []string
+}
+
+func (d *graphDriverProxy) Init(home string, opts []string) error {
+	args := &graphDriverInitRequest{
+		Home: home,
+		Opts: opts,
+	}
+	var ret graphDriverResponse
+	if err := d.client.Call("GraphDriver.Init", args, &ret); err != nil {
+		return err
+	}
+	if ret.Err != "" {
+		return errors.New(ret.Err)
+	}
+	return nil
+}
+
+func (d *graphDriverProxy) String() string {
+	return d.name
+}
+
+func (d *graphDriverProxy) CreateReadWrite(id, parent, mountLabel string, storageOpt map[string]string) error {
+	args := &graphDriverRequest{
+		ID:         id,
+		Parent:     parent,
+		MountLabel: mountLabel,
+	}
+	var ret graphDriverResponse
+	if err := d.client.Call("GraphDriver.CreateReadWrite", args, &ret); err != nil {
+		return err
+	}
+	if ret.Err != "" {
+		return errors.New(ret.Err)
+	}
+	return nil
+}
+
+func (d *graphDriverProxy) Create(id, parent, mountLabel string, storageOpt map[string]string) error {
+	args := &graphDriverRequest{
+		ID:         id,
+		Parent:     parent,
+		MountLabel: mountLabel,
+	}
+	var ret graphDriverResponse
+	if err := d.client.Call("GraphDriver.Create", args, &ret); err != nil {
+		return err
+	}
+	if ret.Err != "" {
+		return errors.New(ret.Err)
+	}
+	return nil
+}
+
+func (d *graphDriverProxy) Remove(id string) error {
+	args := &graphDriverRequest{ID: id}
+	var ret graphDriverResponse
+	if err := d.client.Call("GraphDriver.Remove", args, &ret); err != nil {
+		return err
+	}
+	if ret.Err != "" {
+		return errors.New(ret.Err)
+	}
+	return nil
+}
+
+func (d *graphDriverProxy) Get(id, mountLabel string) (string, error) {
+	args := &graphDriverRequest{
+		ID:         id,
+		MountLabel: mountLabel,
+	}
+	var ret graphDriverResponse
+	if err := d.client.Call("GraphDriver.Get", args, &ret); err != nil {
+		return "", err
+	}
+	var err error
+	if ret.Err != "" {
+		err = errors.New(ret.Err)
+	}
+	return ret.Dir, err
+}
+
+func (d *graphDriverProxy) Put(id string) error {
+	args := &graphDriverRequest{ID: id}
+	var ret graphDriverResponse
+	if err := d.client.Call("GraphDriver.Put", args, &ret); err != nil {
+		return err
+	}
+	if ret.Err != "" {
+		return errors.New(ret.Err)
+	}
+	return nil
+}
+
+func (d *graphDriverProxy) Exists(id string) bool {
+	args := &graphDriverRequest{ID: id}
+	var ret graphDriverResponse
+	if err := d.client.Call("GraphDriver.Exists", args, &ret); err != nil {
+		return false
+	}
+	return ret.Exists
+}
+
+func (d *graphDriverProxy) Status() [][2]string {
+	args := &graphDriverRequest{}
+	var ret graphDriverResponse
+	if err := d.client.Call("GraphDriver.Status", args, &ret); err != nil {
+		return nil
+	}
+	return ret.Status
+}
+
+func (d *graphDriverProxy) GetMetadata(id string) (map[string]string, error) {
+	args := &graphDriverRequest{
+		ID: id,
+	}
+	var ret graphDriverResponse
+	if err := d.client.Call("GraphDriver.GetMetadata", args, &ret); err != nil {
+		return nil, err
+	}
+	if ret.Err != "" {
+		return nil, errors.New(ret.Err)
+	}
+	return ret.Metadata, nil
+}
+
+func (d *graphDriverProxy) Cleanup() error {
+	args := &graphDriverRequest{}
+	var ret graphDriverResponse
+	if err := d.client.Call("GraphDriver.Cleanup", args, &ret); err != nil {
+		return nil
+	}
+	if ret.Err != "" {
+		return errors.New(ret.Err)
+	}
+	return nil
+}
+
+func (d *graphDriverProxy) Diff(id, parent string) (archive.Archive, error) {
+	args := &graphDriverRequest{
+		ID:     id,
+		Parent: parent,
+	}
+	body, err := d.client.Stream("GraphDriver.Diff", args)
+	if err != nil {
+		return nil, err
+	}
+	return archive.Archive(body), nil
+}
+
+func (d *graphDriverProxy) Changes(id, parent string) ([]archive.Change, error) {
+	args := &graphDriverRequest{
+		ID:     id,
+		Parent: parent,
+	}
+	var ret graphDriverResponse
+	if err := d.client.Call("GraphDriver.Changes", args, &ret); err != nil {
+		return nil, err
+	}
+	if ret.Err != "" {
+		return nil, errors.New(ret.Err)
+	}
+
+	return ret.Changes, nil
+}
+
+func (d *graphDriverProxy) ApplyDiff(id, parent string, diff archive.Reader) (int64, error) {
+	var ret graphDriverResponse
+	if err := d.client.SendFile(fmt.Sprintf("GraphDriver.ApplyDiff?id=%s&parent=%s", id, parent), diff, &ret); err != nil {
+		return -1, err
+	}
+	if ret.Err != "" {
+		return -1, errors.New(ret.Err)
+	}
+	return ret.Size, nil
+}
+
+func (d *graphDriverProxy) DiffSize(id, parent string) (int64, error) {
+	args := &graphDriverRequest{
+		ID:     id,
+		Parent: parent,
+	}
+	var ret graphDriverResponse
+	if err := d.client.Call("GraphDriver.DiffSize", args, &ret); err != nil {
+		return -1, err
+	}
+	if ret.Err != "" {
+		return -1, errors.New(ret.Err)
+	}
+	return ret.Size, nil
+}

vendor/github.com/containers/storage/drivers/register/register_aufs.go

@@ -0,0 +1,8 @@
+// +build !exclude_graphdriver_aufs,linux
+
+package register
+
+import (
+	// register the aufs graphdriver
+	_ "github.com/containers/storage/drivers/aufs"
+)

vendor/github.com/containers/storage/drivers/register/register_btrfs.go

@@ -0,0 +1,8 @@
+// +build !exclude_graphdriver_btrfs,linux
+
+package register
+
+import (
+	// register the btrfs graphdriver
+	_ "github.com/containers/storage/drivers/btrfs"
+)

vendor/github.com/containers/storage/drivers/register/register_devicemapper.go

@@ -0,0 +1,8 @@
+// +build !exclude_graphdriver_devicemapper,linux
+
+package register
+
+import (
+	// register the devmapper graphdriver
+	_ "github.com/containers/storage/drivers/devmapper"
+)

vendor/github.com/containers/storage/drivers/register/register_overlay.go

@@ -0,0 +1,9 @@
+// +build !exclude_graphdriver_overlay,linux
+
+package register
+
+import (
+	// register the overlay graphdriver
+	_ "github.com/containers/storage/drivers/overlay"
+	_ "github.com/containers/storage/drivers/overlay2"
+)

vendor/github.com/containers/storage/drivers/register/register_vfs.go

@@ -0,0 +1,6 @@
+package register
+
+import (
+	// register vfs
+	_ "github.com/containers/storage/drivers/vfs"
+)

vendor/github.com/containers/storage/drivers/register/register_windows.go

@@ -0,0 +1,6 @@
+package register
+
+import (
+	// register the windows graph driver
+	_ "github.com/containers/storage/drivers/windows"
+)

vendor/github.com/containers/storage/drivers/register/register_zfs.go

@@ -0,0 +1,8 @@
+// +build !exclude_graphdriver_zfs,linux !exclude_graphdriver_zfs,freebsd, solaris
+
+package register
+
+import (
+	// register the zfs driver
+	_ "github.com/containers/storage/drivers/zfs"
+)

vendor/github.com/containers/storage/drivers/vfs/driver.go

@@ -0,0 +1,145 @@
+package vfs
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+
+	"github.com/containers/storage/drivers"
+	"github.com/containers/storage/pkg/chrootarchive"
+	"github.com/containers/storage/pkg/idtools"
+
+	"github.com/opencontainers/runc/libcontainer/label"
+)
+
+var (
+	// CopyWithTar defines the copy method to use.
+	CopyWithTar = chrootarchive.CopyWithTar
+)
+
+func init() {
+	graphdriver.Register("vfs", Init)
+}
+
+// Init returns a new VFS driver.
+// This sets the home directory for the driver and returns NaiveDiffDriver.
+func Init(home string, options []string, uidMaps, gidMaps []idtools.IDMap) (graphdriver.Driver, error) {
+	d := &Driver{
+		home:    home,
+		uidMaps: uidMaps,
+		gidMaps: gidMaps,
+	}
+	rootUID, rootGID, err := idtools.GetRootUIDGID(uidMaps, gidMaps)
+	if err != nil {
+		return nil, err
+	}
+	if err := idtools.MkdirAllAs(home, 0700, rootUID, rootGID); err != nil {
+		return nil, err
+	}
+	return graphdriver.NewNaiveDiffDriver(d, uidMaps, gidMaps), nil
+}
+
+// Driver holds information about the driver, home directory of the driver.
+// Driver implements graphdriver.ProtoDriver. It uses only basic vfs operations.
+// In order to support layering, files are copied from the parent layer into the new layer. There is no copy-on-write support.
+// Driver must be wrapped in NaiveDiffDriver to be used as a graphdriver.Driver
+type Driver struct {
+	home    string
+	uidMaps []idtools.IDMap
+	gidMaps []idtools.IDMap
+}
+
+func (d *Driver) String() string {
+	return "vfs"
+}
+
+// Status is used for implementing the graphdriver.ProtoDriver interface. VFS does not currently have any status information.
+func (d *Driver) Status() [][2]string {
+	return nil
+}
+
+// GetMetadata is used for implementing the graphdriver.ProtoDriver interface. VFS does not currently have any meta data.
+func (d *Driver) GetMetadata(id string) (map[string]string, error) {
+	return nil, nil
+}
+
+// Cleanup is used to implement graphdriver.ProtoDriver. There is no cleanup required for this driver.
+func (d *Driver) Cleanup() error {
+	return nil
+}
+
+// CreateReadWrite creates a layer that is writable for use as a container
+// file system.
+func (d *Driver) CreateReadWrite(id, parent, mountLabel string, storageOpt map[string]string) error {
+	return d.Create(id, parent, mountLabel, storageOpt)
+}
+
+// Create prepares the filesystem for the VFS driver and copies the directory for the given id under the parent.
+func (d *Driver) Create(id, parent, mountLabel string, storageOpt map[string]string) error {
+	if len(storageOpt) != 0 {
+		return fmt.Errorf("--storage-opt is not supported for vfs")
+	}
+
+	dir := d.dir(id)
+	rootUID, rootGID, err := idtools.GetRootUIDGID(d.uidMaps, d.gidMaps)
+	if err != nil {
+		return err
+	}
+	if err := idtools.MkdirAllAs(filepath.Dir(dir), 0700, rootUID, rootGID); err != nil {
+		return err
+	}
+	if err := idtools.MkdirAs(dir, 0755, rootUID, rootGID); err != nil {
+		return err
+	}
+	opts := []string{"level:s0"}
+	if _, mountLabel, err := label.InitLabels(opts); err == nil {
+		label.SetFileLabel(dir, mountLabel)
+	}
+	if parent == "" {
+		return nil
+	}
+	parentDir, err := d.Get(parent, "")
+	if err != nil {
+		return fmt.Errorf("%s: %s", parent, err)
+	}
+	if err := CopyWithTar(parentDir, dir); err != nil {
+		return err
+	}
+	return nil
+}
+
+func (d *Driver) dir(id string) string {
+	return filepath.Join(d.home, "dir", filepath.Base(id))
+}
+
+// Remove deletes the content from the directory for a given id.
+func (d *Driver) Remove(id string) error {
+	if err := os.RemoveAll(d.dir(id)); err != nil && !os.IsNotExist(err) {
+		return err
+	}
+	return nil
+}
+
+// Get returns the directory for the given id.
+func (d *Driver) Get(id, mountLabel string) (string, error) {
+	dir := d.dir(id)
+	if st, err := os.Stat(dir); err != nil {
+		return "", err
+	} else if !st.IsDir() {
+		return "", fmt.Errorf("%s: not a directory", dir)
+	}
+	return dir, nil
+}
+
+// Put is a noop for vfs that return nil for the error, since this driver has no runtime resources to clean up.
+func (d *Driver) Put(id string) error {
+	// The vfs driver has no runtime resources (e.g. mounts)
+	// to clean up, so we don't need anything here
+	return nil
+}
+
+// Exists checks to see if the directory exists for the given id.
+func (d *Driver) Exists(id string) bool {
+	_, err := os.Stat(d.dir(id))
+	return err == nil
+}

vendor/github.com/containers/storage/drivers/zfs/MAINTAINERS

@@ -0,0 +1,2 @@
+Jörg Thalheim <joerg@higgsboson.tk> (@Mic92)
+Arthur Gautier <baloo@gandi.net> (@baloose)

vendor/github.com/containers/storage/drivers/zfs/zfs.go

@@ -0,0 +1,405 @@
+// +build linux freebsd solaris
+
+package zfs
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"path"
+	"strconv"
+	"strings"
+	"sync"
+	"syscall"
+	"time"
+
+	"github.com/Sirupsen/logrus"
+	"github.com/containers/storage/drivers"
+	"github.com/containers/storage/pkg/idtools"
+	"github.com/containers/storage/pkg/mount"
+	"github.com/containers/storage/pkg/parsers"
+	zfs "github.com/mistifyio/go-zfs"
+	"github.com/opencontainers/runc/libcontainer/label"
+)
+
+type zfsOptions struct {
+	fsName    string
+	mountPath string
+}
+
+func init() {
+	graphdriver.Register("zfs", Init)
+}
+
+// Logger returns a zfs logger implementation.
+type Logger struct{}
+
+// Log wraps log message from ZFS driver with a prefix '[zfs]'.
+func (*Logger) Log(cmd []string) {
+	logrus.Debugf("[zfs] %s", strings.Join(cmd, " "))
+}
+
+// Init returns a new ZFS driver.
+// It takes base mount path and an array of options which are represented as key value pairs.
+// Each option is in the for key=value. 'zfs.fsname' is expected to be a valid key in the options.
+func Init(base string, opt []string, uidMaps, gidMaps []idtools.IDMap) (graphdriver.Driver, error) {
+	var err error
+
+	if _, err := exec.LookPath("zfs"); err != nil {
+		logrus.Debugf("[zfs] zfs command is not available: %v", err)
+		return nil, graphdriver.ErrPrerequisites
+	}
+
+	file, err := os.OpenFile("/dev/zfs", os.O_RDWR, 600)
+	if err != nil {
+		logrus.Debugf("[zfs] cannot open /dev/zfs: %v", err)
+		return nil, graphdriver.ErrPrerequisites
+	}
+	defer file.Close()
+
+	options, err := parseOptions(opt)
+	if err != nil {
+		return nil, err
+	}
+	options.mountPath = base
+
+	rootdir := path.Dir(base)
+
+	if options.fsName == "" {
+		err = checkRootdirFs(rootdir)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	if options.fsName == "" {
+		options.fsName, err = lookupZfsDataset(rootdir)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	zfs.SetLogger(new(Logger))
+
+	filesystems, err := zfs.Filesystems(options.fsName)
+	if err != nil {
+		return nil, fmt.Errorf("Cannot find root filesystem %s: %v", options.fsName, err)
+	}
+
+	filesystemsCache := make(map[string]bool, len(filesystems))
+	var rootDataset *zfs.Dataset
+	for _, fs := range filesystems {
+		if fs.Name == options.fsName {
+			rootDataset = fs
+		}
+		filesystemsCache[fs.Name] = true
+	}
+
+	if rootDataset == nil {
+		return nil, fmt.Errorf("BUG: zfs get all -t filesystem -rHp '%s' should contain '%s'", options.fsName, options.fsName)
+	}
+
+	if err := mount.MakePrivate(base); err != nil {
+		return nil, err
+	}
+	d := &Driver{
+		dataset:          rootDataset,
+		options:          options,
+		filesystemsCache: filesystemsCache,
+		uidMaps:          uidMaps,
+		gidMaps:          gidMaps,
+		ctr:              graphdriver.NewRefCounter(graphdriver.NewDefaultChecker()),
+	}
+	return graphdriver.NewNaiveDiffDriver(d, uidMaps, gidMaps), nil
+}
+
+func parseOptions(opt []string) (zfsOptions, error) {
+	var options zfsOptions
+	options.fsName = ""
+	for _, option := range opt {
+		key, val, err := parsers.ParseKeyValueOpt(option)
+		if err != nil {
+			return options, err
+		}
+		key = strings.ToLower(key)
+		switch key {
+		case "zfs.fsname":
+			options.fsName = val
+		default:
+			return options, fmt.Errorf("Unknown option %s", key)
+		}
+	}
+	return options, nil
+}
+
+func lookupZfsDataset(rootdir string) (string, error) {
+	var stat syscall.Stat_t
+	if err := syscall.Stat(rootdir, &stat); err != nil {
+		return "", fmt.Errorf("Failed to access '%s': %s", rootdir, err)
+	}
+	wantedDev := stat.Dev
+
+	mounts, err := mount.GetMounts()
+	if err != nil {
+		return "", err
+	}
+	for _, m := range mounts {
+		if err := syscall.Stat(m.Mountpoint, &stat); err != nil {
+			logrus.Debugf("[zfs] failed to stat '%s' while scanning for zfs mount: %v", m.Mountpoint, err)
+			continue // may fail on fuse file systems
+		}
+
+		if stat.Dev == wantedDev && m.Fstype == "zfs" {
+			return m.Source, nil
+		}
+	}
+
+	return "", fmt.Errorf("Failed to find zfs dataset mounted on '%s' in /proc/mounts", rootdir)
+}
+
+// Driver holds information about the driver, such as zfs dataset, options and cache.
+type Driver struct {
+	dataset          *zfs.Dataset
+	options          zfsOptions
+	sync.Mutex       // protects filesystem cache against concurrent access
+	filesystemsCache map[string]bool
+	uidMaps          []idtools.IDMap
+	gidMaps          []idtools.IDMap
+	ctr              *graphdriver.RefCounter
+}
+
+func (d *Driver) String() string {
+	return "zfs"
+}
+
+// Cleanup is used to implement graphdriver.ProtoDriver. There is no cleanup required for this driver.
+func (d *Driver) Cleanup() error {
+	return nil
+}
+
+// Status returns information about the ZFS filesystem. It returns a two dimensional array of information
+// such as pool name, dataset name, disk usage, parent quota and compression used.
+// Currently it return 'Zpool', 'Zpool Health', 'Parent Dataset', 'Space Used By Parent',
+// 'Space Available', 'Parent Quota' and 'Compression'.
+func (d *Driver) Status() [][2]string {
+	parts := strings.Split(d.dataset.Name, "/")
+	pool, err := zfs.GetZpool(parts[0])
+
+	var poolName, poolHealth string
+	if err == nil {
+		poolName = pool.Name
+		poolHealth = pool.Health
+	} else {
+		poolName = fmt.Sprintf("error while getting pool information %v", err)
+		poolHealth = "not available"
+	}
+
+	quota := "no"
+	if d.dataset.Quota != 0 {
+		quota = strconv.FormatUint(d.dataset.Quota, 10)
+	}
+
+	return [][2]string{
+		{"Zpool", poolName},
+		{"Zpool Health", poolHealth},
+		{"Parent Dataset", d.dataset.Name},
+		{"Space Used By Parent", strconv.FormatUint(d.dataset.Used, 10)},
+		{"Space Available", strconv.FormatUint(d.dataset.Avail, 10)},
+		{"Parent Quota", quota},
+		{"Compression", d.dataset.Compression},
+	}
+}
+
+// GetMetadata returns image/container metadata related to graph driver
+func (d *Driver) GetMetadata(id string) (map[string]string, error) {
+	return nil, nil
+}
+
+func (d *Driver) cloneFilesystem(name, parentName string) error {
+	snapshotName := fmt.Sprintf("%d", time.Now().Nanosecond())
+	parentDataset := zfs.Dataset{Name: parentName}
+	snapshot, err := parentDataset.Snapshot(snapshotName /*recursive */, false)
+	if err != nil {
+		return err
+	}
+
+	_, err = snapshot.Clone(name, map[string]string{"mountpoint": "legacy"})
+	if err == nil {
+		d.Lock()
+		d.filesystemsCache[name] = true
+		d.Unlock()
+	}
+
+	if err != nil {
+		snapshot.Destroy(zfs.DestroyDeferDeletion)
+		return err
+	}
+	return snapshot.Destroy(zfs.DestroyDeferDeletion)
+}
+
+func (d *Driver) zfsPath(id string) string {
+	return d.options.fsName + "/" + id
+}
+
+func (d *Driver) mountPath(id string) string {
+	return path.Join(d.options.mountPath, "graph", getMountpoint(id))
+}
+
+// CreateReadWrite creates a layer that is writable for use as a container
+// file system.
+func (d *Driver) CreateReadWrite(id, parent, mountLabel string, storageOpt map[string]string) error {
+	return d.Create(id, parent, mountLabel, storageOpt)
+}
+
+// Create prepares the dataset and filesystem for the ZFS driver for the given id under the parent.
+func (d *Driver) Create(id string, parent string, mountLabel string, storageOpt map[string]string) error {
+	err := d.create(id, parent, storageOpt)
+	if err == nil {
+		return nil
+	}
+	if zfsError, ok := err.(*zfs.Error); ok {
+		if !strings.HasSuffix(zfsError.Stderr, "dataset already exists\n") {
+			return err
+		}
+		// aborted build -> cleanup
+	} else {
+		return err
+	}
+
+	dataset := zfs.Dataset{Name: d.zfsPath(id)}
+	if err := dataset.Destroy(zfs.DestroyRecursiveClones); err != nil {
+		return err
+	}
+
+	// retry
+	return d.create(id, parent, storageOpt)
+}
+
+func (d *Driver) create(id, parent string, storageOpt map[string]string) error {
+	name := d.zfsPath(id)
+	quota, err := parseStorageOpt(storageOpt)
+	if err != nil {
+		return err
+	}
+	if parent == "" {
+		mountoptions := map[string]string{"mountpoint": "legacy"}
+		fs, err := zfs.CreateFilesystem(name, mountoptions)
+		if err == nil {
+			err = setQuota(name, quota)
+			if err == nil {
+				d.Lock()
+				d.filesystemsCache[fs.Name] = true
+				d.Unlock()
+			}
+		}
+		return err
+	}
+	err = d.cloneFilesystem(name, d.zfsPath(parent))
+	if err == nil {
+		err = setQuota(name, quota)
+	}
+	return err
+}
+
+func parseStorageOpt(storageOpt map[string]string) (string, error) {
+	// Read size to change the disk quota per container
+	for k, v := range storageOpt {
+		key := strings.ToLower(k)
+		switch key {
+		case "size":
+			return v, nil
+		default:
+			return "0", fmt.Errorf("Unknown option %s", key)
+		}
+	}
+	return "0", nil
+}
+
+func setQuota(name string, quota string) error {
+	if quota == "0" {
+		return nil
+	}
+	fs, err := zfs.GetDataset(name)
+	if err != nil {
+		return err
+	}
+	return fs.SetProperty("quota", quota)
+}
+
+// Remove deletes the dataset, filesystem and the cache for the given id.
+func (d *Driver) Remove(id string) error {
+	name := d.zfsPath(id)
+	dataset := zfs.Dataset{Name: name}
+	err := dataset.Destroy(zfs.DestroyRecursive)
+	if err == nil {
+		d.Lock()
+		delete(d.filesystemsCache, name)
+		d.Unlock()
+	}
+	return err
+}
+
+// Get returns the mountpoint for the given id after creating the target directories if necessary.
+func (d *Driver) Get(id, mountLabel string) (string, error) {
+	mountpoint := d.mountPath(id)
+	if count := d.ctr.Increment(mountpoint); count > 1 {
+		return mountpoint, nil
+	}
+
+	filesystem := d.zfsPath(id)
+	options := label.FormatMountLabel("", mountLabel)
+	logrus.Debugf(`[zfs] mount("%s", "%s", "%s")`, filesystem, mountpoint, options)
+
+	rootUID, rootGID, err := idtools.GetRootUIDGID(d.uidMaps, d.gidMaps)
+	if err != nil {
+		d.ctr.Decrement(mountpoint)
+		return "", err
+	}
+	// Create the target directories if they don't exist
+	if err := idtools.MkdirAllAs(mountpoint, 0755, rootUID, rootGID); err != nil {
+		d.ctr.Decrement(mountpoint)
+		return "", err
+	}
+
+	if err := mount.Mount(filesystem, mountpoint, "zfs", options); err != nil {
+		d.ctr.Decrement(mountpoint)
+		return "", fmt.Errorf("error creating zfs mount of %s to %s: %v", filesystem, mountpoint, err)
+	}
+
+	// this could be our first mount after creation of the filesystem, and the root dir may still have root
+	// permissions instead of the remapped root uid:gid (if user namespaces are enabled):
+	if err := os.Chown(mountpoint, rootUID, rootGID); err != nil {
+		mount.Unmount(mountpoint)
+		d.ctr.Decrement(mountpoint)
+		return "", fmt.Errorf("error modifying zfs mountpoint (%s) directory ownership: %v", mountpoint, err)
+	}
+
+	return mountpoint, nil
+}
+
+// Put removes the existing mountpoint for the given id if it exists.
+func (d *Driver) Put(id string) error {
+	mountpoint := d.mountPath(id)
+	if count := d.ctr.Decrement(mountpoint); count > 0 {
+		return nil
+	}
+	mounted, err := graphdriver.Mounted(graphdriver.FsMagicZfs, mountpoint)
+	if err != nil || !mounted {
+		return err
+	}
+
+	logrus.Debugf(`[zfs] unmount("%s")`, mountpoint)
+
+	err = mount.Unmount(mountpoint)
+	if err != nil {
+		return fmt.Errorf("error unmounting to %s: %v", mountpoint, err)
+	}
+	return err
+}
+
+// Exists checks to see if the cache entry exists for the given id.
+func (d *Driver) Exists(id string) bool {
+	d.Lock()
+	defer d.Unlock()
+	return d.filesystemsCache[d.zfsPath(id)] == true
+}

vendor/github.com/containers/storage/drivers/zfs/zfs_freebsd.go

@@ -0,0 +1,38 @@
+package zfs
+
+import (
+	"fmt"
+	"strings"
+	"syscall"
+
+	"github.com/Sirupsen/logrus"
+	"github.com/containers/storage/drivers"
+)
+
+func checkRootdirFs(rootdir string) error {
+	var buf syscall.Statfs_t
+	if err := syscall.Statfs(rootdir, &buf); err != nil {
+		return fmt.Errorf("Failed to access '%s': %s", rootdir, err)
+	}
+
+	// on FreeBSD buf.Fstypename contains ['z', 'f', 's', 0 ... ]
+	if (buf.Fstypename[0] != 122) || (buf.Fstypename[1] != 102) || (buf.Fstypename[2] != 115) || (buf.Fstypename[3] != 0) {
+		logrus.Debugf("[zfs] no zfs dataset found for rootdir '%s'", rootdir)
+		return graphdriver.ErrPrerequisites
+	}
+
+	return nil
+}
+
+func getMountpoint(id string) string {
+	maxlen := 12
+
+	// we need to preserve filesystem suffix
+	suffix := strings.SplitN(id, "-", 2)
+
+	if len(suffix) > 1 {
+		return id[:maxlen] + "-" + suffix[1]
+	}
+
+	return id[:maxlen]
+}

vendor/github.com/containers/storage/drivers/zfs/zfs_linux.go

@@ -0,0 +1,27 @@
+package zfs
+
+import (
+	"fmt"
+	"syscall"
+
+	"github.com/Sirupsen/logrus"
+	"github.com/containers/storage/drivers"
+)
+
+func checkRootdirFs(rootdir string) error {
+	var buf syscall.Statfs_t
+	if err := syscall.Statfs(rootdir, &buf); err != nil {
+		return fmt.Errorf("Failed to access '%s': %s", rootdir, err)
+	}
+
+	if graphdriver.FsMagic(buf.Type) != graphdriver.FsMagicZfs {
+		logrus.Debugf("[zfs] no zfs dataset found for rootdir '%s'", rootdir)
+		return graphdriver.ErrPrerequisites
+	}
+
+	return nil
+}
+
+func getMountpoint(id string) string {
+	return id
+}

vendor/github.com/containers/storage/drivers/zfs/zfs_solaris.go

@@ -0,0 +1,59 @@
+// +build solaris,cgo
+
+package zfs
+
+/*
+#include <sys/statvfs.h>
+#include <stdlib.h>
+
+static inline struct statvfs *getstatfs(char *s) {
+        struct statvfs *buf;
+        int err;
+        buf = (struct statvfs *)malloc(sizeof(struct statvfs));
+        err = statvfs(s, buf);
+        return buf;
+}
+*/
+import "C"
+import (
+	"path/filepath"
+	"strings"
+	"unsafe"
+
+	log "github.com/Sirupsen/logrus"
+	"github.com/containers/storage/drivers"
+)
+
+func checkRootdirFs(rootdir string) error {
+
+	cs := C.CString(filepath.Dir(rootdir))
+	buf := C.getstatfs(cs)
+
+	// on Solaris buf.f_basetype contains ['z', 'f', 's', 0 ... ]
+	if (buf.f_basetype[0] != 122) || (buf.f_basetype[1] != 102) || (buf.f_basetype[2] != 115) ||
+		(buf.f_basetype[3] != 0) {
+		log.Debugf("[zfs] no zfs dataset found for rootdir '%s'", rootdir)
+		C.free(unsafe.Pointer(buf))
+		return graphdriver.ErrPrerequisites
+	}
+
+	C.free(unsafe.Pointer(buf))
+	C.free(unsafe.Pointer(cs))
+	return nil
+}
+
+/* rootfs is introduced to comply with the OCI spec
+which states that root filesystem must be mounted at <CID>/rootfs/ instead of <CID>/
+*/
+func getMountpoint(id string) string {
+	maxlen := 12
+
+	// we need to preserve filesystem suffix
+	suffix := strings.SplitN(id, "-", 2)
+
+	if len(suffix) > 1 {
+		return filepath.Join(id[:maxlen]+"-"+suffix[1], "rootfs", "root")
+	}
+
+	return filepath.Join(id[:maxlen], "rootfs", "root")
+}

vendor/github.com/containers/storage/drivers/zfs/zfs_unsupported.go

@@ -0,0 +1,11 @@
+// +build !linux,!freebsd,!solaris
+
+package zfs
+
+func checkRootdirFs(rootdir string) error {
+	return nil
+}
+
+func getMountpoint(id string) string {
+	return id
+}