Initial checkin from CRI-O repo

Signed-off-by: Matthew Heon <matthew.heon@gmail.com>

4 files changed, 720 insertions, 0 deletions

diff --git a/vendor/github.com/containers/storage/drivers/btrfs/btrfs.go b/vendor/github.com/containers/storage/drivers/btrfs/btrfs.go
new file mode 100644
index 000000000..abc856c83
--- /dev/null
+++ b/vendor/github.com/containers/storage/drivers/btrfs/btrfs.go
@@ -0,0 +1,677 @@
+// +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"
+	"io/ioutil"
+	"math"
+	"os"
+	"path"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"sync"
+	"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/containers/storage/pkg/system"
+	"github.com/docker/go-units"
+	"github.com/opencontainers/selinux/go-selinux/label"
+	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
+	"golang.org/x/sys/unix"
+)
+
+func init() {
+	graphdriver.Register("btrfs", Init)
+}
+
+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, errors.Wrapf(graphdriver.ErrPrerequisites, "%q is not on a btrfs filesystem", home)
+	}
+
+	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, userDiskQuota, err := parseOptions(options)
+	if err != nil {
+		return nil, err
+	}
+
+	driver := &Driver{
+		home:    home,
+		uidMaps: uidMaps,
+		gidMaps: gidMaps,
+		options: opt,
+	}
+
+	if userDiskQuota {
+		if err := driver.subvolEnableQuota(); err != nil {
+			return nil, err
+		}
+	}
+
+	return graphdriver.NewNaiveDiffDriver(driver, uidMaps, gidMaps), nil
+}
+
+func parseOptions(opt []string) (btrfsOptions, bool, error) {
+	var options btrfsOptions
+	userDiskQuota := false
+	for _, option := range opt {
+		key, val, err := parsers.ParseKeyValueOpt(option)
+		if err != nil {
+			return options, userDiskQuota, err
+		}
+		key = strings.ToLower(key)
+		switch key {
+		case "btrfs.min_space":
+			minSpace, err := units.RAMInBytes(val)
+			if err != nil {
+				return options, userDiskQuota, err
+			}
+			userDiskQuota = true
+			options.minSpace = uint64(minSpace)
+		default:
+			return options, userDiskQuota, fmt.Errorf("Unknown option %s", key)
+		}
+	}
+	return options, userDiskQuota, 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
+	quotaEnabled bool
+	once         sync.Once
+}
+
+// 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
+}
+
+// Metadata returns empty metadata for this driver.
+func (d *Driver) Metadata(id string) (map[string]string, error) {
+	return nil, nil
+}
+
+// Cleanup unmounts the home directory.
+func (d *Driver) Cleanup() error {
+	if err := d.subvolDisableQuota(); 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 := unix.Syscall(unix.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 := unix.Syscall(unix.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 unix.Stat_t
+	if err := unix.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, quotaEnabled bool) 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(), quotaEnabled); 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)
+	}
+
+	if quotaEnabled {
+		if qgroupid, err := subvolLookupQgroup(fullPath); err == nil {
+			var args C.struct_btrfs_ioctl_qgroup_create_args
+			args.qgroupid = C.__u64(qgroupid)
+
+			_, _, errno := unix.Syscall(unix.SYS_IOCTL, getDirFd(dir), C.BTRFS_IOC_QGROUP_CREATE,
+				uintptr(unsafe.Pointer(&args)))
+			if errno != 0 {
+				logrus.Errorf("Failed to delete btrfs qgroup %v for %s: %v", qgroupid, fullPath, errno.Error())
+			}
+		} else {
+			logrus.Errorf("Failed to lookup btrfs qgroup for %s: %v", fullPath, err.Error())
+		}
+	}
+
+	// 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 := unix.Syscall(unix.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 (d *Driver) updateQuotaStatus() {
+	d.once.Do(func() {
+		if !d.quotaEnabled {
+			// In case quotaEnabled is not set, check qgroup and update quotaEnabled as needed
+			if err := subvolQgroupStatus(d.home); err != nil {
+				// quota is still not enabled
+				return
+			}
+			d.quotaEnabled = true
+		}
+	})
+}
+
+func (d *Driver) subvolEnableQuota() error {
+	d.updateQuotaStatus()
+
+	if d.quotaEnabled {
+		return nil
+	}
+
+	dir, err := openDir(d.home)
+	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 := unix.Syscall(unix.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())
+	}
+
+	d.quotaEnabled = true
+
+	return nil
+}
+
+func (d *Driver) subvolDisableQuota() error {
+	d.updateQuotaStatus()
+
+	if !d.quotaEnabled {
+		return nil
+	}
+
+	dir, err := openDir(d.home)
+	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 := unix.Syscall(unix.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())
+	}
+
+	d.quotaEnabled = false
+
+	return nil
+}
+
+func (d *Driver) subvolRescanQuota() error {
+	d.updateQuotaStatus()
+
+	if !d.quotaEnabled {
+		return nil
+	}
+
+	dir, err := openDir(d.home)
+	if err != nil {
+		return err
+	}
+	defer closeDir(dir)
+
+	var args C.struct_btrfs_ioctl_quota_rescan_args
+	_, _, errno := unix.Syscall(unix.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 := unix.Syscall(unix.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
+}
+
+// subvolQgroupStatus performs a BTRFS_IOC_TREE_SEARCH on the root path
+// with search key of BTRFS_QGROUP_STATUS_KEY.
+// In case qgroup is enabled, the retuned key type will match BTRFS_QGROUP_STATUS_KEY.
+// For more details please see https://github.com/kdave/btrfs-progs/blob/v4.9/qgroup.c#L1035
+func subvolQgroupStatus(path string) error {
+	dir, err := openDir(path)
+	if err != nil {
+		return err
+	}
+	defer closeDir(dir)
+
+	var args C.struct_btrfs_ioctl_search_args
+	args.key.tree_id = C.BTRFS_QUOTA_TREE_OBJECTID
+	args.key.min_type = C.BTRFS_QGROUP_STATUS_KEY
+	args.key.max_type = C.BTRFS_QGROUP_STATUS_KEY
+	args.key.max_objectid = C.__u64(math.MaxUint64)
+	args.key.max_offset = C.__u64(math.MaxUint64)
+	args.key.max_transid = C.__u64(math.MaxUint64)
+	args.key.nr_items = 4096
+
+	_, _, errno := unix.Syscall(unix.SYS_IOCTL, getDirFd(dir), C.BTRFS_IOC_TREE_SEARCH,
+		uintptr(unsafe.Pointer(&args)))
+	if errno != 0 {
+		return fmt.Errorf("Failed to search qgroup for %s: %v", path, errno.Error())
+	}
+	sh := (*C.struct_btrfs_ioctl_search_header)(unsafe.Pointer(&args.buf))
+	if sh._type != C.BTRFS_QGROUP_STATUS_KEY {
+		return fmt.Errorf("Invalid qgroup search header type for %s: %v", path, sh._type)
+	}
+	return nil
+}
+
+func subvolLookupQgroup(path string) (uint64, error) {
+	dir, err := openDir(path)
+	if err != nil {
+		return 0, err
+	}
+	defer closeDir(dir)
+
+	var args C.struct_btrfs_ioctl_ino_lookup_args
+	args.objectid = C.BTRFS_FIRST_FREE_OBJECTID
+
+	_, _, errno := unix.Syscall(unix.SYS_IOCTL, getDirFd(dir), C.BTRFS_IOC_INO_LOOKUP,
+		uintptr(unsafe.Pointer(&args)))
+	if errno != 0 {
+		return 0, fmt.Errorf("Failed to lookup qgroup for %s: %v", dir, errno.Error())
+	}
+	if args.treeid == 0 {
+		return 0, fmt.Errorf("Invalid qgroup id for %s: 0", dir)
+	}
+
+	return uint64(args.treeid), 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)
+}
+
+func (d *Driver) quotasDir() string {
+	return path.Join(d.home, "quotas")
+}
+
+func (d *Driver) quotasDirID(id string) string {
+	return path.Join(d.quotasDir(), id)
+}
+
+// CreateReadWrite creates a layer that is writable for use as a container
+// file system.
+func (d *Driver) CreateReadWrite(id, parent string, opts *graphdriver.CreateOpts) error {
+	return d.Create(id, parent, opts)
+}
+
+// Create the filesystem with given id.
+func (d *Driver) Create(id, parent string, opts *graphdriver.CreateOpts) error {
+	quotas := path.Join(d.home, "quotas")
+	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
+		}
+	}
+
+	var storageOpt map[string]string
+	if opts != nil {
+		storageOpt = opts.StorageOpt
+	}
+
+	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 err := idtools.MkdirAllAs(quotas, 0700, rootUID, rootGID); err != nil {
+			return err
+		}
+		if err := ioutil.WriteFile(path.Join(quotas, id), []byte(fmt.Sprint(driver.options.size)), 0644); 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
+		}
+	}
+
+	mountLabel := ""
+	if opts != nil {
+		mountLabel = opts.MountLabel
+	}
+
+	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 err := d.subvolEnableQuota(); err != nil {
+		return err
+	}
+
+	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
+	}
+	quotasDir := d.quotasDirID(id)
+	if _, err := os.Stat(quotasDir); err == nil {
+		if err := os.Remove(quotasDir); err != nil {
+			return err
+		}
+	} else if !os.IsNotExist(err) {
+		return err
+	}
+
+	// Call updateQuotaStatus() to invoke status update
+	d.updateQuotaStatus()
+
+	if err := subvolDelete(d.subvolumesDir(), id, d.quotaEnabled); err != nil {
+		return err
+	}
+	if err := system.EnsureRemoveAll(dir); err != nil {
+		return err
+	}
+	if err := d.subvolRescanQuota(); 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)
+	}
+
+	if quota, err := ioutil.ReadFile(d.quotasDirID(id)); err == nil {
+		if size, err := strconv.ParseUint(string(quota), 10, 64); err == nil && size >= d.options.minSpace {
+			if err := d.subvolEnableQuota(); err != nil {
+				return "", err
+			}
+			if err := subvolLimitQgroup(dir, size); err != nil {
+				return "", err
+			}
+		}
+	}
+
+	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
+}
+
+// AdditionalImageStores returns additional image stores supported by the driver
+func (d *Driver) AdditionalImageStores() []string {
+	return nil
+}
diff --git a/vendor/github.com/containers/storage/drivers/btrfs/dummy_unsupported.go b/vendor/github.com/containers/storage/drivers/btrfs/dummy_unsupported.go
new file mode 100644
index 000000000..f07088887
--- /dev/null
+++ b/vendor/github.com/containers/storage/drivers/btrfs/dummy_unsupported.go
@@ -0,0 +1,3 @@
+// +build !linux !cgo
+
+package btrfs
diff --git a/vendor/github.com/containers/storage/drivers/btrfs/version.go b/vendor/github.com/containers/storage/drivers/btrfs/version.go
new file mode 100644
index 000000000..73d90cdd7
--- /dev/null
+++ b/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)
+}
diff --git a/vendor/github.com/containers/storage/drivers/btrfs/version_none.go b/vendor/github.com/containers/storage/drivers/btrfs/version_none.go
new file mode 100644
index 000000000..f802fbc62
--- /dev/null
+++ b/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
+}