Merge pull request #35514 from thaJeztah/disable-overlay-without-d_type

Remove support for overlay/overlay2 without d_type

daemon/graphdriver/aufs/aufs.go

@@ -89,7 +89,16 @@ func Init(root string, options []string, uidMaps, gidMaps []idtools.IDMap) (grap
 		return nil, graphdriver.ErrNotSupported
 	}
 
-	fsMagic, err := graphdriver.GetFSMagic(root)
+	// Perform feature detection on /var/lib/docker/aufs if it's an existing directory.
+	// This covers situations where /var/lib/docker/aufs is a mount, and on a different
+	// filesystem than /var/lib/docker.
+	// If the path does not exist, fall back to using /var/lib/docker for feature detection.
+	testdir := root
+	if _, err := os.Stat(testdir); os.IsNotExist(err) {
+		testdir = filepath.Dir(testdir)
+	}
+
+	fsMagic, err := graphdriver.GetFSMagic(testdir)
 	if err != nil {
 		return nil, err
 	}

daemon/graphdriver/btrfs/btrfs.go

@@ -51,7 +51,16 @@ type btrfsOptions struct {
 // 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)
+	// Perform feature detection on /var/lib/docker/btrfs if it's an existing directory.
+	// This covers situations where /var/lib/docker/btrfs is a mount, and on a different
+	// filesystem than /var/lib/docker.
+	// If the path does not exist, fall back to using /var/lib/docker for feature detection.
+	testdir := home
+	if _, err := os.Stat(testdir); os.IsNotExist(err) {
+		testdir = filepath.Dir(testdir)
+	}
+
+	fsMagic, err := graphdriver.GetFSMagic(testdir)
 	if err != nil {
 		return nil, err
 	}

daemon/graphdriver/driver.go

@@ -1,7 +1,6 @@
 package graphdriver
 
 import (
-	"errors"
 	"fmt"
 	"io"
 	"os"
@@ -28,13 +27,6 @@ const (
 var (
 	// All registered drivers
 	drivers map[string]InitFunc
-
-	// ErrNotSupported returned when driver is not supported.
-	ErrNotSupported = errors.New("driver not supported")
-	// ErrPrerequisites returned 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")
 )
 
 //CreateOpts contains optional arguments for Create() and CreateReadWrite()
@@ -248,7 +240,7 @@ func New(name string, pg plugingetter.PluginGetter, config Options) (Driver, err
 	for _, name := range list {
 		driver, err := getBuiltinDriver(name, config.Root, config.DriverOptions, config.UIDMaps, config.GIDMaps)
 		if err != nil {
-			if isDriverNotSupported(err) {
+			if IsDriverNotSupported(err) {
 				continue
 			}
 			return nil, err
@@ -260,7 +252,7 @@ func New(name string, pg plugingetter.PluginGetter, config Options) (Driver, err
 	for name, initFunc := range drivers {
 		driver, err := initFunc(filepath.Join(config.Root, name), config.DriverOptions, config.UIDMaps, config.GIDMaps)
 		if err != nil {
-			if isDriverNotSupported(err) {
+			if IsDriverNotSupported(err) {
 				continue
 			}
 			return nil, err
@@ -270,12 +262,6 @@ func New(name string, pg plugingetter.PluginGetter, config Options) (Driver, err
 	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)
@@ -291,6 +277,18 @@ func scanPriorDrivers(root string) map[string]bool {
 	return driversMap
 }
 
+// IsInitialized checks if the driver's home-directory exists and is non-empty.
+func IsInitialized(driverHome string) bool {
+	_, err := os.Stat(driverHome)
+	if os.IsNotExist(err) {
+		return false
+	}
+	if err != nil {
+		logrus.Warnf("graphdriver.IsInitialized: stat failed: %v", err)
+	}
+	return !isEmptyDir(driverHome)
+}
+
 // isEmptyDir checks if a directory is empty. It is used to check if prior
 // storage-driver directories exist. If an error occurs, it also assumes the
 // directory is not empty (which preserves the behavior _before_ this check

daemon/graphdriver/driver_linux.go

@@ -3,8 +3,6 @@
 package graphdriver
 
 import (
-	"path/filepath"
-
 	"github.com/docker/docker/pkg/mount"
 	"golang.org/x/sys/unix"
 )
@@ -82,7 +80,7 @@ var (
 // GetFSMagic returns the filesystem id given the path.
 func GetFSMagic(rootpath string) (FsMagic, error) {
 	var buf unix.Statfs_t
-	if err := unix.Statfs(filepath.Dir(rootpath), &buf); err != nil {
+	if err := unix.Statfs(rootpath, &buf); err != nil {
 		return 0, err
 	}
 	return FsMagic(buf.Type), nil

daemon/graphdriver/errors.go

@@ -0,0 +1,36 @@
+package graphdriver
+
+const (
+	// ErrNotSupported returned when driver is not supported.
+	ErrNotSupported NotSupportedError = "driver not supported"
+	// ErrPrerequisites returned when driver does not meet prerequisites.
+	ErrPrerequisites NotSupportedError = "prerequisites for driver not satisfied (wrong filesystem?)"
+	// ErrIncompatibleFS returned when file system is not supported.
+	ErrIncompatibleFS NotSupportedError = "backing file system is unsupported for this graph driver"
+)
+
+// ErrUnSupported signals that the graph-driver is not supported on the current configuration
+type ErrUnSupported interface {
+	NotSupported()
+}
+
+// NotSupportedError signals that the graph-driver is not supported on the current configuration
+type NotSupportedError string
+
+func (e NotSupportedError) Error() string {
+	return string(e)
+}
+
+// NotSupported signals that a graph-driver is not supported.
+func (e NotSupportedError) NotSupported() {}
+
+// IsDriverNotSupported returns true if the error initializing
+// the graph driver is a non-supported error.
+func IsDriverNotSupported(err error) bool {
+	switch err.(type) {
+	case ErrUnSupported:
+		return true
+	default:
+		return false
+	}
+}

daemon/graphdriver/graphtest/graphtest_unix.go

@@ -42,7 +42,7 @@ func newDriver(t testing.TB, name string, options []string) *Driver {
 	d, err := graphdriver.GetDriver(name, nil, graphdriver.Options{DriverOptions: options, Root: root})
 	if err != nil {
 		t.Logf("graphdriver: %v\n", err)
-		if err == graphdriver.ErrNotSupported || err == graphdriver.ErrPrerequisites || err == graphdriver.ErrIncompatibleFS {
+		if graphdriver.IsDriverNotSupported(err) {
 			t.Skipf("Driver %s not supported", name)
 		}
 		t.Fatal(err)

daemon/graphdriver/overlay/overlay.go

@@ -10,6 +10,7 @@ import (
 	"os"
 	"os/exec"
 	"path"
+	"path/filepath"
 	"strconv"
 
 	"github.com/docker/docker/daemon/graphdriver"
@@ -119,7 +120,16 @@ func Init(home string, options []string, uidMaps, gidMaps []idtools.IDMap) (grap
 		return nil, graphdriver.ErrNotSupported
 	}
 
-	fsMagic, err := graphdriver.GetFSMagic(home)
+	// Perform feature detection on /var/lib/docker/overlay if it's an existing directory.
+	// This covers situations where /var/lib/docker/overlay is a mount, and on a different
+	// filesystem than /var/lib/docker.
+	// If the path does not exist, fall back to using /var/lib/docker for feature detection.
+	testdir := home
+	if _, err := os.Stat(testdir); os.IsNotExist(err) {
+		testdir = filepath.Dir(testdir)
+	}
+
+	fsMagic, err := graphdriver.GetFSMagic(testdir)
 	if err != nil {
 		return nil, err
 	}
@@ -128,11 +138,23 @@ func Init(home string, options []string, uidMaps, gidMaps []idtools.IDMap) (grap
 	}
 
 	switch fsMagic {
-	case graphdriver.FsMagicAufs, graphdriver.FsMagicBtrfs, graphdriver.FsMagicOverlay, graphdriver.FsMagicZfs, graphdriver.FsMagicEcryptfs, graphdriver.FsMagicNfsFs:
+	case graphdriver.FsMagicAufs, graphdriver.FsMagicBtrfs, graphdriver.FsMagicEcryptfs, graphdriver.FsMagicNfsFs, graphdriver.FsMagicOverlay, graphdriver.FsMagicZfs:
 		logrus.Errorf("'overlay' is not supported over %s", backingFs)
 		return nil, graphdriver.ErrIncompatibleFS
 	}
 
+	supportsDType, err := fsutils.SupportsDType(testdir)
+	if err != nil {
+		return nil, err
+	}
+	if !supportsDType {
+		if !graphdriver.IsInitialized(home) {
+			return nil, overlayutils.ErrDTypeNotSupported("overlay", backingFs)
+		}
+		// allow running without d_type only for existing setups (#27443)
+		logrus.Warn(overlayutils.ErrDTypeNotSupported("overlay", backingFs))
+	}
+
 	rootUID, rootGID, err := idtools.GetRootUIDGID(uidMaps, gidMaps)
 	if err != nil {
 		return nil, err
@@ -146,15 +168,6 @@ func Init(home string, options []string, uidMaps, gidMaps []idtools.IDMap) (grap
 		return nil, err
 	}
 
-	supportsDType, err := fsutils.SupportsDType(home)
-	if err != nil {
-		return nil, err
-	}
-	if !supportsDType {
-		// not a fatal error until v17.12 (#27443)
-		logrus.Warn(overlayutils.ErrDTypeNotSupported("overlay", backingFs))
-	}
-
 	d := &Driver{
 		home:          home,
 		uidMaps:       uidMaps,

daemon/graphdriver/overlay2/overlay.go

@@ -136,7 +136,16 @@ func Init(home string, options []string, uidMaps, gidMaps []idtools.IDMap) (grap
 		return nil, err
 	}
 
-	fsMagic, err := graphdriver.GetFSMagic(home)
+	// Perform feature detection on /var/lib/docker/overlay2 if it's an existing directory.
+	// This covers situations where /var/lib/docker/overlay2 is a mount, and on a different
+	// filesystem than /var/lib/docker.
+	// If the path does not exist, fall back to using /var/lib/docker for feature detection.
+	testdir := home
+	if _, err := os.Stat(testdir); os.IsNotExist(err) {
+		testdir = filepath.Dir(testdir)
+	}
+
+	fsMagic, err := graphdriver.GetFSMagic(testdir)
 	if err != nil {
 		return nil, err
 	}
@@ -144,9 +153,8 @@ func Init(home string, options []string, uidMaps, gidMaps []idtools.IDMap) (grap
 		backingFs = fsName
 	}
 
-	// check if they are running over btrfs, aufs, zfs, overlay, or ecryptfs
 	switch fsMagic {
-	case graphdriver.FsMagicAufs, graphdriver.FsMagicZfs, graphdriver.FsMagicOverlay, graphdriver.FsMagicEcryptfs, graphdriver.FsMagicNfsFs:
+	case graphdriver.FsMagicAufs, graphdriver.FsMagicEcryptfs, graphdriver.FsMagicNfsFs, graphdriver.FsMagicOverlay, graphdriver.FsMagicZfs:
 		logrus.Errorf("'overlay2' is not supported over %s", backingFs)
 		return nil, graphdriver.ErrIncompatibleFS
 	case graphdriver.FsMagicBtrfs:
@@ -165,12 +173,23 @@ func Init(home string, options []string, uidMaps, gidMaps []idtools.IDMap) (grap
 		if opts.overrideKernelCheck {
 			logrus.Warn("Using pre-4.0.0 kernel for overlay2, mount failures may require kernel update")
 		} else {
-			if err := supportsMultipleLowerDir(filepath.Dir(home)); err != nil {
+			if err := supportsMultipleLowerDir(testdir); err != nil {
 				logrus.Debugf("Multiple lower dirs not supported: %v", err)
 				return nil, graphdriver.ErrNotSupported
 			}
 		}
 	}
+	supportsDType, err := fsutils.SupportsDType(testdir)
+	if err != nil {
+		return nil, err
+	}
+	if !supportsDType {
+		if !graphdriver.IsInitialized(home) {
+			return nil, overlayutils.ErrDTypeNotSupported("overlay2", backingFs)
+		}
+		// allow running without d_type only for existing setups (#27443)
+		logrus.Warn(overlayutils.ErrDTypeNotSupported("overlay2", backingFs))
+	}
 
 	rootUID, rootGID, err := idtools.GetRootUIDGID(uidMaps, gidMaps)
 	if err != nil {
@@ -185,15 +204,6 @@ func Init(home string, options []string, uidMaps, gidMaps []idtools.IDMap) (grap
 		return nil, err
 	}
 
-	supportsDType, err := fsutils.SupportsDType(home)
-	if err != nil {
-		return nil, err
-	}
-	if !supportsDType {
-		// not a fatal error until v17.12 (#27443)
-		logrus.Warn(overlayutils.ErrDTypeNotSupported("overlay2", backingFs))
-	}
-
 	d := &Driver{
 		home:          home,
 		uidMaps:       uidMaps,

daemon/graphdriver/overlayutils/overlayutils.go

@@ -3,8 +3,9 @@
 package overlayutils
 
 import (
-	"errors"
 	"fmt"
+
+	"github.com/docker/docker/daemon/graphdriver"
 )
 
 // ErrDTypeNotSupported denotes that the backing filesystem doesn't support d_type.
@@ -13,6 +14,7 @@ func ErrDTypeNotSupported(driver, backingFs string) error {
 	if backingFs == "xfs" {
 		msg += " Reformat the filesystem with ftype=1 to enable d_type support."
 	}
-	msg += " Running without d_type support will no longer be supported in Docker 17.12."
-	return errors.New(msg)
+	msg += " Backing filesystems without d_type support are not supported."
+
+	return graphdriver.NotSupportedError(msg)
 }