Merge pull request #1165 from dcermak/fix-mount_program-autodetection

Move the mount_program autodetection into the graphdriver Init()

drivers/overlay/overlay.go

@@ -292,6 +292,31 @@ func Init(home string, options graphdriver.Options) (graphdriver.Driver, error)
 		backingFs = fsName
 	}
 
+	runhome := filepath.Join(options.RunRoot, filepath.Base(home))
+	rootUID, rootGID, err := idtools.GetRootUIDGID(options.UIDMaps, options.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 {
+		return nil, err
+	}
+
+	if err := idtools.MkdirAllAs(runhome, 0700, rootUID, rootGID); err != nil {
+		return nil, err
+	}
+
+	if opts.mountProgram == "" {
+		if supported, err := SupportsNativeOverlay(home, runhome); err != nil {
+			return nil, err
+		} else if !supported {
+			if path, err := exec.LookPath("fuse-overlayfs"); err == nil {
+				opts.mountProgram = path
+			}
+		}
+	}
+
 	if opts.mountProgram != "" {
 		if unshare.IsRootless() && isNetworkFileSystem(fsMagic) && opts.forceMask == nil {
 			m := os.FileMode(0700)
@@ -316,20 +341,6 @@ func Init(home string, options graphdriver.Options) (graphdriver.Driver, error)
 		}
 	}
 
-	rootUID, rootGID, err := idtools.GetRootUIDGID(options.UIDMaps, options.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 {
-		return nil, err
-	}
-	runhome := filepath.Join(options.RunRoot, filepath.Base(home))
-	if err := idtools.MkdirAllAs(runhome, 0700, rootUID, rootGID); err != nil {
-		return nil, err
-	}
-
 	var usingMetacopy bool
 	var supportsDType bool
 	var supportsVolatile *bool
@@ -569,14 +580,11 @@ func cachedFeatureRecord(runhome, feature string, supported bool, text string) (
 	return err
 }
 
-func SupportsNativeOverlay(graphroot, rundir string) (bool, error) {
-	if os.Geteuid() != 0 || graphroot == "" || rundir == "" {
+func SupportsNativeOverlay(home, runhome string) (bool, error) {
+	if os.Geteuid() != 0 || home == "" || runhome == "" {
 		return false, nil
 	}
 
-	home := filepath.Join(graphroot, "overlay")
-	runhome := filepath.Join(rundir, "overlay")
-
 	var contents string
 	flagContent, err := ioutil.ReadFile(getMountProgramFlagFile(home))
 	if err == nil {

types/options.go

@@ -3,14 +3,12 @@ package types
 import (
 	"fmt"
 	"os"
-	"os/exec"
 	"path/filepath"
 	"strings"
 	"sync"
 	"time"
 
 	"github.com/BurntSushi/toml"
-	"github.com/containers/storage/drivers/overlay"
 	cfg "github.com/containers/storage/pkg/config"
 	"github.com/containers/storage/pkg/idtools"
 	"github.com/sirupsen/logrus"
@@ -225,25 +223,11 @@ func getRootlessStorageOpts(rootlessUID int, systemOpts StoreOptions) (StoreOpti
 		opts.GraphDriverName = overlayDriver
 	}
 
-	if opts.GraphDriverName == "" || opts.GraphDriverName == overlayDriver {
-		supported, err := overlay.SupportsNativeOverlay(opts.GraphRoot, rootlessRuntime)
-		if err != nil {
-			return opts, err
-		}
-		if supported {
-			opts.GraphDriverName = overlayDriver
-		} else {
-			if path, err := exec.LookPath("fuse-overlayfs"); err == nil {
-				opts.GraphDriverName = overlayDriver
-				opts.GraphDriverOptions = []string{fmt.Sprintf("overlay.mount_program=%s", path)}
-			}
-		}
-		if opts.GraphDriverName == overlayDriver {
-			for _, o := range systemOpts.GraphDriverOptions {
-				if strings.Contains(o, "ignore_chown_errors") {
-					opts.GraphDriverOptions = append(opts.GraphDriverOptions, o)
-					break
-				}
+	if opts.GraphDriverName == overlayDriver {
+		for _, o := range systemOpts.GraphDriverOptions {
+			if strings.Contains(o, "ignore_chown_errors") {
+				opts.GraphDriverOptions = append(opts.GraphDriverOptions, o)
+				break
 			}
 		}
 	}