create soft link /sbin/mount.juicefs

cmd/main.go

@@ -76,14 +76,17 @@ func Main(args []string) error {
 		},
 	}
 
-	// Called via mount or fstab.
-	if strings.HasSuffix(args[0], "/mount.juicefs") {
+	if calledViaMount(args) {
 		args = handleSysMountArgs(args)
 	}
 
 	return app.Run(reorderOptions(app, args))
 }
 
+func calledViaMount(args []string) bool {
+	return strings.HasSuffix(args[0], "/mount.juicefs")
+}
+
 func handleSysMountArgs(args []string) []string {
 	optionToCmdFlag := map[string]string{
 		"attrcacheto":     "attr-cache",

cmd/mount.go

@@ -441,6 +441,24 @@ func tellFstabOptions(c *cli.Context) string {
 
 var fstab = "/etc/fstab"
 
+func tryToInstallMountExec() error {
+	src, err := filepath.Abs(os.Args[0])
+	if err != nil {
+		return err
+	}
+	err = os.Symlink(src, "/sbin/mount.juicefs")
+	if err != nil {
+		if strings.Contains(fmt.Sprint(err), "file exists") {
+			// safely continue if link already exists
+			return nil
+		}
+		if strings.Contains(fmt.Sprint(err), "permission denied") {
+			return err
+		}
+	}
+	return nil
+}
+
 func updateFstab(c *cli.Context) error {
 	if runtime.GOOS != "linux" {
 		logger.Infof("--update-fstab is ignored in %s", runtime.GOOS)
@@ -450,6 +468,9 @@ func updateFstab(c *cli.Context) error {
 		logger.Infoln("--update-fstab is ignored in container")
 		return nil
 	}
+	if calledViaMount(os.Args) {
+		return nil
+	}
 	addr := expandPathForEmbedded(c.Args().Get(0))
 	mp := c.Args().Get(1)
 	f, err := os.Open(fstab)
@@ -535,6 +556,11 @@ func mount(c *cli.Context) error {
 	logger.Infof("Data use %s", blob)
 
 	if c.Bool("update-fstab") {
+		if !calledViaMount(os.Args) {
+			if err = tryToInstallMountExec(); err != nil {
+				return fmt.Errorf("error creating /sbin/mount.juicefs: %s", err)
+			}
+		}
 		err = updateFstab(c)
 		if err != nil {
 			logger.Fatalf("failed to update fstab: %s", err)

cmd/mount_unix.go

@@ -138,7 +138,7 @@ func mount_flags() []cli.Flag {
 		},
 		&cli.BoolFlag{
 			Name:  "update-fstab",
-			Usage: "add / update entry in /etc/fstab",
+			Usage: "add / update entry in /etc/fstab, will create soft link /sbin/mount.juicefs if not exists",
 		},
 	}
 	return append(selfFlags, cacheFlags(1.0)...)