mount: exit when the file system changes (#4555)

cmd/mount_unix.go

@@ -698,12 +698,21 @@ func launchMount(mp string, conf *vfs.Config) error {
 		cancel()
 		if err == nil {
 			return nil
+		} else {
+			var exitError *exec.ExitError
+			if ok := errors.As(err, &exitError); ok {
+				if waitStatus, ok := exitError.Sys().(syscall.WaitStatus); ok && waitStatus.ExitStatus() == meta.UmountCode {
+					logger.Errorf("received umount exit code")
+					_ = doUmount(mp, true)
+					return nil
+				}
+			}
+			if fuseFd < 0 {
+				logger.Info("transfer FUSE session to others")
+				return nil
+			}
+			time.Sleep(time.Second)
 		}
-		if fuseFd < 0 {
-			logger.Info("transfer FUSE session to others")
-			return nil
-		}
-		time.Sleep(time.Second)
 	}
 }
 

pkg/meta/base.go

@@ -550,6 +550,8 @@ func (m *baseMeta) OnReload(fn func(f *Format)) {
 	m.reloadCb = append(m.reloadCb, fn)
 }
 
+const UmountCode = 11
+
 func (m *baseMeta) refresh() {
 	for {
 		if m.conf.Heartbeat > 0 {
@@ -571,11 +573,17 @@ func (m *baseMeta) refresh() {
 
 		old := m.getFormat()
 		if format, err := m.Load(false); err != nil {
+			if strings.HasPrefix(err.Error(), "database is not formatted") {
+				logger.Errorf("reload setting: %s", err)
+				os.Exit(UmountCode)
+			}
 			logger.Warnf("reload setting: %s", err)
 		} else if format.MetaVersion > MaxVersion {
-			logger.Fatalf("incompatible metadata version %d > max version %d", format.MetaVersion, MaxVersion)
+			logger.Errorf("incompatible metadata version %d > max version %d", format.MetaVersion, MaxVersion)
+			os.Exit(UmountCode)
 		} else if format.UUID != old.UUID {
-			logger.Fatalf("UUID changed from %s to %s", old, format.UUID)
+			logger.Errorf("UUID changed from %s to %s", old.UUID, format.UUID)
+			os.Exit(UmountCode)
 		} else if !reflect.DeepEqual(format, old) {
 			m.msgCallbacks.Lock()
 			cbs := m.reloadCb