func TestFolderErrors(t *testing.T) {
	// This test intentionally avoids starting the folders. If they are
	// started, they will perform an initial scan, which will create missing
	// folder markers and race with the stuff we do in the test.

	fcfg := config.FolderConfiguration{
		ID:      "folder",
		RawPath: "testdata/testfolder",
	}
	cfg := config.Wrap("/tmp/test", config.Configuration{
		Folders: []config.FolderConfiguration{fcfg},
	})

	for _, file := range []string{".stfolder", "testfolder/.stfolder", "testfolder"} {
		if err := os.Remove("testdata/" + file); err != nil && !os.IsNotExist(err) {
			t.Fatal(err)
		}
	}

	ldb := db.OpenMemory()

	// Case 1 - new folder, directory and marker created

	m := model.NewModel(cfg, protocol.LocalDeviceID, "device", "syncthing", "dev", ldb, nil)
	m.AddFolder(fcfg)

	if err := m.CheckFolderHealth("folder"); err != nil {
		t.Error("Unexpected error", cfg.Folders()["folder"].Invalid)
	}

	s, err := os.Stat("testdata/testfolder")
	if err != nil || !s.IsDir() {
		t.Error(err)
	}

	_, err = os.Stat("testdata/testfolder/.stfolder")
	if err != nil {
		t.Error(err)
	}

	if err := os.Remove("testdata/testfolder/.stfolder"); err != nil {
		t.Fatal(err)
	}
	if err := os.Remove("testdata/testfolder/"); err != nil {
		t.Fatal(err)
	}

	// Case 2 - new folder, marker created

	fcfg.RawPath = "testdata/"
	cfg = config.Wrap("/tmp/test", config.Configuration{
		Folders: []config.FolderConfiguration{fcfg},
	})

	m = model.NewModel(cfg, protocol.LocalDeviceID, "device", "syncthing", "dev", ldb, nil)
	m.AddFolder(fcfg)

	if err := m.CheckFolderHealth("folder"); err != nil {
		t.Error("Unexpected error", cfg.Folders()["folder"].Invalid)
	}

	_, err = os.Stat("testdata/.stfolder")
	if err != nil {
		t.Error(err)
	}

	if err := os.Remove("testdata/.stfolder"); err != nil {
		t.Fatal(err)
	}

	// Case 3 - Folder marker missing

	set := db.NewFileSet("folder", ldb)
	set.Update(protocol.LocalDeviceID, []protocol.FileInfo{
		{Name: "dummyfile"},
	})

	m = model.NewModel(cfg, protocol.LocalDeviceID, "device", "syncthing", "dev", ldb, nil)
	m.AddFolder(fcfg)

	if err := m.CheckFolderHealth("folder"); err == nil || err.Error() != "folder marker missing" {
		t.Error("Incorrect error: Folder marker missing !=", m.CheckFolderHealth("folder"))
	}

	// Case 3.1 - recover after folder marker missing

	if err = fcfg.CreateMarker(); err != nil {
		t.Error(err)
	}

	if err := m.CheckFolderHealth("folder"); err != nil {
		t.Error("Unexpected error", cfg.Folders()["folder"].Invalid)
	}

	// Case 4 - Folder path missing

	if err := os.Remove("testdata/testfolder/.stfolder"); err != nil && !os.IsNotExist(err) {
		t.Fatal(err)
	}
	if err := os.Remove("testdata/testfolder"); err != nil && !os.IsNotExist(err) {
//.........这里部分代码省略.........

//.........这里部分代码省略.........
		}
		l.Infoln("Local networks:", strings.Join(networks, ", "))
	}

	dbFile := locations[locDatabase]
	dbOpts := dbOpts(cfg)
	ldb, err := leveldb.OpenFile(dbFile, dbOpts)
	if leveldbIsCorrupted(err) {
		ldb, err = leveldb.RecoverFile(dbFile, dbOpts)
	}
	if leveldbIsCorrupted(err) {
		// The database is corrupted, and we've tried to recover it but it
		// didn't work. At this point there isn't much to do beyond dropping
		// the database and reindexing...
		l.Infoln("Database corruption detected, unable to recover. Reinitializing...")
		if err := resetDB(); err != nil {
			l.Fatalln("Remove database:", err)
		}
		ldb, err = leveldb.OpenFile(dbFile, dbOpts)
	}
	if err != nil {
		l.Fatalln("Cannot open database:", err, "- Is another copy of Syncthing already running?")
	}

	// Remove database entries for folders that no longer exist in the config
	folders := cfg.Folders()
	for _, folder := range db.ListFolders(ldb) {
		if _, ok := folders[folder]; !ok {
			l.Infof("Cleaning data for dropped folder %q", folder)
			db.DropFolder(ldb, folder)
		}
	}

	m := model.NewModel(cfg, myID, myName, "syncthing", Version, ldb)
	cfg.Subscribe(m)

	if t := os.Getenv("STDEADLOCKTIMEOUT"); len(t) > 0 {
		it, err := strconv.Atoi(t)
		if err == nil {
			m.StartDeadlockDetector(time.Duration(it) * time.Second)
		}
	} else if !IsRelease || IsBeta {
		m.StartDeadlockDetector(20 * time.Minute)
	}

	if paused {
		for device := range cfg.Devices() {
			m.PauseDevice(device)
		}
	}

	// Clear out old indexes for other devices. Otherwise we'll start up and
	// start needing a bunch of files which are nowhere to be found. This
	// needs to be changed when we correctly do persistent indexes.
	for _, folderCfg := range cfg.Folders() {
		m.AddFolder(folderCfg)
		for _, device := range folderCfg.DeviceIDs() {
			if device == myID {
				continue
			}
			m.Index(device, folderCfg.ID, nil, 0, nil)
		}
		// Routine to pull blocks from other devices to synchronize the local
		// folder. Does not run when we are in read only (publish only) mode.
		if folderCfg.ReadOnly {
			m.StartFolderRO(folderCfg.ID)

//.........这里部分代码省略.........
		writeRateLimit = ratelimit.NewBucketWithRate(float64(1000*opts.MaxSendKbps), int64(5*1000*opts.MaxSendKbps))
	}
	if opts.MaxRecvKbps > 0 {
		readRateLimit = ratelimit.NewBucketWithRate(float64(1000*opts.MaxRecvKbps), int64(5*1000*opts.MaxRecvKbps))
	}

	if (opts.MaxRecvKbps > 0 || opts.MaxSendKbps > 0) && !opts.LimitBandwidthInLan {
		lans, _ = osutil.GetLans()
		networks := make([]string, 0, len(lans))
		for _, lan := range lans {
			networks = append(networks, lan.String())
		}
		l.Infoln("Local networks:", strings.Join(networks, ", "))
	}

	dbFile := locations[locDatabase]
	ldb, err := leveldb.OpenFile(dbFile, dbOpts())
	if err != nil && errors.IsCorrupted(err) {
		ldb, err = leveldb.RecoverFile(dbFile, dbOpts())
	}
	if err != nil {
		l.Fatalln("Cannot open database:", err, "- Is another copy of Syncthing already running?")
	}

	// Remove database entries for folders that no longer exist in the config
	folders := cfg.Folders()
	for _, folder := range db.ListFolders(ldb) {
		if _, ok := folders[folder]; !ok {
			l.Infof("Cleaning data for dropped folder %q", folder)
			db.DropFolder(ldb, folder)
		}
	}

	m := model.NewModel(cfg, myID, myName, "syncthing", Version, ldb)
	cfg.Subscribe(m)

	if t := os.Getenv("STDEADLOCKTIMEOUT"); len(t) > 0 {
		it, err := strconv.Atoi(t)
		if err == nil {
			m.StartDeadlockDetector(time.Duration(it) * time.Second)
		}
	} else if !IsRelease || IsBeta {
		m.StartDeadlockDetector(20 * 60 * time.Second)
	}

	// Clear out old indexes for other devices. Otherwise we'll start up and
	// start needing a bunch of files which are nowhere to be found. This
	// needs to be changed when we correctly do persistent indexes.
	for _, folderCfg := range cfg.Folders() {
		m.AddFolder(folderCfg)
		for _, device := range folderCfg.DeviceIDs() {
			if device == myID {
				continue
			}
			m.Index(device, folderCfg.ID, nil, 0, nil)
		}
		// Routine to pull blocks from other devices to synchronize the local
		// folder. Does not run when we are in read only (publish only) mode.
		if folderCfg.ReadOnly {
			m.StartFolderRO(folderCfg.ID)
		} else {
			m.StartFolderRW(folderCfg.ID)
		}
	}

	mainSvc.Add(m)