Add folder marker (fixes #762)

cmd/syncthing/main.go

@@ -598,11 +598,25 @@ nextFolder:
 				l.Warnf("Stopping folder %q - path does not exist, but has files in index", folder.ID)
 				cfg.InvalidateFolder(id, "folder path missing")
 				continue nextFolder
+			} else if !folder.HasMarker() {
+				l.Warnf("Stopping folder %q - path exists, but folder marker missing, check for mount issues", folder.ID)
+				cfg.InvalidateFolder(id, "folder marker missing")
+				continue nextFolder
 			}
 		} else if os.IsNotExist(err) {
 			// If we don't have any files in the index, and the directory
 			// doesn't exist, try creating it.
 			err = os.MkdirAll(folder.Path, 0700)
+			if err != nil {
+				l.Warnf("Stopping folder %q - %v", err)
+				cfg.InvalidateFolder(id, err.Error())
+				continue nextFolder
+			}
+			err = folder.CreateMarker()
+		} else if !folder.HasMarker() {
+			// If we don't have any files in the index, and the path does exist
+			// but the marker is not there, create it.
+			err = folder.CreateMarker()
 		}
 
 		if err != nil {

cmd/syncthing/main_test.go

@@ -13,6 +13,107 @@
 // You should have received a copy of the GNU General Public License along
 // with this program. If not, see <http://www.gnu.org/licenses/>.
 
-package main_test
+package main
 
-// Empty test file to generate 0% coverage rather than no coverage
+import (
+	"os"
+	"testing"
+
+	"github.com/syncthing/syncthing/internal/config"
+	"github.com/syncthing/syncthing/internal/files"
+	"github.com/syncthing/syncthing/internal/model"
+	"github.com/syncthing/syncthing/internal/protocol"
+
+	"github.com/syndtr/goleveldb/leveldb"
+	"github.com/syndtr/goleveldb/leveldb/storage"
+)
+
+func TestSanityCheck(t *testing.T) {
+	fcfg := config.FolderConfiguration{
+		ID:   "folder",
+		Path: "testdata/testfolder",
+	}
+	cfg := config.Wrap("/tmp/test", config.Configuration{
+		Folders: []config.FolderConfiguration{fcfg},
+	})
+
+	for _, file := range []string{".stfolder", "testfolder", "testfolder/.stfolder"} {
+		_, err := os.Stat("testdata/" + file)
+		if err == nil {
+			t.Error("Found unexpected file")
+		}
+	}
+
+	db, _ := leveldb.Open(storage.NewMemStorage(), nil)
+
+	// Case 1 - new folder, directory and marker created
+
+	m := model.NewModel(cfg, "device", "syncthing", "dev", db)
+	sanityCheckFolders(cfg, m)
+
+	if cfg.Folders()["folder"].Invalid != "" {
+		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)
+	}
+
+	os.Remove("testdata/testfolder/.stfolder")
+	os.Remove("testdata/testfolder/")
+
+	// Case 2 - new folder, marker created
+
+	fcfg.Path = "testdata/"
+	cfg = config.Wrap("/tmp/test", config.Configuration{
+		Folders: []config.FolderConfiguration{fcfg},
+	})
+
+	m = model.NewModel(cfg, "device", "syncthing", "dev", db)
+	sanityCheckFolders(cfg, m)
+
+	if cfg.Folders()["folder"].Invalid != "" {
+		t.Error("Unexpected error", cfg.Folders()["folder"].Invalid)
+	}
+
+	_, err = os.Stat("testdata/.stfolder")
+	if err != nil {
+		t.Error(err)
+	}
+
+	os.Remove("testdata/.stfolder")
+
+	// Case 3 - marker missing
+
+	set := files.NewSet("folder", db)
+	set.Update(protocol.LocalDeviceID, []protocol.FileInfo{
+		{Name: "dummyfile"},
+	})
+
+	m = model.NewModel(cfg, "device", "syncthing", "dev", db)
+	sanityCheckFolders(cfg, m)
+
+	if cfg.Folders()["folder"].Invalid != "folder marker missing" {
+		t.Error("Incorrect error")
+	}
+
+	// Case 4 - path missing
+
+	fcfg.Path = "testdata/testfolder"
+	cfg = config.Wrap("/tmp/test", config.Configuration{
+		Folders: []config.FolderConfiguration{fcfg},
+	})
+
+	m = model.NewModel(cfg, "device", "syncthing", "dev", db)
+	sanityCheckFolders(cfg, m)
+
+	if cfg.Folders()["folder"].Invalid != "folder path missing" {
+		t.Error("Incorrect error")
+	}
+}