lib: Get rid of buggy filesystem wrapping (#8257)

lib/config/config_test.go

@@ -457,7 +457,7 @@ func TestIssue1262(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	actual := cfg.Folders()["test"].Filesystem().URI()
+	actual := cfg.Folders()["test"].Filesystem(nil).URI()
 	expected := `e:\`
 
 	if actual != expected {
@@ -494,7 +494,7 @@ func TestFolderPath(t *testing.T) {
 		Path: "~/tmp",
 	}
 
-	realPath := folder.Filesystem().URI()
+	realPath := folder.Filesystem(nil).URI()
 	if !filepath.IsAbs(realPath) {
 		t.Error(realPath, "should be absolute")
 	}

lib/config/folderconfiguration.go

@@ -16,6 +16,7 @@ import (
 
 	"github.com/shirou/gopsutil/v3/disk"
 
+	"github.com/syncthing/syncthing/lib/db"
 	"github.com/syncthing/syncthing/lib/fs"
 	"github.com/syncthing/syncthing/lib/protocol"
 	"github.com/syncthing/syncthing/lib/util"
@@ -42,24 +43,29 @@ func (f FolderConfiguration) Copy() FolderConfiguration {
 	return c
 }
 
-func (f FolderConfiguration) Filesystem() fs.Filesystem {
+// Filesystem creates a filesystem for the path and options of this folder.
+// The fset parameter may be nil, in which case no mtime handling on top of
+// the fileystem is provided.
+func (f FolderConfiguration) Filesystem(fset *db.FileSet) fs.Filesystem {
 	// This is intentionally not a pointer method, because things like
-	// cfg.Folders["default"].Filesystem() should be valid.
-	var opts []fs.Option
+	// cfg.Folders["default"].Filesystem(nil) should be valid.
+	opts := make([]fs.Option, 0, 3)
 	if f.FilesystemType == fs.FilesystemTypeBasic && f.JunctionsAsDirs {
 		opts = append(opts, new(fs.OptionJunctionsAsDirs))
 	}
-	filesystem := fs.NewFilesystem(f.FilesystemType, f.Path, opts...)
 	if !f.CaseSensitiveFS {
-		filesystem = fs.NewCaseFilesystem(filesystem)
+		opts = append(opts, new(fs.OptionDetectCaseConflicts))
 	}
-	return filesystem
+	if fset != nil {
+		opts = append(opts, fset.MtimeOption())
+	}
+	return fs.NewFilesystem(f.FilesystemType, f.Path, opts...)
 }
 
 func (f FolderConfiguration) ModTimeWindow() time.Duration {
 	dur := time.Duration(f.RawModTimeWindowS) * time.Second
 	if f.RawModTimeWindowS < 1 && runtime.GOOS == "android" {
-		if usage, err := disk.Usage(f.Filesystem().URI()); err != nil {
+		if usage, err := disk.Usage(f.Filesystem(nil).URI()); err != nil {
 			dur = 2 * time.Second
 			l.Debugf(`Detecting FS at "%v" on android: Setting mtime window to 2s: err == "%v"`, f.Path, err)
 		} else if strings.HasPrefix(strings.ToLower(usage.Fstype), "ext2") || strings.HasPrefix(strings.ToLower(usage.Fstype), "ext3") || strings.HasPrefix(strings.ToLower(usage.Fstype), "ext4") {
@@ -89,7 +95,7 @@ func (f *FolderConfiguration) CreateMarker() error {
 		// begin with.
 		permBits = 0700
 	}
-	fs := f.Filesystem()
+	fs := f.Filesystem(nil)
 	err := fs.Mkdir(DefaultMarkerName, permBits)
 	if err != nil {
 		return err
@@ -106,7 +112,7 @@ func (f *FolderConfiguration) CreateMarker() error {
 
 // CheckPath returns nil if the folder root exists and contains the marker file
 func (f *FolderConfiguration) CheckPath() error {
-	fi, err := f.Filesystem().Stat(".")
+	fi, err := f.Filesystem(nil).Stat(".")
 	if err != nil {
 		if !fs.IsNotExist(err) {
 			return err
@@ -124,7 +130,7 @@ func (f *FolderConfiguration) CheckPath() error {
 		return ErrPathNotDirectory
 	}
 
-	_, err = f.Filesystem().Stat(f.MarkerName)
+	_, err = f.Filesystem(nil).Stat(f.MarkerName)
 	if err != nil {
 		if !fs.IsNotExist(err) {
 			return err
@@ -145,7 +151,7 @@ func (f *FolderConfiguration) CreateRoot() (err error) {
 		permBits = 0700
 	}
 
-	filesystem := f.Filesystem()
+	filesystem := f.Filesystem(nil)
 
 	if _, err = filesystem.Stat("."); fs.IsNotExist(err) {
 		err = filesystem.MkdirAll(".", permBits)
@@ -256,7 +262,7 @@ func (f *FolderConfiguration) CheckAvailableSpace(req uint64) error {
 	if val <= 0 {
 		return nil
 	}
-	fs := f.Filesystem()
+	fs := f.Filesystem(nil)
 	usage, err := fs.Usage(".")
 	if err != nil {
 		return nil

lib/config/migrations.go

@@ -199,7 +199,7 @@ func migrateToConfigV23(cfg *Configuration) {
 	// marker name in later versions.
 
 	for i := range cfg.Folders {
-		fs := cfg.Folders[i].Filesystem()
+		fs := cfg.Folders[i].Filesystem(nil)
 		// Invalid config posted, or tests.
 		if fs == nil {
 			continue
@@ -235,18 +235,18 @@ func migrateToConfigV21(cfg *Configuration) {
 		switch folder.Versioning.Type {
 		case "simple", "trashcan":
 			// Clean out symlinks in the known place
-			cleanSymlinks(folder.Filesystem(), ".stversions")
+			cleanSymlinks(folder.Filesystem(nil), ".stversions")
 		case "staggered":
 			versionDir := folder.Versioning.Params["versionsPath"]
 			if versionDir == "" {
 				// default place
-				cleanSymlinks(folder.Filesystem(), ".stversions")
+				cleanSymlinks(folder.Filesystem(nil), ".stversions")
 			} else if filepath.IsAbs(versionDir) {
 				// absolute
 				cleanSymlinks(fs.NewFilesystem(fs.FilesystemTypeBasic, versionDir), ".")
 			} else {
 				// relative to folder
-				cleanSymlinks(folder.Filesystem(), versionDir)
+				cleanSymlinks(folder.Filesystem(nil), versionDir)
 			}
 		}
 	}