fs: fix compilation on non-Linux/macOS/Windows

internal/fs/fs_local.go

@@ -199,54 +199,6 @@ func (f *pathLocalFile) MakeReadable() error {
 	return nil
 }
 
-type fdLocalFile struct {
-	localFile
-	flag         int
-	metadataOnly bool
-}
-
-var _ File = &fdLocalFile{}
-
-func newFdLocalFile(name string, flag int, metadataOnly bool) (*fdLocalFile, error) {
-	var f *os.File
-	var err error
-	if metadataOnly {
-		f, err = openMetadataHandle(name, flag)
-	} else {
-		f, err = openReadHandle(name, flag)
-	}
-	if err != nil {
-		return nil, err
-	}
-	meta := newFdMetadataHandle(name, f)
-	return &fdLocalFile{
-		localFile: localFile{
-			name: name,
-			f:    f,
-			meta: meta,
-		},
-		flag:         flag,
-		metadataOnly: metadataOnly,
-	}, nil
-}
-
-func (f *fdLocalFile) MakeReadable() error {
-	if !f.metadataOnly {
-		panic("file is already readable")
-	}
-
-	newF, err := reopenMetadataHandle(f.f)
-	// old handle is no longer usable
-	f.f = nil
-	if err != nil {
-		return err
-	}
-	f.f = newF
-	f.meta = newFdMetadataHandle(f.name, newF)
-	f.metadataOnly = false
-	return nil
-}
-
 func buildLocalFile(name string, flag int, metadataOnly bool) (File, error) {
 	useFd := runtime.GOOS == "linux" || runtime.GOOS == "windows" || runtime.GOOS == "darwin"
 	useFd = useFd && feature.Flag.Enabled(feature.FilehandleBasedBackup)

internal/fs/fs_local_fd.go

@@ -0,0 +1,53 @@
+//go:build linux || darwin || windows
+
+package fs
+
+import "os"
+
+type fdLocalFile struct {
+	localFile
+	flag         int
+	metadataOnly bool
+}
+
+var _ File = &fdLocalFile{}
+
+func newFdLocalFile(name string, flag int, metadataOnly bool) (*fdLocalFile, error) {
+	var f *os.File
+	var err error
+	if metadataOnly {
+		f, err = openMetadataHandle(name, flag)
+	} else {
+		f, err = openReadHandle(name, flag)
+	}
+	if err != nil {
+		return nil, err
+	}
+	meta := newFdMetadataHandle(name, f)
+	return &fdLocalFile{
+		localFile: localFile{
+			name: name,
+			f:    f,
+			meta: meta,
+		},
+		flag:         flag,
+		metadataOnly: metadataOnly,
+	}, nil
+}
+
+func (f *fdLocalFile) MakeReadable() error {
+	if !f.metadataOnly {
+		panic("file is already readable")
+	}
+
+	newF, err := reopenMetadataHandle(f.f)
+	// old handle is no longer usable
+	f.f = nil
+	if err != nil {
+		return err
+	}
+	f.f = newF
+	f.meta = newFdMetadataHandle(f.name, newF)
+	f.metadataOnly = false
+	return nil
+}

internal/fs/fs_local_nofd.go

@@ -0,0 +1,7 @@
+//go:build !linux && !darwin && !windows
+
+package fs
+
+func newFdLocalFile(name string, flag int, metadataOnly bool) (File, error) {
+	panic("not supported")
+}