volume/local: extract saving options to a separate method

Differentiate between Windows and Linux, as Windows doesn't support
options, so there's no need to save options to disk,

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

volume/local/local.go

@@ -169,18 +169,8 @@ func (r *Root) Create(name string, opts map[string]string) (volume.Volume, error
 		}
 	}()
 
-	if len(opts) != 0 {
-		if err = v.setOpts(opts); err != nil {
-			return nil, err
-		}
-		var b []byte
-		b, err = json.Marshal(v.opts)
-		if err != nil {
-			return nil, err
-		}
-		if err = os.WriteFile(filepath.Join(v.rootPath, "opts.json"), b, 0600); err != nil {
-			return nil, errdefs.System(errors.Wrap(err, "error while persisting volume options"))
-		}
+	if err = v.setOpts(opts); err != nil {
+		return nil, err
 	}
 
 	r.volumes[name] = v
@@ -352,6 +342,19 @@ func (v *localVolume) Status() map[string]interface{} {
 	return nil
 }
 
+func (v *localVolume) saveOpts() error {
+	var b []byte
+	b, err := json.Marshal(v.opts)
+	if err != nil {
+		return err
+	}
+	err = os.WriteFile(filepath.Join(v.rootPath, "opts.json"), b, 0600)
+	if err != nil {
+		return errdefs.System(errors.Wrap(err, "error while persisting volume options"))
+	}
+	return nil
+}
+
 // getAddress finds out address/hostname from options
 func getAddress(opts string) string {
 	optsList := strings.Split(opts, ",")

volume/local/local_unix.go

@@ -96,7 +96,7 @@ func (v *localVolume) setOpts(opts map[string]string) error {
 		}
 		v.opts.Quota.Size = uint64(size)
 	}
-	return nil
+	return v.saveOpts()
 }
 
 func unmount(path string) {