more mount sync improvements

mount/mount.go

@@ -193,35 +193,17 @@ func (d *Datastore) Put(key ds.Key, value []byte) error {
 func (d *Datastore) Sync(prefix ds.Key) error {
 	// Sync all mount points below the prefix
 	// Sync the mount point right at (or above) the prefix
-	// Return ErrNoMount if no mount points are synced
-	atLeastOneSync := false
-	for _, m := range d.mounts {
-		if m.Prefix.Equal(prefix) {
-			if err := m.Datastore.Sync(ds.NewKey("/")); err != nil {
-				return err
-			}
-			return nil
-		}
-		if m.Prefix.IsAncestorOf(prefix) {
-			s := strings.TrimPrefix(prefix.String(), m.Prefix.String())
-			k := ds.NewKey(s)
-			if err := m.Datastore.Sync(k); err != nil {
-				return err
-			}
-			return nil
+	dstores, mountPts, rest := d.lookupAll(prefix)
+	for i, suffix := range rest {
+		if err := dstores[i].Sync(suffix); err != nil {
+			return err
 		}
 
-		if m.Prefix.IsDescendantOf(prefix) {
-			if err := m.Datastore.Sync(ds.NewKey("/")); err != nil {
-				return err
-			}
-			atLeastOneSync = true
+		if mountPts[i].Equal(prefix) || suffix.String() != "/" {
+			return nil
 		}
 	}
 
-	if !atLeastOneSync {
-		return ErrNoMount
-	}
 	return nil
 }