WIP: cleanup tmp file

Author: zhulongcheng

block.go

@@ -254,7 +254,14 @@ func writeMetaFile(dir string, meta *BlockMeta) error {
 	if err := f.Close(); err != nil {
 		return err
 	}
-	return renameFile(tmp, path)
+
+	if err := renameFile(tmp, path); err != nil {
+		merr.Add(err)
+		merr.Add(os.RemoveAll(tmp))
+		return merr.Err()
+	}
+
+	return nil
 }
 
 // Block represents a directory of time series data covering a continuous time range.