Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,UNPARSEABLE_RELAY autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A0B6BC282C7 for ; Thu, 31 Jan 2019 08:07:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8A4222087F for ; Thu, 31 Jan 2019 08:07:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730373AbfAaIHH (ORCPT ); Thu, 31 Jan 2019 03:07:07 -0500 Received: from out30-56.freemail.mail.aliyun.com ([115.124.30.56]:47916 "EHLO out30-56.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725829AbfAaIHG (ORCPT ); Thu, 31 Jan 2019 03:07:06 -0500 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R291e4;CH=green;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04420;MF=xiaoguang.wang@linux.alibaba.com;NM=1;PH=DS;RN=1;SR=0;TI=SMTPD_---0TJJmERF_1548922024; Received: from 30.5.112.255(mailfrom:xiaoguang.wang@linux.alibaba.com fp:SMTPD_---0TJJmERF_1548922024) by smtp.aliyun-inc.com(127.0.0.1); Thu, 31 Jan 2019 16:07:04 +0800 To: linux-ext4@vger.kernel.org From: Xiaoguang Wang Subject: question about ext4 backup block group descriptors Message-ID: <4fc3271a-3098-afcd-24c1-e2e130e1e86a@linux.alibaba.com> Date: Thu, 31 Jan 2019 16:07:04 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 Content-Type: text/plain; charset=gbk; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org hi, Anyone can help answer when ext4's backup block group descriptors are updated? I had used blktrace to track the corresponding backup block group descriptor block, but didn't find that any backup blocks were written. Thanks in advance. Regards, Xiaoguang Wang