From mboxrd@z Thu Jan 1 00:00:00 1970 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=-0.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_PASS 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 F098CC64EB8 for ; Thu, 4 Oct 2018 08:08:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AAF3F213A2 for ; Thu, 4 Oct 2018 08:08:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="EnFK4BPL" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AAF3F213A2 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=oracle.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-btrfs-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727755AbeJDPAF (ORCPT ); Thu, 4 Oct 2018 11:00:05 -0400 Received: from userp2120.oracle.com ([156.151.31.85]:58872 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727476AbeJDPAF (ORCPT ); Thu, 4 Oct 2018 11:00:05 -0400 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.22/8.16.0.22) with SMTP id w9485hqY091448; Thu, 4 Oct 2018 08:07:59 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=subject : to : references : from : message-id : date : mime-version : in-reply-to : content-type : content-transfer-encoding; s=corp-2018-07-02; bh=G1oWsKTvIUL4hN7fyKBzpFI5P8ifVQxhPz5KqoMakxE=; b=EnFK4BPLy8FumN8UTuYWPSVq6dtLiomChVaZypgs4B/7zleWmNY4q/oUDodq/QQjWjqq RL7xoX6rXCMTfmrZED7WCi/yYZr/8B31ffzJuVi/nJ80UhJ+fzvqmWbg4HH/VnBQln9X VLpO6uUx1NDlrOipREPi0JUWuqeluY2dHNgZvRJWSLeY3KpW9PlpTONlj1b3/+QboG7B z7GdWYNA7u4dODwAkd3082ALxBlhblo7pVO/8nfcaW8v8pQaU05jDz+Oj/0MtYlLVFaW 2gKesmwQCiIvRz2BsuQC70qFf1GPQIUZvm9npXYz59Moou1KBOAqsEDEtHUI438fM8he mA== Received: from userv0021.oracle.com (userv0021.oracle.com [156.151.31.71]) by userp2120.oracle.com with ESMTP id 2mt21radja-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 04 Oct 2018 08:07:59 +0000 Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by userv0021.oracle.com (8.14.4/8.14.4) with ESMTP id w9487w35024470 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 4 Oct 2018 08:07:59 GMT Received: from abhmp0013.oracle.com (abhmp0013.oracle.com [141.146.116.19]) by aserv0122.oracle.com (8.14.4/8.14.4) with ESMTP id w9487wgF010105; Thu, 4 Oct 2018 08:07:58 GMT Received: from [10.186.53.176] (/10.186.53.176) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Thu, 04 Oct 2018 08:07:58 +0000 Subject: Re: [PATCH 1/2] btrfs: Populate btrfs_super_block::log_root_transid To: Qu Wenruo , linux-btrfs@vger.kernel.org References: <20181004054950.11651-1-wqu@suse.com> <20181004054950.11651-2-wqu@suse.com> From: Anand Jain Message-ID: <0ce061ae-eeb3-a338-02e7-631b3818cb8a@oracle.com> Date: Thu, 4 Oct 2018 16:07:51 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20181004054950.11651-2-wqu@suse.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Proofpoint-Virus-Version: vendor=nai engine=5900 definitions=9035 signatures=668707 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=790 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1807170000 definitions=main-1810040083 Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org > we > already expect log tree root generation always to be super block > genration + 1. This is close to what I was looking for by reading the cover-letter, basically what is the impact/bug by not populating it? but can you explain more, I wonder how was check working so long then? > But it could be later used to detect log tree corruption early. If there is no impact/bug its rather a good idea to change this when the early log tree corruption detection part is ready. So that there is absolute clarity. The reason why I am grossly wary is - we have incomplete business about how do we handle the write-hole, say raid1 to begin with. Thanks, Anand