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=-5.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MSGID_FROM_MTA_HEADER,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 E8010C5517A for ; Thu, 29 Oct 2020 07:56:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8B9A420782 for ; Thu, 29 Oct 2020 07:56:19 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=suse.com header.i=@suse.com header.b="Wd2Jjn3k" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732314AbgJ2H4T (ORCPT ); Thu, 29 Oct 2020 03:56:19 -0400 Received: from de-smtp-delivery-102.mimecast.com ([62.140.7.102]:33199 "EHLO de-smtp-delivery-102.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730816AbgJ2HyV (ORCPT ); Thu, 29 Oct 2020 03:54:21 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=mimecast20200619; t=1603958053; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:autocrypt:autocrypt; bh=BdNyVFKfs+Hs1HeF4uqH1G8mVozT7fWuYps69mO7h6k=; b=Wd2Jjn3kkBm/9X+yCW8VwzBwDnS72t0oVCHM2SG6Z3kGSv2XJILXRJHdmafAuFFJ7NZg/J 2RsYcQP0INvMWuRMdJDyxfyjlezDekUS7BFogslGw9rM700628jUUW+TSpYf/Xg07csUng lP2tAThuT8DbWu5/9mq4Pxs3dgberw8= Received: from EUR05-AM6-obe.outbound.protection.outlook.com (mail-am6eur05lp2113.outbound.protection.outlook.com [104.47.18.113]) (Using TLS) by relay.mimecast.com with ESMTP id de-mta-4-xGtdSwdON6SjPL4-qRUx_w-1; Thu, 29 Oct 2020 08:54:11 +0100 X-MC-Unique: xGtdSwdON6SjPL4-qRUx_w-1 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=XzVD4nqOTVRCbrWnLvHXkRaV1TOcj1xkx1NJqMiQ866FXdrbiqm82DcEKtfvrKz7w5fahf9R3Tq/hHKFvsekk9oRcZsCdcwoWzEVd7iQZnT+QxeRoE6NjP858Co4/rXONF1K8CFTRYJjwB44Kx3q9C7Pgi4hpRuRlqYOgQHZUYPZdm0+jCn3i1BATi5JoIpFJ6SLEAwbvJTyC3dsqWmPgxQAHmTXchJw9IcmAa3284OQhzD6BMzz5hMDsivGxkOmUzVxWYriKES3BD4tpBBoOlyOunwRUmxlm+QBZrKFETYG44eCcJKMxQoqSY40dAytbyzHT2jb9Dzd+fYBtRV6AA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=kKRGZsi2k1cd7aNbxObYP5FgZikVa7Jes1e4GL+YNhc=; b=UeT7I76/rU0mLHyEG0mFyfnQhFcRleC3nVd7dz/LMkPOipO1wcNfDUcZ+fqQEwl/lXrS6GNBofCrvx+qIBaemolIqlMjLUgDOle20vTe6H+HgJm+RJRfWCtH/vimn2lnsJ0WM52b6W/K5dzawyiJyS4t4psp6Y5vX1MD5rTogP8u1+dXKqbGRBn4ZWdmJrYZ5zAD1gDYUXCgUdaQyFdZUWAC8rVQTpYB+oFgg4jGQU3jLSw3JYiRcZN0j0FdbdFmJ0GRXE/g19aOfMyvu8JA65yGrBIpnIcCgZ9cUAu+je8cOMOenZ3YZAU9yYtBmopGCwxM+DBfQ3wCh5SHjC+SWQ== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=suse.com; dmarc=pass action=none header.from=suse.com; dkim=pass header.d=suse.com; arc=none Authentication-Results: vger.kernel.org; dkim=none (message not signed) header.d=none;vger.kernel.org; dmarc=none action=none header.from=suse.com; Received: from AM0PR04MB6195.eurprd04.prod.outlook.com (2603:10a6:208:13c::13) by AM0PR04MB7153.eurprd04.prod.outlook.com (2603:10a6:208:1a0::12) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3499.19; Thu, 29 Oct 2020 07:54:09 +0000 Received: from AM0PR04MB6195.eurprd04.prod.outlook.com ([fe80::e147:582c:8301:4b7f]) by AM0PR04MB6195.eurprd04.prod.outlook.com ([fe80::e147:582c:8301:4b7f%7]) with mapi id 15.20.3499.019; Thu, 29 Oct 2020 07:54:09 +0000 Subject: Re: [PATCH v2 2/3] btrfs: file-item: remove the btrfs_find_ordered_sum() call in btrfs_lookup_bio_sums() To: Nikolay Borisov , linux-btrfs@vger.kernel.org References: <20201029071218.49860-1-wqu@suse.com> <20201029071218.49860-3-wqu@suse.com> <12990e1a-6e59-b0e3-5d26-34c80e31b601@suse.com> From: Qu Wenruo Autocrypt: addr=wqu@suse.com; keydata= mQENBFnVga8BCACyhFP3ExcTIuB73jDIBA/vSoYcTyysFQzPvez64TUSCv1SgXEByR7fju3o 8RfaWuHCnkkea5luuTZMqfgTXrun2dqNVYDNOV6RIVrc4YuG20yhC1epnV55fJCThqij0MRL 1NxPKXIlEdHvN0Kov3CtWA+R1iNN0RCeVun7rmOrrjBK573aWC5sgP7YsBOLK79H3tmUtz6b 9Imuj0ZyEsa76Xg9PX9Hn2myKj1hfWGS+5og9Va4hrwQC8ipjXik6NKR5GDV+hOZkktU81G5 gkQtGB9jOAYRs86QG/b7PtIlbd3+pppT0gaS+wvwMs8cuNG+Pu6KO1oC4jgdseFLu7NpABEB AAG0GFF1IFdlbnJ1byA8d3F1QHN1c2UuY29tPokBTQQTAQgAOAIbAwULCQgHAgYVCAkKCwIE FgIDAQIeAQIXgBYhBC3fcuWlpVuonapC4cI9kfOhJf6oBQJdnDWhAAoJEMI9kfOhJf6oZgoH 90uqoGyUh5UWtiT9zjUcvlMTCpd/QSgwagDuY+tEdVPaKlcnTNAvZKWSit8VuocjrOFbTLwb vZ43n5f/l/1QtwMgQei/RMY2XhW+totimzlHVuxVaIDwkF+zc+pUI6lDPnULZHS3mWhbVr9N vZAAYVV7GesyyFpZiNm7GLvLmtEdYbc9OnIAOZb3eKfY3mWEs0eU0MxikcZSOYy3EWY3JES7 J9pFgBrCn4hF83tPH2sphh1GUFii+AUGBMY/dC6VgMKbCugg+u/dTZEcBXxD17m+UcbucB/k F2oxqZBEQrb5SogdIq7Y9dZdlf1m3GRRJTX7eWefZw10HhFhs1mwx7kBDQRZ1YGvAQgAqlPr YeBLMv3PAZ75YhQIwH6c4SNcB++hQ9TCT5gIQNw51+SQzkXIGgmzxMIS49cZcE4KXk/kHw5h ieQeQZa60BWVRNXwoRI4ib8okgDuMkD5Kz1WEyO149+BZ7HD4/yK0VFJGuvDJR8T7RZwB69u VSLjkuNZZmCmDcDzS0c/SJOg5nkxt1iTtgUETb1wNKV6yR9XzRkrEW/qShChyrS9fNN8e9c0 MQsC4fsyz9Ylx1TOY/IF/c6rqYoEEfwnpdlz0uOM1nA1vK+wdKtXluCa79MdfaeD/dt76Kp/ o6CAKLLcjU1Iwnkq1HSrYfY3HZWpvV9g84gPwxwxX0uXquHxLwARAQABiQE8BBgBCAAmAhsM FiEELd9y5aWlW6idqkLhwj2R86El/qgFAl2cNa4FCQlqTn8ACgkQwj2R86El/qhXBAf/eXLP HDNTkHRPxoDnwhscIHJDHlsszke25AFltJQ1adoaYCbsQVv4Mn5rQZ1Gon54IMdxBN3r/B08 rGVPatIfkycMCShr+rFHPKnExhQ7Wr555fq+sQ1GOwOhr1xLEqAhBMp28u9m8hnkqL36v+AF hjTwRtS+tRMZfoG6n72xAj984l56G9NPfs/SOKl6HR0mCDXwJGZAOdtyRmqddi53SXi5N4H1 jWX1xFshp7nIkRm6hEpISEWr/KKLbAiKKbP0ql5tP5PinJeIBlDv4g/0+aGoGg4dELTnfEVk jMC8cJ/LiIaR/OEOF9S2nSeTQoBmusTz+aqkbogvvYGam6uDYw== Message-ID: <13937055-ab09-0a0f-b1e4-bfe7a710f5b1@suse.com> Date: Thu, 29 Oct 2020 15:53:57 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.12.0 In-Reply-To: <12990e1a-6e59-b0e3-5d26-34c80e31b601@suse.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable X-Originating-IP: [149.28.201.231] X-ClientProxiedBy: BY5PR20CA0030.namprd20.prod.outlook.com (2603:10b6:a03:1f4::43) To AM0PR04MB6195.eurprd04.prod.outlook.com (2603:10a6:208:13c::13) MIME-Version: 1.0 X-MS-Exchange-MessageSentRepresentingType: 1 Received: from [0.0.0.0] (149.28.201.231) by BY5PR20CA0030.namprd20.prod.outlook.com (2603:10b6:a03:1f4::43) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.3499.19 via Frontend Transport; Thu, 29 Oct 2020 07:54:07 +0000 X-MS-PublicTrafficType: Email X-MS-Office365-Filtering-Correlation-Id: 73efa2ca-7968-4407-fd20-08d87bdfd10e X-MS-TrafficTypeDiagnostic: AM0PR04MB7153: X-LD-Processed: f7a17af6-1c5c-4a36-aa8b-f5be247aa4ba,ExtFwd X-MS-Exchange-Transport-Forked: True X-Microsoft-Antispam-PRVS: X-MS-Oob-TLC-OOBClassifiers: OLM:8882; X-MS-Exchange-SenderADCheck: 1 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: MM9pjL0RP5DVt4YBPSkPV3p1TLCe6m8Z27d17vqGsi8DQ+ituJZZFILF11cYVluE4QJiXsq9JkPIoDWWhp9sr0Id4b4bVFMAZHSzXL0XMcsyCfr686UK3X5h7xmyK/bcyFebVKAsN/SQJ1RUwbuDi3b8T7WSqLK5+q/ukKobz1IpsEyRnpr8+TYJQ4kFqVs/07TZpKossQc//TJnDQywOwI8vRaVhBccP/4DKedFYI3g01V/M81bk1sr7Opp/4PLyZcJP6HnO5D32wndnhdD5gcMWFK1BqpDXZTeqSsfoKrtRPSbOEwO9mBTpXkPge/682rKv08zyIhES8lwyzqSgPZ2z0NAePYmWBnY08aTTh4/FzMpe6B4yx41ddQjX5BmmDQVL779yiZ/D9woilvzpA== X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:AM0PR04MB6195.eurprd04.prod.outlook.com;PTR:;CAT:NONE;SFS:(39860400002)(366004)(346002)(376002)(136003)(396003)(2906002)(16526019)(36756003)(86362001)(31696002)(2616005)(186003)(6706004)(956004)(52116002)(66476007)(66556008)(66946007)(83380400001)(316002)(6666004)(16576012)(6486002)(31686004)(8676002)(5660300002)(26005)(4744005)(8936002)(478600001)(78286007)(43740500002);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData: 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 X-OriginatorOrg: suse.com X-MS-Exchange-CrossTenant-Network-Message-Id: 73efa2ca-7968-4407-fd20-08d87bdfd10e X-MS-Exchange-CrossTenant-AuthSource: AM0PR04MB6195.eurprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 29 Oct 2020 07:54:09.1757 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: f7a17af6-1c5c-4a36-aa8b-f5be247aa4ba X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: esgXIAAtCFKGxbedQlkEFE2eyePGqC4a6dnVbQM7b7jnWgGIVJAveA2VvHQR70Wx X-MS-Exchange-Transport-CrossTenantHeadersStamped: AM0PR04MB7153 Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On 2020/10/29 =E4=B8=8B=E5=8D=883:47, Nikolay Borisov wrote: >=20 >=20 > On 29.10.20 =D0=B3. 9:12 =D1=87., Qu Wenruo wrote: >> The function btrfs_lookup_bio_sums() is only called for read bios. >> While btrfs_find_ordered_sum() is to search ordered extent sums, which >=20 >=20 > And what if we issue a read for a region which still has in-flight > ordered sums? >=20 Then how could the page tagged with WRITEBACK need we to do the read? At buffered time, we have already dirtied the page, means if we do read, we will get it from page cache directly, no need to trigger read. Thanks, Qu