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=-2.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,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 04843C433DB for ; Tue, 16 Mar 2021 00:30:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A264464F5D for ; Tue, 16 Mar 2021 00:30:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233538AbhCPAaH (ORCPT ); Mon, 15 Mar 2021 20:30:07 -0400 Received: from mout.gmx.net ([212.227.15.15]:56723 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231911AbhCPA3m (ORCPT ); Mon, 15 Mar 2021 20:29:42 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.net; s=badeba3b8450; t=1615854578; bh=cW+jtgzcTKlY5xjWTv1HPPcq3mCD+MlVXpK+0/6XVEg=; h=X-UI-Sender-Class:To:References:From:Subject:Date:In-Reply-To; b=btPLnceYy7qYXwJGiCgVhCTff5XHGzCwwQfIVUQ8IYonZ5chVFlCgPrfQR7UIptG0 mJmclylLqJVLUYAY4DzT+G7PDGK/4uPedDbRi0LXCMj+P7fJtzfrfkvJ4Cfab4AW2Q teA36644uSdYPcPjXmrNz8fyetQjqBeUcHMRPTps= X-UI-Sender-Class: 01bb95c1-4bf8-414a-932a-4f6e2808ef9c Received: from [0.0.0.0] ([149.28.201.231]) by mail.gmx.net (mrgmx004 [212.227.17.184]) with ESMTPSA (Nemesis) id 1MbzyP-1lqt5x0hOJ-00daHn; Tue, 16 Mar 2021 01:29:38 +0100 To: dsterba@suse.cz, Qu Wenruo , linux-btrfs@vger.kernel.org References: <20210315053915.62420-1-wqu@suse.com> <20210315154205.GX7604@twin.jikos.cz> From: Qu Wenruo Subject: Re: [PATCH 0/2] btrfs: fixes for subpage which also affect read-only mount Message-ID: <09680ea1-12c1-eb0e-b3fb-08caff760b04@gmx.com> Date: Tue, 16 Mar 2021 08:29:35 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.0 MIME-Version: 1.0 In-Reply-To: <20210315154205.GX7604@twin.jikos.cz> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:xGm+XwIqMgB1DK+JYA4qupL/tXziO0sbEPe0IZziEUYHI5m4haA 5YRPdEBWOm6SuOwwjXLeLt8BPOXKxeeosUbTMGLglTI9D2enbro94Wd9FWsvgWCxjJd39qp jdJp/NBqfnnMX4XqflZyiP9IcUFUIA71ob1E40ZxCJgBPlbd7YJi8l8HXbV4CtStxbj9gVm M3dlOCvwZ7pJzpg1eJSLQ== X-UI-Out-Filterresults: notjunk:1;V03:K0:v+geSFj1WwQ=:VA2BrqaCQ7/4T0IsL1Jg6Z xV75sGcDEI6RI49SsDGolMu/0rIoh1Iugkq46y51yw71x7Dg873YDMvq7CpHYV1jXIwfljSCS J5y1xDkN1mRsqhrzYcD+H37nod1xw/3CBhY/iyHRZ1fWF1yqw5Os+XKBi83emVo/sU/lKzaOq tpl+2YGlyCoa2MqjT5n9IBUa5kqdQF5p4KendOmsa4rfdjagydK60tECF7JsCr8xLVd35PqyQ jATe+/erhed4EAjlN2CMxQj6RTYy538bl0iboL999C3cNia71x02laMBjIwMRQlFA1hQTwhqf aJb/5peH1msZRkSroOgX4sA6CQS40v3FPxop4TYYwDEnwGgDdumd5VyD4ktBaesXTMY7d4CVv 2BLiAaH4+q8mY6eNITGHHe4P8QzvkpbitUHeCNgoX8odzOUnxIPaVQcFVogbQcHbsTFYH2rxq X6pCG+5Vpwmld/JtU8NasXXyZjzjyApBQQ21vA1MpcvdQQkKd3jICGu2wCn810tDAo7OP56hL lqayI6LA2wKSEclyjSMSB8ZtiN3L73rgs1sfTV3MqHUlAk9b/ptOKXAVEv244oD6C+EyeQm/9 m9rQ1SL8Sr712Q+oT9U7ukOwZmO9/d1VfFEV3P1mM1S0a7PM+fM3V9D6zcon9xxEqydOedh+r eWnnnoLNq4kHxIlxqMB0C1mko95eudYCSkyl44YjxalkPVllHDuzHP/1eWqt9+0jLDtrxRgdo RLa261CscERkWpUMDbofNSUjStfFs9fwbOgprDBMgOv+6gjypOgeYRpegr9NjrLME7U7gpERl pi0n8F0UDbx4+W9NraNb6AxsGTYqT+T6CRZ29aHR3lX7RPBkL7AXrdNlHpUuP9IwC/4m9arS/ 6ZIz6ZxXdEU11UdNlOPg== Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On 2021/3/15 =E4=B8=8B=E5=8D=8811:42, David Sterba wrote: > On Mon, Mar 15, 2021 at 01:39:13PM +0800, Qu Wenruo wrote: >> During the fstests run for btrfs subpage read-write support, generic/47= 5 >> crashes the system with a very high chance. >> >> It turns out the cause is also affecting btrfs subpage read-only mount >> so it's worthy a quick fix. >> >> Also the crash call site shows a new rabbit hole of hard coded >> PAGE_SHIFT in readahead. > > There's still a lot of PAGE_SHIFT use, not all of them are wrong but I > think we'll need to do an audit and categorize the valid uses, otherwise > it'll be a whack-a-mole. > Already did that. The current valid use case for PAGE_SHIFT are: - Grab page Including: * compression * raid56 * relocation * buffered write in file.c * sb cross page check in volumes.c * send * zoned * sb rw in disk-io.c * tree csum in disk-io.c * free space cache v1 - Some legacy code still runs in full page mode Including: * defrag - Verification code That part has way more hardcoded part to be addressed. Will be addressed in the final part, along with selftest enhancement. Although there can be something missing, I believe it shouldn't be that hard to hit during fstests then. Thanks, Qu