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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 17C7EC432C0 for ; Tue, 19 Nov 2019 23:41:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id ED24A222B6 for ; Tue, 19 Nov 2019 23:41:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727226AbfKSXk6 (ORCPT ); Tue, 19 Nov 2019 18:40:58 -0500 Received: from mail-pj1-f66.google.com ([209.85.216.66]:40716 "EHLO mail-pj1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726874AbfKSXk6 (ORCPT ); Tue, 19 Nov 2019 18:40:58 -0500 Received: by mail-pj1-f66.google.com with SMTP id ep1so3335475pjb.7; Tue, 19 Nov 2019 15:40:58 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=LGdI8nMvJO9Yp2V4F8P1ev7tTWwm2jfSwnW1T5/k5as=; b=s1Semn+6Dv5dbkdxqX9rBSd8PZOFcTn99KrRedSZLD5pyv+MYTTDWzY6ytMJ/r5UuM rLeZs01qmvEZH01Zf7DodcBILb1jEBoLAOctWD69HrfpcuCocCIOkwaYLwY8oohX9nuk YDCn1UHt8pOzeq+1szIdWkzmyf+3ZDOOXtew9rRGiaL1EcCf259izmykgt3viJTW1jdt 5DLI6n+vgbOCy6uWwCvewCrM+Kv7XeRir/xpPhksRKCIGAzA4GPHoMyrO1FuwN9kmp9T mxtpaMlfWfXpE4B02sFWvlI38fZSEAIVXXb73CA1sETWB+8BUAGBIidX0YkSD/VmqiMq L84Q== X-Gm-Message-State: APjAAAWwh/uKwrdkcf5MCS8GiZIT4Ib4ze0FBoeZOINvVkCsz+6oTcm7 vVCtUIIt5NG8Nc2VjdSsJrwfZnTIatU= X-Google-Smtp-Source: APXvYqxaqRKCdfDH6V8YoUt6s/ImovXm0GCKDyXavhCF1NO0+J23GblS0JEL8I94w3YrZSAKQMm05Q== X-Received: by 2002:a17:90a:bd95:: with SMTP id z21mr246817pjr.10.1574206857435; Tue, 19 Nov 2019 15:40:57 -0800 (PST) Received: from desktop-bart.svl.corp.google.com ([2620:15c:2cd:202:4308:52a3:24b6:2c60]) by smtp.gmail.com with ESMTPSA id x192sm29727552pfd.96.2019.11.19.15.40.56 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 19 Nov 2019 15:40:56 -0800 (PST) Subject: Re: [PATCH v2] loop: avoid EAGAIN, if offset or block_size are changed To: Jaegeuk Kim , linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net Cc: stable@vger.kernel.org, Jens Axboe , linux-block@vger.kernel.org References: <20190518004751.18962-1-jaegeuk@kernel.org> <20190518005304.GA19446@jaegeuk-macbookpro.roam.corp.google.com> From: Bart Van Assche Message-ID: <1e1aae74-bd6b-dddb-0c88-660aac33872c@acm.org> Date: Tue, 19 Nov 2019 15:40:55 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <20190518005304.GA19446@jaegeuk-macbookpro.roam.corp.google.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On 5/17/19 5:53 PM, Jaegeuk Kim wrote: > This patch tries to avoid EAGAIN due to nrpages!=0 that was originally trying > to drop stale pages resulting in wrong data access. > > Report: https://bugs.chromium.org/p/chromium/issues/detail?id=938958#c38 Please provide a more detailed commit description. What is wrong with the current implementation and why is the new behavior considered the correct behavior? This patch moves draining code from before the following comment to after that comment: /* I/O need to be drained during transfer transition */ Is that comment still correct or should it perhaps be updated? Thanks, Bart.