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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D777DC6FD1D for ; Tue, 4 Apr 2023 16:30:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235574AbjDDQa5 (ORCPT ); Tue, 4 Apr 2023 12:30:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34672 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235607AbjDDQal (ORCPT ); Tue, 4 Apr 2023 12:30:41 -0400 Received: from mail-il1-x12f.google.com (mail-il1-x12f.google.com [IPv6:2607:f8b0:4864:20::12f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4F8565588 for ; Tue, 4 Apr 2023 09:30:30 -0700 (PDT) Received: by mail-il1-x12f.google.com with SMTP id j19so673879ilq.9 for ; Tue, 04 Apr 2023 09:30:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20210112.gappssmtp.com; s=20210112; t=1680625829; x=1683217829; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=TOkwpry92hNrhdoYU8TTu3v6fSyQj7r//Y+P3UzI88A=; b=PU7If7fmWPJOvnSO/gB8yPyKaTXGsUKu08AtS8DCPgNtAikn6AQbEXhYQ/3BQ5642I RJS0x7oUPTRJa0rvvPHOfxGqFaOuwEPINFpOTukb7R5JszpZMNZcvwGG6RUn/+ls7nxi p33fk1XVDg4QOP9G2YJzuFCWjQGPlEwHMTF0vryCDgB55Mt4UXqncrPLsmYIRXS3Ou8W x47NCFroAxf4AiVh9SnXX2ku4qtI03XvxhmTcOTUHRSgDqgZ5o/s8Uqxm+1auA0UdjEy znD2cEwUdqhEXp0uanGTq5aJ/zO9P+C/oUyIr/MO2zxLifm/sXQneFY7RtQZAKNth/OQ Q1BQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1680625829; x=1683217829; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=TOkwpry92hNrhdoYU8TTu3v6fSyQj7r//Y+P3UzI88A=; b=EAKsYZ7Yhb/Nr9Myy1x71XTiCLZzbBvAwO5yEA9TvTSUCiOGcXGh1fWQsruKdPYYf3 a9O3IjrAAAM1JU/2PpqUGtQckyW4LKTmwRKtvWLBl7IEQzbuRjpvPqM1T1u1NnUNZxQx TMIEhG8cHBvl+9OSerwM+w7bxP2DlO4WYimluL/k9VHi2TcfkyrGssIGe0XqIPNAu8bJ N5ZKUyaSbA5LrXy0DBDbHvv1kYB38mWJWWCswL5IRNSmmsgXK2AQjrZa8Mnh6xwOFgCy uyIgQ02sZO+1PUxCQi1uNaaiZu7bat09vyQZf8JNg/luyI7sFUl1d2Jtb45aRcwumk/8 GCsg== X-Gm-Message-State: AAQBX9czEZFe5v+8xnJWDMGDufC7rOIivGMpW/sIl+m8OB7abTzCf1JN LjKLHRmzRWfq+xSgin+scI14cg== X-Google-Smtp-Source: AKy350ZZVL9a/U8emrnKI2yjeUvuM6QC9ftB3e6FNNdToQF8GZaheJaFTnmRLJU5rPzYniAZ11uwbw== X-Received: by 2002:a05:6e02:1a06:b0:326:1d0a:cce6 with SMTP id s6-20020a056e021a0600b003261d0acce6mr237300ild.0.1680625829614; Tue, 04 Apr 2023 09:30:29 -0700 (PDT) Received: from [192.168.1.94] ([96.43.243.2]) by smtp.gmail.com with ESMTPSA id i10-20020a056638380a00b0040b2254447bsm2947197jav.56.2023.04.04.09.30.28 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 04 Apr 2023 09:30:29 -0700 (PDT) Message-ID: Date: Tue, 4 Apr 2023 10:30:28 -0600 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux aarch64; rv:102.0) Gecko/20100101 Thunderbird/102.9.0 Subject: Re: [PATCH] splice: report related fsnotify events Content-Language: en-US To: Amir Goldstein , Jan Kara Cc: viro@zeniv.linux.org.uk, linux-fsdevel@vger.kernel.org, shepjeng@gmail.com, kernel@cccheng.net, Chung-Chiang Cheng , Christian Brauner References: <20230322062519.409752-1-cccheng@synology.com> <80ccc66e-b414-6b68-ae10-59cf38745b45@kernel.dk> <20230404092109.evsvdcv6p2e5bvtf@quack3> From: Jens Axboe In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On 4/4/23 7:45?AM, Amir Goldstein wrote: > On Tue, Apr 4, 2023 at 12:21?PM Jan Kara wrote: >> >> On Mon 03-04-23 11:23:25, Jens Axboe wrote: >>> On 4/3/23 11:15?AM, Amir Goldstein wrote: >>>>> On 4/3/23 11:00?AM, Amir Goldstein wrote: >>>>> io_uring does do it for non-polled IO, I don't think there's much point >>>>> in adding it to IOPOLL however. Not really seeing any use cases where >>>>> that would make sense. >>>>> >>>> >>>> Users subscribe to fsnotify because they want to be notified of changes/ >>>> access to a file. >>>> Why do you think that polled IO should be exempt? >>> >>> Because it's a drastically different use case. If you're doing high >>> performance polled IO, then you'd never rely on something as slow as >>> fsnotify to tell you of any changes that happened to a device or file. >>> That would be counter productive. >> >> Well, I guess Amir wanted to say that the application using fsnotify is not >> necessarily the one doing high performance polled IO. You could have e.g. >> data mirroring application A tracking files that need mirroring to another >> host using fsnotify and if some application B uses high performance polled >> IO to modify a file, application A could miss the modified file. >> >> That being said if I look at exact details, currently I don't see a very >> realistic usecase that would have problems (people don't depend on >> FS_MODIFY or FS_ACCESS events too much, usually they just use FS_OPEN / >> FS_CLOSE), which is likely why nobody reported these issues yet :). >> > > I guess so. > Our monitoring application also does not rely on FS_MODIFY/FS_ACCESS > as they could be too noisy. > > The thing that I find missing is being able to tell if a file was *actually* > accessed/modified in between open and close. > This information could be provided with FS_CLOSE event Agree, it's not a good fit for a lot of common use cases. -- Jens Axboe