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=-1.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, URIBL_BLOCKED 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 89DC8C282D8 for ; Fri, 1 Feb 2019 07:12:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 59EFB20857 for ; Fri, 1 Feb 2019 07:12:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="RjNdbbwU" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726717AbfBAHMr (ORCPT ); Fri, 1 Feb 2019 02:12:47 -0500 Received: from mail-lj1-f195.google.com ([209.85.208.195]:38030 "EHLO mail-lj1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725763AbfBAHMr (ORCPT ); Fri, 1 Feb 2019 02:12:47 -0500 Received: by mail-lj1-f195.google.com with SMTP id c19-v6so4894439lja.5 for ; Thu, 31 Jan 2019 23:12:46 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=zZ6l/FA/GUGfptSWUSsSvsPRMmY7tMc07VEVRU1/bZo=; b=RjNdbbwUIFJ0LwmamP5F0mU3irkYq2z0IVuzFdanXrbhj8sEB4vxYpXt3m3Fy+AB1M SPS0q/lXChAKZa7+XTmR/PS28WXYasFDvxUp+ubNu2T9eyNkNiPyzBdq2/uXlJ4I+rNj IqrPf9cFc5xriouM82L1v7b8OYmIQRv6uSAyo= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=zZ6l/FA/GUGfptSWUSsSvsPRMmY7tMc07VEVRU1/bZo=; b=RlhVUnaJ32+6BIHIVnrY5dyRqoCeY6iBuEP8R630Mfe5N6HDD8n5EnPNP9aCElir9P EVm2TjGvslsjxlUo3kg7h2Q1OJNHtjzghotE2H4AYhKpoV0FVoOpBHjwUPZ8V1Cht0Ka LyD+zaRh3SHsFliFY6D6AttEhMZY9bbynFwQ38zSdxt3L5Aa3mGzropA1fAOJNgQyrHt bE/VcRMqJBkRhTSE000WbRHdM2YyG77gwp8zoamfjEuM9OmKck3xW1MAECE8jgcVbUf8 91x2uZnfMQT+ChNdaP3IHptCp2XP7AzCz0Qw/9XSegLTXyOOhpstlXt5sPS4lWzqQE2M MFMA== X-Gm-Message-State: AJcUukfY+/3ld4SXabVgNfgMBnWKCwXKHFHw4wEv1S4Cix+H9O5mX1tV 4daTnUzdRPiHg0K8gucAeHcUvea0nNY= X-Google-Smtp-Source: ALg8bN5qyvhrhEJ+rL9Mzi6w90+KJopSbyGuMGeszm52yiNF10QN4su0XwUvHRvzQ7A0PkEI64mXJg== X-Received: by 2002:a2e:8719:: with SMTP id m25-v6mr32896497lji.121.1549005165056; Thu, 31 Jan 2019 23:12:45 -0800 (PST) Received: from mail-lj1-f174.google.com (mail-lj1-f174.google.com. [209.85.208.174]) by smtp.gmail.com with ESMTPSA id z9sm1199456lfj.79.2019.01.31.23.12.44 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 31 Jan 2019 23:12:44 -0800 (PST) Received: by mail-lj1-f174.google.com with SMTP id g11-v6so4921313ljk.3 for ; Thu, 31 Jan 2019 23:12:44 -0800 (PST) X-Received: by 2002:a2e:8045:: with SMTP id p5-v6mr29493803ljg.87.1549004749092; Thu, 31 Jan 2019 23:05:49 -0800 (PST) MIME-Version: 1.0 References: <20190130124420.1834-1-vbabka@suse.cz> <20190130124420.1834-3-vbabka@suse.cz> <20190131095644.GR18811@dhcp22.suse.cz> <20190131102348.GT18811@dhcp22.suse.cz> <20190201051355.GV6173@dastard> In-Reply-To: <20190201051355.GV6173@dastard> From: Linus Torvalds Date: Thu, 31 Jan 2019 23:05:32 -0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH 2/3] mm/filemap: initiate readahead even if IOCB_NOWAIT is set for the I/O To: Dave Chinner Cc: Michal Hocko , Jiri Kosina , Vlastimil Babka , Andrew Morton , Linux List Kernel Mailing , Linux-MM , Linux API , Peter Zijlstra , Greg KH , Jann Horn , Dominique Martinet , Andy Lutomirski , Kevin Easton , Matthew Wilcox , Cyril Hrubis , Tejun Heo , "Kirill A . Shutemov" , Daniel Gruss , linux-fsdevel Content-Type: text/plain; charset="UTF-8" Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Thu, Jan 31, 2019 at 9:16 PM Dave Chinner wrote: > > You are conflating "best effort non-blocking operation" with > "atomic guarantee". RWF_NOWAIT/IOCB_NOWAIT is the > former, not the latter. Right. That's my *point*, Dave. It's not 'atomic guarantee", and never will be. We are in 100% agreement. That's what I _said_. And part of "best effort" is very much "not a security information leak". I really don't see why you are so argumentative. As I mentioned earlier in the thread, it's actually quite possible that users will actually find that starting read-ahead is a *good* thing, Dave. Even - in fact *particularly* - the user you brought up: samba using RWF_NOWAIT to try to do things synchronously quickly. So Dave, why are you being so negative? Linus