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=-6.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS 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 A05A9C43463 for ; Fri, 18 Sep 2020 17:19:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 612ED21734 for ; Fri, 18 Sep 2020 17:19:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726368AbgIRRTF (ORCPT ); Fri, 18 Sep 2020 13:19:05 -0400 Received: from outgoing-auth-1.mit.edu ([18.9.28.11]:52360 "EHLO outgoing.mit.edu" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725955AbgIRRTD (ORCPT ); Fri, 18 Sep 2020 13:19:03 -0400 Received: from callcc.thunk.org (pool-72-74-133-215.bstnma.fios.verizon.net [72.74.133.215]) (authenticated bits=0) (User authenticated as tytso@ATHENA.MIT.EDU) by outgoing.mit.edu (8.14.7/8.12.4) with ESMTP id 08IHIwEN007851 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Fri, 18 Sep 2020 13:18:59 -0400 Received: by callcc.thunk.org (Postfix, from userid 15806) id 4850A42003C; Fri, 18 Sep 2020 13:18:58 -0400 (EDT) Date: Fri, 18 Sep 2020 13:18:58 -0400 To: Eric Biggers Cc: Sasha Levin , linux-kernel@vger.kernel.org, stable@vger.kernel.org, linux-ext4@vger.kernel.org Subject: Re: [PATCH AUTOSEL 4.19 059/206] ext4: make dioread_nolock the default Message-ID: <20200918171858.GA80112@mit.edu> References: <20200918020802.2065198-1-sashal@kernel.org> <20200918020802.2065198-59-sashal@kernel.org> <20200918025859.GB3518637@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200918025859.GB3518637@gmail.com> /From: "Theodore Y. Ts'o" From: "Theodore Y. Ts'o" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 17, 2020 at 07:58:59PM -0700, Eric Biggers wrote: > On Thu, Sep 17, 2020 at 10:05:35PM -0400, Sasha Levin wrote: > > From: Theodore Ts'o > > > > [ Upstream commit 244adf6426ee31a83f397b700d964cff12a247d3 ] > > > > This fixes the direct I/O versus writeback race which can reveal stale > > data, and it improves the tail latency of commits on slow devices. > > > > Link: https://lore.kernel.org/r/20200125022254.1101588-1-tytso@mit.edu > > Signed-off-by: Theodore Ts'o > > Signed-off-by: Sasha Levin I > > Any particular reason to be backporting this? I thought I saw some fixes for > dioread_nolock go by, after it was made the default. Are you getting all of > those fixes too? Agreed, making dioread_nolock the default has enough issues that it's not something that I'd suggest backporting at this point. It's a fundamental behavioral change that it's not something we should change in a stable kernel. - Ted