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=-11.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,SPF_HELO_NONE,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 0F17CC433E6 for ; Thu, 4 Feb 2021 16:25:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C900864F4D for ; Thu, 4 Feb 2021 16:25:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237904AbhBDQY6 (ORCPT ); Thu, 4 Feb 2021 11:24:58 -0500 Received: from mail.kernel.org ([198.145.29.99]:48030 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237088AbhBDPE6 (ORCPT ); Thu, 4 Feb 2021 10:04:58 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 3DD3864DBA; Thu, 4 Feb 2021 15:04:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1612451056; bh=5wbQA0pqKCxKwBrohdwsCXvH4TBTm/K0JPHr/Ue0Dlk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=HO8/QAA9f3Fm69AZVQG5mrGLn/ebSPvv2XEssxdlcNXkzp9y3ptZknB219gMREw/v Bu7vHyvQfjEY1bpWXrpIFny2Ii9sSMgdzKEf6wG/g4/A3W1vIoF37UYilj8auz5XTL Wqo1JM5rMZo06v+Tfu6+yacEKPqYnq7a5oJG3IKI= Date: Thu, 4 Feb 2021 16:04:14 +0100 From: Greg Kroah-Hartman To: Jens Axboe Cc: Andres Freund , io-uring@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Bijan Mottahedeh , Sasha Levin Subject: Re: [PATCH 5.4 103/142] Revert "block: end bio with BLK_STS_AGAIN in case of non-mq devs and REQ_NOWAIT" Message-ID: References: <20200601174037.904070960@linuxfoundation.org> <20200601174048.647302799@linuxfoundation.org> <20210203123729.3pfsakawrkoh6qpu@alap3.anarazel.de> <20210203212826.6esa5orgnworwel6@alap3.anarazel.de> <14351e91-5a5f-d742-b087-dc9ec733bbfd@kernel.dk> <20210203235941.2ibyrc5z3desyd2q@alap3.anarazel.de> <207c4fb1-a3cb-9210-e2b6-8e5490872df6@kernel.dk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <207c4fb1-a3cb-9210-e2b6-8e5490872df6@kernel.dk> Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On Thu, Feb 04, 2021 at 07:36:18AM -0700, Jens Axboe wrote: > On 2/3/21 4:59 PM, Andres Freund wrote: > > Hi, > > > > On 2021-02-03 15:58:33 -0700, Jens Axboe wrote: > >> On 2/3/21 3:06 PM, Greg Kroah-Hartman wrote: > >>> On Wed, Feb 03, 2021 at 01:28:26PM -0800, Andres Freund wrote: > >>>> On 2021-02-03 14:03:09 +0100, Greg Kroah-Hartman wrote: > >>>>>> On v5.4.43-101-gbba91cdba612 this fails with > >>>>>> fio: io_u error on file /mnt/t2/test.0.0: Input/output error: write offset=0, buflen=4096 > >>>>>> fio: pid=734, err=5/file:io_u.c:1834, func=io_u error, error=Input/output error > >>>>>> > >>>>>> whereas previously it worked. libaio still works... > >>>>>> > >>>>>> I haven't checked which major kernel version fixed this again, but I did > >>>>>> verify that it's still broken in 5.4.94 and that 5.10.9 works. > >>>>>> > >>>>>> I would suspect it's > >>>>>> > >>>>>> commit 4503b7676a2e0abe69c2f2c0d8b03aec53f2f048 > >>>>>> Author: Jens Axboe > >>>>>> Date: 2020-06-01 10:00:27 -0600 > >>>>>> > >>>>>> io_uring: catch -EIO from buffered issue request failure > >>>>>> > >>>>>> -EIO bubbles up like -EAGAIN if we fail to allocate a request at the > >>>>>> lower level. Play it safe and treat it like -EAGAIN in terms of sync > >>>>>> retry, to avoid passing back an errant -EIO. > >>>>>> > >>>>>> Catch some of these early for block based file, as non-mq devices > >>>>>> generally do not support NOWAIT. That saves us some overhead by > >>>>>> not first trying, then retrying from async context. We can go straight > >>>>>> to async punt instead. > >>>>>> > >>>>>> Signed-off-by: Jens Axboe > >>>>>> > >>>>>> > >>>>>> which isn't in stable/linux-5.4.y > >>>>> > >>>>> Can you test that if the above commit is added, all works well again? > >>>> > >>>> It doesn't apply cleanly, I'll try to resolve the conflict. However, I > >>>> assume that the revert was for a concrete reason - but I can't quite > >>>> figure out what b0beb28097fa04177b3769f4bb7a0d0d9c4ae76e was concretely > >>>> solving, and whether reverting the revert in 5.4 would re-introduce a > >>>> different problem. > >>>> > >>>> commit b0beb28097fa04177b3769f4bb7a0d0d9c4ae76e (tag: block-5.7-2020-05-29, linux-block/block-5.7) > >>>> Author: Jens Axboe > >>>> Date: 2020-05-28 13:19:29 -0600 > >>>> > >>>> Revert "block: end bio with BLK_STS_AGAIN in case of non-mq devs and REQ_NOWAIT" > >>>> > >>>> This reverts commit c58c1f83436b501d45d4050fd1296d71a9760bcb. > >>>> > >>>> io_uring does do the right thing for this case, and we're still returning > >>>> -EAGAIN to userspace for the cases we don't support. Revert this change > >>>> to avoid doing endless spins of resubmits. > >>>> > >>>> Cc: stable@vger.kernel.org # v5.6 > >>>> Reported-by: Bijan Mottahedeh > >>>> Signed-off-by: Jens Axboe > >>>> > >>>> I suspect it just wasn't aimed at 5.4, and that's that, but I'm not > >>>> sure. In which case presumably reverting > >>>> bba91cdba612fbce4f8575c5d94d2b146fb83ea3 would be the right fix, not > >>>> backporting 4503b7676a2e0abe69c2f2c0d8b03aec53f2f048 et al. > > > > Having looked a bit more through the history, I suspect that the reason > > 5.6 doesn't need c58c1f83436b501d45d4050fd1296d71a9760bcb - which I have > > confirmed - is that ext4 was converted to the iomap infrastructure in > > 5.5, but not in 5.4. > > > > I've confirmed that the repro I shared upthread triggers in > > 378f32bab3714f04c4e0c3aee4129f6703805550^ but not in > > 378f32bab3714f04c4e0c3aee4129f6703805550. > > I checked up on this, and I do see the issue as well. As far as > io_uring is concerned, we don't need that revert in 5.4. So I think > the right solution here would be to... revert the revert :-) Thanks for looking at this, I'll go revert the revert now. greg k-h