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,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 6AF6DCA9ED3 for ; Mon, 4 Nov 2019 16:10:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 42DC3214B2 for ; Mon, 4 Nov 2019 16:10:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728474AbfKDQKA (ORCPT ); Mon, 4 Nov 2019 11:10:00 -0500 Received: from outgoing-auth-1.mit.edu ([18.9.28.11]:54168 "EHLO outgoing.mit.edu" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728012AbfKDQKA (ORCPT ); Mon, 4 Nov 2019 11:10:00 -0500 Received: from callcc.thunk.org (ip-12-2-52-196.nyc.us.northamericancoax.com [196.52.2.12]) (authenticated bits=0) (User authenticated as tytso@ATHENA.MIT.EDU) by outgoing.mit.edu (8.14.7/8.12.4) with ESMTP id xA4G8QEQ010632 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 4 Nov 2019 11:08:27 -0500 Received: by callcc.thunk.org (Postfix, from userid 15806) id 05B81420311; Mon, 4 Nov 2019 11:08:23 -0500 (EST) Date: Mon, 4 Nov 2019 11:08:23 -0500 From: "Theodore Y. Ts'o" To: Matthew Bobrowski Cc: Ritesh Harjani , jack@suse.cz, linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [RFC 0/5] Ext4: Add support for blocksize < pagesize for dioread_nolock Message-ID: <20191104160823.GI28764@mit.edu> References: <20191016073711.4141-1-riteshh@linux.ibm.com> <20191023232614.GB1124@mit.edu> <20191029071925.60AABA405B@b06wcsmtp001.portsmouth.uk.ibm.com> <20191103191606.GB8037@mit.edu> <20191104101623.GB27115@bobrowski> <20191104103759.4085C4C046@d06av22.portsmouth.uk.ibm.com> <20191104104913.GC27115@bobrowski> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191104104913.GC27115@bobrowski> User-Agent: Mutt/1.12.2 (2019-09-21) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Mon, Nov 04, 2019 at 09:49:14PM +1100, Matthew Bobrowski wrote: > > It sure may be giving a merge conflict (due to io_end structure). > > But this dioread_nolock series was not dependent over iomap series. > > Uh ha. Well, there's been a chunk of code injected into > ext4_end_io_dio() here and by me removing it, I'm not entirely sure > what the downstream effects will be for this specific change... Yeah, that was probably my failure to do the merge correctly; I'm hoping that Ritesh will be able to fix that up. If not we can throw an "experimental" config to enable dioread_nolock on subpage blocksizes, just to warn people that under some extreme workloads, they might end up corrupting their allocation bitmap, which then might lead to data loss. I suspect it would actually work fine for most users; but out of paranoia, if we can't figure out the generic/270 failure before the merge window, we can just make dioread_nolock_1k experimental for now. - Ted