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 AE015EB64D9 for ; Thu, 15 Jun 2023 08:52:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245263AbjFOIw3 (ORCPT ); Thu, 15 Jun 2023 04:52:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38758 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244277AbjFOIwD (ORCPT ); Thu, 15 Jun 2023 04:52:03 -0400 Received: from mail-qt1-x82b.google.com (mail-qt1-x82b.google.com [IPv6:2607:f8b0:4864:20::82b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C3EF530DB for ; Thu, 15 Jun 2023 01:51:39 -0700 (PDT) Received: by mail-qt1-x82b.google.com with SMTP id d75a77b69052e-3f9c60bc99cso27595181cf.0 for ; Thu, 15 Jun 2023 01:51:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fromorbit-com.20221208.gappssmtp.com; s=20221208; t=1686819099; x=1689411099; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=tCtd60h4V4EHRJD4vwp1PDGCA8q+mlzKDRGda/PgiKA=; b=Jnq28tmV7ZVC/X1/2KIo5xXOOzRtZDU/hLkuKIMu/YCfNX8Y3MwN3C4vhs+Pth9kGI 0JA0zrCLE54cTTOa338uRIQVPJWdSihi0AMTnWuwNQULa0LZ3lH8gFVSh6QQSgqDHku3 DjM8lPkW83/rY3onhCLt6et2m2QA0iyWi9XBK0+1Vgwb2zmA7r7SAupdZoPDaYwgcBgE 2adMK5KVqBFTYXTfw8yNl3T8lLI1++16gSfPAcGLZYfkJTDDPUW9JzUYpJbbGYkMDzZ8 kXxB66693jNdirT/m4XEWUXIsocinenCeMtoko5z/ffPYblXOTSqQrKjjN4JBPSel+vQ P81g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1686819099; x=1689411099; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=tCtd60h4V4EHRJD4vwp1PDGCA8q+mlzKDRGda/PgiKA=; b=hBil3ShBoaWQszHwldDyXJP8KiCO88D0UJ2JvDulYngXIdZTe0txXe3Z+oqk/taPLd nn2gdG3Q1JjoId57YhTUKibPKlSuvK+ODlNfZ5FQNgjbjBQoVW1U3m9+ptq28kYs8jSM vkMs/asZF8Yqe8LDxvsn9UVi6Dodws4gEcj8xidsGxSbd/3MQEQC713/O/Y9g2rBTFgA 12hXdBO9sNT3URNWQqr8hIltzVSTzrieUcvio+El1F5nT/M15WXNB0UZQPjiwmoyHX4J Zps+Ty7A7pUSyfbkgctxfpVR9zpme8Ba1s5rV9PP+xqnt78sDpdjmDuIZF0cGM/74h/1 nXiw== X-Gm-Message-State: AC+VfDyfNQrZ5PpgLPY7gJPjLG9N3ceuXmZWl8hPXHebVsAdIcsMjnlw Lk4A/OakPpi8JI2nkMH0lR+Tsg== X-Google-Smtp-Source: ACHHUZ68AxrCw755I87FG0yFiJfDul/thfltQS6QfCx5gguIzNFJw+y3jyTV9mqBehUOrCi0EVKjxg== X-Received: by 2002:ac8:57ce:0:b0:3f6:c0f7:a5c3 with SMTP id w14-20020ac857ce000000b003f6c0f7a5c3mr5976494qta.32.1686819098779; Thu, 15 Jun 2023 01:51:38 -0700 (PDT) Received: from dread.disaster.area (pa49-180-13-202.pa.nsw.optusnet.com.au. [49.180.13.202]) by smtp.gmail.com with ESMTPSA id p3-20020a62ab03000000b00646e7d2b5a7sm934369pff.112.2023.06.15.01.51.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 15 Jun 2023 01:51:38 -0700 (PDT) Received: from dave by dread.disaster.area with local (Exim 4.96) (envelope-from ) id 1q9ihb-00C0hg-0F; Thu, 15 Jun 2023 18:51:35 +1000 Date: Thu, 15 Jun 2023 18:51:35 +1000 From: Dave Chinner To: Hannes Reinecke Cc: Matthew Wilcox , linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org, Andrew Morton , Christoph Hellwig , Luis Chamberlain Subject: Re: [PATCH 0/7] RFC: high-order folio support for I/O Message-ID: References: <20230614114637.89759-1-hare@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Thu, Jun 15, 2023 at 08:21:10AM +0200, Hannes Reinecke wrote: > On 6/15/23 01:53, Dave Chinner wrote: > > On Wed, Jun 14, 2023 at 05:06:14PM +0200, Hannes Reinecke wrote: > > All you need to do now is run the BS > PS filesytems through a full > > fstests pass (reflink + rmap enabled, auto group), and then we can > > start on the real data integrity validation work. It'll need tens of > > billions of fsx ops run on it, days of recoveryloop testing, days of > > fstress based exercise, etc before we can actually enable it in > > XFS.... > > > Hey, c'mon. I do know _that_. All I'm saying is that now we can _start_ > running tests and figure out corner cases (like NFS crashing on me :-). > With this patchset we now have some infrastructure in place making it > even _possible_ to run those tests. I got to this same point several years ago. You know, that patchset that Luis went back to when he brought up this whole topic again? That's right when I started running fsx, and I realised it didn't cover FICLONERANGE, FIDEDUPERANGE and copy_file_range(). Yep, that's when we first realised we had -zero- test coverage of those operations. Darrick and I spent the next *3 months* pretty much rewriting the VFS level of those operations and fixing all the other bugs in the implementations, just so we could validate they worked correct on BS <= PS. But by then Willy had started working over iomap and filemap for folios, and the bs > PS patches were completely bitrotted and needed rewriting from scratch. Which I now didn't have time to do.... So today is deja vu all over again: the first time I run fsx on a new 64kB BS on 4KB PS implementation it hangs doing something -really weird- and unexpected in copy_file_range(). It shouldn't even be in the splice code doing a physical data copy. So something went wrong in ->remap_file_range(), or maybe in the truncate before it, before it bugged out over out of range readahead in the page cache... I got only 3 fsx ops in today, and at least three bugs have already manifest themselves.... > Don't be so pessimistic ... I'm not pessimistic. I'm being realistic. I'm speaking from experience. Not just as a Linux filesystem engineer who has had to run this fsx-based data integrity validation process from the ground up multiple times in the past decade, but also as an Irix OS engineer that spent many, many hours digging out nasty, subtle bs > ps data corruption bugs of the Irix buffer/page cache. Cheers, Dave. -- Dave Chinner david@fromorbit.com