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=-2.0 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM,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 0C99DC352A4 for ; Thu, 13 Feb 2020 01:00:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C955A20714 for ; Thu, 13 Feb 2020 01:00:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=gmx.net header.i=@gmx.net header.b="UHrIpv1O" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729244AbgBMBAU (ORCPT ); Wed, 12 Feb 2020 20:00:20 -0500 Received: from mout.gmx.net ([212.227.17.20]:46565 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729132AbgBMBAT (ORCPT ); Wed, 12 Feb 2020 20:00:19 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.net; s=badeba3b8450; t=1581555604; bh=qGxjBvebJPKwl15cBDYfFLOTlodLUFVcyPkoBkOXRio=; h=X-UI-Sender-Class:Subject:To:References:From:Date:In-Reply-To; b=UHrIpv1OAvDCBOw1QPLr7c3YFRVHkpT2jglndnF/3gtQ2Ujha5MHKceO01e1AubuZ HBTDqkMgKgqSQ3hJIjjbVDCU250OlAoIzw0dGq2UkMlqhLHfURZ0S+vs0J8RvJoClb ZFmOq/po2IGkfbbJY+es5DAVjb+UUqwrVLHQ4ucY= X-UI-Sender-Class: 01bb95c1-4bf8-414a-932a-4f6e2808ef9c Received: from [0.0.0.0] ([149.28.201.231]) by mail.gmx.com (mrgmx105 [212.227.17.174]) with ESMTPSA (Nemesis) id 1N5G9t-1jRZw61t8X-011E9j; Thu, 13 Feb 2020 02:00:04 +0100 Subject: Re: [PATCH 1/4] btrfs: backref, only collect file extent items matching backref offset To: dsterba@suse.cz, ethanwu , Josef Bacik , linux-btrfs@vger.kernel.org References: <20200207093818.23710-1-ethanwu@synology.com> <20200207093818.23710-2-ethanwu@synology.com> <0badf0be-d481-10fb-c23d-1b69b985e145@toxicpanda.com> <20200210162927.GK2654@twin.jikos.cz> <5901b2be7358137e691b319cbad43111@synology.com> <20200211182159.GD2902@twin.jikos.cz> <8eeca7c0-8283-8cd6-2354-9eb9373c9bd3@gmx.com> <20200212145740.GK2902@twin.jikos.cz> From: Qu Wenruo Autocrypt: addr=quwenruo.btrfs@gmx.com; prefer-encrypt=mutual; keydata= mQENBFnVga8BCACyhFP3ExcTIuB73jDIBA/vSoYcTyysFQzPvez64TUSCv1SgXEByR7fju3o 8RfaWuHCnkkea5luuTZMqfgTXrun2dqNVYDNOV6RIVrc4YuG20yhC1epnV55fJCThqij0MRL 1NxPKXIlEdHvN0Kov3CtWA+R1iNN0RCeVun7rmOrrjBK573aWC5sgP7YsBOLK79H3tmUtz6b 9Imuj0ZyEsa76Xg9PX9Hn2myKj1hfWGS+5og9Va4hrwQC8ipjXik6NKR5GDV+hOZkktU81G5 gkQtGB9jOAYRs86QG/b7PtIlbd3+pppT0gaS+wvwMs8cuNG+Pu6KO1oC4jgdseFLu7NpABEB AAG0IlF1IFdlbnJ1byA8cXV3ZW5ydW8uYnRyZnNAZ214LmNvbT6JAU4EEwEIADgCGwMFCwkI BwIGFQgJCgsCBBYCAwECHgECF4AWIQQt33LlpaVbqJ2qQuHCPZHzoSX+qAUCXZw1oQAKCRDC PZHzoSX+qCY6CACd+mWu3okGwRKXju6bou+7VkqCaHTdyXwWFTsr+/0ly5nUdDtT3yEVggPJ 3VP70wjlrxUjNjFb6iIvGYxiPOrop1NGwGYvQktgRhaIhALG6rPoSSAhGNjwGVRw0km0PlIN D29BTj/lYEk+jVM1YL0QLgAE1AI3krihg/lp/fQT53wLhR8YZIF8ETXbClQG1vJ0cllPuEEv efKxRyiTSjB+PsozSvYWhXsPeJ+KKjFen7ebE5reQTPFzSHctCdPnoR/4jSPlnTlnEvLeqcD ZTuKfQe1gWrPeevQzgCtgBF/WjIOeJs41klnYzC3DymuQlmFubss0jShLOW8eSOOWhLRuQEN BFnVga8BCACqU+th4Esy/c8BnvliFAjAfpzhI1wH76FD1MJPmAhA3DnX5JDORcgaCbPEwhLj 1xlwTgpeT+QfDmGJ5B5BlrrQFZVE1fChEjiJvyiSAO4yQPkrPVYTI7Xj34FnscPj/IrRUUka 68MlHxPtFnAHr25VIuOS41lmYKYNwPNLRz9Ik6DmeTG3WJO2BQRNvXA0pXrJH1fNGSsRb+pK EKHKtL1803x71zQxCwLh+zLP1iXHVM5j8gX9zqupigQR/Cel2XPS44zWcDW8r7B0q1eW4Jrv 0x19p4P923voqn+joIAostyNTUjCeSrUdKth9jcdlam9X2DziA/DHDFfS5eq4fEvABEBAAGJ ATwEGAEIACYCGwwWIQQt33LlpaVbqJ2qQuHCPZHzoSX+qAUCXZw1rgUJCWpOfwAKCRDCPZHz oSX+qFcEB/95cs8cM1OQdE/GgOfCGxwgckMeWyzOR7bkAWW0lDVp2hpgJuxBW/gyfmtBnUai fnggx3EE3ev8HTysZU9q0h+TJwwJKGv6sUc8qcTGFDtavnnl+r6xDUY7A6GvXEsSoCEEynby 72byGeSovfq/4AWGNPBG1L61Exl+gbqfvbECP3ziXnob009+z9I4qXodHSYINfAkZkA523JG ap12LndJeLk3gfWNZfXEWyGnuciRGbqESkhIRav8ootsCIops/SqXm0/k+Kcl4gGUO/iD/T5 oagaDh0QtOd8RWSMwLxwn8uIhpH84Q4X1LadJ5NCgGa6xPP5qqRuiC+9gZqbq4Nj Message-ID: <0aa5bb89-d8ed-973b-9cd2-8e787fabe301@gmx.com> Date: Thu, 13 Feb 2020 08:59:56 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.2 MIME-Version: 1.0 In-Reply-To: <20200212145740.GK2902@twin.jikos.cz> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="LVRo5u79gKGlX3gt2Rp7rMI6Whiw7gUnB" X-Provags-ID: V03:K1:Ju/KlYzRCp21GEGvezCsSeMAIGqcfHqLW3pgOTpAlk6j0pgazqU VaQDOKoE7IWt3vmrS9rXdtjeAFkb52th35mF8WDc21ak5ClzbFCaIF3isnDwwAO0KowOa32 QF8IogwatY1GbQveQc+YEPRYMyY6cddnHAblW9voKnjUo+j9/GfiVCfhPM2GlEMjtMt2/0O QgaLrW/ag9nSE/DsgxIcQ== X-UI-Out-Filterresults: notjunk:1;V03:K0:e9VzlB5QnSU=:NXI8bIu/gxLhhjBA1U/pgi 3UmIT+TXnt/xoBgPqC2XEIcdV/VHoRQzEmApRQyfHikyRDWs6cfV+Utx76Xg4M8l4FGFRGBzv F/dC1beOwYtAmcV6vk7Lk0mWd5p/vCJo+5mej0V6bBSCalL3QKbV3BJZCJaMin+sRCS63uHsM LC/1hYISEw6a07K/X3IVjQfGMxv/6GE5uQAykQvDUZjaKfoFqI2acVJsIbjzGg5JKsAUPX2rp k6kwP6UCEVb1akb9bbBJ2aJBwhxmoYJWC6/WEorJK5xbjB5gPXQvn9WybtD8599/GC5zva79n Ou8P+dQiZrTZWTRG/Pfe704OYKCzGi+Mk17bpiUlZoxLnvT6AklLEPjsrzAVsf30PRXtcTiWY 2GLTR5/YzCyO0I5JBHwi/8aqAucJBhozrg3VO7qSVOfO8OIvJpaso530+dTBJ7dUpaW18ORha aC4MVg+HOb6kMXnGvP8DfeNFSb51gKNmROcOvGxS9AN/V/5pkiNYIQ++dmv5/eXO7jnIk1n7M 8aSEejIYWgKZlrNojF+xYXIws2coFAUDUYkh9DBFp9sb/1Dd8OL0MjWr4aF6pxXeOOMRtl7+n C6r9PPzi3m8qnygVjyPVRt/F362mNFGb84a9LV/Vu7LgVzighmQy1rQensRa1Mv39TsUiAFE6 rS/XWynO5lGQ1JDLYDW9C/hf/Rw5O+k0Yb5VTzVx5PGK5AaH8u78ttSaWJA2kRNTD69s7yLfT UnCi4DXUutoaFxZwwB1MQWXapNWXmznoOonzDNIsd8jcNYX89TY5GoevXGO1/HHI8yIn9ncKE dwsr4NGKtkLeRFR8onuLq24kBbSh4CJx2tmA2Wgy2FDySRZdTg1cDJbTxSd2yahseWXwBbByX ftaQklDPGnjKDsMsKcHCAYNvFrTTusCCgjw/nT0NvwR9XL1kXq/GREWSIEQvvqgspjFLK7TMB HD3SHWoGf02lDWWLglcirW1zaUD+kxNamDIzVWtCYZyMOuoqkvb+BCA6CTruQDd1wjZJuuUWM WAjog0lRdnCs5+2LxBCBkHVRcJSV7kYcg8aIWhal52zaICkKa41xVMXO9f/OuA7kb4z8eAfUi jbnGliHhsCSshv9w+l+4c4PfgrMyTrYjN4Cs30GGN/GZpLkCRfVtjQJqkwZMPws4YTgCisIxD tXmmmQTZmOvgTTRJ17gReWuy06BmLkWww25ZqKApO7zLYBIj7d7EYzYNNltltA7rVoeDOWEIb xGC8jUVNBwFc3k3Xu Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --LVRo5u79gKGlX3gt2Rp7rMI6Whiw7gUnB Content-Type: multipart/mixed; boundary="5OxFGrU5fHatDCFEdjev0CQZqEf6MWnVc" --5OxFGrU5fHatDCFEdjev0CQZqEf6MWnVc Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 2020/2/12 =E4=B8=8B=E5=8D=8810:57, David Sterba wrote: > On Wed, Feb 12, 2020 at 08:11:56PM +0800, Qu Wenruo wrote: >>>>> >>>>> This looks like an existing bug, IIRC Zygo reported it before. >>>>> >>>>> Btrfs balance just randomly failed at data reloc tree. >>>>> >>>>> Thus I don't believe it's related to Ethan's patches. >>>> >>>> Ok, than the patches make it more likely to happen, which could mean= >>>> that faster backref processing hits some race window. As there could= be >>>> more we should first fix the bug you say Zygo reported. >>> >>> I added a log to check if find_parent_nodes is ever called under >>> test btrfs/125. It turns out that btrfs/125 doesn't pass through the >>> function. What my patches do is all under find_parent_nodes. >> >> Balance goes through its own backref cache, thus it doesn't utilize th= e >> path you're modifying. >> >> So don't worry your patches look pretty good. >> >> Furthermore, this csum mismatch is not related to backref walk, but th= e >> data csum and the data in data reloc tree, which are all created by ba= lance. >> >> So there is really no reason to block such good optimization. >=20 > I don't mean to block the patchset but when I test patchsets from 5 > people and tests start to fail I need to know what's the cause and if > there's a fix in sight. So far the test failed 2 out of 2 (once the > branch itself and then with for-next), I can do more rounds but at this= > point it's too reliable to reproduce so there is some connection. >=20 > Sometimes it looks like I blame the messenger and complaining under > patches that don't cause the bugs, but often I don't have anyting bette= r > than new warnings between 2 test rounds. Once we have more eyes on the > problem we'll narrow it down and find the root cause. >=20 BTW, from your initial report, the csum looks pretty long. Are you testing with those new csum algos? And could that be the reason why it's much easier to reproduce? Thanks, Qu --5OxFGrU5fHatDCFEdjev0CQZqEf6MWnVc-- --LVRo5u79gKGlX3gt2Rp7rMI6Whiw7gUnB Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEELd9y5aWlW6idqkLhwj2R86El/qgFAl5En4wACgkQwj2R86El /qimkwf/V3dzj+73htoW6JmB7oiD6TRpBbLY7h/KYzJiW0D+TLuQzy1TkeuwxvtL ACFQcQPfxElS6AXXDrpFjQwUV2p6730FzwrD+3Gm+W4GX6ntmHRw4/IorfMbhGXp E0Wr7iGd6ZYeGSFCsF6QqYGol4irmcrEVllFGxFAxqmprRDOTImDVSjrO6pAL1WO e+9JJTEq1oIu1BNlbOHU5vyIwqVl8RZaSQGb4IiQjiYtvY1ZRC4kzq+2NNvXtOr+ 2e5up8aVF6BkrTLf3mcT8E9QBPv6h6vniLPlwCAlGNr/4gqufCHQ5gFxWCZZAZ1K AiUz9wrtIdJQQppSKTa7S8fNScVP6g== =M1fN -----END PGP SIGNATURE----- --LVRo5u79gKGlX3gt2Rp7rMI6Whiw7gUnB--