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,URIBL_BLOCKED,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 D8A44C432C0 for ; Fri, 22 Nov 2019 12:35:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9AF7220714 for ; Fri, 22 Nov 2019 12:35:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=gmx.net header.i=@gmx.net header.b="kPg+QheF" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727827AbfKVMfC (ORCPT ); Fri, 22 Nov 2019 07:35:02 -0500 Received: from mout.gmx.net ([212.227.15.19]:43601 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726985AbfKVMfC (ORCPT ); Fri, 22 Nov 2019 07:35:02 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.net; s=badeba3b8450; t=1574426099; bh=MsyhrDc5juCA/PJVNt/vufw90DWNYn4tQQTGlRycy8A=; h=X-UI-Sender-Class:Subject:To:References:From:Date:In-Reply-To; b=kPg+QheFbK9fuhspXTQ0yROwkyTRmfJlvxC34Mcgc9C1M/7+OcSu35YhxufFwzTQY PyRZwfBYrpvmhUvxnLNzB1mjdunYwcnJJUyKjER14y2mY38zlcYeB9ujYLHzRutnPb /M+KNIS52sa6/lfM03ivemCcrRxk5wZ48put6hQE= X-UI-Sender-Class: 01bb95c1-4bf8-414a-932a-4f6e2808ef9c Received: from [0.0.0.0] ([13.231.109.76]) by mail.gmx.com (mrgmx004 [212.227.17.184]) with ESMTPSA (Nemesis) id 1MfHEP-1hvlKD2sWJ-00gt3L; Fri, 22 Nov 2019 13:34:59 +0100 Subject: Re: freezes during snapshot creation/deletion -- to be expected? (Was: Re: btrfs based backup?) To: Christian Pernegger , linux-btrfs References: <20191112183425.GA1257@tik.uni-stuttgart.de> <7f628741-b32e-24dc-629f-97338fde3d16@googlemail.com> <3e5cd446-3527-17ef-9ab8-d6ad01d740d0@gmx.com> <4544ecff-b70e-09fb-6fd3-e2c03d848c1c@googlemail.com> <2b0f68d6-6d27-2f14-0b44-8a40abad6542@googlemail.com> 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: Date: Fri, 22 Nov 2019 20:34:55 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.2 MIME-Version: 1.0 In-Reply-To: Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="f68w20e5xWRTxY4xNJ8iloVFPGBsxBYVe" X-Provags-ID: V03:K1:YdHWiY2iANCUeqJ7NbhxmfFSlDOplSZXZ6gTyzB7FWEyoX93hdA OmJjzVyF0BJE9oTbuxjeSX6lcigmjOFBH1rdpPeHXfbnkL73yINlrpnLFMn/y3KNJe0Dz3y zMEipzfWgEunp5QbbVSG0hbdTZYcbWWYttwSvQPtH7kVSqEYEbzxX/991ke8KK9izZdPMWj ABRm5B7uURWJcKeiWBDcQ== X-UI-Out-Filterresults: notjunk:1;V03:K0:BPpAV8lRwyU=:gaHr2bZWEtYi6xmn5rkxgl 0leCJmu8N1U2wbBiT+0+lxtWKHLI1D+GWGIXP6dmf8EVtt02LTI9WexOYy0j5IGne1l5ClsFM uoPhnHBD/Ze4SLm9BQ0KiS0Uv9Q1sl/J7kyMd/gf0C63/A/6GOabYYkpftvQQM1d+SFu0D237 Rqe/suP9hT1wh4dM93PIEDaXIJZuPytCOUuRNF6kdKkXlk1RZIXxfh74FVMy8+U31M3S2RROc Kd6zxUEL+lZnUEm9P86auLAqkbL4TGqDpGc721RLRhCALx6FxklldmNzUtRIx66FpsPbZU+HH JR9FEZ6TmCXjzWQRToyLkdUm3McRIpanhXqnxjV/TXsUz+NxOfqhO4t3DM0vOOX4ZZNyUMuQk Y/iBUJQkC3j+33jd14mAyvfn7KpngyjNzcXE+6Bc5JHPr80oSY1RiRMH7cRkHlquZV3A2dvuK qnYprCI6kFjTdj8eXbNjR8RBJ5VDn6E+fzXEFzK4gj55nxg+FxL4if77CBtfRfsKNMrzAgtJK 7JySmnV8lePFWGsbRxA8aIBNAbTxFuNl8b7PyQNblAOYS364DS2e6lb7Yl3632iEDss3kBqpq 3Nr7n78LaFkT70DVXSHiOSHu+A2aO08D2zQj44JzzdnjzBb9OjP+oxQF0yaOkstQCof1nt2JF ohwYSQ48KUgq+OqUKWaYnmXLeKhcBmAhPIVX8I7CCREou67dtyP8IQsQBSMXMVhSx/j90vC73 JJ8vKqUB7gq6qPFpM+Na6AeCX6jElmnavZIIMhYereHLiv+f+GjGG81jF/hKwpRT3lMRA/JF2 pRAGIQDx32uYJEAHNiYKPLATNjQLPbHbFDpcvJtu9dKQckKCgrkCN8FOdzahOhGSomWQCyL5d 8JnTIWAQxvShEHJyQ8LvSYY3hJDSpojd0gEhdaq3yOONbhVnEEJXZigT2eJudRl4J1LdnVtxw qiSU2yzAdGY6c2Gztfma+WDIdOJqpD0KzWgpdaDtSdY9srJclTAeEBgd6TThdjqyi8lv4AQ2C 3hOY+AkY2uAu8SrnFijXyRVV6AvM2hkP11aNAxO5Dg3RZfOaR7Hu7Nltou6CgJtFQBkZtQ8eL Ch7Rbhl72WW54Qhs8YtG/Q17daBk8nKnOT2sUX30V9zSft0f8Jn/dZ5P5WQWjJOC7zGmzDCiH uI6ZLdvO+reYqlSwT4efR4SLMrVAP9bHSbkRO1Kq3TzLZSWv01Mtj5TZlNU3xdv5gwOwjKWYG EbOWx9RQCRsi/qiEspS7DFbmBZ5dL6Z1dL16MWz55C/l7fMptaG6s4RqSSk4= 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) --f68w20e5xWRTxY4xNJ8iloVFPGBsxBYVe Content-Type: multipart/mixed; boundary="5nyhGZzh3nkf4oV6hkxrewjlvEESdAW8Z" --5nyhGZzh3nkf4oV6hkxrewjlvEESdAW8Z Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 2019/11/22 =E4=B8=8B=E5=8D=888:30, Christian Pernegger wrote: > Am Fr., 22. Nov. 2019 um 00:57 Uhr schrieb Oliver Freyermuth > : >>> 2) I'm wondering if this couldn't be improved. [...] >> >> You can check e.g. the man page btrfs-quota(8) for a short discussion = on why doing quota correctly >> with btrfs is not as easy as it may seem. >=20 > I've read that and I appreciate the difficulties in getting accurate > usage information (or even defining what that means) from a COW > filesystem. IMHO, performance, and the trade-off between performance > and up-to-the-minute accuracy are separate issues. >=20 > FWIW, running btrfs quota disable, enable, and rescan got rid of the > orphan qgroups. The full rescan ran for all of 3 seconds and didn't > block. BTW, for the empty qgroup auto delete, we have pending patch for that already. Just not merged yet. https://patchwork.kernel.org/patch/11195067/ But still, for snapshot deletion part, there is still a performance impac= t. (For completely independent subvolume, IIRC there is a quick path for it, thus no performance penalty then) Thanks, Qu >=20 > Cheers, > C. >=20 --5nyhGZzh3nkf4oV6hkxrewjlvEESdAW8Z-- --f68w20e5xWRTxY4xNJ8iloVFPGBsxBYVe Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEELd9y5aWlW6idqkLhwj2R86El/qgFAl3X1e8ACgkQwj2R86El /qj0jwf/QiNta2DWLhR78A/f16yqLvah7NpJ29d9R9TFaQI+s3fhZP3HZH3+8jP2 SKItvrv8ucY9tqIWRkBneto+sk9spWSWEg/glXE5D0PKmoNbZNsdzM7DEPezjD/Z 6QYSZdlK2L5vs7AWNR/PT9nBWGOu175lEpHXbhnAD5wd5N3K6sg1+Niy6E7jQX8X Z8F3cq0KWqqYrdarRY12nCWY3jPo0jWK2+e/BmPkJFqc26Od+NdW9g0GtSr+B3G9 D+1nRXWrVNSgxMqpsYkKyA18kAG9KDN05L3FSQWricccEn/Fs2Zz7z6CjCodWlgT 9C3WpAcR6SxyDBuEHhH5jNa1K87Sdw== =3Au/ -----END PGP SIGNATURE----- --f68w20e5xWRTxY4xNJ8iloVFPGBsxBYVe--