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=-8.2 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 02743C3F2CD for ; Tue, 3 Mar 2020 00:32:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B58E02467B for ; Tue, 3 Mar 2020 00:32:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=gmx.net header.i=@gmx.net header.b="N2dyALou" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726838AbgCCAcA (ORCPT ); Mon, 2 Mar 2020 19:32:00 -0500 Received: from mout.gmx.net ([212.227.15.19]:53655 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726752AbgCCAb7 (ORCPT ); Mon, 2 Mar 2020 19:31:59 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.net; s=badeba3b8450; t=1583195514; bh=kNGE0Rl2nD3lklkR0tBX7sWbzKXng3SRHFzQbR4BLjo=; h=X-UI-Sender-Class:Subject:To:References:From:Date:In-Reply-To; b=N2dyALouVJjSqhiw9i9F3g7FEvMC6oNkZP0zU7ceC9/uw/iLlLY7DGECKPkzbvdh+ UJpKr6e0ZOhcrOzmRKJOoyV0ii/ZWP809wl9D+JdhxjXoTUoVB6ewQaIfFrQEvYokD RDUFQeqQcOYeO949mJ4qMg2rPuKF+Q0YFNqriN6s= X-UI-Sender-Class: 01bb95c1-4bf8-414a-932a-4f6e2808ef9c Received: from [0.0.0.0] ([149.28.201.231]) by mail.gmx.com (mrgmx005 [212.227.17.184]) with ESMTPSA (Nemesis) id 1MplXz-1jinVk1ljZ-00qFEr; Tue, 03 Mar 2020 01:31:54 +0100 Subject: Re: [PATCH 5/7] btrfs: clear BTRFS_ROOT_DEAD_RELOC_TREE before dropping the reloc root To: Josef Bacik , kernel-team@fb.com, linux-btrfs@vger.kernel.org References: <20200302184757.44176-1-josef@toxicpanda.com> <20200302184757.44176-6-josef@toxicpanda.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: <0b219848-9cbc-400e-e967-3cbab2fcdd4c@gmx.com> Date: Tue, 3 Mar 2020 08:31:50 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: <20200302184757.44176-6-josef@toxicpanda.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="FLCvvYgSpEeYmFbivSxsjklPfa7pwLN9Z" X-Provags-ID: V03:K1:AOrsbgCSFHsP7tR16ZYOWJeB3h1oMTuDu5GqLnP4HnIdOdWym4v bkSTVTrMtZuglv0hG84JfiDyd0V2Ge9cJVCPrnhlBaqeW8veIXk4K/DiNJpWiyncUU4bBfH I/AVhUnVbJw4ZZ0XX3PFVYsD5jwktk67dWa4ubut1j5RD3ymfdZAkrYQqrCfn+u5SI1EF4d eEpsvI/8yZPnQ7U5XxI7Q== X-UI-Out-Filterresults: notjunk:1;V03:K0:O2miL/HjGSI=:vddlUFO+WB+uisWuoNREr3 7Mpot+mJ4m/YoeP4fOcc721R2s9DAksmSm1uyOVRUen8e9WvhfdnAOpTjEaZDwvt91v5WaoDi 6fLovBzmPm7VA74bjGP20genIcoLIFv//vvSZPFgMeUW0AB4YHoopJSqYbnKXiI6PbujQX1kQ 5e++oJlaUkxuOmWMNP3a44cm8WdmjnmuZpE34dTUZN79cY07AVxBSg7RvTKD0N18oPJbiJKL+ DFcYjGH8YMyQf+/41h5AMC73FR1yPLO7+VvCXTYbIcKm/B4vYeGnxuHTkmohl0XU02SortyYy ISuZn6IZnO/AQMPGOADo/sApgQYSK/UWefutcL24WqRlHd49QT78Ehtf78t/3oWLIVkzPFwiX RnaYmSScTRScvQar+Lo1eFJECJpOKgYNEUDADVxtLXdXlxXRf1wwwDs4dSY0oHAvPKGPKZkZl +jwnVkNwGTkUtj/GwBI/lcfFF4VuYX4sfM8GEpD+BToB3x43BI8KDWLeY6EAFvvKiRkEnZb7n N2VN7uZBKuJwvXGLvoxYc2AWS8wFyW6weFQbE0wn4dPzaakHy8eLmlFt6HYuMJ3LlzsalBVqi 3lO2TVqcznNnrTDSGiQclSqGMdlUGFG8JK+0Y0ENKiOfMYxZPlHgdzlalbhSCJE+81ysZgGOg oftxlIn6ZloU8tktPUv3u1IIsoV9medTJJM+mJeN3nMMEIiDUBrmsGp2az3DAJ7vxEIFejJrs CxterUPOflec79OQxeBLy/CouJhiAfEzlMZLqoHQxfjTXvgYcj3SATgIG4bAz8sDctqZYqalj gnBB+C8W+NyoGrpW1d1Sxb3s+cyzjYumbU19yJbNQNhYgS+AWhkqVZRYYRQKzgM88KYrIkpcB rdwdGgm5WakedikYb1C5GsD5QR8RelpyphE76nwDnJ0AmuZWieWVdp1eLBpHTKzWBXuJr16tG ojeywC6BNPuVZXSXGksxsPq4BY1A2XLeRUHZHppwSrEzjYoITCJLfNb4vIuOgmKT4hZoiwbxH IwW6DpSqLl8upvoZ0BMrPMgaSg2Qfs1+aEDVb40I3kJwx795ycy7GTTHrwk1sEHQrtXjSiz/C MvSRNc/8Tx/Ee+A1+nFAYKY8EBTO5Ua1NyigY7+FXQMRLiyCegW+d3nbJKsh7xF4U3oI9vqp3 CpyGx2OaRhyUNurIoxSiT2MyVmG3cJA6y8x5S8QRbXvc83brIOFVt8XKSSOIeitfh4T16ZVRe BCYBNAGwy7eHO6oXt 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) --FLCvvYgSpEeYmFbivSxsjklPfa7pwLN9Z Content-Type: multipart/mixed; boundary="O7GB2XNrkrOfcysS0yroSGYiuHWSiccbG" --O7GB2XNrkrOfcysS0yroSGYiuHWSiccbG Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 2020/3/3 =E4=B8=8A=E5=8D=882:47, Josef Bacik wrote: > We were doing the clear dance for the reloc root after doing the drop o= f > the reloc root, which means we have a giant window where we could miss > having BTRFS_ROOT_DEAD_RELOC_TREE unset and the reloc_root =3D=3D NULL.= Sorry I didn't see the problem of having BTRF_ROOT_DEAD_RELOC_TREE and reloc_root =3D=3D NULL. The whole idea of BTRFS_ROOT_DEAD_RELOC_TREE is to avoid accessing root->reloc_root, no matter if reloc_root is NULL or not. Or did I miss anything? Thanks, Qu >=20 > Signed-off-by: Josef Bacik > --- > fs/btrfs/relocation.c | 13 +++++++------ > 1 file changed, 7 insertions(+), 6 deletions(-) >=20 > diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c > index e60450c44406..acd21c156378 100644 > --- a/fs/btrfs/relocation.c > +++ b/fs/btrfs/relocation.c > @@ -2291,18 +2291,19 @@ static int clean_dirty_subvols(struct reloc_con= trol *rc) > =20 > list_del_init(&root->reloc_dirty_list); > root->reloc_root =3D NULL; > - if (reloc_root) { > - > - ret2 =3D btrfs_drop_snapshot(reloc_root, NULL, 0, 1); > - if (ret2 < 0 && !ret) > - ret =3D ret2; > - } > /* > * Need barrier to ensure clear_bit() only happens after > * root->reloc_root =3D NULL. Pairs with have_reloc_root. > */ > smp_wmb(); > clear_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state); > + > + if (reloc_root) { > + > + ret2 =3D btrfs_drop_snapshot(reloc_root, NULL, 0, 1); > + if (ret2 < 0 && !ret) > + ret =3D ret2; > + } > btrfs_put_root(root); > } else { > /* Orphan reloc tree, just clean it up */ >=20 --O7GB2XNrkrOfcysS0yroSGYiuHWSiccbG-- --FLCvvYgSpEeYmFbivSxsjklPfa7pwLN9Z Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEELd9y5aWlW6idqkLhwj2R86El/qgFAl5dpXYACgkQwj2R86El /qjIVAf/QI90Z8GzXtB9n6gCAjsMOZpjCs5Zk980R2JZAxBwLzoFndngvPmJh+47 EY3y1mjVBtuOuyZtysdU84du07M5kxwmCsQ0J5nRqqXaVdOYWCaCngkmgFHFNAsk 9kOu7OnVOMKWIo5ggMF4YugYN9Ncx2djlILzAVEYg3Plb6raxsIFpr8Hy6/pCv2f 7sZx/SqHljS+dORTReuXVWTMj3yKKsYEJHi5KU0KNnkZgai34tW1vgp1quPdEqLd W1hRUvK4jqIXrczUKVWNi8GgscsH21lBtizVbE/UJjCjAZSU5ruwnWTBJarnWWQ2 mDFkGpZJkIhMdfdRN9/DGDu/PM0PgQ== =n6vw -----END PGP SIGNATURE----- --FLCvvYgSpEeYmFbivSxsjklPfa7pwLN9Z--