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=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 631DDC10F0E for ; Mon, 15 Apr 2019 09:03:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 24C1220693 for ; Mon, 15 Apr 2019 09:03:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=gmx.net header.i=@gmx.net header.b="N+6zM5wJ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726995AbfDOJDl (ORCPT ); Mon, 15 Apr 2019 05:03:41 -0400 Received: from mout.gmx.net ([212.227.17.22]:48507 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725796AbfDOJDl (ORCPT ); Mon, 15 Apr 2019 05:03:41 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.net; s=badeba3b8450; t=1555319016; bh=N9GIQ4JRr3L4LmFUW0R1uuP09eoizJbXqXHr1GJdWtQ=; h=X-UI-Sender-Class:Subject:To:Cc:References:From:Date:In-Reply-To; b=N+6zM5wJS2NIEM1fuOjYycE3AkUFR1V1AQAHJq4evBJygWA8h2lyaBMBv18J1QyCT bpRSlQz8hxCqvaHK4YgqG8KKov9lR8v/gELg/SCas+BQDRh9dMdfVlc7yJojM2GjEU wLT2ZCwK5irC8M3dh36TEqy06iqVZ/H719JMBk/s= X-UI-Sender-Class: 01bb95c1-4bf8-414a-932a-4f6e2808ef9c Received: from [0.0.0.0] ([210.140.77.29]) by mail.gmx.com (mrgmx101 [212.227.17.174]) with ESMTPSA (Nemesis) id 0LkTSx-1gjuxg30RP-00cN7n; Mon, 15 Apr 2019 11:03:36 +0200 Subject: Re: [PATCH] Btrfs: do not start a transaction during fiemap To: Filipe Manana Cc: linux-btrfs References: <20190415082900.2023-1-fdmanana@kernel.org> <3b22cc0c-7152-8345-e766-d439e9c34d00@gmx.com> From: Qu Wenruo Openpgp: preference=signencrypt Autocrypt: addr=quwenruo.btrfs@gmx.com; prefer-encrypt=mutual; keydata= mQENBFnVga8BCACyhFP3ExcTIuB73jDIBA/vSoYcTyysFQzPvez64TUSCv1SgXEByR7fju3o 8RfaWuHCnkkea5luuTZMqfgTXrun2dqNVYDNOV6RIVrc4YuG20yhC1epnV55fJCThqij0MRL 1NxPKXIlEdHvN0Kov3CtWA+R1iNN0RCeVun7rmOrrjBK573aWC5sgP7YsBOLK79H3tmUtz6b 9Imuj0ZyEsa76Xg9PX9Hn2myKj1hfWGS+5og9Va4hrwQC8ipjXik6NKR5GDV+hOZkktU81G5 gkQtGB9jOAYRs86QG/b7PtIlbd3+pppT0gaS+wvwMs8cuNG+Pu6KO1oC4jgdseFLu7NpABEB AAG0IlF1IFdlbnJ1byA8cXV3ZW5ydW8uYnRyZnNAZ214LmNvbT6JAVQEEwEIAD4CGwMFCwkI BwIGFQgJCgsCBBYCAwECHgECF4AWIQQt33LlpaVbqJ2qQuHCPZHzoSX+qAUCWdWCnQUJCWYC bgAKCRDCPZHzoSX+qAR8B/94VAsSNygx1C6dhb1u1Wp1Jr/lfO7QIOK/nf1PF0VpYjTQ2au8 ihf/RApTna31sVjBx3jzlmpy+lDoPdXwbI3Czx1PwDbdhAAjdRbvBmwM6cUWyqD+zjVm4RTG rFTPi3E7828YJ71Vpda2qghOYdnC45xCcjmHh8FwReLzsV2A6FtXsvd87bq6Iw2axOHVUax2 FGSbardMsHrya1dC2jF2R6n0uxaIc1bWGweYsq0LXvLcvjWH+zDgzYCUB0cfb+6Ib/ipSCYp 3i8BevMsTs62MOBmKz7til6Zdz0kkqDdSNOq8LgWGLOwUTqBh71+lqN2XBpTDu1eLZaNbxSI ilaVuQENBFnVga8BCACqU+th4Esy/c8BnvliFAjAfpzhI1wH76FD1MJPmAhA3DnX5JDORcga CbPEwhLj1xlwTgpeT+QfDmGJ5B5BlrrQFZVE1fChEjiJvyiSAO4yQPkrPVYTI7Xj34FnscPj /IrRUUka68MlHxPtFnAHr25VIuOS41lmYKYNwPNLRz9Ik6DmeTG3WJO2BQRNvXA0pXrJH1fN GSsRb+pKEKHKtL1803x71zQxCwLh+zLP1iXHVM5j8gX9zqupigQR/Cel2XPS44zWcDW8r7B0 q1eW4Jrv0x19p4P923voqn+joIAostyNTUjCeSrUdKth9jcdlam9X2DziA/DHDFfS5eq4fEv ABEBAAGJATwEGAEIACYWIQQt33LlpaVbqJ2qQuHCPZHzoSX+qAUCWdWBrwIbDAUJA8JnAAAK CRDCPZHzoSX+qA3xB/4zS8zYh3Cbm3FllKz7+RKBw/ETBibFSKedQkbJzRlZhBc+XRwF61mi f0SXSdqKMbM1a98fEg8H5kV6GTo62BzvynVrf/FyT+zWbIVEuuZttMk2gWLIvbmWNyrQnzPl mnjK4AEvZGIt1pk+3+N/CMEfAZH5Aqnp0PaoytRZ/1vtMXNgMxlfNnb96giC3KMR6U0E+siA 4V7biIoyNoaN33t8m5FwEwd2FQDG9dAXWhG13zcm9gnk63BN3wyCQR+X5+jsfBaS4dvNzvQv h8Uq/YGjCoV1ofKYh3WKMY8avjq25nlrhzD/Nto9jHp8niwr21K//pXVA81R2qaXqGbql+zo Message-ID: Date: Mon, 15 Apr 2019 17:03:32 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="8ktuN0OjXa5rJxEagnU7O6S94Xa7wvKnA" X-Provags-ID: V03:K1:R0yiAN3fOQOQvnA84nm5L181s686CHJEWUkyFYv+JtJsNzTOv9q SAfoalqR48+hQxufuFFR4u10W51dfddosbfbzq3EJMheQsHfYXJFUz78gg5DAmNV+eSL6Q2 fYLExlKOF9Do9rLC9RgzJ3oB6a2M7dWxzFivw51UmRy4Vn7txy76YSVurcnr2eqgoCJE07k 6wYosOdI4f1EFiZvpooqw== X-UI-Out-Filterresults: notjunk:1;V03:K0:Kk0w1pgT084=:lie3a5TYryUGFjdb/dK2uR +Mg+Y4VA2/9lj1TIqPj1QZQWPZehhqDnVlYi61WOG3BslGF5FfNwz7Uakwu7tRaC+ytB2WVBj QYAB3bf4mIjcf7JhFcW6NJ0mdgJWtruqBGovwXWsx3U+Kk6ET2MAf/aOVGDj/HHdC70NyQV8y dZ83FRjFFD1Bxi3AColJwFIP8Ai2CHgS0xDATTA2ptYFOG/7MHHwIfUzxblIO/hH7ZRtfqi1y WzNJAuDrVdwLF49qSroxqvDyUCUZmNgMB0rqCYURmglsKb1wJuX3j6zFVBWlBcoT9uUfFm02Z vu3yGKdR3OXasaX7aTo6uUsdmA9H3gDTn76p+73Huuf4HhX0Tr7w4jmw/SEaGDs5AUwy6dDis yFobQUQ+L0KeSEr7lBvbmB76Q7tCa3kv/JATZywdsBiOm9dhbGKFU4MPIJ0iO/l2Y+de4WjIB O3kph8H30x6bYmoKJqEQvOrsRzBfkKBolwhggeaPgAL4jptfIyw1YTdBsqWuw69B1bGvw06vp 4nYZxW1BXDb4j9CvBAbMBBazwxNKTvruQTDEsexRb/wpyjbeN8i77Wj3K8/SyPNlA+h8Ru1MY HORjYpMEvzENylKUcWMrEOFA7tVlPdYcFJlYJff2y6LL54tVmS+/2Gosj/JORkd6gYeP1FDqb 7TC+E8tD9ElhgQxghb8JIPgR94a++60PkEHN6sczjqcdvekVbYMhI07Gu2+PWFb5mPSwCU0MC OEzI+Dtb+oGXldz70mEkczJaK2NsYGOR/kslsqwf9kwCnzNmVfqKVvoyxL7KmHaVQ6dFtPC4a pcP0bIn0C25LoRSEinVuOravNkRDA0q4cUQ1oURK1l+maIznaWXgt69ZRAcfUH6zdIDhDRDsc KwACtVGaYUxcMaWjVZ9xCKhT2CCjfkjbv5MfhnHTN6xOoFFY2U4bzMFzkmS6Rr 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) --8ktuN0OjXa5rJxEagnU7O6S94Xa7wvKnA Content-Type: multipart/mixed; boundary="ulcMocJH37zA0vjZMXlNIlfoHqSfPqvlB"; protected-headers="v1" From: Qu Wenruo To: Filipe Manana Cc: linux-btrfs Message-ID: Subject: Re: [PATCH] Btrfs: do not start a transaction during fiemap References: <20190415082900.2023-1-fdmanana@kernel.org> <3b22cc0c-7152-8345-e766-d439e9c34d00@gmx.com> In-Reply-To: --ulcMocJH37zA0vjZMXlNIlfoHqSfPqvlB Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable [snip] >> >> My concern is, if at this timing there is no running transaction, so w= e >> continue with trans =3D=3D NULL. >> >> But before we continue, some one started a transaction and >> increased/decreased the extent reference number, this doesn't look as = safe. >=20 > So? >=20 > If an extent is not shared but right before btrfs_check_shared() > returns it becomes shared? We will report it as not shared. > It's the same type of "problem". Well, even if btrfs_check_shared() just return 1 no brain, it won't cause any problem. Just make nodatacow not that nodatacow. Reviewed-by: Qu Wenruo Thanks, Qu >=20 >> >> Or did I miss something? >> >> Thanks, >> Qu >>> trans =3D NULL; >>> down_read(&fs_info->commit_root_sem); >>> } else { >>> @@ -1523,6 +1527,7 @@ int btrfs_check_shared(struct btrfs_root *root,= u64 inum, u64 bytenr) >>> } else { >>> up_read(&fs_info->commit_root_sem); >>> } >>> +out: >>> ulist_free(tmp); >>> ulist_free(roots); >>> return ret; >>> >> --ulcMocJH37zA0vjZMXlNIlfoHqSfPqvlB-- --8ktuN0OjXa5rJxEagnU7O6S94Xa7wvKnA Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEELd9y5aWlW6idqkLhwj2R86El/qgFAly0SOQACgkQwj2R86El /qjCqAf/cMzyW9siVRTursrtNTWn3cSa5hG/w7qwH0sXCCG8eXiqE/xeAJJYRC4d bOEAqTpEFNq7bHKJivvdSZNEPHndikcKkdEXPP7owcCo41QMdO98mA12AZQg6u4u KpnhIZhp9gQaQ00yS9m8ASCNsjyBQez6gfuCTXCM2SxC3yrszyeOysDOT1i5u4F8 3gpzE+2gLnR9vSOJgCikDAqE+UyivkWX29/9qAR3Y3ZiHsP7B63XZeB/PtDIDpDB M06lU09eTptiMTONgugPzvlyrhwyFDSTmpc8/WRWt6BoIXktDdv+YavxZ/CEjwG4 VbRANK9uuSKVyeOCkTUVypdhQd20qA== =YDLd -----END PGP SIGNATURE----- --8ktuN0OjXa5rJxEagnU7O6S94Xa7wvKnA--