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=-8.0 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, URIBL_BLOCKED,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 1FB90C432C3 for ; Tue, 26 Nov 2019 05:00:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CB9BF20722 for ; Tue, 26 Nov 2019 05:00:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=gmx.net header.i=@gmx.net header.b="Er36ERUK" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725769AbfKZFAZ (ORCPT ); Tue, 26 Nov 2019 00:00:25 -0500 Received: from mout.gmx.net ([212.227.15.15]:37085 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725372AbfKZFAY (ORCPT ); Tue, 26 Nov 2019 00:00:24 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.net; s=badeba3b8450; t=1574744361; bh=K35Rcq3emrwL0Nwq87qkJss0qJNyBuAsWx3qB5DxAFM=; h=X-UI-Sender-Class:Subject:To:References:From:Date:In-Reply-To; b=Er36ERUKYf/63phSup/ZYx4L77odKEh7WV7iXpqe8ldtrMMaZ08wpWw9QOeFSRTSi DmTQHQ1eowjCZzjrGGWt6w22QaapJbhgJC5FAC0sfT46xOvt/joJbO4EMnqbx+FcIS UgFWioMtOHwk+A14u/bnfITTVk/I/J5LcTJ2D/iY= X-UI-Sender-Class: 01bb95c1-4bf8-414a-932a-4f6e2808ef9c Received: from [0.0.0.0] ([13.231.109.76]) by mail.gmx.com (mrgmx005 [212.227.17.184]) with ESMTPSA (Nemesis) id 1Mzyya-1hddnj0qCU-00wzQX; Tue, 26 Nov 2019 05:59:21 +0100 Subject: Re: [PATCH 3/4] btrfs: fix force usage in inc_block_group_ro To: Josef Bacik , linux-btrfs@vger.kernel.org, kernel-team@fb.com, wqu@suse.com References: <20191125144011.146722-1-josef@toxicpanda.com> <20191125144011.146722-4-josef@toxicpanda.com> <64dec4e1-a602-454c-e9d5-af8f39aaf97a@gmx.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: <38b1b3ab-abd3-57b0-c94a-178980d4dea5@gmx.com> Date: Tue, 26 Nov 2019 12:59:16 +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: <64dec4e1-a602-454c-e9d5-af8f39aaf97a@gmx.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="l5SimTX4qU7FBOG3oBZT3jg1cBTU7GFuO" X-Provags-ID: V03:K1:7b62EPqG/MLDBpO/Hi/Bq2nk+OUYsDR4qZpDumRR9xSU60XICJh MaKwOIE46qKLNTK8R0qxlu57+3oDk4zzG1MkPzhl5qp0/IPCHi5R/ov2HyJku/fflXUM+VX oHRDV6P2QtPTvOIj+iMy7aW1jSMb9huRiALOCzbpUC4da7HdivDrdMmbWgggMOsCf6mzYbK aQetbfhkKVttY4ZgK4HUA== X-UI-Out-Filterresults: notjunk:1;V03:K0:bv2XKd9aOQk=:VsPWGXOYGO4MAvhgAmW0bD UOd5F2WJ3ygMa2owddxkNKVfMn6x4dS73lmdOdz9i61FXFQsf+PL2Mu4owjKED14P06CaBdR7 K6sJqd9R9lNzdtk4tVGvD4YTTHMNvvGmFvK17BhPtyX1eFVMug2E+LWiVNhrgu+TR/8qY5RhJ uLhtAPYxBV91dEBQXBy4UGpaEogE9OQJHqYSAa3BT6Vwvx1LaqXF5XtCPWYJghG4RnS+CsS4B 2FFYDUOjPzXV0Bp4Q1w/Jkpo4ssrmZusqJoGroV1SQ3ZiCh7GY+bxZpB4BjyARBMXomTGe1xB bANEtzmK/gFYDa/VEf4ntSjc92S+c7S5tybMWUuJdQnNlDW1chfSQxwpyZYH1HyFU82u53s0g GePQYT6poSngHLA6e9nT+NvBAlaxurpMJzMGdlNaDWSQCJpJasvLn/5WHOb24jKCcw5PqnGMy upneCBYzlmJhivjujNj6TixfyugDqrkZoYtRvb/7bxm+HJ9XkF+2+3OtzPC4u+8vFlDvECw/k a/BcYEzGZkxmczaZ3vp/RQSdh6/mgUrFI+naBgtBken7KLO2vh/qh+R8dbq/qytHyvXyGjahX MqnR5B3e7QnF3P6WLYPzWFYa46Ome1YBJvopH2gBdcet96bF/rYTedBhMjTITl09LwhF0v90Q Vf4suHoOasGO2e50UACIDZsp6iq2doztb69zPEoXN73PXcOEhCuyxOqUwRMd41EgrKifTpJIr bT15T+EUaPEuj+Gc9e7KtoEvk7JDYXrJ0bexQoGjkTI8CH5T67ucO6HYWAv7sWZj94EVrlgch ukFydYJh1c6A1ySrAEi9ydZt+bUJ8vXVuS15jCyrvf0gN0wCo9VwQibtqSrFg/4chAlkv4duO akvYQQezvYCqhdcLKjd2n5jbLEzPvANAuwrdQ/yZqMdyO1+0zcHEKF3rEb7j37ZMQMyJKLpYu GnUHAikKbJxJGyERFUeLP7fjty6ILpaTCHLhNq0iUPhcN+QAIe3VnlcXlbyAq/CBGqk+aJtml Ekhs8ExY0AXcpcXb8TdbgE7E145kCrgmHZt7Bchxfc+Du50L+zOnXsQc0YiNG5VO1PC9MHK7P xkHeNxTh1D1UT9ioE2kwbuGRXV1GaDo7AO+P8HvHxav0PnsUo+wS94OWxe6ReJbvQ0/B1VMqI DjjzjisTByl5BTGobQrGMBvGUF8lw7/x+LsGq4Wod3Z07FYze3pbjvhCcAdRvX6Nn7eqXZMvF vpoOKD6xNjNqxfo+ng8CMQzi7OmujC7E08K0Ji9FcK7inHUy4/U4BnCMKDHQ= 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) --l5SimTX4qU7FBOG3oBZT3jg1cBTU7GFuO Content-Type: multipart/mixed; boundary="OoCyMymmfTCFqM2RLdKpMBp3oXZMSPjjo" --OoCyMymmfTCFqM2RLdKpMBp3oXZMSPjjo Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 2019/11/26 =E4=B8=8A=E5=8D=8810:43, Qu Wenruo wrote: >=20 >=20 > On 2019/11/25 =E4=B8=8B=E5=8D=8810:40, Josef Bacik wrote: >> For some reason we've translated the do_chunk_alloc that goes into >> btrfs_inc_block_group_ro to force in inc_block_group_ro, but these are= >> two different things. >> >> force for inc_block_group_ro is used when we are forcing the block gro= up >> read only no matter what, for example when the underlying chunk is >> marked read only. We need to not do the space check here as this bloc= k >> group needs to be read only. >> >> btrfs_inc_block_group_ro() has a do_chunk_alloc flag that indicates th= at >> we need to pre-allocate a chunk before marking the block group read >> only. This has nothing to do with forcing, and in fact we _always_ wa= nt >> to do the space check in this case, so unconditionally pass false for >> force in this case. >=20 > I think the patch order makes thing a little hard to grasp here. > Without the last patch, the idea itself is not correct. >=20 > The reason to force ro is because we want to avoid empty chunk to be > allocated, especially for scrub case. >=20 >=20 > If you put the last patch before this one, it's more clear, as then we > can accept over-commit, we won't return false ENOSPC and no empty chunk= > created. >=20 > BTW, with the last patch applied, we can remove that @force parameter > for inc_block_group_ro(). My bad, @force parameter is still needed. Didn't notice that until all patches applied. Thanks, Qu >=20 > Thanks, > Qu >> >> Then fixup inc_block_group_ro to honor force as it's expected and >> documented to do. >> >> Signed-off-by: Josef Bacik >> --- >> fs/btrfs/block-group.c | 6 ++++-- >> 1 file changed, 4 insertions(+), 2 deletions(-) >> >> diff --git a/fs/btrfs/block-group.c b/fs/btrfs/block-group.c >> index db539bfc5a52..3ffbc2e0af21 100644 >> --- a/fs/btrfs/block-group.c >> +++ b/fs/btrfs/block-group.c >> @@ -1190,8 +1190,10 @@ static int inc_block_group_ro(struct btrfs_bloc= k_group *cache, int force) >> spin_lock(&sinfo->lock); >> spin_lock(&cache->lock); >> =20 >> - if (cache->ro) { >> + if (cache->ro || force) { >> cache->ro++; >> + if (list_empty(&cache->ro_list)) >> + list_add_tail(&cache->ro_list, &sinfo->ro_bgs); >> ret =3D 0; >> goto out; >> } >> @@ -2063,7 +2065,7 @@ int btrfs_inc_block_group_ro(struct btrfs_block_= group *cache, >> } >> } >> =20 >> - ret =3D inc_block_group_ro(cache, !do_chunk_alloc); >> + ret =3D inc_block_group_ro(cache, false); >> if (!do_chunk_alloc) >> goto unlock_out; >> if (!ret) >> >=20 --OoCyMymmfTCFqM2RLdKpMBp3oXZMSPjjo-- --l5SimTX4qU7FBOG3oBZT3jg1cBTU7GFuO Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEELd9y5aWlW6idqkLhwj2R86El/qgFAl3csSQACgkQwj2R86El /qjAYwf+JTxQQotEE8yR2n6Ev5OwS04IXLlcdr7fb1cG7r2P70hlMKch50cQqujb 6b/Tp9lKolOJbbpZiVlLLWzdTPV93uKp5U0hl5ooi6Il+NtVvWdO1rfdDlFsiNzg XIqpEIIWbt2NOoJlQRIiLngc5Ajd8ZTEf5p/PTIj5EXkBP/EzTdZPFhZBVUh2Ptv zU09+s7siGeh/CNqGDxQqS18hyHMwe/1T4uNQ0ph5o2t0QYI8Ah8D9460/0puuvy YFhWrsD2TUWZlWKdVjhc52AGrL2gg7gesmUF0RM9KNLm5DpJGrt5S59MUXZxQ7/A XQZGqFAN0/XEB7MZU+KCHtZDjlSxPg== =JHKM -----END PGP SIGNATURE----- --l5SimTX4qU7FBOG3oBZT3jg1cBTU7GFuO--