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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9C0EECD3425 for ; Tue, 19 Sep 2023 00:37:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230333AbjISAh0 (ORCPT ); Mon, 18 Sep 2023 20:37:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55704 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229508AbjISAhY (ORCPT ); Mon, 18 Sep 2023 20:37:24 -0400 Received: from mout.gmx.net (mout.gmx.net [212.227.15.18]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 46AD98E; Mon, 18 Sep 2023 17:37:18 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.com; s=s31663417; t=1695083826; x=1695688626; i=quwenruo.btrfs@gmx.com; bh=Vsshq0J5dMVAnGNx93Po1CDB8savgZn4lYGAa8RnC3M=; h=X-UI-Sender-Class:Date:Subject:To:Cc:References:From:In-Reply-To; b=TfEO55ZudSqHvAlSCHo1iDTpq+Us6R53lArvR9/btjK7Mr5emwC4VWPSp1XHhwDc+An3Us5UtTC ROFMh1eIDWkFPT8srN6kicG9F4+KgvgGudRM30wio2J8QRyWwBOCDg5YMhvRDjL7fg6zO33szAMEU XRlig5u2bL6RjBzNEau8jWNBhqFFjeg6Fv0g4SMs95AoMJevHOOJRJAL6HsehtDsSmgwZSskfhtl0 rtfdSLcFzb6VtgV1ueek1hEBvM4l64VW3OAchCoSd6mgs6unx3jf4t3OBv0D6G+vrq0Gd6qFM0jCV fZydILUDs9LRW/JHC36TfTtCSd7cyOsmfO0A== X-UI-Sender-Class: 724b4f7f-cbec-4199-ad4e-598c01a50d3a Received: from [172.16.0.117] ([218.215.59.251]) by mail.gmx.net (mrgmx004 [212.227.17.184]) with ESMTPSA (Nemesis) id 1MbRk3-1rFWZ63laj-00btlu; Tue, 19 Sep 2023 02:37:06 +0200 Message-ID: Date: Tue, 19 Sep 2023 10:07:00 +0930 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/4] btrfs: fix 64bit division in btrfs_insert_striped_mirrored_raid_extents Content-Language: en-US To: dsterba@suse.cz, Johannes Thumshirn Cc: Geert Uytterhoeven , Chris Mason , Josef Bacik , David Sterba , Qu Wenru , "linux-btrfs@vger.kernel.org" , "linux-kernel@vger.kernel.org" References: <20230918-rst-updates-v1-0-17686dc06859@wdc.com> <20230918-rst-updates-v1-1-17686dc06859@wdc.com> <20230918162448.GI2747@suse.cz> From: Qu Wenruo Autocrypt: addr=quwenruo.btrfs@gmx.com; keydata= xsBNBFnVga8BCACyhFP3ExcTIuB73jDIBA/vSoYcTyysFQzPvez64TUSCv1SgXEByR7fju3o 8RfaWuHCnkkea5luuTZMqfgTXrun2dqNVYDNOV6RIVrc4YuG20yhC1epnV55fJCThqij0MRL 1NxPKXIlEdHvN0Kov3CtWA+R1iNN0RCeVun7rmOrrjBK573aWC5sgP7YsBOLK79H3tmUtz6b 9Imuj0ZyEsa76Xg9PX9Hn2myKj1hfWGS+5og9Va4hrwQC8ipjXik6NKR5GDV+hOZkktU81G5 gkQtGB9jOAYRs86QG/b7PtIlbd3+pppT0gaS+wvwMs8cuNG+Pu6KO1oC4jgdseFLu7NpABEB AAHNIlF1IFdlbnJ1byA8cXV3ZW5ydW8uYnRyZnNAZ214LmNvbT7CwJQEEwEIAD4CGwMFCwkI BwIGFQgJCgsCBBYCAwECHgECF4AWIQQt33LlpaVbqJ2qQuHCPZHzoSX+qAUCY00iVQUJDToH pgAKCRDCPZHzoSX+qNKACACkjDLzCvcFuDlgqCiS4ajHAo6twGra3uGgY2klo3S4JespWifr BLPPak74oOShqNZ8yWzB1Bkz1u93Ifx3c3H0r2vLWrImoP5eQdymVqMWmDAq+sV1Koyt8gXQ XPD2jQCrfR9nUuV1F3Z4Lgo+6I5LjuXBVEayFdz/VYK63+YLEAlSowCF72Lkz06TmaI0XMyj jgRNGM2MRgfxbprCcsgUypaDfmhY2nrhIzPUICURfp9t/65+/PLlV4nYs+DtSwPyNjkPX72+ LdyIdY+BqS8cZbPG5spCyJIlZonADojLDYQq4QnufARU51zyVjzTXMg5gAttDZwTH+8LbNI4 mm2YzsBNBFnVga8BCACqU+th4Esy/c8BnvliFAjAfpzhI1wH76FD1MJPmAhA3DnX5JDORcga CbPEwhLj1xlwTgpeT+QfDmGJ5B5BlrrQFZVE1fChEjiJvyiSAO4yQPkrPVYTI7Xj34FnscPj /IrRUUka68MlHxPtFnAHr25VIuOS41lmYKYNwPNLRz9Ik6DmeTG3WJO2BQRNvXA0pXrJH1fN GSsRb+pKEKHKtL1803x71zQxCwLh+zLP1iXHVM5j8gX9zqupigQR/Cel2XPS44zWcDW8r7B0 q1eW4Jrv0x19p4P923voqn+joIAostyNTUjCeSrUdKth9jcdlam9X2DziA/DHDFfS5eq4fEv ABEBAAHCwHwEGAEIACYCGwwWIQQt33LlpaVbqJ2qQuHCPZHzoSX+qAUCY00ibgUJDToHvwAK CRDCPZHzoSX+qK6vB/9yyZlsS+ijtsvwYDjGA2WhVhN07Xa5SBBvGCAycyGGzSMkOJcOtUUf tD+ADyrLbLuVSfRN1ke738UojphwkSFj4t9scG5A+U8GgOZtrlYOsY2+cG3R5vjoXUgXMP37 INfWh0KbJodf0G48xouesn08cbfUdlphSMXujCA8y5TcNyRuNv2q5Nizl8sKhUZzh4BascoK DChBuznBsucCTAGrwPgG4/ul6HnWE8DipMKvkV9ob1xJS2W4WJRPp6QdVrBWJ9cCdtpR6GbL iQi22uZXoSPv/0oUrGU+U5X4IvdnvT+8viPzszL5wXswJZfqfy8tmHM85yjObVdIG6AlnrrD In-Reply-To: <20230918162448.GI2747@suse.cz> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:g6wU1E3eS03p7ukyt5DQ8Th6LKa0MjsAkw+cckrqx+z84LW+Cf9 W2sqJ1phYSxbJgtjD69fX4/mTxE9fgGUHVEPCaj3bMh+JOWCbFXgl9GhFMpmBiNMVmvGnRV D70/OIA6FTHRMyM3BZrHHLWNgNB+QSWwYB3ysYpMkQ84MOkYPwuE5iIhm7oPY2YXOekHUt1 oKaxaMua3aceD+i6+m1MA== UI-OutboundReport: notjunk:1;M01:P0:K3fp69p0tcc=;Xmdc9S+tM46YMzT2cyKrbc0vB3E 0eLjhZpNqcoi/nCWNmFT3aqvfblCSBCfYc3KK/DK8iGDSPRd7eA7Dcsc8ufAzBu0tpvU0tY79 UtI7MHWn7lWQCfL1fkQm/nGubWYwGgpWrtlhqD9WJcVgBee/jyd6a0COHHYjMBW2TXUeH06mn 2AlINejkLfWP/zZ+V6KYsrcIDXqKVK7HbV5Zc3UQseGRWkxk/S4rJDiep1QB63vttUfKjbPkp BsTFOlnQQ3+rO+GQC3+NTm2P2gDX0JIaFefJTPvdCvDMBrF00wCxmgmSNDa2I+g75X5IGby/2 LKsGYHXzUoFWPwMpvjgvARgc9oTVqVIyDkj/BMyz2JpbgL4RFUHLPof1asFt9Rr0zvDFqvJDJ 83ah2ZxEO/bqYievVp2Emus6nnnH1c+oOTXuH+hqKihlZeoplzfk7rRp7xSyvoWn9PhrADl1n 4RObNPaf5YXWwKmYgJ1kVqbUQFosB+B1PMb2aOk7Y2iy/s7wM+v0KVxIWzaav2C+sIL56ln8c 3WsDqOsq2hsW/1J5oLEyPugHaYfkwAT7IP9HkHxoR+aXYVxw6Gy33GCCPLIrc4CgEdLz8NYhE XyirNGLuRKZbY/9mUinjJ1S3eoQXk4x50f+lhrgziL0gwvOk7q/PJ3ZygwzCQVTDq+ZrtPhJS aWCzoGiSnqLCx+u1RCh+TqxFRt/XrZRzAgIrIgoyo2dW1G4C2nJFla7RDDTmhy+g/54OeHmVZ mv0ecA1lc9ZAXrjn8Jm97B8ZaCxcpJmvPYyNh4+h/RURvkwKS+InEY/Opj/4oJh8BgfKJ5hqe 8AphwxZlWX2WtWLHWGEwbSviIz6V3WjQ4EqlWYd4+21DaH2ST7ZVgHStFeqKcEdFUc6weaqIj QSOkQohTi5bXa0wChD4nd3WVJjxOegXOp/eDRc1GXtg1k9xeaOFXFC0elOSqbqAHDh6sviyOU KbV12jbH98qiiyP9j988i0GlgC8= Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2023/9/19 01:54, David Sterba wrote: > On Mon, Sep 18, 2023 at 03:03:10PM +0000, Johannes Thumshirn wrote: >> On 18.09.23 16:19, Geert Uytterhoeven wrote: >>> Hi Johannes, >>> >>> On Mon, Sep 18, 2023 at 4:14=E2=80=AFPM Johannes Thumshirn >>> wrote: >>>> Fix modpost error due to 64bit division on 32bit systems in >>>> btrfs_insert_striped_mirrored_raid_extents. >>>> >>>> Cc: Geert Uytterhoeven >>>> Signed-off-by: Johannes Thumshirn >>> >>> Thanks for your patch! >>> >>>> --- a/fs/btrfs/raid-stripe-tree.c >>>> +++ b/fs/btrfs/raid-stripe-tree.c >>>> @@ -148,10 +148,10 @@ static int btrfs_insert_striped_mirrored_raid_e= xtents( >>>> { >>>> struct btrfs_io_context *bioc; >>>> struct btrfs_io_context *rbioc; >>>> - const int nstripes =3D list_count_nodes(&ordered->bioc_list); >>>> - const int index =3D btrfs_bg_flags_to_raid_index(map_type); >>>> - const int substripes =3D btrfs_raid_array[index].sub_stripes; >>>> - const int max_stripes =3D trans->fs_info->fs_devices->rw_devi= ces / substripes; >>>> + const size_t nstripes =3D list_count_nodes(&ordered->bioc_lis= t); >>>> + const enum btrfs_raid_types index =3D btrfs_bg_flags_to_raid_= index(map_type); >>>> + const u8 substripes =3D btrfs_raid_array[index].sub_stripes; >>>> + const int max_stripes =3D div_u64(trans->fs_info->fs_devices-= >rw_devices, substripes); >>> >>> What if the quotient does not fit in a signed 32-bit value? >> >> Then you've bought a lot of HDDs ;-) >> >> Jokes aside, yes this is theoretically correct. Dave can you fix >> max_stripes up to be u64 when applying? > > I think we can keep it int, or unsigned int if needed, we can't hit such > huge values for rw_devices. The 'theoretically' would fit for a machine > with infinite resources, otherwise the maximum number of devices I'd > expect is a few thousand. In fact, we already have an check in btrfs_validate_super(), if the num_devices is over 1<<31, we would reject the fs. I think we should be safe to further reduce the threshold. U16_MAX sounds a valid and sane value to me. If no rejection I can send out a patch for this. And later change internal rw_devices/num_devices to u16. Thanks, Qu