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=-7.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, NICE_REPLY_A,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 B344FC433FE for ; Fri, 4 Dec 2020 07:48:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6919B2255F for ; Fri, 4 Dec 2020 07:48:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727452AbgLDHsP (ORCPT ); Fri, 4 Dec 2020 02:48:15 -0500 Received: from mout.gmx.net ([212.227.15.15]:37797 "EHLO mout.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726669AbgLDHsP (ORCPT ); Fri, 4 Dec 2020 02:48:15 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.net; s=badeba3b8450; t=1607068002; bh=4ouVk1YV4k5qoj34RwePLmzOCN7jUyTnaN5fk9R2CTQ=; h=X-UI-Sender-Class:Subject:To:Cc:References:From:Date:In-Reply-To; b=CE24v2o7gGrWMIiYNRa3GMHmrMVal3V5CoIpDfoEjFJrq+vfCpAoXWV2YT5uqMnCe jVpXYbwuUVh7Nwtm8lT0FY/Fur4KqMbKKY0MN/qwyhToJCglQjB643kbZITjO1CUrk TQ7AxVLH2jPgI+GPJ0X1uf71D2wf4Bx2EzeoGdSQ= 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 1MDhhN-1kvEnu0lYl-00AjHM; Fri, 04 Dec 2020 08:46:41 +0100 Subject: Re: [PATCH] btrfs: qgroup: don't commit transaction when we already hold the handle To: Nikolay Borisov , Qu Wenruo , linux-btrfs@vger.kernel.org Cc: Filipe Manana , David Sterba References: <20201204012448.26546-2-wqu@suse.com> <4fce0773-a0ba-4c74-0134-8bc22a95d23e@suse.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, 4 Dec 2020 15:46:37 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.12.0 MIME-Version: 1.0 In-Reply-To: <4fce0773-a0ba-4c74-0134-8bc22a95d23e@suse.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:klMP435mwLqYJ0s6pS/uzAtaNO0upkfNX4v5dHUii774MV5aBRD p6gwVDEgD/uu7oH5Reb/C34VZ5sL4oYmR6Ezh0w/F+qu3J5oORmjDnUZXwyTY7ig2WDvkDY wA7BzquMkn1BHmZCzANs7tEm92rqgBABdM4gmu+zmUgSlmFxDcVd1bWJM2qLc2luRfBxvfl xplCFvzrfov44HdFXh8LA== X-UI-Out-Filterresults: notjunk:1;V03:K0:s+LcHYpgVQU=:1cIjW10pUbLyIMMcN+xfat xsn2M1hXwjjcb6EgwstO8vUyqz768QIWuyvw+m1GxtTn1hDHO6LO2F+tiBGxENdXXw2pH+sLN NYcyKc1zQFJA6ta3hEuj029jlSCMIKFGScycXUTvxElazBalfKJHO9jGq2nvJ200mUmwsdbVk vVbgKnwqeD0KlvWeizjQOj235JzticALg/ONT2R/s9qEKoFbYC685c76lUwP4luYXX89XUFOV U7cGNYA6ZRgHKVi5L3G2TnUWHXS55pH21gYZU6pYP/tov11O425EMGjRnv6Eka4c65kZ8J6jQ +jTfG1WDMG77/ugFTl/sO6ifgOID41OvbwfWbWxbZCDHWwtMjALH1LUr7VNZ7CDKokC+nTRb6 T6Nvu5MVXmMTL072QVjH8WM2+PFak/UYSx2rRFJ6SowU+GP5Dh/QPcUqPC6MVMZIC62nD3AST 3sN1qmWJOsMBULabPANO+vbhsVRjWk4EnCGTaJhOrXRFBIee4CNR/wL0v1d6Hkn5crv6Q3GJZ 7Bb4NcuKsMoGnVKFnV2AZRwX/O/r2WTXE/58EpvL4oQc1Q336lgOZB3y99aVPCHfkq+dPLx8w adW7/zhIfiQeFcLwa6z//rFEqhRZlv/K/46+ijvgEouKhGJU0MK9bAU3oUPaUEaEMDxFj0aet Gh8a9Td/LkDUPoTBxAiAzBxevGaDqAIgtknr+mj0rTitcOWpaK1QGhmllV2K2H/14lMtI0JMw T43jlBjZa6JF2XS2tGlVPeUDr8+6/08o9QKmI8USNc56eWnLZ/NMFXLbkdaBW3iOF3cExIgur i28xzEowT1Cafa1IbUyFBK3rToBdHMFKZEsuMJyOrBt5n+1pAtXGC7QGjIoWSrUZXvangXxig OmeWQg0JERvqkTj/YVIw== Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On 2020/12/4 =E4=B8=8B=E5=8D=883:37, Nikolay Borisov wrote: > > > On 4.12.20 =D0=B3. 3:24 =D1=87., Qu Wenruo wrote: >> [BUG] >> When running the following script, btrfs will trigger an ASSERT(): >> >> #/bin/bash >> mkfs.btrfs -f $dev >> mount $dev $mnt >> xfs_io -f -c "pwrite 0 1G" $mnt/file >> sync >> btrfs quota enable $mnt >> btrfs quota rescan -w $mnt >> >> # Manually set the limit below current usage >> btrfs qgroup limit 512M $mnt $mnt >> >> # Crash happens >> touch $mnt/file >> >> The dmesg looks like this: >> >> assertion failed: refcount_read(&trans->use_count) =3D=3D 1, in fs/bt= rfs/transaction.c:2022 >> ------------[ cut here ]------------ >> kernel BUG at fs/btrfs/ctree.h:3230! >> invalid opcode: 0000 [#1] SMP PTI >> RIP: 0010:assertfail.constprop.0+0x18/0x1a [btrfs] >> btrfs_commit_transaction.cold+0x11/0x5d [btrfs] >> try_flush_qgroup+0x67/0x100 [btrfs] >> __btrfs_qgroup_reserve_meta+0x3a/0x60 [btrfs] >> btrfs_delayed_update_inode+0xaa/0x350 [btrfs] >> btrfs_update_inode+0x9d/0x110 [btrfs] >> btrfs_dirty_inode+0x5d/0xd0 [btrfs] >> touch_atime+0xb5/0x100 >> iterate_dir+0xf1/0x1b0 >> __x64_sys_getdents64+0x78/0x110 >> do_syscall_64+0x33/0x80 >> entry_SYSCALL_64_after_hwframe+0x44/0xa9 >> RIP: 0033:0x7fb5afe588db >> >> [CAUSE] >> In try_flush_qgroup(), we assume we don't hold a transaction handle at >> all. This is true for data reservation and mostly true for metadata. >> Since data space reservation always happens before we start a >> transaction, and for most metadata operation we reserve space in >> start_transaction(). >> >> But there is an exception, btrfs_delayed_inode_reserve_metadata(). >> It holds a transaction handle, while still trying to reserve extra >> metadata space. >> >> When we hit EDQUOT inside btrfs_delayed_inode_reserve_metadata(), we >> will join current transaction and commit, while we still have >> transaction handle from qgroup code. >> >> [FIX] >> Let's check current->journal before we join the transaction. >> >> If current->journal is unset or BTRFS_SEND_TRANS_STUB, it means >> we are not holding a transaction, thus are able to join and then commit >> transaction. >> >> If current->journal is a valid transaction handle, we avoid committing >> transaction and just end it >> >> This is less effective than committing current transaction, as it won't >> free metadata reserved space, but we may still free some data space >> before new data writes. >> >> Bugzilla: https://bugzilla.suse.com/show_bug.cgi?id=3D1178634 >> Fixes: c53e9653605d ("btrfs: qgroup: try to flush qgroup space when we = get -EDQUOT") >> Reviewed-by: Filipe Manana >> Signed-off-by: Qu Wenruo >> Signed-off-by: David Sterba > > Wasn't this submitted already? Also are you going to turn the example > script into a fstest? > Sorry, I forgot to cleanup my patches directory. (Facepalm The fstests is already submitted: https://patchwork.kernel.org/project/linux-btrfs/patch/20201111113152.1367= 29-1-wqu@suse.com/ Thanks, Qu