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=-16.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 61784C12002 for ; Mon, 19 Jul 2021 08:47:29 +0000 (UTC) Received: from lists.sourceforge.net (lists.sourceforge.net [216.105.38.7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 0F4C361009 for ; Mon, 19 Jul 2021 08:47:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0F4C361009 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linux-f2fs-devel-bounces@lists.sourceforge.net Received: from [127.0.0.1] (helo=sfs-ml-2.v29.lw.sourceforge.com) by sfs-ml-2.v29.lw.sourceforge.com with esmtp (Exim 4.92.3) (envelope-from ) id 1m5Ovw-0005fr-Hj; Mon, 19 Jul 2021 08:47:28 +0000 Received: from [172.30.20.202] (helo=mx.sourceforge.net) by sfs-ml-2.v29.lw.sourceforge.com with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.92.3) (envelope-from ) id 1m5Ovh-0005fO-6Q for linux-f2fs-devel@lists.sourceforge.net; Mon, 19 Jul 2021 08:47:13 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sourceforge.net; s=x; h=Content-Transfer-Encoding:MIME-Version:Message-Id: Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:In-Reply-To:References:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=n52Xd09uF7fVdydjYwLQFSvpBzzcRbr2FEtcULwVcrA=; b=VR1DEOr3+Y31PlPqYE7EhIjdkr MBTFHPAM8QRCEuB12YezfIg/LBxL/4qr1fzqqCQo6YUBrychfJ+qFFIedLF0NdCNVJc/w/axGjMYU M2IZn7vVt7Rr736XC1nlThdsbD9V8k86hvC2/gLX1GazC8VIgqBEplT/XKk5CSgOlk1E=; DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sf.net; s=x ; h=Content-Transfer-Encoding:MIME-Version:Message-Id:Date:Subject:Cc:To:From :Sender:Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To: References:List-Id:List-Help:List-Unsubscribe:List-Subscribe:List-Post: List-Owner:List-Archive; bh=n52Xd09uF7fVdydjYwLQFSvpBzzcRbr2FEtcULwVcrA=; b=e oNrSvVp7Lq/7RNsbFPr9nL59zXMaTmmqozHClFbBvnzoIhWDq45+5IR6rC4DqXrClnoIEaROQXMBG b7cRikayEUrPKUwruWDWxWxMF98TF3+x1UzL6yklELanyWqharEZjuYcFJkYrkaUV0jSLeeLAO+5V wvn3mM9gGA2B4SHc=; Received: from mail.kernel.org ([198.145.29.99]) by sfi-mx-2.v28.lw.sourceforge.com with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.92.3) id 1m5OvX-0004Es-6s for linux-f2fs-devel@lists.sourceforge.net; Mon, 19 Jul 2021 08:47:12 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id CC18161205; Mon, 19 Jul 2021 08:46:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1626684417; bh=daX8Yahq0WHsytcdNmcklqy9cMfNwPouHchyxbatIqk=; h=From:To:Cc:Subject:Date:From; b=fbhXbIYe3RLIcA2Fjxut4c4qG/Dr90fmT936dW2yYUqK5V0J9ZtwOUO9JYPbo+4CC 9LcQVrrQiurES9hzqdkdzpZ9gC9PsZTH8H8RgvNyeCJxOr9Xjb5NiTIvw+ELwpYbEX ziEpEAkuu86WjUiA/UcMWHVWiRyBI9ZYXybcZJ9UIHv1NQ9jeZGmvdyQlo7EeKYN+G K6BXrCaxfX826tcppzNyEur+huMlTmtEEGrkjApgRDBmN24BtQ5SHsC4v1v/9scWUV 2sJxHPkuTl897f6pMD0STky0zClnPRzpQUa36FT7/Zyh8aMQEodgeqyhPrlBYZs+ii HX/sGUOfa8Cyg== From: Chao Yu To: jaegeuk@kernel.org Date: Mon, 19 Jul 2021 16:46:47 +0800 Message-Id: <20210719084647.26027-1-chao@kernel.org> X-Mailer: git-send-email 2.22.1 MIME-Version: 1.0 X-Headers-End: 1m5OvX-0004Es-6s Subject: [f2fs-dev] [PATCH] f2fs: quota: fix potential deadlock X-BeenThere: linux-f2fs-devel@lists.sourceforge.net X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Chao Yu , linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net xfstest generic/587 reports a deadlock issue as below: ====================================================== WARNING: possible circular locking dependency detected 5.14.0-rc1 #69 Not tainted ------------------------------------------------------ repquota/8606 is trying to acquire lock: ffff888022ac9320 (&sb->s_type->i_mutex_key#18){+.+.}-{3:3}, at: f2fs_quota_sync+0x207/0x300 [f2fs] but task is already holding lock: ffff8880084bcde8 (&sbi->quota_sem){.+.+}-{3:3}, at: f2fs_quota_sync+0x59/0x300 [f2fs] which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&sbi->quota_sem){.+.+}-{3:3}: __lock_acquire+0x648/0x10b0 lock_acquire+0x128/0x470 down_read+0x3b/0x2a0 f2fs_quota_sync+0x59/0x300 [f2fs] f2fs_quota_on+0x48/0x100 [f2fs] do_quotactl+0x5e3/0xb30 __x64_sys_quotactl+0x23a/0x4e0 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae -> #1 (&sbi->cp_rwsem){++++}-{3:3}: __lock_acquire+0x648/0x10b0 lock_acquire+0x128/0x470 down_read+0x3b/0x2a0 f2fs_unlink+0x353/0x670 [f2fs] vfs_unlink+0x1c7/0x380 do_unlinkat+0x413/0x4b0 __x64_sys_unlinkat+0x50/0xb0 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae -> #0 (&sb->s_type->i_mutex_key#18){+.+.}-{3:3}: check_prev_add+0xdc/0xb30 validate_chain+0xa67/0xb20 __lock_acquire+0x648/0x10b0 lock_acquire+0x128/0x470 down_write+0x39/0xc0 f2fs_quota_sync+0x207/0x300 [f2fs] do_quotactl+0xaff/0xb30 __x64_sys_quotactl+0x23a/0x4e0 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae other info that might help us debug this: Chain exists of: &sb->s_type->i_mutex_key#18 --> &sbi->cp_rwsem --> &sbi->quota_sem Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&sbi->quota_sem); lock(&sbi->cp_rwsem); lock(&sbi->quota_sem); lock(&sb->s_type->i_mutex_key#18); *** DEADLOCK *** 3 locks held by repquota/8606: #0: ffff88801efac0e0 (&type->s_umount_key#53){++++}-{3:3}, at: user_get_super+0xd9/0x190 #1: ffff8880084bc380 (&sbi->cp_rwsem){++++}-{3:3}, at: f2fs_quota_sync+0x3e/0x300 [f2fs] #2: ffff8880084bcde8 (&sbi->quota_sem){.+.+}-{3:3}, at: f2fs_quota_sync+0x59/0x300 [f2fs] stack backtrace: CPU: 6 PID: 8606 Comm: repquota Not tainted 5.14.0-rc1 #69 Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006 Call Trace: dump_stack_lvl+0xce/0x134 dump_stack+0x17/0x20 print_circular_bug.isra.0.cold+0x239/0x253 check_noncircular+0x1be/0x1f0 check_prev_add+0xdc/0xb30 validate_chain+0xa67/0xb20 __lock_acquire+0x648/0x10b0 lock_acquire+0x128/0x470 down_write+0x39/0xc0 f2fs_quota_sync+0x207/0x300 [f2fs] do_quotactl+0xaff/0xb30 __x64_sys_quotactl+0x23a/0x4e0 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f883b0b4efe The root cause is ABBA deadlock of inode lock and cp_rwsem, reorder locks in f2fs_quota_sync() as below to fix this issue: - lock inode - lock cp_rwsem - lock quota_sem Fixes: db6ec53b7e03 ("f2fs: add a rw_sem to cover quota flag changes") Signed-off-by: Chao Yu --- fs/f2fs/super.c | 84 ++++++++++++++++++++++++++++--------------------- 1 file changed, 48 insertions(+), 36 deletions(-) diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c index 8fecd3050ccd..72eb9d70969f 100644 --- a/fs/f2fs/super.c +++ b/fs/f2fs/super.c @@ -2518,6 +2518,33 @@ static int f2fs_enable_quotas(struct super_block *sb) return 0; } +static int f2fs_quota_sync_file(struct f2fs_sb_info *sbi, int type) +{ + struct quota_info *dqopt = sb_dqopt(sbi->sb); + struct address_space *mapping = dqopt->files[type]->i_mapping; + int ret = 0; + + ret = dquot_writeback_dquots(sbi->sb, type); + if (ret) + goto out; + + ret = filemap_fdatawrite(mapping); + if (ret) + goto out; + + /* if we are using journalled quota */ + if (is_journalled_quota(sbi)) + goto out; + + ret = filemap_fdatawait(mapping); + + truncate_inode_pages(&dqopt->files[type]->i_data, 0); +out: + if (ret) + set_sbi_flag(sbi, SBI_QUOTA_NEED_REPAIR); + return ret; +} + int f2fs_quota_sync(struct super_block *sb, int type) { struct f2fs_sb_info *sbi = F2FS_SB(sb); @@ -2525,57 +2552,42 @@ int f2fs_quota_sync(struct super_block *sb, int type) int cnt; int ret; - /* - * do_quotactl - * f2fs_quota_sync - * down_read(quota_sem) - * dquot_writeback_dquots() - * f2fs_dquot_commit - * block_operation - * down_read(quota_sem) - */ - f2fs_lock_op(sbi); - - down_read(&sbi->quota_sem); - ret = dquot_writeback_dquots(sb, type); - if (ret) - goto out; - /* * Now when everything is written we can discard the pagecache so * that userspace sees the changes. */ for (cnt = 0; cnt < MAXQUOTAS; cnt++) { - struct address_space *mapping; if (type != -1 && cnt != type) continue; - if (!sb_has_quota_active(sb, cnt)) - continue; - mapping = dqopt->files[cnt]->i_mapping; + if (!sb_has_quota_active(sb, type)) + return 0; - ret = filemap_fdatawrite(mapping); - if (ret) - goto out; + inode_lock(dqopt->files[cnt]); - /* if we are using journalled quota */ - if (is_journalled_quota(sbi)) - continue; + /* + * do_quotactl + * f2fs_quota_sync + * down_read(quota_sem) + * dquot_writeback_dquots() + * f2fs_dquot_commit + * block_operation + * down_read(quota_sem) + */ + f2fs_lock_op(sbi); + down_read(&sbi->quota_sem); - ret = filemap_fdatawait(mapping); - if (ret) - set_sbi_flag(F2FS_SB(sb), SBI_QUOTA_NEED_REPAIR); + ret = f2fs_quota_sync_file(sbi, cnt); + + up_read(&sbi->quota_sem); + f2fs_unlock_op(sbi); - inode_lock(dqopt->files[cnt]); - truncate_inode_pages(&dqopt->files[cnt]->i_data, 0); inode_unlock(dqopt->files[cnt]); + + if (ret) + break; } -out: - if (ret) - set_sbi_flag(F2FS_SB(sb), SBI_QUOTA_NEED_REPAIR); - up_read(&sbi->quota_sem); - f2fs_unlock_op(sbi); return ret; } -- 2.22.1 _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel