From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from szxga08-in.huawei.com (szxga08-in.huawei.com [45.249.212.255]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C61DD182D9 for ; Fri, 10 Jan 2025 01:44:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.255 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736473489; cv=none; b=P7el6w82slQ2aqA3NYpDw/Tm6WgIj8K4YQckK0oequaYs4NxYRlpeiR/iXNzDLv0vpBYGPWx9gMlPTXFh6RHUjN1+CMyyJkF65GAPCJhqeijTySIE36Yff11FK3M1TckVZaMoOaHROeKBfxcwkggcaZNodPPshM8tcE+9IpaZ3E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736473489; c=relaxed/simple; bh=svLML4wMWWwv1AigsewckX5rfi3s5X1cifxe805bbTA=; h=Date:From:To:CC:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=lJuWBGgr2UBnHrO9xnUkATMZMf8J4D64BPi37BAjldb0bTXjkB39u+3iyugajiBZB10hMXBmm7BnzPNGIScIPhjLS5tuF/1OmopGdqyf980ZMZrQM52s7XzDXIhMJBQpvjB4RA1z4/KNTYqsDjVLepljkIL8ZFroAkAV0SCvqOI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=45.249.212.255 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.19.163.252]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4YTkrV6plbz1W3t6; Fri, 10 Jan 2025 09:40:58 +0800 (CST) Received: from dggpemf500017.china.huawei.com (unknown [7.185.36.126]) by mail.maildlp.com (Postfix) with ESMTPS id D51D41800D1; Fri, 10 Jan 2025 09:44:42 +0800 (CST) Received: from localhost (10.175.112.188) by dggpemf500017.china.huawei.com (7.185.36.126) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.11; Fri, 10 Jan 2025 09:44:42 +0800 Date: Fri, 10 Jan 2025 09:40:15 +0800 From: Long Li To: "Darrick J. Wong" CC: , , , , , , Subject: Re: [PATCH v2] xfs: fix mount hang during primary superblock recovery failure Message-ID: References: <20250109021320.429625-1-leo.lilong@huawei.com> <20250109044142.GM1306365@frogsfrogsfrogs> Precedence: bulk X-Mailing-List: linux-xfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Disposition: inline In-Reply-To: <20250109044142.GM1306365@frogsfrogsfrogs> X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To dggpemf500017.china.huawei.com (7.185.36.126) On Wed, Jan 08, 2025 at 08:41:42PM -0800, Darrick J. Wong wrote: > On Thu, Jan 09, 2025 at 10:13:20AM +0800, Long Li wrote: > > When mounting an image containing a log with sb modifications that require > > log replay, the mount process hang all the time and stack as follows: > > > > [root@localhost ~]# cat /proc/557/stack > > [<0>] xfs_buftarg_wait+0x31/0x70 > > [<0>] xfs_buftarg_drain+0x54/0x350 > > [<0>] xfs_mountfs+0x66e/0xe80 > > [<0>] xfs_fs_fill_super+0x7f1/0xec0 > > [<0>] get_tree_bdev_flags+0x186/0x280 > > [<0>] get_tree_bdev+0x18/0x30 > > [<0>] xfs_fs_get_tree+0x1d/0x30 > > [<0>] vfs_get_tree+0x2d/0x110 > > [<0>] path_mount+0xb59/0xfc0 > > [<0>] do_mount+0x92/0xc0 > > [<0>] __x64_sys_mount+0xc2/0x160 > > [<0>] x64_sys_call+0x2de4/0x45c0 > > [<0>] do_syscall_64+0xa7/0x240 > > [<0>] entry_SYSCALL_64_after_hwframe+0x76/0x7e > > > > During log recovery, while updating the in-memory superblock from the > > primary SB buffer, if an error is encountered, such as superblock > > corruption occurs or some other reasons, we will proceed to out_release > > and release the xfs_buf. However, this is insufficient because the > > xfs_buf's log item has already been initialized and the xfs_buf is held > > by the buffer log item as follows, the xfs_buf will not be released, > > causing the mount thread to hang. > > Can you post a regression test for us, pretty please? :) > I performed regression testing by mounting specific images that can be obtained through fault injection on kernels without metadir feature support. I can provide it if anyone needs it.The image is big and inconvenient to send in the mail. The detailed steps are as follows: 1) Kernel Build - The latest realtime AG update bug [1] remains unfixed - Build kernel without CONFIG_XFS_RT 2) Mount XFS Image (superblock needs replay, incompatible with metadir and no realtime subvolume) 3) Mount Result Verification - Without the current patch: mount thread hangs indefinitely - With the current patch: mount thread does not hang, but XFS is shut down The xfstests already have the fault injection test, and this test requires mounting specific images on specifically-compiled kernels, making it impractical to incorporate into xfstests. > > xlog_recover_do_primary_sb_buffer > > xlog_recover_do_reg_buffer > > xlog_recover_validate_buf_type > > xfs_buf_item_init(bp, mp) > > > > The solution is straightforward, we simply need to allow it to be > > handled by the normal buffer write process. The filesystem will be > > shutdown before the submission of buffer_list in xlog_do_recovery_pass(), > > ensuring the correct release of the xfs_buf as follows: > > > > xlog_do_recovery_pass > > error = xlog_recover_process > > xlog_recover_process_data > > xlog_recover_process_ophdr > > xlog_recovery_process_trans > > ... > > xlog_recover_buf_commit_pass2 > > error = xlog_recover_do_primary_sb_buffer > > //Encounter error and return > > if (error) > > goto out_writebuf > > ... > > out_writebuf: > > xfs_buf_delwri_queue(bp, buffer_list) //add bp to list > > return error > > ... > > if (!list_empty(&buffer_list)) > > if (error) > > xlog_force_shutdown(log, SHUTDOWN_LOG_IO_ERROR); //shutdown first > > xfs_buf_delwri_submit(&buffer_list); //write buffer in list > > __xfs_buf_submit > > if (bp->b_mount->m_log && xlog_is_shutdown(bp->b_mount->m_log)) > > xfs_buf_ioend_fail(bp) //release bp correctly > > > > Please add: > Cc: # v6.12 > > > Fixes: 6a18765b54e2 ("xfs: update the file system geometry after recoverying superblock buffers") > > Signed-off-by: Long Li > > --- > > v1->v2: Add code comments and add the fixed stack description to the > > commit message. > > fs/xfs/xfs_buf_item_recover.c | 11 ++++++++++- > > 1 file changed, 10 insertions(+), 1 deletion(-) > > > > diff --git a/fs/xfs/xfs_buf_item_recover.c b/fs/xfs/xfs_buf_item_recover.c > > index 3d0c6402cb36..04122bbdd5f3 100644 > > --- a/fs/xfs/xfs_buf_item_recover.c > > +++ b/fs/xfs/xfs_buf_item_recover.c > > @@ -1079,7 +1079,7 @@ xlog_recover_buf_commit_pass2( > > error = xlog_recover_do_primary_sb_buffer(mp, item, bp, buf_f, > > current_lsn); > > if (error) > > - goto out_release; > > + goto out_writebuf; > > > > /* Update the rt superblock if we have one. */ > > if (xfs_has_rtsb(mp) && mp->m_rtsb_bp) { > > @@ -1096,6 +1096,15 @@ xlog_recover_buf_commit_pass2( > > xlog_recover_do_reg_buffer(mp, item, bp, buf_f, current_lsn); > > } > > > > + /* > > + * Buffer held by buf log item during 'normal' buffer recovery must > > + * be committed through buffer I/O submission path to ensure proper > > + * release. When error occurs during do sb buffer recovery, log > > "...during sb buffer recovery..." > > and with those two things amended, > Reviewed-by: "Darrick J. Wong" > > --D Ok, thanks for your review. Long Li.