From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 677854685 for ; Wed, 8 Jan 2025 00:34:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736296450; cv=none; b=NB+WPmGrKfR13z059iwln9oyW8AdNrd8LraRwoirTbTMeTYPWzS0MKHJuE0D9R3VxaFnIo/Pwzc/3QlVGiDLgP50jZA3lb9hv1r79HRRkxegfjaD3k7wquO6js9IzKCwoHHI4QpuaJfZmIECYGRV/Ui/k2JH5I6a6hAnTYK84QU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736296450; c=relaxed/simple; bh=vkvuXCW9gQ94mfIXsjmB5d/YuIFc7gqC/kLKuoJN740=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=IoOABwd+/jwnaQNT73pIA5miLlt0bAqrXWFM6QKATtS9bmkNc6ULqNhYKGmMA2kk95luuZfUDcLtNBDhGY7ImVFvSKD+AIrqOtox4/Ioxl35/Vz/FuaqYUrDzVVHkx5GNDcy1WuOTsPlYxDaTfidClxWNiZiPpIfg+jFTBmV7QI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=c0P1xEQT; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="c0P1xEQT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D69B1C4CED6; Wed, 8 Jan 2025 00:34:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1736296449; bh=vkvuXCW9gQ94mfIXsjmB5d/YuIFc7gqC/kLKuoJN740=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=c0P1xEQTNGpYkSUWbM0SxsBLEPv8HebYj08HLwVh1HIJC29F4bmiPnobRriveafQH HCMJ2OQ5coE4Ipal1G2ibzPoIUZoJ1MmYOuVHz5pyvldjXNp/5x6wtkaczRF5MsJnZ Jr21Zk5rdtEHdv/Cft8Zp/eUR0Fx3epbL4kZf7lFkeZTQSvHaW4vg2pRQa0J0AWRWi BjxrP/UC60F8OGdZWDEis/c5BR/Hk04Xfi4LxvDZqyYENKgnogqS2yDq1jcO1wgHTm oYCfgqvp5vHsgQ0eHvs/zdIMccOUoXH9QW9AKD+70KI9w8kzsUynCwnZyc+U+4n9z2 THqyFO0YChKXQ== Date: Tue, 7 Jan 2025 16:34:09 -0800 From: "Darrick J. Wong" To: Long Li Cc: cem@kernel.org, linux-xfs@vger.kernel.org, david@fromorbit.com, yi.zhang@huawei.com, houtao1@huawei.com, yangerkun@huawei.com, lonuxli.64@gmail.com Subject: Re: [PATCH 2/2] xfs: fix mount hang during primary superblock recovery failure Message-ID: <20250108003409.GM6174@frogsfrogsfrogs> References: <20241231023423.656128-1-leo.lilong@huawei.com> <20241231023423.656128-3-leo.lilong@huawei.com> <20250106195541.GL6174@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=us-ascii Content-Disposition: inline In-Reply-To: On Tue, Jan 07, 2025 at 09:39:10PM +0800, Long Li wrote: > On Mon, Jan 06, 2025 at 11:55:41AM -0800, Darrick J. Wong wrote: > > On Tue, Dec 31, 2024 at 10:34:23AM +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. > > > > > > 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(), > > > > What shuts it down? If xlog_recover_do_primary_sb_buffer trips over > > something like "mp->m_sb.sb_rgcount < orig_rgcount" then we haven't shut > > anything down yet. Am I missing something? > > > > --D > > > > Hi Darrick, > > Sorry for being unclear. I was referring to the shutdown in xlog_do_recovery_pass(). > Here's the specific flow after the fix: > > 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 buffer_list > return error > ... > if (!list_empty(&buffer_list)) > if (error) > xlog_force_shutdown(log, SHUTDOWN_LOG_IO_ERROR); //log shutdown first > xfs_buf_delwri_submit(&buffer_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 > > It might be clearer to put this process into a commit message. Yes please, put that in a code comment. That was too subtle for me to figure out. :/ --D > Thanks, > Long Li >