From: Stephen Hemminger Subject: [PATCH] ext2: clear uptodate flag on super block I/O error Date: Mon, 16 Nov 2009 16:04:49 -0800 Message-ID: <20091116160449.3fc5e958@nehalam> References: <20091111123340.703f5c86@nehalam> <200911112234.24180.elendil@planet.nl> <20091113144727.575cf038@nehalam> <20091113150719.9d31dde2.akpm@linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: Christoph Hellwig , Jan Kara , Nick Piggin , jens.axboe@oracle.com, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org To: Andrew Morton Return-path: In-Reply-To: <20091113150719.9d31dde2.akpm@linux-foundation.org> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org This fixes a WARN backtrace in mark_buffer_dirty() that occurs during unmount when a USB or floppy device is removed. I reported this a kernel regression, but looks like it might have been there for longer than that. The super block update from a previous operation has marked the buffer as in error, and the flag has to be cleared before doing the update. (Similar code already exists in ext4). Signed-off-by: Stephen Hemminger --- a/fs/ext2/super.c 2009-11-16 15:55:36.399078475 -0800 +++ b/fs/ext2/super.c 2009-11-16 15:59:49.814765923 -0800 @@ -1121,8 +1121,20 @@ static void ext2_sync_super(struct super static int ext2_sync_fs(struct super_block *sb, int wait) { struct ext2_super_block *es = EXT2_SB(sb)->s_es; + struct buffer_head *sbh = EXT2_SB(sb)->s_sbh; lock_kernel(); + if (buffer_write_io_error(sbh)) { + /* + * This happens if USB or floppy device is yanked out. + * Maybe user put device back in so warn and update again. + */ + printk(KERN_ERR + "EXT2-fs: previous I/O error to superblock detected\n"); + clear_buffer_write_io_error(sbh); + set_buffer_uptodate(sbh); + } + if (es->s_state & cpu_to_le16(EXT2_VALID_FS)) { ext2_debug("setting valid to 0\n"); es->s_state &= cpu_to_le16(~EXT2_VALID_FS);