From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-eopbgr750132.outbound.protection.outlook.com ([40.107.75.132]:51328 "EHLO NAM02-BL2-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727311AbeLaTsq (ORCPT ); Mon, 31 Dec 2018 14:48:46 -0500 From: Theodore Ts'o To: Ext4 Developers List CC: Theodore Ts'o , Subject: [PATCH 1/3] ext4: avoid kernel warning when writing the superblock to a dead device Date: Mon, 31 Dec 2018 14:48:34 -0500 Message-ID: <20181231194836.3761-1-tytso@mit.edu> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain Sender: linux-ext4-owner@vger.kernel.org List-ID: The xfstests generic/475 test switches the underlying device with dm-error while running a stress test. This results in a large number of file system errors, and since we can't lock the buffer head when marking the superblock dirty in the ext4_grp_locked_error() case, it's possible the superblock to be !buffer_uptodate() without buffer_write_io_error() being true. We need to set buffer_uptodate() before we call mark_buffer_dirty() or this will trigger a WARN_ON. It's safe to do this since the superblock must have been properly read into memory or the mount would have been successful. So if buffer_uptodate() is not set, we can safely assume that this happened due to a failed attempt to write the superblock. Signed-off-by: Theodore Ts'o Cc: stable@vger.kernel.org --- fs/ext4/super.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/ext4/super.c b/fs/ext4/super.c index d6c142d73d99..fb12d3c17c1b 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -4902,7 +4902,7 @@ static int ext4_commit_super(struct super_block *sb, int sync) ext4_superblock_csum_set(sb); if (sync) lock_buffer(sbh); - if (buffer_write_io_error(sbh)) { + if (buffer_write_io_error(sbh) || !buffer_uptodate(sbh)) { /* * Oh, dear. A previous attempt to write the * superblock failed. This could happen because the -- 2.19.1