From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758842Ab3AOXq5 (ORCPT ); Tue, 15 Jan 2013 18:46:57 -0500 Received: from mail.kernel.org ([198.145.19.201]:45936 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933149Ab3AOWuP (ORCPT ); Tue, 15 Jan 2013 17:50:15 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , alan@lxorguk.ukuu.org.uk, Michael Tokarev , "Theodore Tso" Subject: [ 060/171] ext4: do not try to write superblock on ro remount w/o journal Date: Tue, 15 Jan 2013 14:43:45 -0800 Message-Id: <20130115224317.738621533@linuxfoundation.org> X-Mailer: git-send-email 1.8.1.336.g94702dd In-Reply-To: <20130115224313.394976595@linuxfoundation.org> References: <20130115224313.394976595@linuxfoundation.org> User-Agent: quilt/0.60-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Michael Tokarev commit d096ad0f79a782935d2e06ae8fb235e8c5397775 upstream. When a journal-less ext4 filesystem is mounted on a read-only block device (blockdev --setro will do), each remount (for other, unrelated, flags, like suid=>nosuid etc) results in a series of scary messages from kernel telling about I/O errors on the device. This is becauese of the following code ext4_remount(): if (sbi->s_journal == NULL) ext4_commit_super(sb, 1); at the end of remount procedure, which forces writing (flushing) of a superblock regardless whenever it is dirty or not, if the filesystem is readonly or not, and whenever the device itself is readonly or not. We only need call ext4_commit_super when the file system had been previously mounted read/write. Thanks to Eric Sandeen for help in diagnosing this issue. Signed-off-By: Michael Tokarev Signed-off-by: "Theodore Ts'o" Signed-off-by: Greg Kroah-Hartman --- fs/ext4/super.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -4506,7 +4506,7 @@ static int ext4_remount(struct super_blo } ext4_setup_system_zone(sb); - if (sbi->s_journal == NULL) + if (sbi->s_journal == NULL && !(old_sb_flags & MS_RDONLY)) ext4_commit_super(sb, 1); #ifdef CONFIG_QUOTA