From: Eric Sandeen Subject: Re: [PATCH] ext3: Don't update superblock write time when filesystem is read-only Date: Thu, 17 Sep 2009 09:46:59 -0500 Message-ID: <4AB24BE3.1090406@redhat.com> References: <1253114473-16240-1-git-send-email-tytso@mit.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Jan Kara , Ext4 Developers List To: "Theodore Ts'o" Return-path: Received: from mx1.redhat.com ([209.132.183.28]:42540 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752038AbZIQOrA (ORCPT ); Thu, 17 Sep 2009 10:47:00 -0400 In-Reply-To: <1253114473-16240-1-git-send-email-tytso@mit.edu> Sender: linux-ext4-owner@vger.kernel.org List-ID: Theodore Ts'o wrote: > This avoids updating the superblock write time when we are mounting > the root file system read/only but we need to replay the journal; at > that point, for people who are east of GMT and who make their clock > tick in localtime for Windows bug-for-bug compatibility, and this will > cause e2fsck to complain and force a full file system check. Just out of curiosity, why does e2fsck even care? Why is a fairly common & explainable time delta the trigger for a full fsck? It seems like this solution may have some implications for forensics, etc. Thanks, -Eric > Signed-off-by: "Theodore Ts'o" > --- > fs/ext3/super.c | 13 ++++++++++++- > 1 files changed, 12 insertions(+), 1 deletions(-) > > diff --git a/fs/ext3/super.c b/fs/ext3/super.c > index a8d80a7..62c86af 100644 > --- a/fs/ext3/super.c > +++ b/fs/ext3/super.c > @@ -2321,7 +2321,18 @@ static int ext3_commit_super(struct super_block *sb, > > if (!sbh) > return error; > - es->s_wtime = cpu_to_le32(get_seconds()); > + /* > + * If the file system is mounted read-only, don't update the > + * superblock write time. This avoids updating the superblock > + * write time when we are mounting the root file system > + * read/only but we need to replay the journal; at that point, > + * for people who are east of GMT and who make their clock > + * tick in localtime for Windows bug-for-bug compatibility, > + * the clock is set in the future, and this will cause e2fsck > + * to complain and force a full file system check. > + */ > + if (!(sb->s_flags & MS_RDONLY)) > + es->s_wtime = cpu_to_le32(get_seconds()); > es->s_free_blocks_count = cpu_to_le32(ext3_count_free_blocks(sb)); > es->s_free_inodes_count = cpu_to_le32(ext3_count_free_inodes(sb)); > BUFFER_TRACE(sbh, "marking dirty");