From patchwork Wed Jul 11 13:46:42 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Artem Bityutskiy X-Patchwork-Id: 170469 Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 96D5F2C0205 for ; Wed, 11 Jul 2012 23:46:39 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932530Ab2GKNqN (ORCPT ); Wed, 11 Jul 2012 09:46:13 -0400 Received: from mga14.intel.com ([143.182.124.37]:23534 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932612Ab2GKNpO (ORCPT ); Wed, 11 Jul 2012 09:45:14 -0400 Received: from azsmga002.ch.intel.com ([10.2.17.35]) by azsmga102.ch.intel.com with ESMTP; 11 Jul 2012 06:45:14 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.71,315,1320652800"; d="scan'208";a="121164808" Received: from blue.fi.intel.com (HELO np.fi.intel.com) ([10.237.72.50]) by AZSMGA002.ch.intel.com with ESMTP; 11 Jul 2012 06:45:12 -0700 From: Artem Bityutskiy To: Theodore Tso , Jan Kara Cc: Linux FS Maling List , Linux Kernel Maling List , Ext4 Mailing List Subject: [PATCHv7 3/5] ext4: remove unnecessary superblock dirtying Date: Wed, 11 Jul 2012 16:46:42 +0300 Message-Id: <1342014404-14834-4-git-send-email-dedekind1@gmail.com> X-Mailer: git-send-email 1.7.7.6 In-Reply-To: <1342014404-14834-1-git-send-email-dedekind1@gmail.com> References: <1342014404-14834-1-git-send-email-dedekind1@gmail.com> Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org From: Artem Bityutskiy This patch changes the 'ext4_handle_dirty_super()' function which submits the superblock for I/O in the following cases: 1. When creating the first large file on a file system without EXT4_FEATURE_RO_COMPAT_LARGE_FILE feature. 2. When re-sizing the file-system. 3. When creating an xattr on a file-system without the EXT4_FEATURE_COMPAT_EXT_ATTR feature. If the file-system has journal enabled, the superblock is written via the journal. We do not modify this path. If the file-system has no journal, this function, falls back to just marking the superblock as dirty using the 's_dirt' superblock flag. This means that it delays the actual superblock I/O submission by 5 seconds (default setting). Namely, the 'sync_supers()' kernel thread will call 'ext4_write_super()' later and will actually submit the superblock for I/O. And this is the behavior this patch modifies: we stop using 's_dirt' and just mark the superblock buffer as dirty right away. Indeed, all 3 cases above are extremely rare and it does not add any value to delay the I/O submission for them. Note: 'ext4_handle_dirty_super()' executes '__ext4_handle_dirty_super()' with 'now = 0'. This patch basically makes the 'now' argument unneeded and it will be deleted in one of the next patches. This patch also removes 's_dirt' condition on the unmount path because we never set it anymore, so we should not test it. Tested using xfstests for both journalled and non-journalled ext4. Signed-off-by: Artem Bityutskiy Reviewed-by: Jan Kara --- fs/ext4/ext4_jbd2.c | 5 ++--- fs/ext4/super.c | 2 +- 2 files changed, 3 insertions(+), 4 deletions(-) diff --git a/fs/ext4/ext4_jbd2.c b/fs/ext4/ext4_jbd2.c index 90f7c2e..c19ab6a 100644 --- a/fs/ext4/ext4_jbd2.c +++ b/fs/ext4/ext4_jbd2.c @@ -151,11 +151,10 @@ int __ext4_handle_dirty_super(const char *where, unsigned int line, if (err) ext4_journal_abort_handle(where, line, __func__, bh, handle, err); - } else if (now) { + } else { ext4_superblock_csum_set(sb, (struct ext4_super_block *)bh->b_data); mark_buffer_dirty(bh); - } else - sb->s_dirt = 1; + } return err; } diff --git a/fs/ext4/super.c b/fs/ext4/super.c index eb7aa3e..a391c53 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -896,7 +896,7 @@ static void ext4_put_super(struct super_block *sb) EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER); es->s_state = cpu_to_le16(sbi->s_mount_state); } - if (sb->s_dirt || !(sb->s_flags & MS_RDONLY)) + if (!(sb->s_flags & MS_RDONLY)) ext4_commit_super(sb, 1); if (sbi->s_proc) {