From: Jan Kara Subject: Re: [PATCH v2] ext3: Update ctime in ext3_splice_branch() only when needed Date: Wed, 8 Feb 2012 10:33:07 +0100 Message-ID: <20120208093307.GB24625@quack.suse.cz> References: <4F322585.3010407@sx.jp.nec.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: ext4 , jan Kara , Andreas Dilger To: Kazuya Mio Return-path: Received: from cantor2.suse.de ([195.135.220.15]:38960 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751634Ab2BHJdJ (ORCPT ); Wed, 8 Feb 2012 04:33:09 -0500 Content-Disposition: inline In-Reply-To: <4F322585.3010407@sx.jp.nec.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Wed 08-02-12 16:34:29, Kazuya Mio wrote: > Currently ext3 updates ctime in ext3_splice_branch() which is called whenever > we allocate one block. But it is wasteful because ext3 doesn't support > nanosecond timestamp. This leads to a performance loss. > > Signed-off-by: Kazuya Mio Thanks. The patch looks good. I've added it to my tree. Honza > --- > fs/ext3/inode.c | 9 ++++++--- > 1 file changed, 6 insertions(+), 3 deletions(-) > diff --git a/fs/ext3/inode.c b/fs/ext3/inode.c > index 2d0afec..3c7fd63 100644 > --- a/fs/ext3/inode.c > +++ b/fs/ext3/inode.c > @@ -756,6 +756,7 @@ static int ext3_splice_branch(handle_t *handle, struct inode *inode, > struct ext3_block_alloc_info *block_i; > ext3_fsblk_t current_block; > struct ext3_inode_info *ei = EXT3_I(inode); > + struct timespec now; > > block_i = ei->i_block_alloc_info; > /* > @@ -795,9 +796,11 @@ static int ext3_splice_branch(handle_t *handle, struct inode *inode, > } > > /* We are done with atomic stuff, now do the rest of housekeeping */ > - > - inode->i_ctime = CURRENT_TIME_SEC; > - ext3_mark_inode_dirty(handle, inode); > + now = CURRENT_TIME_SEC; > + if (!timespec_equal(&inode->i_ctime, &now) || !where->bh) { > + inode->i_ctime = now; > + ext3_mark_inode_dirty(handle, inode); > + } > /* ext3_mark_inode_dirty already updated i_sync_tid */ > atomic_set(&ei->i_datasync_tid, handle->h_transaction->t_tid); > -- Jan Kara SUSE Labs, CR