From: Jan Kara Subject: Re: [PATCH] fs:ext3: remove lock_buffer in bclean() and setup_new_group_blocks Date: Wed, 5 Dec 2012 15:41:07 +0100 Message-ID: <20121205144107.GE5706@quack.suse.cz> References: <1354412428-8938-1-git-send-email-dinggnu@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Jan Kara , Andrew Morton , Andreas Dilger , linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org To: Cong Ding Return-path: Received: from cantor2.suse.de ([195.135.220.15]:44162 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754215Ab2LEOlJ (ORCPT ); Wed, 5 Dec 2012 09:41:09 -0500 Content-Disposition: inline In-Reply-To: <1354412428-8938-1-git-send-email-dinggnu@gmail.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Sun 02-12-12 01:40:28, Cong Ding wrote: > it's not necessary to lock the buffers because no one touches them > beyond the file system. Although I agree those locks are not strictly necessary, I prefer to keep them because the general rula is buffer contents should be changed under buffer lock unless we have a good reason to do otherwise. And here the cost of additional lock is really marginal... Honza > > Signed-off-by: Cong Ding > --- > fs/ext3/resize.c | 4 ---- > 1 files changed, 0 insertions(+), 4 deletions(-) > > diff --git a/fs/ext3/resize.c b/fs/ext3/resize.c > index 0f814f3..f76fcd6 100644 > --- a/fs/ext3/resize.c > +++ b/fs/ext3/resize.c > @@ -122,10 +122,8 @@ static struct buffer_head *bclean(handle_t *handle, struct super_block *sb, > brelse(bh); > bh = ERR_PTR(err); > } else { > - lock_buffer(bh); > memset(bh->b_data, 0, sb->s_blocksize); > set_buffer_uptodate(bh); > - unlock_buffer(bh); > } > > return bh; > @@ -242,10 +240,8 @@ static int setup_new_group_blocks(struct super_block *sb, > brelse(gdb); > goto exit_bh; > } > - lock_buffer(gdb); > memcpy(gdb->b_data, sbi->s_group_desc[i]->b_data, gdb->b_size); > set_buffer_uptodate(gdb); > - unlock_buffer(gdb); > err = ext3_journal_dirty_metadata(handle, gdb); > if (err) { > brelse(gdb); > -- > 1.7.4.5 > -- Jan Kara SUSE Labs, CR