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Message-ID: <20121205144107.GE5706@quack.suse.cz>
Date: Wed, 5 Dec 2012 15:41:07 +0100
From: Jan Kara <jack@...e.cz>
To: Cong Ding <dinggnu@...il.com>
Cc: Jan Kara <jack@...e.cz>, Andrew Morton <akpm@...ux-foundation.org>,
Andreas Dilger <adilger.kernel@...ger.ca>,
linux-ext4@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] fs:ext3: remove lock_buffer in bclean() and
setup_new_group_blocks
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 <dinggnu@...il.com>
> ---
> 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 <jack@...e.cz>
SUSE Labs, CR
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