Received-SPF: pass (google.com: domain of linux-ext4+bounces-2488-linux.lists.archive=gmail.com@vger.kernel.org designates 139.178.88.99 as permitted sender) client-ip=139.178.88.99;
Date: Sun, 12 May 2024 13:22:05 +0200
From: Jan Kara <jack@suse.cz>
To: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: tytso@mit.edu, jack@suse.com, linux-ext4@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 7/9] jbd2: remove dead equality check of
 j_commit_[sequence/request] in kjournald2
Message-ID: <20240512112205.6bknpxlpovqxjfkm@quack3>
References: <20240506141801.1165315-1-shikemeng@huaweicloud.com>
 <20240506141801.1165315-8-shikemeng@huaweicloud.com>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20240506141801.1165315-8-shikemeng@huaweicloud.com>

On Mon 06-05-24 22:17:59, Kemeng Shi wrote:
> In kjournald2, two equality checks of j_commit_[sequence/request] are
> under the same j_state_lock. As j_commit_[sequence/request] are updated
> concurrently with j_state_lock held during runtime, the second check is
> unnecessary.
> The j_commit_sequence is only updated concurrently in
> jbd2_journal_commit_transaction with j_state_lock held.
> The j_commit_request is only updated concurrently in
> __jbd2_log_start_commit with j_state_lock held.
> Also see comment in struct journal_s about lock rule of j_commit_sequence
> and j_commit_request.
> 
> Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
>  fs/jbd2/journal.c | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
> index 01e33b643e4d..e8f592fbd6e1 100644
> --- a/fs/jbd2/journal.c
> +++ b/fs/jbd2/journal.c
> @@ -224,8 +224,6 @@ static int kjournald2(void *arg)
>  
>  		prepare_to_wait(&journal->j_wait_commit, &wait,
>  				TASK_INTERRUPTIBLE);
> -		if (journal->j_commit_sequence != journal->j_commit_request)
> -			should_sleep = 0;
>  		transaction = journal->j_running_transaction;
>  		if (transaction && time_after_eq(jiffies,
>  						transaction->t_expires))
> -- 
> 2.30.0
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR