linux-kernel - Re: [PATCH 2/9] jbd2: remove unused return info from jbd2_journal_write_metadata

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Date: Tue, 7 May 2024 19:51:14 +0800
From: Zhang Yi <yi.zhang@...weicloud.com>
To: Kemeng Shi <shikemeng@...weicloud.com>
Cc: linux-ext4@...r.kernel.org, linux-kernel@...r.kernel.org, tytso@....edu,
 jack@...e.com
Subject: Re: [PATCH 2/9] jbd2: remove unused return info from
 jbd2_journal_write_metadata_buffer

On 2024/5/6 22:17, Kemeng Shi wrote:
> The done_copy_out info from jbd2_journal_write_metadata_buffer is not
> used. Simply remove it.
> 
> Signed-off-by: Kemeng Shi <shikemeng@...weicloud.com>
> ---
>  fs/jbd2/journal.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
> index 207b24e12ce9..068031f35aea 100644
> --- a/fs/jbd2/journal.c
> +++ b/fs/jbd2/journal.c
> @@ -320,7 +320,6 @@ static void journal_kill_thread(journal_t *journal)
>   *
>   * On success:
>   * Bit 0 set == escape performed on the data
> - * Bit 1 set == buffer copy-out performed (kfree the data after IO)
>   */
>  
>  int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
> @@ -455,7 +454,7 @@ int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
>  	set_buffer_shadow(bh_in);
>  	spin_unlock(&jh_in->b_state_lock);
>  
> -	return do_escape | (done_copy_out << 1);
> +	return do_escape;
>  }
>  

I checked the history, it seems that this bit has not been used since
the very beginning when the jbd code was merged in, I suppose we could
drop it. Since there is only one flag that is still in use, why not just
drop the flag and pass out do_escape through an output parameter, or
directly pass tag_flag, after that we could also drop the weird
"if (flags & 1)" check in jbd2_journal_commit_transaction()?

Thanks,
Yi.