linux-kernel - Re: [PATCH v3 5/8] jbd2: remove unneeded done_copy_out variable in jbd2_journal_write_metadata

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Message-ID: <01115725-c0ca-6bca-c6e2-5f75e1a5c13a@huaweicloud.com>
Date: Wed, 31 Jul 2024 19:57:16 +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 v3 5/8] jbd2: remove unneeded done_copy_out variable in
 jbd2_journal_write_metadata_buffer

On 2024/7/31 17:29, Kemeng Shi wrote:
> It's more intuitive to use jh_in->b_frozen_data directly instead of
> done_copy_out variable. Simply remove unneeded done_copy_out variable
> and use b_frozen_data instead.
> 
> Signed-off-by: Kemeng Shi <shikemeng@...weicloud.com>

Looks good to me.

Reviewed-by: Zhang Yi <yi.zhang@...wei.com>

> ---
>  fs/jbd2/journal.c | 21 ++++++++-------------
>  1 file changed, 8 insertions(+), 13 deletions(-)
> 
> diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c
> index 9c1ffb0dc740..f17d05bc61df 100644
> --- a/fs/jbd2/journal.c
> +++ b/fs/jbd2/journal.c
> @@ -318,7 +318,6 @@ int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
>  				  struct buffer_head **bh_out,
>  				  sector_t blocknr)
>  {
> -	int done_copy_out = 0;
>  	int do_escape = 0;
>  	char *mapped_data;
>  	struct buffer_head *new_bh;
> @@ -349,7 +348,6 @@ int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
>  	 * we use that version of the data for the commit.
>  	 */
>  	if (jh_in->b_frozen_data) {
> -		done_copy_out = 1;
>  		new_folio = virt_to_folio(jh_in->b_frozen_data);
>  		new_offset = offset_in_folio(new_folio, jh_in->b_frozen_data);
>  		mapped_data = jh_in->b_frozen_data;
> @@ -357,17 +355,15 @@ int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
>  		new_folio = bh_in->b_folio;
>  		new_offset = offset_in_folio(new_folio, bh_in->b_data);
>  		mapped_data = kmap_local_folio(new_folio, new_offset);
> -	}
> -
> -	/*
> -	 * Fire data frozen trigger if data already wasn't frozen.  Do this
> -	 * before checking for escaping, as the trigger may modify the magic
> -	 * offset.  If a copy-out happens afterwards, it will have the correct
> -	 * data in the buffer.
> -	 */
> -	if (!done_copy_out)
> +		/*
> +		 * Fire data frozen trigger if data already wasn't frozen. Do
> +		 * this before checking for escaping, as the trigger may modify
> +		 * the magic offset.  If a copy-out happens afterwards, it will
> +		 * have the correct data in the buffer.
> +		 */
>  		jbd2_buffer_frozen_trigger(jh_in, mapped_data,
>  					   jh_in->b_triggers);
> +	}
>  
>  	/*
>  	 * Check for escaping
> @@ -380,7 +376,7 @@ int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
>  	/*
>  	 * Do we need to do a data copy?
>  	 */
> -	if (do_escape && !done_copy_out) {
> +	if (do_escape && !jh_in->b_frozen_data) {
>  		char *tmp;
>  
>  		spin_unlock(&jh_in->b_state_lock);
> @@ -408,7 +404,6 @@ int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
>  copy_done:
>  		new_folio = virt_to_folio(jh_in->b_frozen_data);
>  		new_offset = offset_in_folio(new_folio, jh_in->b_frozen_data);
> -		done_copy_out = 1;
>  	}
>  
>  	/*
>