linux-kernel - Re: [PATCH 3/4] fs: befs: Remove useless calls to brelse in befs_find_brun

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Message-ID: <5777AACD.4000806@osg.samsung.com>
Date:	Sat, 02 Jul 2016 12:51:41 +0100
From:	Luis de Bethencourt <luisbg@....samsung.com>
To:	Salah Triki <salah.triki@...il.com>, akpm@...ux-foundation.org,
	viro@...iv.linux.org.uk
CC:	mhocko@...e.com, vdavydov@...tuozzo.com,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/4] fs: befs: Remove useless calls to brelse in befs_find_brun_dblindirect

On 02/07/16 09:05, Salah Triki wrote:
> The calls to brelse are useless since dbl_indir_block and indir_block
> are NULL.
> 
> Signed-off-by: Salah Triki <salah.triki@...il.com>
> ---
>  fs/befs/datastream.c | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/fs/befs/datastream.c b/fs/befs/datastream.c
> index e224b9a..b68b6f9 100644
> --- a/fs/befs/datastream.c
> +++ b/fs/befs/datastream.c
> @@ -471,7 +471,6 @@ befs_find_brun_dblindirect(struct super_block *sb,
>  			   (unsigned long)
>  			   iaddr2blockno(sb, &data->double_indirect) +
>  			   dbl_which_block);
> -		brelse(dbl_indir_block);
>  		return BEFS_ERR;
>  	}
>  
> @@ -496,7 +495,6 @@ befs_find_brun_dblindirect(struct super_block *sb,
>  		befs_error(sb, "%s couldn't read the indirect block "
>  			   "at blockno %lu", __func__, (unsigned long)
>  			   iaddr2blockno(sb, &indir_run) + which_block);
> -		brelse(indir_block);
>  		return BEFS_ERR;
>  	}
>  
> 

Great catch!

This went unnoticed because brelse() checks if the buffer_head is NULL before
decrementing the reference count. Which in these two cases they clearly are NULL.

Acked-by: Luis de Bethencourt <luisbg@....samsung.com>

Thanks!
Luis