linux-ext4 - Re: [PATCH v2 8/9] ext4: set the type of max_zeroout to unsigned int to avoid overflow

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Date: Thu, 14 Mar 2024 11:35:44 +0100
From: Jan Kara <jack@...e.cz>
To: Baokun Li <libaokun1@...wei.com>
Cc: linux-ext4@...r.kernel.org, tytso@....edu, adilger.kernel@...ger.ca,
	jack@...e.cz, ritesh.list@...il.com, ojaswin@...ux.ibm.com,
	adobriyan@...il.com, linux-kernel@...r.kernel.org,
	yi.zhang@...wei.com, yangerkun@...wei.com
Subject: Re: [PATCH v2 8/9] ext4: set the type of max_zeroout to unsigned int
 to avoid overflow

On Tue 27-02-24 17:11:47, Baokun Li wrote:
> The max_zeroout is of type int and the s_extent_max_zeroout_kb is of
> type uint, and the s_extent_max_zeroout_kb can be freely modified via
> the sysfs interface. When the block size is 1024, max_zeroout may
> overflow, so declare it as unsigned int to avoid overflow.
> 
> Signed-off-by: Baokun Li <libaokun1@...wei.com>

Indeed. The patch looks good. Feel free to add:

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

								Honza

> ---
>  fs/ext4/extents.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
> index e57054bdc5fd..e067f2dd0335 100644
> --- a/fs/ext4/extents.c
> +++ b/fs/ext4/extents.c
> @@ -3402,9 +3402,10 @@ static int ext4_ext_convert_to_initialized(handle_t *handle,
>  	struct ext4_extent *ex, *abut_ex;
>  	ext4_lblk_t ee_block, eof_block;
>  	unsigned int ee_len, depth, map_len = map->m_len;
> -	int allocated = 0, max_zeroout = 0;
>  	int err = 0;
>  	int split_flag = EXT4_EXT_DATA_VALID2;
> +	int allocated = 0;
> +	unsigned int max_zeroout = 0;
>  
>  	ext_debug(inode, "logical block %llu, max_blocks %u\n",
>  		  (unsigned long long)map->m_lblk, map_len);
> -- 
> 2.31.1
> 
-- 
Jan Kara <jack@...e.com>
SUSE Labs, CR