Date:   Thu, 9 Mar 2023 12:42:24 +0100
From:   Jan Kara <jack@suse.cz>
To:     Ojaswin Mujoo <ojaswin@linux.ibm.com>
Cc:     linux-ext4@vger.kernel.org, Theodore Ts'o <tytso@mit.edu>,
        Ritesh Harjani <riteshh@linux.ibm.com>,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        Jan Kara <jack@suse.cz>, Ritesh Harjani <ritesh.list@gmail.com>
Subject: Re: [RFC 03/11] ext4: mballoc: Fix getting the right group desc in
 ext4_mb_prefetch_fini
Message-ID: <20230309114224.rj5grbon3g2wxzly@quack3>
References: <cover.1674822311.git.ojaswin@linux.ibm.com>
 <85bbcb3774e38de65b737ef0000241ddbdda73aa.1674822311.git.ojaswin@linux.ibm.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <85bbcb3774e38de65b737ef0000241ddbdda73aa.1674822311.git.ojaswin@linux.ibm.com>
Precedence: bulk

On Fri 27-01-23 18:07:30, Ojaswin Mujoo wrote:
> group descriptor and group info are not of the same group in
> ext4_mb_prefetch_fini(). This problem was found during code
> review/walkthrough and seems like a bug, so fix it.
> 
> Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
> Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>

Looks good to me. Feel free to add:

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

								Honza

> ---
>  fs/ext4/mballoc.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
> index 572e79a698d4..8b22cc07b054 100644
> --- a/fs/ext4/mballoc.c
> +++ b/fs/ext4/mballoc.c
> @@ -2569,14 +2569,14 @@ ext4_group_t ext4_mb_prefetch(struct super_block *sb, ext4_group_t group,
>  void ext4_mb_prefetch_fini(struct super_block *sb, ext4_group_t group,
>  			   unsigned int nr)
>  {
> -	while (nr-- > 0) {
> -		struct ext4_group_desc *gdp = ext4_get_group_desc(sb, group,
> -								  NULL);
> -		struct ext4_group_info *grp = ext4_get_group_info(sb, group);
> +	struct ext4_group_desc *gdp;
> +	struct ext4_group_info *grp;
>  
> +	while (nr-- > 0) {
>  		if (!group)
>  			group = ext4_get_groups_count(sb);
>  		group--;
> +		gdp = ext4_get_group_desc(sb, group, NULL);
>  		grp = ext4_get_group_info(sb, group);
>  
>  		if (EXT4_MB_GRP_NEED_INIT(grp) &&
> -- 
> 2.31.1
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR