linux-kernel - Re: [PATCH v2 7/8] ext4: avoid allocating blocks from corrupted group in ext4_mb_find_by

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Message-ID: <20240104104733.d6oyepneq7ky7ote@quack3>
Date: Thu, 4 Jan 2024 11:47:33 +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, linux-kernel@...r.kernel.org,
	yi.zhang@...wei.com, yangerkun@...wei.com, yukuai3@...wei.com
Subject: Re: [PATCH v2 7/8] ext4: avoid allocating blocks from corrupted
 group in ext4_mb_find_by_goal()

On Thu 21-12-23 23:05:57, Baokun Li wrote:
> Places the logic for checking if the group's block bitmap is corrupt under
> the protection of the group lock to avoid allocating blocks from the group
> with a corrupted block bitmap.
> 
> Signed-off-by: Baokun Li <libaokun1@...wei.com>

Looks good. Feel free to add:

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

								Honza

> ---
>  fs/ext4/mballoc.c | 9 ++++-----
>  1 file changed, 4 insertions(+), 5 deletions(-)
> 
> diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
> index 2bb29f0077bd..b862ca2750fd 100644
> --- a/fs/ext4/mballoc.c
> +++ b/fs/ext4/mballoc.c
> @@ -2340,12 +2340,10 @@ int ext4_mb_find_by_goal(struct ext4_allocation_context *ac,
>  	if (err)
>  		return err;
>  
> -	if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(e4b->bd_info))) {
> -		ext4_mb_unload_buddy(e4b);
> -		return 0;
> -	}
> -
>  	ext4_lock_group(ac->ac_sb, group);
> +	if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(e4b->bd_info)))
> +		goto out;
> +
>  	max = mb_find_extent(e4b, ac->ac_g_ex.fe_start,
>  			     ac->ac_g_ex.fe_len, &ex);
>  	ex.fe_logical = 0xDEADFA11; /* debug value */
> @@ -2378,6 +2376,7 @@ int ext4_mb_find_by_goal(struct ext4_allocation_context *ac,
>  		ac->ac_b_ex = ex;
>  		ext4_mb_use_best_found(ac, e4b);
>  	}
> +out:
>  	ext4_unlock_group(ac->ac_sb, group);
>  	ext4_mb_unload_buddy(e4b);
>  
> -- 
> 2.31.1
> 
-- 
Jan Kara <jack@...e.com>
SUSE Labs, CR