Re: [PATCH] ocfs2: replace BUG_ON() at ocfs2_num_free_extents() with ocfs2_error()

[Joseph Qi]

On 10/19/23 3:18 AM, Jia Rui wrote:
> The BUG_ON() at ocfs2_num_free_extents() handles the error that
> l_tree_deepth of leaf extent block just read form disk is invalid.
> This error is mostly caused by file system metadata corruption on
> the disk. There is no need to call BUG_ON() to handle such errors.
> We can return error code, since the caller can deal with errors
> from ocfs2_num_free_extents(). Also, we should make the file
> system read-only to avoid the damage from expanding.
> 
> Therefore, BUG_ON() is removed and ocfs2_error() is called instead.
> 
> Signed-off-by: Jia Rui <jindui71@xxxxxxxxx>

Looks reasonable.
Reviewed-by: Joseph Qi <joseph.qi@xxxxxxxxxxxxxxxxx>

> ---
>  fs/ocfs2/alloc.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/ocfs2/alloc.c b/fs/ocfs2/alloc.c
> index aef58f1395c8..d6bcf00f6843 100644
> --- a/fs/ocfs2/alloc.c
> +++ b/fs/ocfs2/alloc.c
> @@ -967,7 +967,14 @@ int ocfs2_num_free_extents(struct ocfs2_extent_tree *et)
>  		el = &eb->h_list;
>  	}
>  
> -	BUG_ON(el->l_tree_depth != 0);
> +	if (el->l_tree_depth != 0) {
> +		retval = ocfs2_error(ocfs2_metadata_cache_get_super(et->et_ci),
> +				"Owner %llu has leaf extent block %llu with an invalid l_tree_depth of %u\n",
> +				(unsigned long long)ocfs2_metadata_cache_owner(et->et_ci),
> +				(unsigned long long)last_eb_blk,
> +				le16_to_cpu(el->l_tree_depth));
> +		goto bail;
> +	}
>  
>  	retval = le16_to_cpu(el->l_count) - le16_to_cpu(el->l_next_free_rec);
>  bail: