Re: [PATCH] fs: ntfs: super: added return error value while map failed

[Johannes Thumshirn]

On 29/06/2021 12:41, lijian_8010a29@xxxxxxx wrote:
> From: lijian <lijian@xxxxxxxxxx>
> 
> When lookup_extent_mapping failed, should return '-ENOENT'.
> 
> Signed-off-by: lijian <lijian@xxxxxxxxxx>
> ---
>  fs/btrfs/extent_map.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/fs/btrfs/extent_map.c b/fs/btrfs/extent_map.c
> index 4a8e02f7b6c7..e9d9f2bfc11d 100644
> --- a/fs/btrfs/extent_map.c
> +++ b/fs/btrfs/extent_map.c
> @@ -305,8 +305,10 @@ int unpin_extent_cache(struct extent_map_tree *tree, u64 start, u64 len,
>  
>  	WARN_ON(!em || em->start != start);
>  
> -	if (!em)
> +	if (!em) {
> +		ret = -ENOENT;
>  		goto out;
> +	}
>  
>  	em->generation = gen;
>  	clear_bit(EXTENT_FLAG_PINNED, &em->flags);
> 

You'll still need to properly handle the returned error in the caller,
otherwise this patch makes no sense at all.

Also the subject should be something like "btrfs: handle failures from unpin_extent_cache" or
sth. like this.