Re: [PATCH 1/7] Btrfs: replace BUG() with WARN_ONCE in raid56

["Holger Hoffstätte" <holger@applied-asynchrony.com>]

On 05/14/16 02:06, Liu Bo wrote:
> This BUG() has been triggered by a fuzz testing image, but in fact
> btrfs can handle this gracefully by returning -EIO.
> 
> Thus, use WARN_ONCE for warning purpose and don't leave a possible
> kernel panic.
> 
> Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
> ---
>  fs/btrfs/raid56.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/btrfs/raid56.c b/fs/btrfs/raid56.c
> index 0b7792e..863f7fe 100644
> --- a/fs/btrfs/raid56.c
> +++ b/fs/btrfs/raid56.c
> @@ -2139,7 +2139,7 @@ int raid56_parity_recover(struct btrfs_root *root, struct bio *bio,
>  
>  	rbio->faila = find_logical_bio_stripe(rbio, bio);
>  	if (rbio->faila == -1) {
> -		BUG();
> +		WARN_ONCE(1, KERN_WARNING "rbio->faila is -1\n");

I'm generally in favor of not BUGing out for no good reason, but what
is e.g. an admin (or user) supposed to do when he sees this message?
Same for the other rather cryptic WARNs - they contain no actionable
information, and are most likely going to be ignored as "debug spam".
IMHO things that can be ignored can be deleted.

thanks,
Holger