Re: [PATCH 1/3] btrfs: warn for num_devices below 0

[Nikolay Borisov <nborisov@suse.com>]

On 10.07.2018 21:22, Anand Jain wrote:
> In preparation to de-duplicate a section of code where we deduce the
> num_devices, use warn instead of bug.
> 
> Signed-off-by: Anand Jain <anand.jain@oracle.com>
> ---
>  fs/btrfs/volumes.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
> index eb78bb8d1108..ce6faeb8bcf8 100644
> --- a/fs/btrfs/volumes.c
> +++ b/fs/btrfs/volumes.c
> @@ -3813,7 +3813,7 @@ int btrfs_balance(struct btrfs_fs_info *fs_info,
>  	num_devices = fs_info->fs_devices->num_devices;
>  	btrfs_dev_replace_read_lock(&fs_info->dev_replace);
>  	if (btrfs_dev_replace_is_ongoing(&fs_info->dev_replace)) {
> -		BUG_ON(num_devices < 1);
> +		WARN_ON(num_devices < 1);

Isn't dev_replace_is_ongoing && num_devices < 1 indeed a logical bug
situation? Under what condition can it happen that you deem "non
critical" ?

>  		num_devices--;
>  	}
>  	btrfs_dev_replace_read_unlock(&fs_info->dev_replace);
>