Re: [PATCH 3/3] btrfs: use ioctl args support mask for device delete

[Marcos Paulo de Souza <mpdesouza@suse.de>]

On Fri, 2020-02-21 at 14:02 +0100, David Sterba wrote:
> When the device remove v2 ioctl was added, the full support mask was
> added to sanity check the flags. However this would allow to let the
> subvolume related flags to be accepted. This is not supposed to
> happen.
> 
> Use the correct support mask, which means that now any of
> BTRFS_SUBVOL_CREATE_ASYNC, BTRFS_SUBVOL_RDONLY or
> BTRFS_SUBVOL_QGROUP_INHERIT will be rejected as ENOTSUPP. Though this
> is
> a user-visible change, specifying subvolume flags for device deletion
> does not make sense and there are hopefully no applications doing
> that.
> 
> Signed-off-by: David Sterba <dsterba@suse.com>
> ---
>  fs/btrfs/ioctl.c | 3 +--
>  1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> index a7872cacd0aa..cd2d11dcd477 100644
> --- a/fs/btrfs/ioctl.c
> +++ b/fs/btrfs/ioctl.c
> @@ -3075,8 +3075,7 @@ static long btrfs_ioctl_rm_dev_v2(struct file
> *file, void __user *arg)
>  		goto err_drop;
>  	}
>  
> -	/* Check for compatibility reject unknown flags */
> -	if (vol_args->flags & ~BTRFS_VOL_ARG_V2_FLAGS_SUPPORTED) {
> +	if (vol_args->flags & ~BTRFS_DEVICE_REMOVE_ARGS_MASK) {
>  		ret = -EOPNOTSUPP;
>  		goto out;
>  	}

Looks good to me,
Reviewed-by: Marcos Paulo de Souza <mpdesouza@suse.com>