[PATCH v6 35/40] fs: introduce MOUNT_ATTR_IDMAP

[Christoph Hellwig]

>  /*
>   * mount_setattr()
> @@ -127,9 +128,10 @@ struct mount_attr {
>  	__u64 attr_set;
>  	__u64 attr_clr;
>  	__u64 propagation;
> +	__u64 userns_fd;
>  };
>  
>  /* List of all mount_attr versions. */
> -#define MOUNT_ATTR_SIZE_VER0	24 /* sizeof first published struct */
> +#define MOUNT_ATTR_SIZE_VER0	32 /* sizeof first published struct */

I think this hunk needs to go into the patch adding the structure.