[RFC PATCH v14 06/10] landlock: Add syscall implementation

[Al Viro]

On Mon, Feb 24, 2020 at 05:02:11PM +0100, Mickaël Salaün wrote:

> +static int get_path_from_fd(u64 fd, struct path *path)

> +	/*
> +	 * Only allows O_PATH FD: enable to restrict ambiant (FS) accesses
> +	 * without requiring to open and risk leaking or misuing a FD.  Accept
> +	 * removed, but still open directory (S_DEAD).
> +	 */
> +	if (!(f.file->f_mode & FMODE_PATH) || !f.file->f_path.mnt ||
					      ^^^^^^^^^^^^^^^^^^^
Could you explain what that one had been be about?  The underlined
subexpression is always false; was that supposed to check some
condition and if so, which one?