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Date: Sun, 18 Jun 2006 23:58:05 -0700
From: Andrew Morton <akpm@osdl.org>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 4/7] fuse: add POSIX file locking support
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On Mon, 12 Jun 2006 14:29:20 +0200
Miklos Szeredi <miklos@szeredi.hu> wrote:

> +/*
> + * It would be nice to scramble the ID space, so that the value of the
> + * files_struct pointer is not exposed to userspace.  Symmetric crypto
> + * functions are overkill, since the inverse function doesn't need to
> + * be implemented (though it does have to exist).  Is there something
> + * simpler?
> + */
> +static inline u64 fuse_lock_owner_id(fl_owner_t id)
> +{
> +	return (unsigned long) id;
> +}

Add a constant, not-known-to-userspace offset to all ids?