[Cluster-devel] [PATCH 07/10] locks: define a lm_setup handler for leases

[Christoph Hellwig <hch@infradead.org>]

I like this change a lot!  But one caveat:

> +	/*
> +	 * Despite the fact that it's an int return function, __f_setown never
> +	 * returns an error. Just ignore any error return here, but spew a
> +	 * WARN_ON_ONCE in case this ever changes.
> +	 */
> +	WARN_ON_ONCE(__f_setown(filp, task_pid(current), PIDTYPE_PID, 0));

I don't think this is a good idea.  The errors in __f_setown come from
the security modules, and they could change easily.  If you can convince
the LSM people to change their file_set_fowner routine to return void
we could change __f_setown to return void as well and be done with it,
but without that this looks too dangerous.