ceph: close holes in structs ceph_mds_session and ceph_mds_request

	/* protected by s_cap_lock */

	spinlock_t        s_cap_lock;

	refcount_t        s_ref;

	struct list_head  s_caps;     /* all caps issued by this session */

	struct ceph_cap  *s_cap_iterator;

	int               s_nr_caps;

	unsigned long     s_renew_requested; /* last time we sent a renew req */

	u64               s_renew_seq;

	refcount_t        s_ref;

	struct list_head  s_waiting;  /* waiting requests */

	struct list_head  s_unsafe;   /* unsafe requests */

};

	struct rb_node r_node;

	struct ceph_mds_client *r_mdsc;

	struct kref       r_kref;

	int r_op;                    /* mds op code */

	/* operation on what? */

	int               r_resend_mds; /* mds to resend to next, if any*/

	u32               r_sent_on_mseq; /* cap mseq request was sent at*/

	struct kref       r_kref;

	struct list_head  r_wait;

	struct completion r_completion;

	struct completion r_safe_completion;