diff --git a/sys/sys/jail.h b/sys/sys/jail.h
index 74d524790a0..117e13401a2 100644
--- a/sys/sys/jail.h
+++ b/sys/sys/jail.h
@@ -149,30 +149,32 @@ struct prison {
 	int		 pr_ref;			/* (p) refcount */
 	int		 pr_uref;			/* (p) user (alive) refcount */
 	unsigned	 pr_flags;			/* (p) PR_* flags */
-	char		 pr_path[MAXPATHLEN];		/* (c) chroot path */
-	struct cpuset	*pr_cpuset;			/* (p) cpuset */
-	struct vnode	*pr_root;			/* (c) vnode to rdir */
-	char		 pr_hostname[MAXHOSTNAMELEN];	/* (p) jail hostname */
-	char		 pr_name[MAXHOSTNAMELEN];	/* (p) admin jail name */
-	struct prison	*pr_parent;			/* (c) containing jail */
-	int		 pr_securelevel;		/* (p) securelevel */
-	struct task	 pr_task;			/* (d) destroy task */
-	struct mtx	 pr_mtx;
-	struct osd	 pr_osd;			/* (p) additional data */
-	int		 pr_ip4s;			/* (p) number of v4 IPs */
-	struct in_addr	*pr_ip4;			/* (p) v4 IPs of jail */
-	int		 pr_ip6s;			/* (p) number of v6 IPs */
-	struct in6_addr	*pr_ip6;			/* (p) v6 IPs of jail */
 	LIST_HEAD(, prison) pr_children;		/* (a) list of child jails */
 	LIST_ENTRY(prison) pr_sibling;			/* (a) next in parent's list */
+	struct prison	*pr_parent;			/* (c) containing jail */
+	struct mtx	 pr_mtx;
+	struct task	 pr_task;			/* (d) destroy task */
+	struct osd	 pr_osd;			/* (p) additional data */
+	struct cpuset	*pr_cpuset;			/* (p) cpuset */
+	struct vnet	*pr_vnet;			/* (c) network stack */
+	struct vnode	*pr_root;			/* (c) vnode to rdir */
+	int		 pr_ip4s;			/* (p) number of v4 IPs */
+	int		 pr_ip6s;			/* (p) number of v6 IPs */
+	struct in_addr	*pr_ip4;			/* (p) v4 IPs of jail */
+	struct in6_addr	*pr_ip6;			/* (p) v6 IPs of jail */
+	void		*pr_sparep[4];
 	int		 pr_childcount;			/* (a) number of child jails */
+	int		 pr_childmax;			/* (p) maximum child jails */
 	unsigned	 pr_allow;			/* (p) PR_ALLOW_* flags */
+	int		 pr_securelevel;		/* (p) securelevel */
 	int		 pr_enforce_statfs;		/* (p) statfs permission */
+	int		 pr_spare[5];
+	unsigned long	 pr_hostid;			/* (p) jail hostid */
+	char		 pr_name[MAXHOSTNAMELEN];	/* (p) admin jail name */
+	char		 pr_path[MAXPATHLEN];		/* (c) chroot path */
+	char		 pr_hostname[MAXHOSTNAMELEN];	/* (p) jail hostname */
 	char		 pr_domainname[MAXHOSTNAMELEN];	/* (p) jail domainname */
 	char		 pr_hostuuid[HOSTUUIDLEN];	/* (p) jail hostuuid */
-	unsigned long	 pr_hostid;			/* (p) jail hostid */
-	struct vnet	*pr_vnet;			/* (c) network stack */
-	int		 pr_childmax;			/* (p) maximum child jails */
 };
 #endif /* _KERNEL || _WANT_PRISON */