[the previous commit to pseudofs_vncache.c got the wrong log message]

YA pseudofs megacommit, part 2:

 - Merge the pfs_vnode and pfs_vdata structures, and make the vnode cache
   a doubly-linked list.  This eliminates the need to walk the list in
   pfs_vncache_free().

 - Add an exit callout which revokes vnodes associated with the process
   that just exited.  Since it needs to lock the cache when it does this,
   pfs_vncache_mutex needs MTX_RECURSE.

sys/fs/pseudofs/pseudofs_internal.h

@@ -42,6 +42,8 @@ SYSCTL_DECL(_vfs_pfs);
 struct pfs_vdata {
 	struct pfs_node	*pvd_pn;
 	pid_t		 pvd_pid;
+	struct vnode	*pvd_vnode;
+	struct pfs_vdata*pvd_prev, *pvd_next;
 };
 
 /*