vncache_enter
vp = vncache_enter(&st, NULL, name, fd);
vp = vncache_enter(&st, dvp, name, fd);
vp = vncache_enter(&st, dvp, name, fd);
*vpp = vncache_enter(&st, dvp, name, fd);
vnode_t *vncache_enter(struct stat *, vnode_t *, char *, int);