MTOV
vp = MTOV(mnp);
MTOV(mnp)->v_vfsp = vfsp;
vn_exists(MTOV(mnp));
vnode_t *vp = MTOV(&mnt->mnt_node);
struct vnode *vp = MTOV(mnp);
vp = MTOV(mnp);
vnode_t *vp = MTOV(mnp);
*vpp = MTOV(nmnp);
#define MTOD(pnp) ((struct mntdata *)MTOV(pnp)->v_vfsp->vfs_data)