msdosfs_root
.vfs_root = msdosfs_root,
int msdosfs_root(struct mount *, struct vnode **);
int msdosfs_root(struct mount *, struct vnode **);
if (msdosfs_root(pmp, &rootvp) != 0)
int msdosfs_root(struct msdosfsmount *, struct mkfsvnode *);