zfs: read the root znode on mount

bsd/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_vfsops.c

@@ -968,7 +968,7 @@ zfs_domount(vfs_t *vfsp, char *osname)
 	uint64_t recordsize, fsid_guid;
 	int error = 0;
 	zfsvfs_t *zfsvfs;
-	vnode_t *vp;
+	znode_t *rootzp;
 
 	ASSERT(vfsp);
 	ASSERT(osname);
@@ -1018,6 +1018,11 @@ zfs_domount(vfs_t *vfsp, char *osname)
 		error = zfsvfs_setup(zfsvfs, B_TRUE);
 	}
 
+	error = zfs_zget(zfsvfs, zfsvfs->z_root, &rootzp);
+	if (error == 0)
+		vfsp->m_root->v_data = rootzp;
+
+
 #ifdef notyet
 	if (!zfsvfs->z_issnap)
 		zfsctl_create(zfsvfs);