mdb_zfs_btree_hdr_t
mdb_zfs_btree_hdr_t btc_hdr;
mdb_zfs_btree_hdr_t btl_hdr;
mdb_zfs_btree_hdr_t *bwd_node;
btree_leftmost_child(uintptr_t addr, mdb_zfs_btree_hdr_t *buf)