zfs_btree_poison_node
zfs_btree_poison_node(tree, &l_neighbor->btc_hdr);
zfs_btree_poison_node(tree, hdr);
zfs_btree_poison_node(tree, new_root_hdr);
zfs_btree_poison_node(tree, new_par_hdr);
zfs_btree_poison_node(tree, par_hdr);
zfs_btree_poison_node(tree, par_hdr);
zfs_btree_poison_node(tree, new_hdr);