nat_get_nid
f2fs_radix_tree_insert(&nm_i->nat_root, nat_get_nid(ne), ne);
else if (radix_tree_insert(&nm_i->nat_root, nat_get_nid(ne), ne))
radix_tree_delete(&nm_i->nat_root, nat_get_nid(e));
nid_t nid = nat_get_nid(ne);
nid = nat_get_nid(natvec[found - 1]) + 1;