prelim_ref_insert
prelim_ref_insert(fs_info, preftree, ref, sc);
prelim_ref_insert(ctx->fs_info, &preftrees->direct, ref,
prelim_ref_insert(ctx->fs_info, &preftrees->direct,
prelim_ref_insert(ctx->fs_info, &preftrees->direct, ref, NULL);
prelim_ref_insert(fs_info, &preftrees->indirect, ref, NULL);