ret = glfs_read(g->fd, io_u->xfer_buf, io_u->xfer_buflen, 0);
else if (io_u->ddir == DDIR_WRITE)
ret = glfs_write(g->fd, io_u->xfer_buf, io_u->xfer_buflen, 0);
+ else if (io_u->ddir == DDIR_SYNC)
+ ret = glfs_fsync(g->fd);
+ else if (io_u->ddir == DDIR_DATASYNC)
+ ret = glfs_fdatasync(g->fd);
else {
log_err("unsupported operation.\n");
return -EINVAL;