ubifs_add_bud_to_log
err = ubifs_add_bud_to_log(c, GCHD, gc_lnum, 0);
err = ubifs_add_bud_to_log(c, jhead, lnum, offs);
int ubifs_add_bud_to_log(struct ubifs_info *c, int jhead, int lnum, int offs);