Function zap_cursor_retrieve

freebsd/contrib/openzfs/module/zfs/zap_micro.c:1552–1616

}

int
zap_cursor_retrieve(zap_cursor_t *zc, zap_attribute_t *za)
{
	int err;

	if (zc->zc_hash == -1ULL)
		return (SET_ERROR(ENOENT));

	if (zc->zc_zap == NULL) {
		int hb;
		err = zap_lockdir(zc->zc_objset, zc->zc_zapobj, NULL,
		    RW_READER, TRUE, FALSE, NULL, &zc->zc_zap);
		if (err != 0)
			return (err);

		/*
		 * To support zap_cursor_init_serialized, advance, retrieve,
		 * we must add to the existing zc_cd, which may already
		 * be 1 due to the zap_cursor_advance.
		 */
		ASSERT(zc->zc_hash == 0);
		hb = zap_hashbits(zc->zc_zap);
		zc->zc_hash = zc->zc_serialized << (64 - hb);
		zc->zc_cd += zc->zc_serialized >> hb;
		if (zc->zc_cd >= zap_maxcd(zc->zc_zap)) /* corrupt serialized */
			zc->zc_cd = 0;
	} else {
		rw_enter(&zc->zc_zap->zap_rwlock, RW_READER);
	}
	if (!zc->zc_zap->zap_ismicro) {
		err = fzap_cursor_retrieve(zc->zc_zap, zc, za);
	} else {
		avl_index_t idx;
		mzap_ent_t mze_tofind;

		mze_tofind.mze_hash = zc->zc_hash;
		mze_tofind.mze_cd = zc->zc_cd;

		mzap_ent_t *mze =
		    avl_find(&zc->zc_zap->zap_m.zap_avl, &mze_tofind, &idx);
		if (mze == NULL) {
			mze = avl_nearest(&zc->zc_zap->zap_m.zap_avl,
			    idx, AVL_AFTER);
		}
		if (mze) {
			mzap_ent_phys_t *mzep = MZE_PHYS(zc->zc_zap, mze);
			ASSERT3U(mze->mze_cd, ==, mzep->mze_cd);
			za->za_normalization_conflict =
			    mzap_normalization_conflict(zc->zc_zap, NULL, mze);
			za->za_integer_length = 8;
			za->za_num_integers = 1;
			za->za_first_integer = mzep->mze_value;
			(void) strlcpy(za->za_name, mzep->mze_name,
			    sizeof (za->za_name));
			zc->zc_hash = mze->mze_hash;
			zc->zc_cd = mze->mze_cd;
			err = 0;
		} else {