Function zap_expand_leaf

freebsd/contrib/openzfs/module/zfs/zap.c:627–714

}

static int
zap_expand_leaf(zap_name_t *zn, zap_leaf_t *l,
    void *tag, dmu_tx_t *tx, zap_leaf_t **lp)
{
	zap_t *zap = zn->zn_zap;
	uint64_t hash = zn->zn_hash;
	int err;
	int old_prefix_len = zap_leaf_phys(l)->l_hdr.lh_prefix_len;

	ASSERT3U(old_prefix_len, <=, zap_f_phys(zap)->zap_ptrtbl.zt_shift);
	ASSERT(RW_LOCK_HELD(&zap->zap_rwlock));

	ASSERT3U(ZAP_HASH_IDX(hash, old_prefix_len), ==,
	    zap_leaf_phys(l)->l_hdr.lh_prefix);

	if (zap_tryupgradedir(zap, tx) == 0 ||
	    old_prefix_len == zap_f_phys(zap)->zap_ptrtbl.zt_shift) {
		/* We failed to upgrade, or need to grow the pointer table */
		objset_t *os = zap->zap_objset;
		uint64_t object = zap->zap_object;

		zap_put_leaf(l);
		zap_unlockdir(zap, tag);
		err = zap_lockdir(os, object, tx, RW_WRITER,
		    FALSE, FALSE, tag, &zn->zn_zap);
		zap = zn->zn_zap;
		if (err != 0)
			return (err);
		ASSERT(!zap->zap_ismicro);

		while (old_prefix_len ==
		    zap_f_phys(zap)->zap_ptrtbl.zt_shift) {
			err = zap_grow_ptrtbl(zap, tx);
			if (err != 0)
				return (err);
		}

		err = zap_deref_leaf(zap, hash, tx, RW_WRITER, &l);
		if (err != 0)
			return (err);

		if (zap_leaf_phys(l)->l_hdr.lh_prefix_len != old_prefix_len) {
			/* it split while our locks were down */
			*lp = l;
			return (0);
		}
	}
	ASSERT(RW_WRITE_HELD(&zap->zap_rwlock));
	ASSERT3U(old_prefix_len, <, zap_f_phys(zap)->zap_ptrtbl.zt_shift);
	ASSERT3U(ZAP_HASH_IDX(hash, old_prefix_len), ==,
	    zap_leaf_phys(l)->l_hdr.lh_prefix);

	int prefix_diff = zap_f_phys(zap)->zap_ptrtbl.zt_shift -
	    (old_prefix_len + 1);
	uint64_t sibling =
	    (ZAP_HASH_IDX(hash, old_prefix_len + 1) | 1) << prefix_diff;

	/* check for i/o errors before doing zap_leaf_split */