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https://gitlab.isc.org/isc-projects/bind9
synced 2025-08-29 13:38:26 +00:00
Refactor check_stale_header() function
The check_stale_header() function now updates header_prev directly so it doesn't have to be handled in the outer loop; it's always set to the correct value of the previous header in the chain.
This commit is contained in:
Ondřej Surý
Evan Hunt
parent
b24981ea02
commit
53d9ef5bd0
@ -1196,97 +1196,92 @@ static bool
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check_stale_header(qpcnode_t *node, dns_slabheader_t *header,
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isc_rwlocktype_t *nlocktypep, isc_rwlock_t *nlock,
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qpc_search_t *search, dns_slabheader_t **header_prev) {
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if (!ACTIVE(header, search->now)) {
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dns_ttl_t stale = header->expire +
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STALE_TTL(header, search->qpdb);
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/*
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* If this data is in the stale window keep it and if
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* DNS_DBFIND_STALEOK is not set we tell the caller to
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* skip this record. We skip the records with ZEROTTL
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* (these records should not be cached anyway).
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*/
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DNS_SLABHEADER_CLRATTR(header, DNS_SLABHEADERATTR_STALE_WINDOW);
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if (!ZEROTTL(header) && KEEPSTALE(search->qpdb) &&
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stale > search->now)
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{
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mark(header, DNS_SLABHEADERATTR_STALE);
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*header_prev = header;
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/*
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* If DNS_DBFIND_STALESTART is set then it means we
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* failed to resolve the name during recursion, in
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* this case we mark the time in which the refresh
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* failed.
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*/
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if ((search->options & DNS_DBFIND_STALESTART) != 0) {
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atomic_store_release(
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&header->last_refresh_fail_ts,
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search->now);
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} else if ((search->options &
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DNS_DBFIND_STALEENABLED) != 0 &&
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search->now <
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(atomic_load_acquire(
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&header->last_refresh_fail_ts) +
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search->qpdb->serve_stale_refresh))
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{
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/*
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* If we are within interval between last
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* refresh failure time + 'stale-refresh-time',
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* then don't skip this stale entry but use it
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* instead.
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*/
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DNS_SLABHEADER_SETATTR(
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header,
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DNS_SLABHEADERATTR_STALE_WINDOW);
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return false;
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} else if ((search->options &
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DNS_DBFIND_STALETIMEOUT) != 0)
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{
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/*
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* We want stale RRset due to timeout, so we
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* don't skip it.
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*/
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return false;
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}
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return (search->options & DNS_DBFIND_STALEOK) == 0;
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}
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/*
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* This rdataset is stale. If no one else is using the
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* node, we can clean it up right now, otherwise we mark
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* it as ancient, and the node as dirty, so it will get
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* cleaned up later.
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*/
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if ((header->expire < search->now - QPDB_VIRTUAL) &&
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(*nlocktypep == isc_rwlocktype_write ||
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NODE_TRYUPGRADE(nlock, nlocktypep) == ISC_R_SUCCESS))
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{
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/*
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* We update the node's status only when we can
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* get write access; otherwise, we leave others
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* to this work. Periodical cleaning will
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* eventually take the job as the last resort.
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* We won't downgrade the lock, since other
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* rdatasets are probably stale, too.
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*/
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if (isc_refcount_current(&node->references) == 0) {
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clean_stale_headers(header);
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if (*header_prev != NULL) {
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(*header_prev)->next = header->next;
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} else {
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node->data = header->next;
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}
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dns_slabheader_destroy(&header);
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} else {
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mark_ancient(header);
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*header_prev = header;
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}
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} else {
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*header_prev = header;
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}
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return true;
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if (ACTIVE(header, search->now)) {
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*header_prev = header;
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return false;
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}
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return false;
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isc_stdtime_t stale = header->expire + STALE_TTL(header, search->qpdb);
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/*
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* If this data is in the stale window keep it and if
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* DNS_DBFIND_STALEOK is not set we tell the caller to
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* skip this record. We skip the records with ZEROTTL
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* (these records should not be cached anyway).
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*/
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DNS_SLABHEADER_CLRATTR(header, DNS_SLABHEADERATTR_STALE_WINDOW);
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if (!ZEROTTL(header) && KEEPSTALE(search->qpdb) && stale > search->now)
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{
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mark(header, DNS_SLABHEADERATTR_STALE);
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*header_prev = header;
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/*
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* If DNS_DBFIND_STALESTART is set then it means we
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* failed to resolve the name during recursion, in
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* this case we mark the time in which the refresh
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* failed.
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*/
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if ((search->options & DNS_DBFIND_STALESTART) != 0) {
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atomic_store_release(&header->last_refresh_fail_ts,
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search->now);
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} else if ((search->options & DNS_DBFIND_STALEENABLED) != 0 &&
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search->now <
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(atomic_load_acquire(
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&header->last_refresh_fail_ts) +
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search->qpdb->serve_stale_refresh))
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{
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/*
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* If we are within interval between last
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* refresh failure time + 'stale-refresh-time',
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* then don't skip this stale entry but use it
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* instead.
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*/
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DNS_SLABHEADER_SETATTR(header,
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DNS_SLABHEADERATTR_STALE_WINDOW);
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return false;
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} else if ((search->options & DNS_DBFIND_STALETIMEOUT) != 0) {
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/*
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* We want stale RRset due to timeout, so we
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* don't skip it.
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*/
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return false;
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}
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return (search->options & DNS_DBFIND_STALEOK) == 0;
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}
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/*
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* This rdataset is stale. If no one else is using the
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* node, we can clean it up right now, otherwise we mark
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* it as ancient, and the node as dirty, so it will get
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* cleaned up later.
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*/
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if ((header->expire < search->now - QPDB_VIRTUAL) &&
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(*nlocktypep == isc_rwlocktype_write ||
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NODE_TRYUPGRADE(nlock, nlocktypep) == ISC_R_SUCCESS))
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{
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/*
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* We update the node's status only when we can
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* get write access; otherwise, we leave others
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* to this work. Periodical cleaning will
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* eventually take the job as the last resort.
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* We won't downgrade the lock, since other
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* rdatasets are probably stale, too.
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*/
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if (isc_refcount_current(&node->references) == 0) {
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clean_stale_headers(header);
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if (*header_prev != NULL) {
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(*header_prev)->next = header->next;
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} else {
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node->data = header->next;
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}
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dns_slabheader_destroy(&header);
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} else {
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mark_ancient(header);
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*header_prev = header;
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}
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} else {
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*header_prev = header;
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}
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return true;
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}
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static isc_result_t
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@ -1312,19 +1307,17 @@ check_zonecut(qpcnode_t *node, void *arg DNS__DB_FLARG) {
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if (check_stale_header(node, header, &nlocktype, nlock, search,
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&header_prev))
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{
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/* Do nothing. */
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} else if (header->type == dns_rdatatype_dname &&
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EXISTS(header) && !ANCIENT(header))
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continue;
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}
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if (header->type == dns_rdatatype_dname && EXISTS(header) &&
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!ANCIENT(header))
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{
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dname_header = header;
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header_prev = header;
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} else if (header->type == DNS_SIGTYPE(dns_rdatatype_dname) &&
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EXISTS(header) && !ANCIENT(header))
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{
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sigdname_header = header;
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header_prev = header;
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} else {
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header_prev = header;
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}
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}
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@ -1387,8 +1380,10 @@ find_deepest_zonecut(qpc_search_t *search, qpcnode_t *node,
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if (check_stale_header(node, header, &nlocktype, nlock,
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search, &header_prev))
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{
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/* Do nothing. */
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} else if (EXISTS(header) && !ANCIENT(header)) {
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continue;
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}
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if (EXISTS(header) && !ANCIENT(header)) {
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/*
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* We've found an extant rdataset. See if
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* we're interested in it.
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@ -1406,9 +1401,6 @@ find_deepest_zonecut(qpc_search_t *search, qpcnode_t *node,
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break;
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}
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}
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header_prev = header;
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} else {
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header_prev = header;
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}
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}
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@ -1533,8 +1525,8 @@ find_coveringnsec(qpc_search_t *search, const dns_name_t *name,
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{
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continue;
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}
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if (!EXISTS(header) || DNS_TYPEPAIR_TYPE(header->type) == 0) {
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header_prev = header;
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continue;
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}
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if (header->type == matchtype) {
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@ -1548,7 +1540,6 @@ find_coveringnsec(qpc_search_t *search, const dns_name_t *name,
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break;
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}
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}
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header_prev = header;
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}
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if (found != NULL) {
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bindrdataset(search->qpdb, node, found, search->now, nlocktype,
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@ -1724,8 +1715,10 @@ qpcache_find(dns_db_t *db, const dns_name_t *name, dns_dbversion_t *version,
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if (check_stale_header(node, header, &nlocktype, nlock, &search,
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&header_prev))
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{
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/* Do nothing. */
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} else if (EXISTS(header) && !ANCIENT(header)) {
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continue;
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}
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if (EXISTS(header) && !ANCIENT(header)) {
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/*
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* We now know that there is at least one active
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* non-stale rdataset at this node.
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@ -1811,9 +1804,6 @@ qpcache_find(dns_db_t *db, const dns_name_t *name, dns_dbversion_t *version,
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*/
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cnamesig = header;
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}
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header_prev = header;
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} else {
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header_prev = header;
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}
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}
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@ -2110,7 +2100,10 @@ qpcache_findzonecut(dns_db_t *db, const dns_name_t *name, unsigned int options,
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*/
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break;
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}
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} else if (EXISTS(header) && !ANCIENT(header)) {
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continue;
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}
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if (EXISTS(header) && !ANCIENT(header)) {
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if (header->type == dns_rdatatype_ns) {
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found = header;
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if (foundsig != NULL) {
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@ -2124,9 +2117,6 @@ qpcache_findzonecut(dns_db_t *db, const dns_name_t *name, unsigned int options,
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break;
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}
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}
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header_prev = header;
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} else {
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header_prev = header;
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}
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}
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