Always return DNS_R_UNCHANGED when new slabheader was not added

Change the add() function in the dns_qpcache to properly return
DNS_R_UNCHANGED if the newheader was not actually consumed, and move
the dns_slabheader_destroy() call outside of the add() function.

diff --git a/lib/dns/qpcache.c b/lib/dns/qpcache.c
index c5de17203a02e16d4a47459eccc527deeac837bc..c61b57a50aff74bf00d6f495cf486c379c993e79 100644 (file)
--- a/lib/dns/qpcache.c
+++ b/lib/dns/qpcache.c
@@ -55,6 +55,7 @@
 #include <dns/rdatatype.h>
 #include <dns/stats.h>
 #include <dns/time.h>
+#include <dns/types.h>
 #include <dns/view.h>
 
 #include "db_p.h"
@@ -841,9 +842,9 @@ static void
 mark(dns_slabheader_t *header, uint_least16_t flag) {
        uint_least16_t attributes = atomic_load_acquire(&header->attributes);
        uint_least16_t newattributes = 0;
+       qpcache_t *qpdb = HEADERNODE(header)->qpdb;
        dns_stats_t *stats = NULL;
 
-       qpcache_t *qpdb = HEADERNODE(header)->qpdb;
        /*
         * If we are already ancient there is nothing to do.
         */
@@ -860,10 +861,8 @@ mark(dns_slabheader_t *header, uint_least16_t flag) {
         * RRtype.
         */
        stats = dns_db_getrrsetstats(&qpdb->common);
-       if (stats != NULL) {
-               update_rrsetstats(stats, header->typepair, attributes, false);
-               update_rrsetstats(stats, header->typepair, newattributes, true);
-       }
+       update_rrsetstats(stats, header->typepair, attributes, false);
+       update_rrsetstats(stats, header->typepair, newattributes, true);
 }
 
 static void
@@ -2654,7 +2653,6 @@ add(qpcache_t *qpdb, qpcnode_t *qpnode,
                                         * The NXDOMAIN/NODATA(QTYPE=ANY)
                                         * is more trusted.
                                         */
-                                       dns_slabheader_destroy(&newheader);
                                        if (addedrdataset != NULL) {
                                                bindrdataset(
                                                        qpdb, qpnode, topheader,
@@ -2703,7 +2701,6 @@ find_header:
                 * Deleting an already non-existent rdataset has no effect.
                 */
                if (!EXISTS(header) && !EXISTS(newheader)) {
-                       dns_slabheader_destroy(&newheader);
                        return DNS_R_UNCHANGED;
                }
 
@@ -2717,7 +2714,6 @@ find_header:
                if (trust < header->trust &&
                    (ACTIVE(header, now) || !EXISTS(header)))
                {
-                       dns_slabheader_destroy(&newheader);
                        if (addedrdataset != NULL) {
                                bindrdataset(qpdb, qpnode, header, now,
                                             nlocktype, tlocktype,
@@ -2764,13 +2760,12 @@ find_header:
                                header->closest = newheader->closest;
                                newheader->closest = NULL;
                        }
-                       dns_slabheader_destroy(&newheader);
                        if (addedrdataset != NULL) {
                                bindrdataset(qpdb, qpnode, header, now,
                                             nlocktype, tlocktype,
                                             addedrdataset DNS__DB_FLARG_PASS);
                        }
-                       return ISC_R_SUCCESS;
+                       return DNS_R_UNCHANGED;
                }
 
                /*
@@ -2819,13 +2814,12 @@ find_header:
                                header->closest = newheader->closest;
                                newheader->closest = NULL;
                        }
-                       dns_slabheader_destroy(&newheader);
                        if (addedrdataset != NULL) {
                                bindrdataset(qpdb, qpnode, header, now,
                                             nlocktype, tlocktype,
                                             addedrdataset DNS__DB_FLARG_PASS);
                        }
-                       return ISC_R_SUCCESS;
+                       return DNS_R_UNCHANGED;
                }
 
                qpcache_miss(qpdb, newheader, &nlocktype,
@@ -2848,7 +2842,6 @@ find_header:
                 * The type already doesn't exist; no point trying
                 * to delete it.
                 */
-               dns_slabheader_destroy(&newheader);
                return DNS_R_UNCHANGED;
        } else {
                /* No rdatasets of the given type exist at the node. */
@@ -3051,7 +3044,6 @@ qpcache_addrdataset(dns_db_t *db, dns_dbnode_t *node, dns_dbversion_t *version,
                result = addnoqname(qpnode->mctx, newheader, qpdb->maxrrperset,
                                    rdataset);
                if (result != ISC_R_SUCCESS) {
-                       dns_slabheader_destroy(&newheader);
                        return result;
                }
        }
@@ -3059,7 +3051,6 @@ qpcache_addrdataset(dns_db_t *db, dns_dbnode_t *node, dns_dbversion_t *version,
                result = addclosest(qpnode->mctx, newheader, qpdb->maxrrperset,
                                    rdataset);
                if (result != ISC_R_SUCCESS) {
-                       dns_slabheader_destroy(&newheader);
                        return result;
                }
        }
@@ -3125,8 +3116,12 @@ qpcache_addrdataset(dns_db_t *db, dns_dbnode_t *node, dns_dbversion_t *version,
        result = add(qpdb, qpnode, name, newheader, options, addedrdataset, now,
                     nlocktype, tlocktype DNS__DB_FLARG_PASS);
 
-       if (result == ISC_R_SUCCESS && delegating) {
-               qpnode->delegating = 1;
+       if (result == ISC_R_SUCCESS) {
+               if (delegating) {
+                       qpnode->delegating = 1;
+               }
+       } else {
+               dns_slabheader_destroy(&newheader);
        }
 
        NODE_UNLOCK(nlock, &nlocktype);
@@ -3181,6 +3176,9 @@ qpcache_deleterdataset(dns_db_t *db, dns_dbnode_t *node,
        NODE_WRLOCK(nlock, &nlocktype);
        result = add(qpdb, qpnode, NULL, newheader, DNS_DBADD_FORCE, NULL, 0,
                     nlocktype, isc_rwlocktype_none DNS__DB_FLARG_PASS);
+       if (result != ISC_R_SUCCESS) {
+               dns_slabheader_destroy(&newheader);
+       }
        NODE_UNLOCK(nlock, &nlocktype);
 
        return result;