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4338. [bug] Reimplement change 4324 as it wasn't properly doing
all the required book keeping. [RT #41941]
(cherry picked from commit 558278974e)
This commit is contained in:
Mark Andrews
parent
5cc724937d
commit
a84d2e5e04
3 changed files with 66 additions and 100 deletions
3
CHANGES
3
CHANGES
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@ -1,3 +1,6 @@
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4338. [bug] Reimplement change 4324 as it wasn't properly doing
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all the required book keeping. [RT #41941]
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4337. [bug] The previous change exposed a latent flaw in
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key refresh queries for managed-keys when
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a cached DNSKEY had TTL 0. [RT #41986]
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103
lib/dns/rbt.c
103
lib/dns/rbt.c
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@ -242,12 +242,15 @@ dns_rbt_addonlevel(dns_rbtnode_t *node, dns_rbtnode_t *current, int order,
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dns_rbtnode_t **rootp);
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static void
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dns_rbt_deletefromlevel(dns_rbtnode_t *delete, dns_rbtnode_t **rootp);
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deletefromlevel(dns_rbtnode_t *delete, dns_rbtnode_t **rootp);
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static void
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deletetreeflat(dns_rbt_t *rbt, unsigned int quantum, isc_boolean_t unhash,
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dns_rbtnode_t **nodep);
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static void
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freenode(dns_rbt_t *rbt, dns_rbtnode_t **nodep);
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/*
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* Initialize a red/black tree of trees.
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*/
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@ -1371,91 +1374,29 @@ dns_rbt_deletenode(dns_rbt_t *rbt, dns_rbtnode_t *node, isc_boolean_t recurse)
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}
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}
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for (;;) {
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/*
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* Note the node that points to the level of the node
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* that is being deleted. If the deleted node is the
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* top level, parent will be set to NULL.
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*/
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parent = get_upper_node(node);
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/*
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* Note the node that points to the level of the node
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* that is being deleted. If the deleted node is the
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* top level, parent will be set to NULL.
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*/
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parent = get_upper_node(node);
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/*
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* This node now has no down pointer (either because it didn't
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* have one to start, or because it was recursively removed).
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* So now the node needs to be removed from this level.
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*/
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dns_rbt_deletefromlevel(node, parent == NULL ? &rbt->root :
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&DOWN(parent));
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/*
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* This node now has no down pointer, so now it needs
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* to be removed from this level.
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*/
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deletefromlevel(node, parent == NULL ? &rbt->root : &DOWN(parent));
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if (DATA(node) != NULL && rbt->data_deleter != NULL)
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rbt->data_deleter(DATA(node), rbt->deleter_arg);
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if (DATA(node) != NULL && rbt->data_deleter != NULL)
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rbt->data_deleter(DATA(node), rbt->deleter_arg);
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unhash_node(rbt, node);
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unhash_node(rbt, node);
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#if DNS_RBT_USEMAGIC
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node->magic = 0;
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node->magic = 0;
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#endif
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dns_rbtnode_refdestroy(node);
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isc_mem_put(rbt->mctx, node, NODE_SIZE(node));
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rbt->nodecount--;
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dns_rbtnode_refdestroy(node);
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/*
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* There are now two special cases that can exist that
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* would not have existed if the tree had been created
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* using only the names that now exist in it. (This is
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* all related to join_nodes() as described in this
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* function's introductory comment.) Both cases exist
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* when the deleted node's parent (the node that pointed
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* to the deleted node's level) is not null but it has
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* no data: parent != NULL && DATA(parent) == NULL.
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*
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* The first case is that the deleted node was the last
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* on its level: DOWN(parent) == NULL. This case can
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* only exist if the parent was previously deleted --
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* and so now, apparently, the parent should go away.
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* That can't be done though because there might be
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* external references to it, such as through a
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* nodechain. XXXMUKS: We don't care about this.
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*
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* The other case also involves a parent with no data,
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* but with the deleted node being the next-to-last node
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* instead of the last: LEFT(DOWN(parent)) == NULL &&
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* RIGHT(DOWN(parent)) == NULL. Presumably now the
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* remaining node on the level should be joined with the
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* parent, but it's already been described why that
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* can't be done.
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*/
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/*
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* Is this the root?.
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*/
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if (parent == NULL)
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break;
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/*
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* If the node deletion did not cause the subtree to disappear
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* completely, return early.
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*/
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if (DOWN(parent) != NULL)
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break;
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/*
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* If the upper node is not empty, it cannot be deleted.
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*/
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if (DATA(parent) != NULL)
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break;
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/*
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* If upper node is the root node (.), don't attempt to
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* delete it. The root node must always exist.
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*/
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if (parent == rbt->root)
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break;
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/*
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* Ascend up the tree and delete the upper node.
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*/
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node = parent;
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}
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freenode(rbt, &node);
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/*
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* This function never fails.
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@ -1869,7 +1810,7 @@ dns_rbt_addonlevel(dns_rbtnode_t *node, dns_rbtnode_t *current, int order,
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* true red/black tree on a single level.
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*/
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static void
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dns_rbt_deletefromlevel(dns_rbtnode_t *delete, dns_rbtnode_t **rootp) {
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deletefromlevel(dns_rbtnode_t *delete, dns_rbtnode_t **rootp) {
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dns_rbtnode_t *child, *sibling, *parent;
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dns_rbtnode_t *successor;
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@ -1726,6 +1726,24 @@ delete_node(dns_rbtdb_t *rbtdb, dns_rbtnode_t *node)
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}
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}
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/*
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* Caller must be holding the node lock.
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*/
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static inline void
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new_reference(dns_rbtdb_t *rbtdb, dns_rbtnode_t *node) {
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unsigned int lockrefs, noderefs;
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isc_refcount_t *lockref;
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INSIST(!ISC_LINK_LINKED(node, deadlink));
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dns_rbtnode_refincrement0(node, &noderefs);
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if (noderefs == 1) { /* this is the first reference to the node */
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lockref = &rbtdb->node_locks[node->locknum].references;
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isc_refcount_increment0(lockref, &lockrefs);
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INSIST(lockrefs != 0);
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}
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INSIST(noderefs != 0);
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}
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/*%
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* Clean up dead nodes. These are nodes which have no references, and
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* have no data. They are dead but we could not or chose not to delete
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@ -1750,31 +1768,35 @@ cleanup_dead_nodes(dns_rbtdb_t *rbtdb, int bucketnum) {
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INSIST(dns_rbtnode_refcurrent(node) == 0 &&
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node->data == NULL);
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delete_node(rbtdb, node);
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if (node->parent != NULL &&
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node->parent->down == node && node->left == NULL &&
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node->right == NULL && rbtdb->task != NULL)
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{
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isc_event_t *ev;
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dns_db_t *db;
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ev = isc_event_allocate(rbtdb->common.mctx, NULL,
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DNS_EVENT_RBTPRUNE,
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prune_tree, node,
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sizeof(isc_event_t));
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if (ev != NULL) {
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new_reference(rbtdb, node);
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db = NULL;
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attach((dns_db_t *)rbtdb, &db);
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ev->ev_sender = db;
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isc_task_send(rbtdb->task, &ev);
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} else {
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ISC_LIST_APPEND(rbtdb->deadnodes[bucketnum],
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node, deadlink);
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}
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} else {
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delete_node(rbtdb, node);
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}
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node = ISC_LIST_HEAD(rbtdb->deadnodes[bucketnum]);
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count--;
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}
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}
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/*
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* Caller must be holding the node lock.
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*/
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static inline void
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new_reference(dns_rbtdb_t *rbtdb, dns_rbtnode_t *node) {
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unsigned int lockrefs, noderefs;
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isc_refcount_t *lockref;
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INSIST(!ISC_LINK_LINKED(node, deadlink));
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dns_rbtnode_refincrement0(node, &noderefs);
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if (noderefs == 1) { /* this is the first reference to the node */
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lockref = &rbtdb->node_locks[node->locknum].references;
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isc_refcount_increment0(lockref, &lockrefs);
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INSIST(lockrefs != 0);
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}
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INSIST(noderefs != 0);
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}
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/*
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* This function is assumed to be called when a node is newly referenced
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* and can be in the deadnode list. In that case the node must be retrieved
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