rangevargetrelid-callback.patch

diff --git a/src/backend/catalog/index.c b/src/backend/catalog/index.c
index 99e130c..2eab82b 100644
--- a/src/backend/catalog/index.c
+++ b/src/backend/catalog/index.c
@@ -111,7 +111,6 @@ static void validate_index_heapscan(Relation heapRelation,
 						IndexInfo *indexInfo,
 						Snapshot snapshot,
 						v_i_state *state);
-static Oid	IndexGetRelation(Oid indexId);
 static bool ReindexIsCurrentlyProcessingIndex(Oid indexOid);
 static void SetReindexProcessing(Oid heapOid, Oid indexOid);
 static void ResetReindexProcessing(void);
@@ -2763,7 +2762,7 @@ validate_index_heapscan(Relation heapRelation,
  * IndexGetRelation: given an index's relation OID, get the OID of the
  * relation it is an index on.	Uses the system cache.
  */
-static Oid
+Oid
 IndexGetRelation(Oid indexId)
 {
 	HeapTuple	tuple;
diff --git a/src/backend/catalog/namespace.c b/src/backend/catalog/namespace.c
index 6d4d4b1..c74168c 100644
--- a/src/backend/catalog/namespace.c
+++ b/src/backend/catalog/namespace.c
@@ -219,10 +219,14 @@ Datum		pg_is_other_temp_schema(PG_FUNCTION_ARGS);
  * otherwise raise an error.
  *
  * If nowait = true, throw an error if we'd have to wait for a lock.
+ *
+ * Callback allows caller to check permissions or acquire additional locks
+ * prior to grabbing the relation lock.
  */
 Oid
-RangeVarGetRelid(const RangeVar *relation, LOCKMODE lockmode, bool missing_ok,
-				 bool nowait)
+RangeVarGetRelidExtended(const RangeVar *relation, LOCKMODE lockmode,
+						 bool missing_ok, bool nowait,
+						 RangeVarGetRelidCallback callback)
 {
 	uint64		inval_count;
 	Oid			relId;
@@ -336,6 +340,19 @@ RangeVarGetRelid(const RangeVar *relation, LOCKMODE lockmode, bool missing_ok,
 		}
 
 		/*
+		 * Invoke caller-supplied callback, if any.
+		 *
+		 * This callback is a good place to check permissions: we haven't taken
+		 * the table lock yet (and it's really best to check permissions before
+		 * locking anything!), but we've gotten far enough to know what OID we
+		 * think we should lock.  Of course, concurrent DDL might things while
+		 * we're waiting for the lock, but in that case the callback will be
+		 * invoked again for the new OID.
+		 */
+		if (callback)
+			callback(relation, relId, oldRelId);
+
+		/*
 		 * Lock relation.  This will also accept any pending invalidation
 		 * messages.  If we got back InvalidOid, indicating not found, then
 		 * there's nothing to lock, but we accept invalidation messages
diff --git a/src/backend/commands/indexcmds.c b/src/backend/commands/indexcmds.c
index 69aa5bf..174a194 100644
--- a/src/backend/commands/indexcmds.c
+++ b/src/backend/commands/indexcmds.c
@@ -63,7 +63,10 @@ static void ComputeIndexAttrs(IndexInfo *indexInfo,
 static Oid GetIndexOpClass(List *opclass, Oid attrType,
 				char *accessMethodName, Oid accessMethodId);
 static char *ChooseIndexNameAddition(List *colnames);
-
+static void RangeVarCallbackForReindexTable(const RangeVar *relation,
+								Oid relId, Oid oldRelId);
+static void RangeVarCallbackForReindexIndex(const RangeVar *relation,
+								Oid relId, Oid oldRelId);
 
 /*
  * CheckIndexCompatible
@@ -1725,33 +1728,47 @@ void
 ReindexIndex(RangeVar *indexRelation)
 {
 	Oid			indOid;
+
+	/* lock level used here should match index lock reindex_index() */
+	indOid = RangeVarGetRelidExtended(indexRelation, AccessExclusiveLock,
+									  false, false,
+									  RangeVarCallbackForReindexIndex);
+
+	reindex_index(indOid, false);
+}
+
+/*
+ * Check permissions on table before acquiring relation lock; also lock
+ * the heap before the RangeVarGetRelid() takes the index lock, to avoid
+ * deadlocks.
+ */
+static void
+RangeVarCallbackForReindexIndex(const RangeVar *relation,
+								Oid relId, Oid oldRelId)
+{
 	HeapTuple	tuple;
 
-	/*
-	 * XXX: This is not safe in the presence of concurrent DDL. We should
-	 * take AccessExclusiveLock here, but that would violate the rule that
-	 * indexes should only be locked after their parent tables.  For now,
-	 * we live with it.
-	 */
-	indOid = RangeVarGetRelid(indexRelation, NoLock, false, false);
-	tuple = SearchSysCache1(RELOID, ObjectIdGetDatum(indOid));
+	tuple = SearchSysCache1(RELOID, ObjectIdGetDatum(relId));
 	if (!HeapTupleIsValid(tuple))
-		elog(ERROR, "cache lookup failed for relation %u", indOid);
+		elog(ERROR, "cache lookup failed for relation %u", relId);
 
 	if (((Form_pg_class) GETSTRUCT(tuple))->relkind != RELKIND_INDEX)
 		ereport(ERROR,
 				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
 				 errmsg("\"%s\" is not an index",
-						indexRelation->relname)));
+						relation->relname)));
 
 	/* Check permissions */
-	if (!pg_class_ownercheck(indOid, GetUserId()))
+	if (!pg_class_ownercheck(relId, GetUserId()))
 		aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
-					   indexRelation->relname);
+					   relation->relname);
 
-	ReleaseSysCache(tuple);
+	/* lock levels here should match reindex_index() heap lock */
+	if (OidIsValid(oldRelId))
+		UnlockRelationOid(IndexGetRelation(oldRelId), ShareLock);
+	LockRelationOid(IndexGetRelation(relId), ShareLock);
 
-	reindex_index(indOid, false);
+	ReleaseSysCache(tuple);
 }
 
 /*
@@ -1762,13 +1779,29 @@ void
 ReindexTable(RangeVar *relation)
 {
 	Oid			heapOid;
-	HeapTuple	tuple;
 
 	/* The lock level used here should match reindex_relation(). */
-	heapOid = RangeVarGetRelid(relation, ShareLock, false, false);
-	tuple = SearchSysCache1(RELOID, ObjectIdGetDatum(heapOid));
+	heapOid = RangeVarGetRelidExtended(relation, ShareLock, false, false,
+									   RangeVarCallbackForReindexTable);
+
+	if (!reindex_relation(heapOid, REINDEX_REL_PROCESS_TOAST))
+		ereport(NOTICE,
+				(errmsg("table \"%s\" has no indexes",
+						relation->relname)));
+}
+
+/*
+ * Check permissions on table before acquiring relation lock.
+ */
+static void
+RangeVarCallbackForReindexTable(const RangeVar *relation,
+								Oid relId, Oid oldRelId)
+{
+	HeapTuple	tuple;
+
+	tuple = SearchSysCache1(RELOID, ObjectIdGetDatum(relId));
 	if (!HeapTupleIsValid(tuple))		/* shouldn't happen */
-		elog(ERROR, "cache lookup failed for relation %u", heapOid);
+		elog(ERROR, "cache lookup failed for relation %u", relId);
 
 	if (((Form_pg_class) GETSTRUCT(tuple))->relkind != RELKIND_RELATION &&
 		((Form_pg_class) GETSTRUCT(tuple))->relkind != RELKIND_TOASTVALUE)
@@ -1778,16 +1811,11 @@ ReindexTable(RangeVar *relation)
 						relation->relname)));
 
 	/* Check permissions */
-	if (!pg_class_ownercheck(heapOid, GetUserId()))
+	if (!pg_class_ownercheck(relId, GetUserId()))
 		aclcheck_error(ACLCHECK_NOT_OWNER, ACL_KIND_CLASS,
 					   relation->relname);
 
 	ReleaseSysCache(tuple);
-
-	if (!reindex_relation(heapOid, REINDEX_REL_PROCESS_TOAST))
-		ereport(NOTICE,
-				(errmsg("table \"%s\" has no indexes",
-						relation->relname)));
 }
 
 /*
diff --git a/src/include/catalog/index.h b/src/include/catalog/index.h
index 8b78b05..5b09b9f 100644
--- a/src/include/catalog/index.h
+++ b/src/include/catalog/index.h
@@ -99,5 +99,6 @@ extern bool reindex_relation(Oid relid, int flags);
 
 extern bool ReindexIsProcessingHeap(Oid heapOid);
 extern bool ReindexIsProcessingIndex(Oid indexOid);
+extern Oid IndexGetRelation(Oid indexId);
 
 #endif   /* INDEX_H */
diff --git a/src/include/catalog/namespace.h b/src/include/catalog/namespace.h
index 904c6fd..97f8e72 100644
--- a/src/include/catalog/namespace.h
+++ b/src/include/catalog/namespace.h
@@ -47,9 +47,15 @@ typedef struct OverrideSearchPath
 	bool		addTemp;		/* implicitly prepend temp schema? */
 } OverrideSearchPath;
 
+typedef void (*RangeVarGetRelidCallback)(const RangeVar *relation, Oid relId,
+	Oid oldRelId);
 
-extern Oid	RangeVarGetRelid(const RangeVar *relation, LOCKMODE lockmode,
-				 bool missing_ok, bool nowait);
+#define RangeVarGetRelid(relation, lockmode, missing_ok, nowait) \
+		RangeVarGetRelidExtended(relation, lockmode, missing_ok, nowait, NULL)
+
+extern Oid	RangeVarGetRelidExtended(const RangeVar *relation,
+						 LOCKMODE lockmode, bool missing_ok, bool nowait,
+						 RangeVarGetRelidCallback callback);
 extern Oid	RangeVarGetCreationNamespace(const RangeVar *newRelation);
 extern Oid	RangeVarGetAndCheckCreationNamespace(const RangeVar *newRelation);
 extern void RangeVarAdjustRelationPersistence(RangeVar *newRelation, Oid nspid);