Check relkind for both BRIN and GIST indexes

Previously, only the access method was checked for BRIN and GIST indexes,
allowing non-index relations to be passed.

This commit also removes the pointless IS_INDEX macro.

Suggested-by: Japin Li <japinli@hotmail.com>
Suggested-by: Andrey Borodin <x4mmm@yandex-team.ru>
Reviewed-by: Andreas Karlsson <andreas@proxel.se>
Reviewed-by: Kirill Reshke <reshkekirill@gmail.com>
Reviewed-by: Álvaro Herrera <alvherre@kurilemu.de>

Discussion: https://postgr.es/m/MEAPR01MB3031A889D4B3F610E9D2A3AFB68FA@MEAPR01MB3031.ausprd01.prod.outlook.com
Discussion: https://postgr.es/m/BFCA6110-EC97-4569-917A-747A72F62CE8@yandex-team.ru

Author: japinli

contrib/pageinspect/brinfuncs.c

@@ -29,7 +29,7 @@ PG_FUNCTION_INFO_V1(brin_page_items);
 PG_FUNCTION_INFO_V1(brin_metapage_info);
 PG_FUNCTION_INFO_V1(brin_revmap_data);
 
-#define IS_BRIN(r) ((r)->rd_rel->relam == BRIN_AM_OID)
+#define IS_BRIN(r) ((r)->rd_rel->relkind == RELKIND_INDEX && (r)->rd_rel->relam == BRIN_AM_OID)
 
 typedef struct brin_column_state
 {

contrib/pageinspect/btreefuncs.c

@@ -49,8 +49,7 @@ PG_FUNCTION_INFO_V1(bt_page_stats_1_9);
 PG_FUNCTION_INFO_V1(bt_page_stats);
 PG_FUNCTION_INFO_V1(bt_multi_page_stats);
 
-#define IS_INDEX(r) ((r)->rd_rel->relkind == RELKIND_INDEX)
-#define IS_BTREE(r) ((r)->rd_rel->relam == BTREE_AM_OID)
+#define IS_BTREE(r) ((r)->rd_rel->relkind == RELKIND_INDEX && (r)->rd_rel->relam == BTREE_AM_OID)
 
 /* ------------------------------------------------
  * structure for single btree page statistics
@@ -225,7 +224,7 @@ check_relation_block_range(Relation rel, int64 blkno)
 static void
 bt_index_block_validate(Relation rel, int64 blkno)
 {
-	if (!IS_INDEX(rel) || !IS_BTREE(rel))
+	if (!IS_BTREE(rel))
 		ereport(ERROR,
 				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
 				 errmsg("\"%s\" is not a %s index",
@@ -858,7 +857,7 @@ bt_metap(PG_FUNCTION_ARGS)
 	relrv = makeRangeVarFromNameList(textToQualifiedNameList(relname));
 	rel = relation_openrv(relrv, AccessShareLock);
 
-	if (!IS_INDEX(rel) || !IS_BTREE(rel))
+	if (!IS_BTREE(rel))
 		ereport(ERROR,
 				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
 				 errmsg("\"%s\" is not a %s index",

contrib/pageinspect/gistfuncs.c

@@ -31,7 +31,7 @@ PG_FUNCTION_INFO_V1(gist_page_opaque_info);
 PG_FUNCTION_INFO_V1(gist_page_items);
 PG_FUNCTION_INFO_V1(gist_page_items_bytea);
 
-#define IS_GIST(r) ((r)->rd_rel->relam == GIST_AM_OID)
+#define IS_GIST(r) ((r)->rd_rel->relkind == RELKIND_INDEX && (r)->rd_rel->relam == GIST_AM_OID)
 
 
 static Page verify_gist_page(bytea *raw_page);

contrib/pageinspect/hashfuncs.c

@@ -28,8 +28,7 @@ PG_FUNCTION_INFO_V1(hash_page_items);
 PG_FUNCTION_INFO_V1(hash_bitmap_info);
 PG_FUNCTION_INFO_V1(hash_metapage_info);
 
-#define IS_INDEX(r) ((r)->rd_rel->relkind == RELKIND_INDEX)
-#define IS_HASH(r) ((r)->rd_rel->relam == HASH_AM_OID)
+#define IS_HASH(r) ((r)->rd_rel->relkind == RELKIND_INDEX && (r)->rd_rel->relam == HASH_AM_OID)
 
 /* ------------------------------------------------
  * structure for single hash page statistics
@@ -420,7 +419,7 @@ hash_bitmap_info(PG_FUNCTION_ARGS)
 	 */
 	indexRel = relation_open(indexRelid, AccessShareLock);
 
-	if (!IS_INDEX(indexRel) || !IS_HASH(indexRel))
+	if (!IS_HASH(indexRel))
 		ereport(ERROR,
 				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
 				 errmsg("\"%s\" is not a %s index",