MDEV-28462 Race condition between instant alter and AHI access

- InnoDB AHI tries to access the concurrent instant alter column,
leads to asan failure. Instant alter column should acquire the
clustered index search latch in exclusive mode before changing
the table cache definition.

- Removed the default parameter for the function
btr_search_drop_page_hash_index()

- Addressed the DWITH_INNODB_AHI=0 compilation failure
by passing two parameters from all callers of
btr_search_drop_page_hash_index()

storage/innobase/btr/btr0btr.cc

@@ -994,7 +994,7 @@ static void btr_free_root(buf_block_t* block, mtr_t* mtr, bool invalidate)
 					| MTR_MEMO_PAGE_SX_FIX));
 	ut_ad(mtr->is_named_space(block->page.id.space()));
 
-	btr_search_drop_page_hash_index(block);
+	btr_search_drop_page_hash_index(block, false);
 
 	header = buf_block_get_frame(block) + PAGE_HEADER + PAGE_BTR_SEG_TOP;
 #ifdef UNIV_BTR_DEBUG
@@ -1496,7 +1496,7 @@ btr_page_reorganize_low(
 	buf_frame_copy(temp_page, page);
 
 	if (!recovery) {
-		btr_search_drop_page_hash_index(block);
+		btr_search_drop_page_hash_index(block, false);
 	}
 
 	/* Save the cursor position. */
@@ -1785,7 +1785,7 @@ btr_page_empty(
 	ut_a(!page_zip || page_zip_validate(page_zip, page, index));
 #endif /* UNIV_ZIP_DEBUG */
 
-	btr_search_drop_page_hash_index(block);
+	btr_search_drop_page_hash_index(block, false);
 
 	/* Recreate the page: note that global data on page (possible
 	segment headers, next page-field, etc.) is preserved intact */
@@ -3410,7 +3410,7 @@ btr_lift_page_up(
 		mem_heap_free(heap);
 	}
 
-	btr_search_drop_page_hash_index(block);
+	btr_search_drop_page_hash_index(block, false);
 
 	/* Make the father empty */
 	btr_page_empty(father_block, father_page_zip, index, page_level, mtr);
@@ -3728,7 +3728,7 @@ btr_compress(
 			goto err_exit;
 		}
 
-		btr_search_drop_page_hash_index(block);
+		btr_search_drop_page_hash_index(block, false);
 
 		/* Remove the page from the level list */
 		if (DB_SUCCESS != btr_level_list_remove(index->table->space_id,
@@ -3848,7 +3848,7 @@ btr_compress(
 			goto err_exit;
 		}
 
-		btr_search_drop_page_hash_index(block);
+		btr_search_drop_page_hash_index(block, false);
 
 #ifdef UNIV_BTR_DEBUG
 		if (merge_page_zip && left_page_no == FIL_NULL) {
@@ -4081,7 +4081,7 @@ btr_discard_only_page_on_level(
 		ut_ad(fil_page_index_page_check(page));
 		ut_ad(block->page.id.space() == index->table->space->id);
 		ut_ad(mtr_memo_contains(mtr, block, MTR_MEMO_PAGE_X_FIX));
-		btr_search_drop_page_hash_index(block);
+		btr_search_drop_page_hash_index(block, false);
 
 		if (dict_index_is_spatial(index)) {
 			/* Check any concurrent search having this page */
@@ -4221,7 +4221,7 @@ btr_discard_page(
 
 	page = buf_block_get_frame(block);
 	ut_a(page_is_comp(merge_page) == page_is_comp(page));
-	btr_search_drop_page_hash_index(block);
+	btr_search_drop_page_hash_index(block, false);
 
 	if (left_page_no == FIL_NULL && !page_is_leaf(page)) {
 

storage/innobase/btr/btr0defragment.cc

@@ -486,7 +486,7 @@ btr_defragment_merge_pages(
 		free it. */
 		lock_update_merge_left(to_block, orig_pred,
 				       from_block);
-		btr_search_drop_page_hash_index(from_block);
+		btr_search_drop_page_hash_index(from_block, false);
 
 		ut_a(DB_SUCCESS == btr_level_list_remove(
 			index->table->space_id,

storage/innobase/btr/btr0sea.cc

@@ -682,7 +682,7 @@ btr_search_update_hash_ref(
 
 	if (cursor->index != index) {
 		ut_ad(cursor->index->id == index->id);
-		btr_search_drop_page_hash_index(block);
+		btr_search_drop_page_hash_index(block, false);
 		return;
 	}
 
@@ -1312,7 +1312,7 @@ void btr_search_drop_page_hash_when_freed(const page_id_t page_id)
 			dropping the table (preventing eviction). */
 			ut_ad(index->table->get_ref_count() > 0
 			      || mutex_own(&dict_sys->mutex));
-			btr_search_drop_page_hash_index(block);
+			btr_search_drop_page_hash_index(block, false);
 		}
 	}
 
@@ -1384,7 +1384,7 @@ btr_search_build_page_hash_index(
 	}
 
 	if (rebuild) {
-		btr_search_drop_page_hash_index(block);
+		btr_search_drop_page_hash_index(block, false);
 	}
 
 	/* Check that the values for hash index build are sensible */
@@ -1610,7 +1610,7 @@ btr_search_move_or_delete_hash_entries(
 
 	if (new_block->index) {
 drop_exit:
-		btr_search_drop_page_hash_index(block);
+		btr_search_drop_page_hash_index(block, false);
 		return;
 	}
 
@@ -1686,7 +1686,7 @@ void btr_search_update_hash_on_delete(btr_cur_t* cursor)
 
 	if (index != cursor->index) {
 		ut_ad(index->id == cursor->index->id);
-		btr_search_drop_page_hash_index(block);
+		btr_search_drop_page_hash_index(block, false);
 		return;
 	}
 
@@ -1766,7 +1766,7 @@ btr_search_update_hash_node_on_insert(btr_cur_t* cursor, rw_lock_t* ahi_latch)
 
 	if (cursor->index != index) {
 		ut_ad(cursor->index->id == index->id);
-		btr_search_drop_page_hash_index(block);
+		btr_search_drop_page_hash_index(block, false);
 		return;
 	}
 
@@ -1861,7 +1861,7 @@ btr_search_update_hash_on_insert(btr_cur_t* cursor, rw_lock_t* ahi_latch)
 #endif
 	if (index != cursor->index) {
 		ut_ad(index->id == cursor->index->id);
-		btr_search_drop_page_hash_index(block);
+		btr_search_drop_page_hash_index(block, false);
 		return;
 	}
 

storage/innobase/buf/buf0buf.cc

@@ -5414,7 +5414,7 @@ buf_page_create(
 		}
 #ifdef BTR_CUR_HASH_ADAPT
 		if (drop_hash_entry) {
-			btr_search_drop_page_hash_index(block);
+			btr_search_drop_page_hash_index(block, false);
 		}
 #endif /* BTR_CUR_HASH_ADAPT */
 

storage/innobase/buf/buf0lru.cc

@@ -1608,10 +1608,12 @@ buf_LRU_free_page(
 	order to avoid bogus Valgrind or MSAN warnings.*/
 	buf_block_t* block = reinterpret_cast<buf_block_t*>(bpage);
 
+#ifdef BTR_CUR_HASH_ADAPT
 	MEM_MAKE_DEFINED(block->frame, srv_page_size);
-	btr_search_drop_page_hash_index(block);
+	btr_search_drop_page_hash_index(block, false);
 	MEM_UNDEFINED(block->frame, srv_page_size);
 
+#endif /* BTR_CUR_HASH_ADAPT */
 	buf_pool_mutex_enter(buf_pool);
 
 	if (b) {

storage/innobase/handler/handler0alter.cc

@@ -4371,8 +4371,18 @@ innobase_add_instant_try(
 	DBUG_ASSERT(ctx->old_table->n_cols == ctx->old_n_cols);
 
 	dict_table_t* user_table = ctx->old_table;
-	user_table->instant_add_column(*ctx->instant_table);
 	dict_index_t* index = dict_table_get_first_index(user_table);
+
+#ifdef BTR_CUR_HASH_ADAPT
+	/* Acquire the ahi latch to avoid the race condition
+	between ahi access and instant alter table */
+	rw_lock_t* ahi_latch = btr_get_search_latch(index);
+	rw_lock_x_lock(ahi_latch);
+#endif /* BTR_CUR_HASH_ADAPT */
+	user_table->instant_add_column(*ctx->instant_table);
+#ifdef BTR_CUR_HASH_ADAPT
+	rw_lock_x_unlock(ahi_latch);
+#endif /* BTR_CUR_HASH_ADAPT */
 	/* The table may have been emptied and may have lost its
 	'instant-add-ness' during this instant ADD COLUMN. */
 

storage/innobase/include/btr0sea.h

@@ -102,7 +102,7 @@ btr_search_move_or_delete_hash_entries(
 @param[in]	garbage_collect	drop ahi only if the index is marked
 				as freed */
 void btr_search_drop_page_hash_index(buf_block_t* block,
-				     bool garbage_collect= false);
+				     bool garbage_collect);
 
 /** Drop possible adaptive hash index entries when a page is evicted
 from the buffer pool or freed in a file, or the index is being dropped.

storage/innobase/page/page0zip.cc

@@ -4759,7 +4759,7 @@ page_zip_reorganize(
 	mtr_log_t	log_mode = mtr_set_log_mode(mtr, MTR_LOG_NONE);
 
 	temp_block = buf_block_alloc(buf_pool);
-	btr_search_drop_page_hash_index(block);
+	btr_search_drop_page_hash_index(block, false);
 	temp_page = temp_block->frame;
 
 	/* Copy the old page to temporary space */