MDEV-19513: Rename dict_operation_lock to dict_sys.latch

dict_sys.lock(), dict_sys_lock(): Acquire both mutex and latch.

dict_sys.unlock(), dict_sys_unlock(): Release both mutex and latch.

dict_sys.assert_locked(): Assert that both mutex and latch are held.

storage/innobase/dict/dict0crea.cc

@@ -2327,8 +2327,7 @@ dict_delete_tablespace_and_datafiles(
 {
 	dberr_t		err = DB_SUCCESS;
 
-	ut_ad(rw_lock_own(dict_operation_lock, RW_LOCK_X));
-	ut_ad(mutex_own(&dict_sys.mutex));
+	ut_d(dict_sys.assert_locked());
 	ut_ad(srv_sys_tablespaces_open);
 
 	trx->op_info = "delete tablespace and datafiles from dictionary";

storage/innobase/dict/dict0defrag_bg.cc

@@ -1,6 +1,6 @@
 /*****************************************************************************
 
-Copyright (c) 2016, 2018, MariaDB Corporation.
+Copyright (c) 2016, 2019, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -244,8 +244,7 @@ dict_stats_save_defrag_summary(
 		return DB_SUCCESS;
 	}
 
-	rw_lock_x_lock(dict_operation_lock);
-	mutex_enter(&dict_sys.mutex);
+	dict_sys_lock();
 
 	ret = dict_stats_save_index_stat(index, now, "n_pages_freed",
 					 index->stat_defrag_n_pages_freed,
@@ -254,8 +253,7 @@ dict_stats_save_defrag_summary(
 					 " last defragmentation run.",
 					 NULL);
 
-	mutex_exit(&dict_sys.mutex);
-	rw_lock_x_unlock(dict_operation_lock);
+	dict_sys_unlock();
 
 	return (ret);
 }
@@ -295,9 +293,7 @@ dict_stats_save_defrag_stats(
 		return DB_SUCCESS;
 	}
 
-	rw_lock_x_lock(dict_operation_lock);
-
-	mutex_enter(&dict_sys.mutex);
+	dict_sys_lock();
 	ret = dict_stats_save_index_stat(index, now, "n_page_split",
 					 index->stat_defrag_n_page_split,
 					 NULL,
@@ -327,8 +323,6 @@ dict_stats_save_defrag_stats(
 		NULL);
 
 end:
-	mutex_exit(&dict_sys.mutex);
-	rw_lock_x_unlock(dict_operation_lock);
-
-	return (ret);
+	dict_sys_unlock();
+	return ret;
 }

storage/innobase/dict/dict0dict.cc

@@ -87,16 +87,6 @@ ib_warn_row_too_big(const dict_table_t*	table);
 /** the dictionary system */
 dict_sys_t	dict_sys;
 
-/** @brief the data dictionary rw-latch protecting dict_sys
-
-table create, drop, etc. reserve this in X-mode; implicit or
-backround operations purge, rollback, foreign key checks reserve this
-in S-mode; we cannot trust that MySQL protects implicit or background
-operations a table drop since MySQL does not know of them; therefore
-we need this; NOTE: a transaction which reserves this must keep book
-on the mode in trx_t::dict_operation_lock_mode */
-rw_lock_t*	dict_operation_lock;
-
 /** Percentage of compression failures that are allowed in a single
 round */
 ulong	zip_failure_threshold_pct = 5;
@@ -530,8 +520,7 @@ dict_table_close_and_drop(
 {
 	dberr_t err = DB_SUCCESS;
 
-	ut_ad(mutex_own(&dict_sys.mutex));
-	ut_ad(rw_lock_own(dict_operation_lock, RW_LOCK_X));
+	ut_d(dict_sys.assert_locked());
 	ut_ad(trx->dict_operation != TRX_DICT_OP_NONE);
 	ut_ad(trx_state_eq(trx, TRX_STATE_ACTIVE));
 
@@ -1034,9 +1023,6 @@ dict_table_col_in_clustered_key(
 void dict_sys_t::create()
 {
   ut_ad(!is_initialised());
-  dict_operation_lock = static_cast<rw_lock_t*>(
-    ut_zalloc_nokey(sizeof(*dict_operation_lock)));
-
   ut_d(m_initialised= true);
   UT_LIST_INIT(table_LRU, &dict_table_t::table_LRU);
   UT_LIST_INIT(table_non_LRU, &dict_table_t::table_LRU);
@@ -1050,8 +1036,7 @@ void dict_sys_t::create()
   table_id_hash= hash_create(hash_size);
   temp_id_hash= hash_create(hash_size);
 
-  rw_lock_create(dict_operation_lock_key,
-		 dict_operation_lock, SYNC_DICT_OPERATION);
+  rw_lock_create(dict_operation_lock_key, &latch, SYNC_DICT_OPERATION);
 
   if (!srv_read_only_mode)
   {
@@ -1260,9 +1245,7 @@ dict_table_can_be_evicted(
 /*======================*/
 	dict_table_t*	table)		/*!< in: table to test */
 {
-	ut_ad(mutex_own(&dict_sys.mutex));
-	ut_ad(rw_lock_own(dict_operation_lock, RW_LOCK_X));
-
+	ut_d(dict_sys.assert_locked());
 	ut_a(table->can_be_evicted);
 	ut_a(table->foreign_set.empty());
 	ut_a(table->referenced_set.empty());
@@ -1328,8 +1311,7 @@ dict_make_room_in_cache(
 
 	ut_a(pct_check > 0);
 	ut_a(pct_check <= 100);
-	ut_ad(mutex_own(&dict_sys.mutex));
-	ut_ad(rw_lock_own(dict_operation_lock, RW_LOCK_X));
+	ut_d(dict_sys.assert_locked());
 	ut_ad(dict_lru_validate());
 
 	i = len = UT_LIST_GET_LEN(dict_sys.table_LRU);
@@ -1939,9 +1921,7 @@ void dict_sys_t::remove(dict_table_t* table, bool lru, bool keep)
 		and free the index pages. */
 		trx_t* trx = trx_create();
 
-		ut_ad(mutex_own(&dict_sys.mutex));
-		ut_ad(rw_lock_own(dict_operation_lock, RW_LOCK_X));
-
+		ut_d(dict_sys.assert_locked());
 		/* Mimic row_mysql_lock_data_dictionary(). */
 		trx->dict_operation_lock_mode = RW_X_LATCH;
 
@@ -5817,8 +5797,7 @@ dict_index_set_merge_threshold(
 	ut_ad(!dict_table_is_comp(dict_sys.sys_tables));
 	ut_ad(!dict_table_is_comp(dict_sys.sys_indexes));
 
-	rw_lock_x_lock(dict_operation_lock);
-	mutex_enter(&dict_sys.mutex);
+	dict_sys_lock();
 
 	heap = mem_heap_create(sizeof(dtuple_t) + 2 * (sizeof(dfield_t)
 			       + sizeof(que_fork_t) + sizeof(upd_node_t)
@@ -5866,8 +5845,7 @@ dict_index_set_merge_threshold(
 	mtr_commit(&mtr);
 	mem_heap_free(heap);
 
-	mutex_exit(&dict_sys.mutex);
-	rw_lock_x_unlock(dict_operation_lock);
+	dict_sys_unlock();
 }
 
 #ifdef UNIV_DEBUG
@@ -6449,11 +6427,7 @@ void dict_sys_t::close()
 
   mutex_exit(&mutex);
   mutex_free(&mutex);
-
-  rw_lock_free(dict_operation_lock);
-
-  ut_free(dict_operation_lock);
-  dict_operation_lock = NULL;
+  rw_lock_free(&latch);
 
   mutex_free(&dict_foreign_err_mutex);
 
@@ -6806,8 +6780,7 @@ dict_space_is_empty(
 	mtr_t		mtr;
 	bool		found = false;
 
-	rw_lock_x_lock(dict_operation_lock);
-	mutex_enter(&dict_sys.mutex);
+	dict_sys_lock();
 	mtr_start(&mtr);
 
 	for (rec = dict_startscan_system(&pcur, &mtr, SYS_TABLES);
@@ -6828,8 +6801,7 @@ dict_space_is_empty(
 	}
 
 	mtr_commit(&mtr);
-	mutex_exit(&dict_sys.mutex);
-	rw_lock_x_unlock(dict_operation_lock);
+	dict_sys_unlock();
 
 	return(!found);
 }
@@ -6847,8 +6819,7 @@ dict_space_get_id(
 	ulint		name_len = strlen(name);
 	ulint		id = ULINT_UNDEFINED;
 
-	rw_lock_x_lock(dict_operation_lock);
-	mutex_enter(&dict_sys.mutex);
+	dict_sys_lock();
 	mtr_start(&mtr);
 
 	for (rec = dict_startscan_system(&pcur, &mtr, SYS_TABLESPACES);
@@ -6877,8 +6848,7 @@ dict_space_get_id(
 	}
 
 	mtr_commit(&mtr);
-	mutex_exit(&dict_sys.mutex);
-	rw_lock_x_unlock(dict_operation_lock);
+	dict_sys_unlock();
 
 	return(id);
 }

storage/innobase/dict/dict0load.cc

@@ -884,8 +884,7 @@ dict_update_filepath(
 	dberr_t		err = DB_SUCCESS;
 	trx_t*		trx;
 
-	ut_ad(rw_lock_own(dict_operation_lock, RW_LOCK_X));
-	ut_ad(mutex_own(&dict_sys.mutex));
+	ut_d(dict_sys.assert_locked());
 
 	trx = trx_create();
 	trx->op_info = "update filepath";
@@ -952,8 +951,7 @@ dict_replace_tablespace_and_filepath(
 	DBUG_EXECUTE_IF("innodb_fail_to_update_tablespace_dict",
 			return(DB_INTERRUPTED););
 
-	ut_ad(rw_lock_own(dict_operation_lock, RW_LOCK_X));
-	ut_ad(mutex_own(&dict_sys.mutex));
+	ut_d(dict_sys.assert_locked());
 	ut_ad(filepath);
 
 	trx = trx_create();
@@ -1350,8 +1348,7 @@ static ulint dict_check_sys_tables()
 
 	DBUG_ENTER("dict_check_sys_tables");
 
-	ut_ad(rw_lock_own(dict_operation_lock, RW_LOCK_X));
-	ut_ad(mutex_own(&dict_sys.mutex));
+	ut_d(dict_sys.assert_locked());
 
 	mtr_start(&mtr);
 
@@ -1487,8 +1484,7 @@ void dict_check_tablespaces_and_store_max_id()
 
 	DBUG_ENTER("dict_check_tablespaces_and_store_max_id");
 
-	rw_lock_x_lock(dict_operation_lock);
-	mutex_enter(&dict_sys.mutex);
+	dict_sys_lock();
 
 	/* Initialize the max space_id from sys header */
 	mtr_start(&mtr);
@@ -1505,8 +1501,7 @@ void dict_check_tablespaces_and_store_max_id()
 	max_space_id = dict_check_sys_tables();
 	fil_set_max_space_id_if_bigger(max_space_id);
 
-	mutex_exit(&dict_sys.mutex);
-	rw_lock_x_unlock(dict_operation_lock);
+	dict_sys_unlock();
 
 	DBUG_VOID_RETURN;
 }
@@ -2833,7 +2828,7 @@ dict_load_tablespace(
 	}
 
 	/* Try to open the tablespace.  We set the 2nd param (fix_dict) to
-	false because we do not have an x-lock on dict_operation_lock */
+	false because we do not have an x-lock on dict_sys.latch */
 	table->space = fil_ibd_open(
 		true, false, FIL_TYPE_TABLESPACE, table->space_id,
 		dict_tf_to_fsp_flags(table->flags),

storage/innobase/dict/dict0stats.cc

@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 2009, 2018, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2015, 2018, MariaDB Corporation.
+Copyright (c) 2015, 2019, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -283,8 +283,7 @@ dict_stats_exec_sql(
 	dberr_t	err;
 	bool	trx_started = false;
 
-	ut_ad(rw_lock_own(dict_operation_lock, RW_LOCK_X));
-	ut_ad(mutex_own(&dict_sys.mutex));
+	ut_d(dict_sys.assert_locked());
 
 	if (!dict_stats_persistent_storage_check(true)) {
 		pars_info_free(pinfo);
@@ -2313,8 +2312,7 @@ dict_stats_save_index_stat(
 	char		table_utf8[MAX_TABLE_UTF8_LEN];
 
 	ut_ad(!trx || trx->internal || trx->mysql_thd);
-	ut_ad(rw_lock_own(dict_operation_lock, RW_LOCK_X));
-	ut_ad(mutex_own(&dict_sys.mutex));
+	ut_d(dict_sys.assert_locked());
 
 	dict_fs2utf8(index->table->name.m_name, db_utf8, sizeof(db_utf8),
 		     table_utf8, sizeof(table_utf8));
@@ -2449,8 +2447,7 @@ dict_stats_save(
 		     table_utf8, sizeof(table_utf8));
 
 	now = ut_time();
-	rw_lock_x_lock(dict_operation_lock);
-	mutex_enter(&dict_sys.mutex);
+	dict_sys_lock();
 
 	pinfo = pars_info_create();
 
@@ -2488,13 +2485,10 @@ dict_stats_save(
 	if (ret != DB_SUCCESS) {
 		ib::error() << "Cannot save table statistics for table "
 			<< table->name << ": " << ut_strerr(ret);
-
-		mutex_exit(&dict_sys.mutex);
-		rw_lock_x_unlock(dict_operation_lock);
-
+func_exit:
+		dict_sys_unlock();
 		dict_stats_snapshot_free(table);
-
-		return(ret);
+		return ret;
 	}
 
 	trx_t*	trx = trx_create();
@@ -2595,13 +2589,7 @@ dict_stats_save(
 
 end:
 	trx_free(trx);
-
-	mutex_exit(&dict_sys.mutex);
-	rw_lock_x_unlock(dict_operation_lock);
-
-	dict_stats_snapshot_free(table);
-
-	return(ret);
+	goto func_exit;
 }
 
 /*********************************************************************//**
@@ -3406,8 +3394,7 @@ dict_stats_drop_index(
 
 	pars_info_add_str_literal(pinfo, "index_name", iname);
 
-	rw_lock_x_lock(dict_operation_lock);
-	mutex_enter(&dict_sys.mutex);
+	dict_sys_lock();
 
 	ret = dict_stats_exec_sql(
 		pinfo,
@@ -3419,8 +3406,7 @@ dict_stats_drop_index(
 		"index_name = :index_name;\n"
 		"END;\n", NULL);
 
-	mutex_exit(&dict_sys.mutex);
-	rw_lock_x_unlock(dict_operation_lock);
+	dict_sys_unlock();
 
 	if (ret == DB_STATS_DO_NOT_EXIST) {
 		ret = DB_SUCCESS;
@@ -3468,8 +3454,7 @@ dict_stats_delete_from_table_stats(
 	pars_info_t*	pinfo;
 	dberr_t		ret;
 
-	ut_ad(rw_lock_own(dict_operation_lock, RW_LOCK_X));
-	ut_ad(mutex_own(&dict_sys.mutex));
+	ut_d(dict_sys.assert_locked());
 
 	pinfo = pars_info_create();
 
@@ -3504,8 +3489,7 @@ dict_stats_delete_from_index_stats(
 	pars_info_t*	pinfo;
 	dberr_t		ret;
 
-	ut_ad(rw_lock_own(dict_operation_lock, RW_LOCK_X));
-	ut_ad(mutex_own(&dict_sys.mutex));
+	ut_d(dict_sys.assert_locked());
 
 	pinfo = pars_info_create();
 
@@ -3541,8 +3525,7 @@ dict_stats_drop_table(
 	char		table_utf8[MAX_TABLE_UTF8_LEN];
 	dberr_t		ret;
 
-	ut_ad(rw_lock_own(dict_operation_lock, RW_LOCK_X));
-	ut_ad(mutex_own(&dict_sys.mutex));
+	ut_d(dict_sys.assert_locked());
 
 	/* skip tables that do not contain a database name
 	e.g. if we are dropping SYS_TABLES */
@@ -3617,8 +3600,7 @@ dict_stats_rename_table_in_table_stats(
 	pars_info_t*	pinfo;
 	dberr_t		ret;
 
-	ut_ad(rw_lock_own(dict_operation_lock, RW_LOCK_X));
-	ut_ad(mutex_own(&dict_sys.mutex));
+	ut_d(dict_sys.assert_locked());
 
 	pinfo = pars_info_create();
 
@@ -3661,8 +3643,7 @@ dict_stats_rename_table_in_index_stats(
 	pars_info_t*	pinfo;
 	dberr_t		ret;
 
-	ut_ad(rw_lock_own(dict_operation_lock, RW_LOCK_X));
-	ut_ad(mutex_own(&dict_sys.mutex));
+	ut_d(dict_sys.assert_locked());
 
 	pinfo = pars_info_create();
 
@@ -3705,9 +3686,6 @@ dict_stats_rename_table(
 	char		new_table_utf8[MAX_TABLE_UTF8_LEN];
 	dberr_t		ret;
 
-	ut_ad(!rw_lock_own(dict_operation_lock, RW_LOCK_X));
-	ut_ad(!mutex_own(&dict_sys.mutex));
-
 	/* skip innodb_table_stats and innodb_index_stats themselves */
 	if (strcmp(old_name, TABLE_STATS_NAME) == 0
 	    || strcmp(old_name, INDEX_STATS_NAME) == 0
@@ -3723,8 +3701,7 @@ dict_stats_rename_table(
 	dict_fs2utf8(new_name, new_db_utf8, sizeof(new_db_utf8),
 		     new_table_utf8, sizeof(new_table_utf8));
 
-	rw_lock_x_lock(dict_operation_lock);
-	mutex_enter(&dict_sys.mutex);
+	dict_sys_lock();
 
 	ulint	n_attempts = 0;
 	do {
@@ -3744,11 +3721,9 @@ dict_stats_rename_table(
 		}
 
 		if (ret != DB_SUCCESS) {
-			mutex_exit(&dict_sys.mutex);
-			rw_lock_x_unlock(dict_operation_lock);
+			dict_sys_unlock();
 			os_thread_sleep(200000 /* 0.2 sec */);
-			rw_lock_x_lock(dict_operation_lock);
-			mutex_enter(&dict_sys.mutex);
+			dict_sys_lock();
 		}
 	} while ((ret == DB_DEADLOCK
 		  || ret == DB_DUPLICATE_KEY
@@ -3776,8 +3751,7 @@ dict_stats_rename_table(
 			 TABLE_STATS_NAME_PRINT,
 			 new_db_utf8, new_table_utf8,
 			 old_db_utf8, old_table_utf8);
-		mutex_exit(&dict_sys.mutex);
-		rw_lock_x_unlock(dict_operation_lock);
+		dict_sys_unlock();
 		return(ret);
 	}
 	/* else */
@@ -3800,19 +3774,16 @@ dict_stats_rename_table(
 		}
 
 		if (ret != DB_SUCCESS) {
-			mutex_exit(&dict_sys.mutex);
-			rw_lock_x_unlock(dict_operation_lock);
+			dict_sys_unlock();
 			os_thread_sleep(200000 /* 0.2 sec */);
-			rw_lock_x_lock(dict_operation_lock);
-			mutex_enter(&dict_sys.mutex);
+			dict_sys_lock();
 		}
 	} while ((ret == DB_DEADLOCK
 		  || ret == DB_DUPLICATE_KEY
 		  || ret == DB_LOCK_WAIT_TIMEOUT)
 		 && n_attempts < 5);
 
-	mutex_exit(&dict_sys.mutex);
-	rw_lock_x_unlock(dict_operation_lock);
+	dict_sys_unlock();
 
 	if (ret != DB_SUCCESS) {
 		snprintf(errstr, errstr_sz,
@@ -3853,12 +3824,10 @@ dict_stats_rename_index(
 	const char*		old_index_name,	/*!< in: old index name */
 	const char*		new_index_name)	/*!< in: new index name */
 {
-	rw_lock_x_lock(dict_operation_lock);
-	mutex_enter(&dict_sys.mutex);
+	dict_sys_lock();
 
 	if (!dict_stats_persistent_storage_check(true)) {
-		mutex_exit(&dict_sys.mutex);
-		rw_lock_x_unlock(dict_operation_lock);
+		dict_sys_unlock();
 		return(DB_STATS_DO_NOT_EXIST);
 	}
 
@@ -3891,8 +3860,7 @@ dict_stats_rename_index(
 		"index_name = :old_index_name;\n"
 		"END;\n", NULL);
 
-	mutex_exit(&dict_sys.mutex);
-	rw_lock_x_unlock(dict_operation_lock);
+	dict_sys_unlock();
 
 	return(ret);
 }

storage/innobase/dict/dict0stats_bg.cc

@@ -313,7 +313,7 @@ dict_stats_thread_init()
 	   dict_stats_update_if_needed() is called and it may be acquired
 	   inside that function (thus a level <=SYNC_DICT would do).
 	3) from row_drop_table_for_mysql() after dict_sys.mutex (SYNC_DICT)
-	   and dict_operation_lock (SYNC_DICT_OPERATION) have been locked
+	   and dict_sys.latch (SYNC_DICT_OPERATION) have been locked
 	   (thus a level <SYNC_DICT && <SYNC_DICT_OPERATION would do)
 	So we choose SYNC_STATS_AUTO_RECALC to be about below SYNC_DICT. */
 

storage/innobase/fil/fil0fil.cc

@@ -3178,11 +3178,12 @@ fil_ibd_open(
 	ulint		tablespaces_found = 0;
 	ulint		valid_tablespaces_found = 0;
 
-	ut_ad(!fix_dict || rw_lock_own(dict_operation_lock, RW_LOCK_X));
+	if (fix_dict) {
+		ut_d(dict_sys.assert_locked());
+		ut_ad(!srv_read_only_mode);
+		ut_ad(srv_log_file_size != 0);
+	}
 
-	ut_ad(!fix_dict || mutex_own(&dict_sys.mutex));
-	ut_ad(!fix_dict || !srv_read_only_mode);
-	ut_ad(!fix_dict || srv_log_file_size != 0);
 	ut_ad(fil_type_is_data(purpose));
 
 	/* Table flags can be ULINT_UNDEFINED if
@@ -4766,7 +4767,7 @@ fil_space_validate_for_mtr_commit(
 	/* We are serving mtr_commit(). While there is an active
 	mini-transaction, we should have !space->stop_new_ops. This is
 	guaranteed by meta-data locks or transactional locks, or
-	dict_operation_lock (X-lock in DROP, S-lock in purge).
+	dict_sys.latch (X-lock in DROP, S-lock in purge).
 
 	However, a file I/O thread can invoke change buffer merge
 	while fil_check_pending_operations() is waiting for operations

storage/innobase/handler/ha_innodb.cc

@@ -20452,10 +20452,10 @@ for purge thread */
 static TABLE* innodb_find_table_for_vc(THD* thd, dict_table_t* table)
 {
 	if (THDVAR(thd, background_thread)) {
-		/* Purge thread acquires dict_operation_lock while
-		processing undo log record. Release the dict_operation_lock
+		/* Purge thread acquires dict_sys.latch while
+		processing undo log record. Release it
 		before acquiring MDL on the table. */
-		rw_lock_s_unlock(dict_operation_lock);
+		rw_lock_s_unlock(&dict_sys.latch);
 		return innodb_acquire_mdl(thd, table);
 	} else {
 		if (table->vc_templ->mysql_table_query_id

storage/innobase/handler/handler0alter.cc

@@ -746,8 +746,7 @@ inline void dict_table_t::rollback_instant(
 	const char*	old_v_col_names,
 	const ulint*	col_map)
 {
-	ut_ad(mutex_own(&dict_sys.mutex));
-	ut_ad(rw_lock_own(dict_operation_lock, RW_LOCK_X));
+	ut_d(dict_sys.assert_locked());
 	dict_index_t* index = indexes.start;
 	mtr_t mtr;
 	mtr.start();
@@ -4741,8 +4740,7 @@ innobase_update_gis_column_type(
 
 	DBUG_ASSERT(trx_get_dict_operation(trx) == TRX_DICT_OP_INDEX);
 	ut_ad(trx->dict_operation_lock_mode == RW_X_LATCH);
-	ut_ad(mutex_own(&dict_sys.mutex));
-	ut_ad(rw_lock_own(dict_operation_lock, RW_LOCK_X));
+	ut_d(dict_sys.assert_locked());
 
 	info = pars_info_create();
 
@@ -6733,7 +6731,7 @@ new_clustered_failed:
 			ut_a(ctx->new_table == temp_table);
 			/* n_ref_count must be 1, because purge cannot
 			be executing on this very table as we are
-			holding dict_operation_lock X-latch. */
+			holding dict_sys.latch X-latch. */
 			DBUG_ASSERT(ctx->new_table->get_ref_count() == 1);
 			DBUG_ASSERT(ctx->new_table->id != 0);
 			DBUG_ASSERT(ctx->new_table->id == ctx->trx->table_id);
@@ -6946,8 +6944,7 @@ error_handling_drop_uncached:
 op_ok:
 #endif /* UNIV_DEBUG */
 		ut_ad(ctx->trx->dict_operation_lock_mode == RW_X_LATCH);
-		ut_ad(mutex_own(&dict_sys.mutex));
-		ut_ad(rw_lock_own(dict_operation_lock, RW_LOCK_X));
+		ut_d(dict_sys.assert_locked());
 
 		DICT_TF2_FLAG_SET(ctx->new_table, DICT_TF2_FTS);
 		if (ctx->need_rebuild()) {
@@ -7091,7 +7088,7 @@ error_handled:
 		trx_commit_for_mysql(ctx->trx);
 		/* n_ref_count must be 1, because purge cannot
 		be executing on this very table as we are
-		holding dict_operation_lock X-latch. */
+		holding dict_sys.latch X-latch. */
 		DBUG_ASSERT(user_table->get_ref_count() == 1 || ctx->online);
 
 		online_retry_drop_indexes_with_trx(user_table, ctx->trx);
@@ -7233,9 +7230,7 @@ rename_index_try(
 	trx_t*			trx)
 {
 	DBUG_ENTER("rename_index_try");
-
-	ut_ad(mutex_own(&dict_sys.mutex));
-	ut_ad(rw_lock_own(dict_operation_lock, RW_LOCK_X));
+	ut_d(dict_sys.assert_locked());
 	ut_ad(trx->dict_operation_lock_mode == RW_X_LATCH);
 
 	pars_info_t*	pinfo;
@@ -7293,9 +7288,7 @@ void
 innobase_rename_index_cache(dict_index_t* index, const char* new_name)
 {
 	DBUG_ENTER("innobase_rename_index_cache");
-
-	ut_ad(mutex_own(&dict_sys.mutex));
-	ut_ad(rw_lock_own(dict_operation_lock, RW_LOCK_X));
+	ut_d(dict_sys.assert_locked());
 
 	size_t	old_name_len = strlen(index->name);
 	size_t	new_name_len = strlen(new_name);
@@ -8261,10 +8254,7 @@ ha_innobase::inplace_alter_table(
 	bool			rebuild_templ = false;
 	DBUG_ENTER("inplace_alter_table");
 	DBUG_ASSERT(!srv_read_only_mode);
-
 	ut_ad(!sync_check_iterate(sync_check()));
-	ut_ad(!rw_lock_own(dict_operation_lock, RW_LOCK_X));
-	ut_ad(!rw_lock_own(dict_operation_lock, RW_LOCK_S));
 
 	DEBUG_SYNC(m_user_thd, "innodb_inplace_alter_table_enter");
 
@@ -8476,10 +8466,7 @@ innobase_online_rebuild_log_free(
 	dict_table_t*	table)
 {
 	dict_index_t* clust_index = dict_table_get_first_index(table);
-
-	ut_ad(mutex_own(&dict_sys.mutex));
-	ut_ad(rw_lock_own(dict_operation_lock, RW_LOCK_X));
-
+	ut_d(dict_sys.assert_locked());
 	rw_lock_x_lock(&clust_index->lock);
 
 	if (clust_index->online_log) {
@@ -8752,8 +8739,7 @@ innobase_drop_foreign_try(
 
 	DBUG_ASSERT(trx_get_dict_operation(trx) == TRX_DICT_OP_INDEX);
 	ut_ad(trx->dict_operation_lock_mode == RW_X_LATCH);
-	ut_ad(mutex_own(&dict_sys.mutex));
-	ut_ad(rw_lock_own(dict_operation_lock, RW_LOCK_X));
+	ut_d(dict_sys.assert_locked());
 
 	/* Drop the constraint from the data dictionary. */
 	static const char sql[] =
@@ -8811,8 +8797,7 @@ innobase_rename_column_try(
 
 	DBUG_ASSERT(trx_get_dict_operation(trx) == TRX_DICT_OP_INDEX);
 	ut_ad(trx->dict_operation_lock_mode == RW_X_LATCH);
-	ut_ad(mutex_own(&dict_sys.mutex));
-	ut_ad(rw_lock_own(dict_operation_lock, RW_LOCK_X));
+	ut_d(dict_sys.assert_locked());
 
 	if (new_clustered) {
 		goto rename_foreign;
@@ -9088,8 +9073,7 @@ innobase_rename_or_enlarge_column_try(
 
 	DBUG_ASSERT(trx_get_dict_operation(trx) == TRX_DICT_OP_INDEX);
 	ut_ad(trx->dict_operation_lock_mode == RW_X_LATCH);
-	ut_ad(mutex_own(&dict_sys.mutex));
-	ut_ad(rw_lock_own(dict_operation_lock, RW_LOCK_X));
+	ut_d(dict_sys.assert_locked());
 
 	ulint n_base;
 
@@ -10512,7 +10496,7 @@ alter_stats_norebuild(
 	in a separate transaction from trx, because lock waits are not
 	allowed in a data dictionary transaction. (Lock waits are possible
 	on the statistics table, because it is directly accessible by users,
-	not covered by the dict_operation_lock.)
+	not covered by the dict_sys.latch.)
 
 	Because the data dictionary changes were already committed, orphaned
 	rows may be left in the statistics table if the system crashes.

storage/innobase/handler/i_s.cc

@@ -2869,19 +2869,19 @@ i_s_fts_deleted_generic_fill(
 	}
 
 	/* Prevent DDL to drop fts aux tables. */
-	rw_lock_s_lock(dict_operation_lock);
+	rw_lock_s_lock(&dict_sys.latch);
 
 	user_table = dict_table_open_on_name(
 		fts_internal_tbl_name, FALSE, FALSE, DICT_ERR_IGNORE_NONE);
 
 	if (!user_table) {
-		rw_lock_s_unlock(dict_operation_lock);
+		rw_lock_s_unlock(&dict_sys.latch);
 
 		DBUG_RETURN(0);
 	} else if (!dict_table_has_fts_index(user_table)) {
 		dict_table_close(user_table, FALSE, FALSE);
 
-		rw_lock_s_unlock(dict_operation_lock);
+		rw_lock_s_unlock(&dict_sys.latch);
 
 		DBUG_RETURN(0);
 	}
@@ -2917,7 +2917,7 @@ i_s_fts_deleted_generic_fill(
 
 	dict_table_close(user_table, FALSE, FALSE);
 
-	rw_lock_s_unlock(dict_operation_lock);
+	rw_lock_s_unlock(&dict_sys.latch);
 
 	DBUG_RETURN(ret);
 }
@@ -3730,13 +3730,13 @@ i_s_fts_index_table_fill(
 	}
 
 	/* Prevent DDL to drop fts aux tables. */
-	rw_lock_s_lock(dict_operation_lock);
+	rw_lock_s_lock(&dict_sys.latch);
 
 	user_table = dict_table_open_on_name(
 		fts_internal_tbl_name, FALSE, FALSE, DICT_ERR_IGNORE_NONE);
 
 	if (!user_table) {
-		rw_lock_s_unlock(dict_operation_lock);
+		rw_lock_s_unlock(&dict_sys.latch);
 
 		DBUG_RETURN(0);
 	}
@@ -3757,7 +3757,7 @@ i_s_fts_index_table_fill(
 
 	dict_table_close(user_table, FALSE, FALSE);
 
-	rw_lock_s_unlock(dict_operation_lock);
+	rw_lock_s_unlock(&dict_sys.latch);
 
 	ut_free(conv_str.f_str);
 
@@ -3899,19 +3899,19 @@ i_s_fts_config_fill(
 	fields = table->field;
 
 	/* Prevent DDL to drop fts aux tables. */
-	rw_lock_s_lock(dict_operation_lock);
+	rw_lock_s_lock(&dict_sys.latch);
 
 	user_table = dict_table_open_on_name(
 		fts_internal_tbl_name, FALSE, FALSE, DICT_ERR_IGNORE_NONE);
 
 	if (!user_table) {
-		rw_lock_s_unlock(dict_operation_lock);
+		rw_lock_s_unlock(&dict_sys.latch);
 
 		DBUG_RETURN(0);
 	} else if (!dict_table_has_fts_index(user_table)) {
 		dict_table_close(user_table, FALSE, FALSE);
 
-		rw_lock_s_unlock(dict_operation_lock);
+		rw_lock_s_unlock(&dict_sys.latch);
 
 		DBUG_RETURN(0);
 	}
@@ -3971,7 +3971,7 @@ i_s_fts_config_fill(
 
 	dict_table_close(user_table, FALSE, FALSE);
 
-	rw_lock_s_unlock(dict_operation_lock);
+	rw_lock_s_unlock(&dict_sys.latch);
 
 	DBUG_RETURN(ret);
 }
@@ -6338,7 +6338,7 @@ i_s_sys_tables_fill_table_stats(
 	}
 
 	heap = mem_heap_create(1000);
-	rw_lock_s_lock(dict_operation_lock);
+	rw_lock_s_lock(&dict_sys.latch);
 	mutex_enter(&dict_sys.mutex);
 	mtr_start(&mtr);
 
@@ -6372,11 +6372,11 @@ i_s_sys_tables_fill_table_stats(
 					    err_msg);
 		}
 
-		rw_lock_s_unlock(dict_operation_lock);
+		rw_lock_s_unlock(&dict_sys.latch);
 		mem_heap_empty(heap);
 
 		/* Get the next record */
-		rw_lock_s_lock(dict_operation_lock);
+		rw_lock_s_lock(&dict_sys.latch);
 		mutex_enter(&dict_sys.mutex);
 
 		mtr_start(&mtr);
@@ -6385,7 +6385,7 @@ i_s_sys_tables_fill_table_stats(
 
 	mtr_commit(&mtr);
 	mutex_exit(&dict_sys.mutex);
-	rw_lock_s_unlock(dict_operation_lock);
+	rw_lock_s_unlock(&dict_sys.latch);
 	mem_heap_free(heap);
 
 	DBUG_RETURN(0);

storage/innobase/include/dict0dict.h

@@ -1471,6 +1471,15 @@ public:
 					and DROP TABLE, as well as reading
 					the dictionary data for a table from
 					system tables */
+	/** @brief the data dictionary rw-latch protecting dict_sys
+
+	Table create, drop, etc. reserve this in X-mode; implicit or
+	backround operations purge, rollback, foreign key checks reserve this
+	in S-mode; not all internal InnoDB operations are covered by MDL.
+
+	This latch also prevents lock waits when accessing the InnoDB
+	data dictionary tables. @see trx_t::dict_operation_lock_mode */
+	rw_lock_t	latch;
 	row_id_t	row_id;		/*!< the next row id to assign;
 					NOTE that at a checkpoint this
 					must be written to the dict system
@@ -1501,7 +1510,6 @@ private:
 	/** hash table of temporary table IDs */
 	hash_table_t*	temp_id_hash;
 public:
-
 	/** @return a new temporary table ID */
 	table_id_t get_temporary_table_id() {
 		return temp_table_id.fetch_add(1, std::memory_order_relaxed);
@@ -1603,14 +1611,36 @@ public:
   }
   /** Acquire a reference to a cached table. */
   inline void acquire(dict_table_t* table);
+
+#ifdef UNIV_DEBUG
+  /** Assert that the data dictionary is locked */
+  void assert_locked()
+  {
+    ut_ad(mutex_own(&mutex));
+    ut_ad(rw_lock_own(&latch, RW_LOCK_X));
+  }
+#endif
+  /** Lock the data dictionary cache. */
+  void lock(const char* file, unsigned line)
+  {
+    rw_lock_x_lock_func(&latch, 0, file, line);
+    mutex_enter_loc(&mutex, file, line);
+  }
+
+  /** Unlock the data dictionary cache. */
+  void unlock()
+  {
+    mutex_exit(&mutex);
+    rw_lock_x_unlock(&latch);
+  }
 };
 
 /** the data dictionary cache */
 extern dict_sys_t	dict_sys;
-/** the data dictionary rw-latch protecting dict_sys */
-extern rw_lock_t*	dict_operation_lock;
 
 #define dict_table_prevent_eviction(table) dict_sys.prevent_eviction(table)
+#define dict_sys_lock() dict_sys.lock(__FILE__, __LINE__)
+#define dict_sys_unlock() dict_sys.unlock()
 
 /** dummy index for ROW_FORMAT=REDUNDANT supremum and infimum records */
 extern dict_index_t*	dict_ind_redundant;

storage/innobase/include/dict0mem.h

@@ -948,12 +948,12 @@ struct dict_index_t {
 				dictionary cache */
 	unsigned	to_be_dropped:1;
 				/*!< TRUE if the index is to be dropped;
-				protected by dict_operation_lock */
+				protected by dict_sys.latch */
 	unsigned	online_status:2;
 				/*!< enum online_index_status.
 				Transitions from ONLINE_INDEX_COMPLETE (to
 				ONLINE_INDEX_CREATION) are protected
-				by dict_operation_lock and
+				by dict_sys.latch and
 				dict_sys.mutex. Other changes are
 				protected by index->lock. */
 	unsigned	uncommitted:1;
@@ -1835,8 +1835,7 @@ public:
 	/** TRUE if the table is to be dropped, but not yet actually dropped
 	(could in the background drop list). It is turned on at the beginning
 	of row_drop_table_for_mysql() and turned off just before we start to
-	update system tables for the drop. It is protected by
-	dict_operation_lock. */
+	update system tables for the drop. It is protected by dict_sys.latch. */
 	unsigned				to_be_dropped:1;
 
 	/** Number of non-virtual columns defined so far. */

storage/innobase/include/fil0fil.h

@@ -134,7 +134,7 @@ struct fil_space_t {
 				the tablespace to disk; dropping of the
 				tablespace is forbidden if this is positive */
 	/** Number of pending buffer pool operations accessing the tablespace
-	without holding a table lock or dict_operation_lock S-latch
+	without holding a table lock or dict_sys.latch S-latch
 	that would prevent the table (and tablespace) from being
 	dropped. An example is change buffer merge.
 	The tablespace cannot be dropped while this is nonzero,

storage/innobase/include/log0log.ic

@@ -1,7 +1,7 @@
 /*****************************************************************************
 
 Copyright (c) 1995, 2015, Oracle and/or its affiliates. All Rights Reserved.
-Copyright (c) 2017, 2018, MariaDB Corporation.
+Copyright (c) 2017, 2019, MariaDB Corporation.
 
 This program is free software; you can redistribute it and/or modify it under
 the terms of the GNU General Public License as published by the Free Software
@@ -485,7 +485,7 @@ log_free_check(void)
 	static const latch_level_t latches[] = {
 		SYNC_DICT,		/* dict_sys.mutex during
 					commit_try_rebuild() */
-		SYNC_DICT_OPERATION,	/* dict_operation_lock X-latch during
+		SYNC_DICT_OPERATION,	/* dict_sys.latch X-latch during
 					commit_try_rebuild() */
 		SYNC_FTS_CACHE,		/* fts_cache_t::lock */
 		SYNC_INDEX_TREE		/* index->lock */

storage/innobase/include/row0mysql.h

@@ -418,7 +418,7 @@ will remain locked.
 @param[in]	create_failed	true=create table failed
 				because e.g. foreign key column
 @param[in]	nonatomic	Whether it is permitted to release
-				and reacquire dict_operation_lock
+				and reacquire dict_sys.latch
 @return error code */
 dberr_t
 row_drop_table_for_mysql(

storage/innobase/include/trx0trx.h

@@ -690,7 +690,7 @@ with exactly one user transaction. There are some exceptions to this:
 
 * For DDL operations, a subtransaction is allocated that modifies the
 data dictionary tables. Lock waits and deadlocks are prevented by
-acquiring the dict_operation_lock before starting the subtransaction
+acquiring the dict_sys.latch before starting the subtransaction
 and releasing it after committing the subtransaction.
 
 * The purge system uses a special transaction that is not associated
@@ -924,8 +924,8 @@ public:
 	ib_uint32_t	dict_operation_lock_mode;
 					/*!< 0, RW_S_LATCH, or RW_X_LATCH:
 					the latch mode trx currently holds
-					on dict_operation_lock. Protected
-					by dict_operation_lock. */
+					on dict_sys.latch. Protected
+					by dict_sys.latch. */
 
 	time_t		start_time;	/*!< time the state last time became
 					TRX_STATE_ACTIVE */

storage/innobase/row/row0import.cc

@@ -3856,7 +3856,7 @@ row_import_for_mysql(
 
 	/* Prevent DDL operations while we are checking. */
 
-	rw_lock_s_lock_func(dict_operation_lock, 0, __FILE__, __LINE__);
+	rw_lock_s_lock(&dict_sys.latch);
 
 	row_import	cfg;
 
@@ -3881,14 +3881,14 @@ row_import_for_mysql(
 			autoinc = cfg.m_autoinc;
 		}
 
-		rw_lock_s_unlock_gen(dict_operation_lock, 0);
+		rw_lock_s_unlock(&dict_sys.latch);
 
 		DBUG_EXECUTE_IF("ib_import_set_index_root_failure",
 				err = DB_TOO_MANY_CONCURRENT_TRXS;);
 
 	} else if (cfg.m_missing) {
 
-		rw_lock_s_unlock_gen(dict_operation_lock, 0);
+		rw_lock_s_unlock(&dict_sys.latch);
 
 		/* We don't have a schema file, we will have to discover
 		the index root pages from the .ibd file and skip the schema
@@ -3920,7 +3920,7 @@ row_import_for_mysql(
 		space_flags = fetchIndexRootPages.get_space_flags();
 
 	} else {
-		rw_lock_s_unlock_gen(dict_operation_lock, 0);
+		rw_lock_s_unlock(&dict_sys.latch);
 	}
 
 	if (err != DB_SUCCESS) {
@@ -4011,7 +4011,7 @@ row_import_for_mysql(
 
 	/* Open the tablespace so that we can access via the buffer pool.
 	We set the 2nd param (fix_dict = true) here because we already
-	have an x-lock on dict_operation_lock and dict_sys.mutex.
+	have an x-lock on dict_sys.latch and dict_sys.mutex.
 	The tablespace is initially opened as a temporary one, because
 	we will not be writing any redo log for it before we have invoked
 	fil_space_t::set_imported() to declare it a persistent tablespace. */

storage/innobase/row/row0ins.cc

@@ -1543,7 +1543,7 @@ row_ins_set_exclusive_rec_lock(
 /***************************************************************//**
 Checks if foreign key constraint fails for an index entry. Sets shared locks
 which lock either the success or the failure of the constraint. NOTE that
-the caller must have a shared latch on dict_operation_lock.
+the caller must have a shared latch on dict_sys.latch.
 @return DB_SUCCESS, DB_NO_REFERENCED_ROW, or DB_ROW_IS_REFERENCED */
 dberr_t
 row_ins_check_foreign_constraint(
@@ -1584,7 +1584,7 @@ row_ins_check_foreign_constraint(
 	upd_node= NULL;
 #endif /* WITH_WSREP */
 
-	ut_ad(rw_lock_own(dict_operation_lock, RW_LOCK_S));
+	ut_ad(rw_lock_own(&dict_sys.latch, RW_LOCK_S));
 
 	err = DB_SUCCESS;
 
@@ -1990,7 +1990,7 @@ row_ins_check_foreign_constraints(
 			}
 
 			/* NOTE that if the thread ends up waiting for a lock
-			we will release dict_operation_lock temporarily!
+			we will release dict_sys.latch temporarily!
 			But the counter on the table protects the referenced
 			table from being dropped while the check is running. */
 

storage/innobase/row/row0log.cc

@@ -3111,7 +3111,7 @@ row_log_table_apply(
 
 	stage->begin_phase_log_table();
 
-	ut_ad(!rw_lock_own(dict_operation_lock, RW_LOCK_S));
+	ut_ad(!rw_lock_own(&dict_sys.latch, RW_LOCK_S));
 	clust_index = dict_table_get_first_index(old_table);
 
 	if (clust_index->online_log->n_rows == 0) {

storage/innobase/row/row0merge.cc

@@ -3755,10 +3755,9 @@ row_merge_drop_index_dict(
 	pars_info_t*	info;
 
 	ut_ad(!srv_read_only_mode);
-	ut_ad(mutex_own(&dict_sys.mutex));
 	ut_ad(trx->dict_operation_lock_mode == RW_X_LATCH);
 	ut_ad(trx_get_dict_operation(trx) == TRX_DICT_OP_INDEX);
-	ut_ad(rw_lock_own(dict_operation_lock, RW_LOCK_X));
+	ut_d(dict_sys.assert_locked());
 
 	info = pars_info_create();
 	pars_info_add_ull_literal(info, "indexid", index_id);
@@ -3818,17 +3817,16 @@ row_merge_drop_indexes_dict(
 	pars_info_t*	info;
 
 	ut_ad(!srv_read_only_mode);
-	ut_ad(mutex_own(&dict_sys.mutex));
 	ut_ad(trx->dict_operation_lock_mode == RW_X_LATCH);
 	ut_ad(trx_get_dict_operation(trx) == TRX_DICT_OP_INDEX);
-	ut_ad(rw_lock_own(dict_operation_lock, RW_LOCK_X));
+	ut_d(dict_sys.assert_locked());
 
 	/* It is possible that table->n_ref_count > 1 when
 	locked=TRUE. In this case, all code that should have an open
 	handle to the table be waiting for the next statement to execute,
 	or waiting for a meta-data lock.
 
-	A concurrent purge will be prevented by dict_operation_lock. */
+	A concurrent purge will be prevented by dict_sys.latch. */
 
 	info = pars_info_create();
 	pars_info_add_ull_literal(info, "tableid", table_id);
@@ -3868,10 +3866,9 @@ row_merge_drop_indexes(
 	dict_index_t*	next_index;
 
 	ut_ad(!srv_read_only_mode);
-	ut_ad(mutex_own(&dict_sys.mutex));
 	ut_ad(trx->dict_operation_lock_mode == RW_X_LATCH);
 	ut_ad(trx_get_dict_operation(trx) == TRX_DICT_OP_INDEX);
-	ut_ad(rw_lock_own(dict_operation_lock, RW_LOCK_X));
+	ut_d(dict_sys.assert_locked());
 
 	index = dict_table_get_first_index(table);
 	ut_ad(dict_index_is_clust(index));
@@ -3885,7 +3882,7 @@ row_merge_drop_indexes(
 	handle to the table be waiting for the next statement to execute,
 	or waiting for a meta-data lock.
 
-	A concurrent purge will be prevented by dict_operation_lock. */
+	A concurrent purge will be prevented by dict_sys.latch. */
 
 	if (!locked && (table->get_ref_count() > 1
 			|| UT_LIST_GET_FIRST(table->locks))) {
@@ -4320,7 +4317,7 @@ row_merge_rename_tables_dict(
 
 	ut_ad(!srv_read_only_mode);
 	ut_ad(old_table != new_table);
-	ut_ad(mutex_own(&dict_sys.mutex));
+	ut_d(dict_sys.assert_locked());
 	ut_a(trx->dict_operation_lock_mode == RW_X_LATCH);
 	ut_ad(trx_get_dict_operation(trx) == TRX_DICT_OP_TABLE
 	      || trx_get_dict_operation(trx) == TRX_DICT_OP_INDEX);

storage/innobase/row/row0mysql.cc

@@ -2121,7 +2121,7 @@ row_mysql_freeze_data_dictionary_func(
 {
 	ut_a(trx->dict_operation_lock_mode == 0);
 
-	rw_lock_s_lock_inline(dict_operation_lock, 0, file, line);
+	rw_lock_s_lock_inline(&dict_sys.latch, 0, file, line);
 
 	trx->dict_operation_lock_mode = RW_S_LATCH;
 }
@@ -2137,7 +2137,7 @@ row_mysql_unfreeze_data_dictionary(
 
 	ut_a(trx->dict_operation_lock_mode == RW_S_LATCH);
 
-	rw_lock_s_unlock(dict_operation_lock);
+	rw_lock_s_unlock(&dict_sys.latch);
 
 	trx->dict_operation_lock_mode = 0;
 }
@@ -2321,14 +2321,8 @@ row_mysql_lock_data_dictionary_func(
 {
 	ut_a(trx->dict_operation_lock_mode == 0
 	     || trx->dict_operation_lock_mode == RW_X_LATCH);
-
-	/* Serialize data dictionary operations with dictionary mutex:
-	no deadlocks or lock waits can occur then in these operations */
-
-	rw_lock_x_lock_inline(dict_operation_lock, 0, file, line);
+	dict_sys.lock(file, line);
 	trx->dict_operation_lock_mode = RW_X_LATCH;
-
-	mutex_enter(&dict_sys.mutex);
 }
 
 /*********************************************************************//**
@@ -2339,16 +2333,9 @@ row_mysql_unlock_data_dictionary(
 	trx_t*	trx)	/*!< in/out: transaction */
 {
 	ut_ad(lock_trx_has_sys_table_locks(trx) == NULL);
-
 	ut_a(trx->dict_operation_lock_mode == RW_X_LATCH);
-
-	/* Serialize data dictionary operations with dictionary mutex:
-	no deadlocks can occur then in these operations */
-
-	mutex_exit(&dict_sys.mutex);
-	rw_lock_x_unlock(dict_operation_lock);
-
 	trx->dict_operation_lock_mode = 0;
+	dict_sys.unlock();
 }
 
 /*********************************************************************//**
@@ -2370,8 +2357,7 @@ row_create_table_for_mysql(
 	que_thr_t*	thr;
 	dberr_t		err;
 
-	ut_ad(rw_lock_own(dict_operation_lock, RW_LOCK_X));
-	ut_ad(mutex_own(&dict_sys.mutex));
+	ut_d(dict_sys.assert_locked());
 	ut_ad(trx->dict_operation_lock_mode == RW_X_LATCH);
 
 	DBUG_EXECUTE_IF(
@@ -2511,8 +2497,7 @@ row_create_index_for_mysql(
 	ulint		len;
 	dict_table_t*	table = index->table;
 
-	ut_ad(rw_lock_own(dict_operation_lock, RW_LOCK_X));
-	ut_ad(mutex_own(&dict_sys.mutex));
+	ut_d(dict_sys.assert_locked());
 
 	for (i = 0; i < index->n_def; i++) {
 		/* Check that prefix_len and actual length
@@ -3303,7 +3288,7 @@ will remain locked.
 @param[in]	create_failed	true=create table failed
 				because e.g. foreign key column
 @param[in]	nonatomic	Whether it is permitted to release
-				and reacquire dict_operation_lock
+				and reacquire dict_sys.latch
 @return error code or DB_SUCCESS */
 dberr_t
 row_drop_table_for_mysql(
@@ -3342,8 +3327,7 @@ row_drop_table_for_mysql(
 		nonatomic = true;
 	}
 
-	ut_ad(mutex_own(&dict_sys.mutex));
-	ut_ad(rw_lock_own(dict_operation_lock, RW_LOCK_X));
+	ut_d(dict_sys.assert_locked());
 
 	table = dict_table_open_on_name(
 		name, TRUE, FALSE,

storage/innobase/row/row0purge.cc

@@ -102,7 +102,7 @@ row_purge_remove_clust_if_poss_low(
 	purge_node_t*	node,	/*!< in/out: row purge node */
 	ulint		mode)	/*!< in: BTR_MODIFY_LEAF or BTR_MODIFY_TREE */
 {
-	ut_ad(rw_lock_own(dict_operation_lock, RW_LOCK_S)
+	ut_ad(rw_lock_own(&dict_sys.latch, RW_LOCK_S)
 	      || node->vcol_info.is_used());
 
 	dict_index_t* index = dict_table_get_first_index(node->table);
@@ -790,7 +790,7 @@ whose old history can no longer be observed.
 @param[in,out]	mtr	mini-transaction (will be started and committed) */
 static void row_purge_reset_trx_id(purge_node_t* node, mtr_t* mtr)
 {
-	ut_ad(rw_lock_own(dict_operation_lock, RW_LOCK_S)
+	ut_ad(rw_lock_own(&dict_sys.latch, RW_LOCK_S)
 	      || node->vcol_info.is_used());
 	/* Reset DB_TRX_ID, DB_ROLL_PTR for old records. */
 	mtr->start();
@@ -867,7 +867,7 @@ row_purge_upd_exist_or_extern_func(
 {
 	mem_heap_t*	heap;
 
-	ut_ad(rw_lock_own(dict_operation_lock, RW_LOCK_S)
+	ut_ad(rw_lock_own(&dict_sys.latch, RW_LOCK_S)
 	      || node->vcol_info.is_used());
 	ut_ad(!node->table->skip_alter_undo);
 
@@ -1058,7 +1058,7 @@ row_purge_parse_undo_rec(
 	for this row */
 
 try_again:
-	rw_lock_s_lock_inline(dict_operation_lock, 0, __FILE__, __LINE__);
+	rw_lock_s_lock_inline(&dict_sys.latch, 0, __FILE__, __LINE__);
 
 	node->table = dict_table_open_on_id(
 		table_id, FALSE, DICT_TABLE_OP_NORMAL);
@@ -1089,7 +1089,7 @@ try_again:
 		if (!mysqld_server_started) {
 
 			dict_table_close(node->table, FALSE, FALSE);
-			rw_lock_s_unlock(dict_operation_lock);
+			rw_lock_s_unlock(&dict_sys.latch);
 			if (srv_shutdown_state != SRV_SHUTDOWN_NONE) {
 				return(false);
 			}
@@ -1119,7 +1119,7 @@ inaccessible:
 		dict_table_close(node->table, FALSE, FALSE);
 		node->table = NULL;
 err_exit:
-		rw_lock_s_unlock(dict_operation_lock);
+		rw_lock_s_unlock(&dict_sys.latch);
 		node->skip(table_id, trx_id);
 		return(false);
 	}
@@ -1255,10 +1255,10 @@ row_purge(
 				node, undo_rec, thr, updated_extern);
 
 			if (!node->vcol_info.is_used()) {
-				rw_lock_s_unlock(dict_operation_lock);
+				rw_lock_s_unlock(&dict_sys.latch);
 			}
 
-			ut_ad(!rw_lock_own(dict_operation_lock, RW_LOCK_S));
+			ut_ad(!rw_lock_own(&dict_sys.latch, RW_LOCK_S));
 
 			if (purged
 			    || srv_shutdown_state != SRV_SHUTDOWN_NONE

storage/innobase/row/row0umod.cc

@@ -270,7 +270,7 @@ row_undo_mod_clust(
 	ut_ad(thr_get_trx(thr) == node->trx);
 	ut_ad(node->trx->dict_operation_lock_mode);
 	ut_ad(node->trx->in_rollback);
-	ut_ad(rw_lock_own_flagged(dict_operation_lock,
+	ut_ad(rw_lock_own_flagged(&dict_sys.latch,
 				  RW_LOCK_FLAG_X | RW_LOCK_FLAG_S));
 
 	log_free_check();
@@ -327,7 +327,7 @@ row_undo_mod_clust(
 	}
 
 	/* Online rebuild cannot be initiated while we are holding
-	dict_operation_lock and index->lock. (It can be aborted.) */
+	dict_sys.latch and index->lock. (It can be aborted.) */
 	ut_ad(online || !dict_index_is_online_ddl(index));
 
 	if (err == DB_SUCCESS && online) {

storage/innobase/row/row0undo.cc

@@ -420,7 +420,7 @@ row_undo(
 
 	/* Prevent DROP TABLE etc. while we are rolling back this row.
 	If we are doing a TABLE CREATE or some other dictionary operation,
-	then we already have dict_operation_lock locked in x-mode. Do not
+	then we already have dict_sys.latch locked in x-mode. Do not
 	try to lock again, because that would cause a hang. */
 
 	trx_t* trx = node->trx;

storage/innobase/row/row0upd.cc

@@ -122,7 +122,7 @@ row_upd_changes_first_fields_binary(
 Checks if index currently is mentioned as a referenced index in a foreign
 key constraint.
 
-NOTE that since we do not hold dict_operation_lock when leaving the
+NOTE that since we do not hold dict_sys.latch when leaving the
 function, it may be that the referencing table has been dropped when
 we leave this function: this function is only for heuristic use!
 
@@ -289,7 +289,7 @@ row_upd_check_references_constraints(
 			}
 
 			/* NOTE that if the thread ends up waiting for a lock
-			we will release dict_operation_lock temporarily!
+			we will release dict_sys.latch temporarily!
 			But the inc_fk_checks() protects foreign_table from
 			being dropped while the check is running. */
 
@@ -397,7 +397,7 @@ wsrep_row_upd_check_foreign_constraints(
 			}
 
 			/* NOTE that if the thread ends up waiting for a lock
-			we will release dict_operation_lock temporarily!
+			we will release dict_sys.latch temporarily!
 			But the counter on the table protects 'foreign' from
 			being dropped while the check is running. */
 

storage/innobase/srv/srv0srv.cc

@@ -1996,16 +1996,12 @@ srv_master_evict_from_table_cache(
 {
 	ulint	n_tables_evicted = 0;
 
-	rw_lock_x_lock(dict_operation_lock);
-
-	dict_mutex_enter_for_mysql();
+	dict_sys_lock();
 
 	n_tables_evicted = dict_make_room_in_cache(
 		innobase_get_table_cache_size(), pct_check);
 
-	dict_mutex_exit_for_mysql();
-
-	rw_lock_x_unlock(dict_operation_lock);
+	dict_sys_unlock();
 
 	return(n_tables_evicted);
 }