MDEV-29504/MDEV-29849 TRUNCATE breaks FOREIGN KEY locking

ha_innobase::referenced_by_foreign_key(): Protect the check with
dict_sys.freeze(), to prevent races with TRUNCATE TABLE.
The test innodb.instant_alter_crash has been adjusted for this
additional locking.

dict_table_is_referenced_by_foreign_key(): Removed (merged to
the only caller).

create_table_info_t::create_table(): Ignore missing indexes for
FOREIGN KEY constraints if foreign_key_checks=0.

create_table_info_t::create_table_update_dict(): Rewritten as
a static function. Do not return any error.

ha_innobase::create(): When trx!=nullptr and we are operating
on a persistent table, do not rollback, commit, or release the
data dictionary latch.

ha_innobase::truncate(): Protect the entire critical section
with an exclusive dict_sys.latch, so that
ha_innobase::referenced_by_foreign_key() on referenced tables
will return a consistent result. In case of a failure,
invoke dict_load_foreigns() to restore also any FOREIGN KEY
constraints.

ha_innobase::free_foreign_key_create_info(): Define inline.

lock_release(): Disregard innodb_evict_tables_on_commit_debug=ON
when dict_sys.locked() holds. It would hold when fts_load_stopword()
is invoked by create_table_info_t::create_table_update_dict().

dict_sys_t::locked(): Return whether the current thread is holding
the exclusive dict_sys.latch.

dict_sys_t::frozen_not_locked(): Return whether any thread is
holding a shared dict_sys.latch.

In the test main.mysql_upgrade, the InnoDB persistent statistics
will no longer be recalculated in ha_innobase::open() as part of
CHECK TABLE ... FOR UPGRADE. They were deleted earlier in the test.

Tested by: Matthias Leich

1 files changed, 5 insertions, 17 deletions

diff --git a/storage/innobase/dict/dict0dict.cc b/storage/innobase/dict/dict0dict.cc
index 43ccf8c4d09..362b949e10f 100644
--- a/storage/innobase/dict/dict0dict.cc
+++ b/storage/innobase/dict/dict0dict.cc
@@ -685,8 +685,7 @@ dict_acquire_mdl_shared(dict_table_t *table,
   }
   else
   {
-    ut_ad(dict_sys.frozen());
-    ut_ad(!dict_sys.locked());
+    ut_ad(dict_sys.frozen_not_locked());
     db_len= dict_get_db_name_len(table->name.m_name);
   }
 
@@ -1003,7 +1002,7 @@ void dict_sys_t::lock_wait(SRW_LOCK_ARGS(const char *file, unsigned line))
     latch_ex_wait_start.store(0, std::memory_order_relaxed);
     ut_ad(!latch_readers);
     ut_ad(!latch_ex);
-    ut_d(latch_ex= true);
+    ut_d(latch_ex= pthread_self());
     return;
   }
 
@@ -1021,15 +1020,15 @@ void dict_sys_t::lock_wait(SRW_LOCK_ARGS(const char *file, unsigned line))
   latch.wr_lock(SRW_LOCK_ARGS(file, line));
   ut_ad(!latch_readers);
   ut_ad(!latch_ex);
-  ut_d(latch_ex= true);
+  ut_d(latch_ex= pthread_self());
 }
 
 #ifdef UNIV_PFS_RWLOCK
 ATTRIBUTE_NOINLINE void dict_sys_t::unlock()
 {
-  ut_ad(latch_ex);
+  ut_ad(latch_ex == pthread_self());
   ut_ad(!latch_readers);
-  ut_d(latch_ex= false);
+  ut_d(latch_ex= 0);
   latch.wr_unlock();
 }
 
@@ -2749,17 +2748,6 @@ dict_index_build_internal_fts(
 }
 /*====================== FOREIGN KEY PROCESSING ========================*/
 
-/*********************************************************************//**
-Checks if a table is referenced by foreign keys.
-@return TRUE if table is referenced by a foreign key */
-ibool
-dict_table_is_referenced_by_foreign_key(
-/*====================================*/
-	const dict_table_t*	table)	/*!< in: InnoDB table */
-{
-	return(!table->referenced_set.empty());
-}
-
 /**********************************************************************//**
 Removes a foreign constraint struct from the dictionary cache. */
 void