Merge.

mysql-test/r/lock_multi.result

@@ -219,3 +219,34 @@ flush tables with read lock;;
 connection: default
 flush tables;
 drop table t1;
+#
+# Bug#47249 assert in MDL_global_lock::is_lock_type_compatible
+#
+DROP TABLE IF EXISTS t1;
+DROP VIEW  IF EXISTS v1;
+#
+# Test 1: LOCK TABLES v1 WRITE, t1 READ;
+#
+CREATE TABLE t1 ( f1 integer );
+CREATE VIEW v1 AS SELECT f1 FROM t1 ;
+# Connection 2
+LOCK TABLES v1 WRITE, t1 READ;
+FLUSH TABLE t1;
+# Connection 1
+LOCK TABLES t1 WRITE;
+FLUSH TABLE t1;
+DROP TABLE t1;
+DROP VIEW v1;
+#
+# Test 2: LOCK TABLES t1 WRITE, v1 READ;
+#
+CREATE TABLE t1 ( f1 integer );
+CREATE VIEW v1 AS SELECT f1 FROM t1 ;
+# Connection 2
+LOCK TABLES t1 WRITE, v1 READ;
+FLUSH TABLE t1;
+# Connection 1
+LOCK TABLES t1 WRITE;
+FLUSH TABLE t1;
+DROP TABLE t1;
+DROP VIEW v1;

mysql-test/t/lock_multi.test

@@ -664,5 +664,63 @@ connection flush;
 --reap
 connection default;
 disconnect flush;
+
+
+--echo #
+--echo # Bug#47249 assert in MDL_global_lock::is_lock_type_compatible
+--echo #
+
+--disable_warnings
+DROP TABLE IF EXISTS t1;
+DROP VIEW  IF EXISTS v1;
+--enable_warnings
+
+--echo #
+--echo # Test 1: LOCK TABLES v1 WRITE, t1 READ;
+--echo #
+
+CREATE TABLE t1 ( f1 integer );
+CREATE VIEW v1 AS SELECT f1 FROM t1 ;
+
+--echo # Connection 2
+connect (con2,localhost,root);
+LOCK TABLES v1 WRITE, t1 READ;
+FLUSH TABLE t1;
+disconnect con2;
+--source include/wait_until_disconnected.inc
+
+--echo # Connection 1
+connection default;
+LOCK TABLES t1 WRITE;
+FLUSH TABLE t1;                                    # Assertion happened here
+
+# Cleanup
+DROP TABLE t1;
+DROP VIEW v1;
+
+--echo #
+--echo # Test 2: LOCK TABLES t1 WRITE, v1 READ;
+--echo #
+
+CREATE TABLE t1 ( f1 integer );
+CREATE VIEW v1 AS SELECT f1 FROM t1 ;
+
+--echo # Connection 2
+connect (con2,localhost,root);
+LOCK TABLES t1 WRITE, v1 READ;
+FLUSH TABLE t1;
+disconnect con2;
+--source include/wait_until_disconnected.inc
+
+--echo # Connection 1
+connection default;
+LOCK TABLES t1 WRITE;
+FLUSH TABLE t1;                                    # Assertion happened here
+
+# Cleanup
+DROP TABLE t1;
+DROP VIEW v1;
+
+
 # Wait till all disconnects are completed
 --source include/wait_until_count_sessions.inc

sql/mdl.cc

@@ -1005,6 +1005,9 @@ MDL_ticket::upgrade_shared_lock_to_exclusive()
   if (m_type == MDL_EXCLUSIVE)
     DBUG_RETURN(FALSE);
 
+  /* Only allow upgrades from MDL_SHARED_UPGRADABLE */
+  DBUG_ASSERT(m_type == MDL_SHARED_UPGRADABLE);
+
   pthread_mutex_lock(&LOCK_mdl);
 
   old_msg= MDL_ENTER_COND(thd, mysys_var);

sql/mdl.h

@@ -254,6 +254,10 @@ public:
                          mdl_cached_object_release_hook release_hook);
   const MDL_context *get_ctx() const { return m_ctx; }
   bool is_shared() const { return m_type < MDL_EXCLUSIVE; }
+  bool is_upgradable_or_exclusive() const
+  {
+    return m_type == MDL_SHARED_UPGRADABLE || m_type == MDL_EXCLUSIVE;
+  }
   bool upgrade_shared_lock_to_exclusive();
   void downgrade_exclusive_lock();
 private:

sql/sql_base.cc

@@ -130,6 +130,8 @@ static bool tdc_wait_for_old_versions(THD *thd,
 static bool
 has_write_table_with_auto_increment(TABLE_LIST *tables);
 
+TABLE *find_table_for_mdl_upgrade(TABLE *list, const char *db,
+                                  const char *table_name);
 
 uint cached_open_tables(void)
 {
@@ -999,8 +1001,8 @@ bool close_cached_tables(THD *thd, TABLE_LIST *tables, bool have_lock,
          table_list= table_list->next_global)
     {
       /* A check that the table was locked for write is done by the caller. */
-      TABLE *table= find_locked_table(thd->open_tables, table_list->db,
-                                      table_list->table_name);
+      TABLE *table= find_table_for_mdl_upgrade(thd->open_tables, table_list->db,
+                                               table_list->table_name);
 
       /* May return NULL if this table has already been closed via an alias. */
       if (! table)
@@ -2942,6 +2944,34 @@ TABLE *find_write_locked_table(TABLE *list, const char *db, const char *table_na
 }
 
 
+/**
+   Find instance of TABLE with MDL_SHARED_UPGRADABLE or
+   MDL_EXCLUSIVE lock from the list of open tables.
+
+   @param list       List of TABLE objects to be searched
+   @param db         Database name.
+   @param table_name Name of table.
+
+   @return Pointer to MDL_SHARED_UPGRADABLE or MDL_EXCLUSIVE
+           TABLE instance, NULL otherwise.
+*/
+
+TABLE *find_table_for_mdl_upgrade(TABLE *list, const char *db,
+                                  const char *table_name)
+{
+  TABLE *tab= find_locked_table(list, db, table_name);
+
+  while (tab != NULL)
+  {
+    if (tab->mdl_ticket != NULL &&
+        tab->mdl_ticket->is_upgradable_or_exclusive())
+      return tab;
+    tab= find_locked_table(tab->next, db, table_name);
+  }
+  return NULL;
+}
+
+
 /***********************************************************************
   class Locked_tables_list implementation. Declared in sql_class.h
 ************************************************************************/