Backport of revno: 2617.56.21

Bug #45066 FLUSH TABLES WITH READ LOCK deadlocks against LOCK TABLE

Test coverage for combinations of LOCK TABLE READ / WRITE and 
FLUSH TABLES / FLUSH TABLES WITH READ LOCK added to lock.test.
LOCK and FLUSH are executed sequentially from one connection.

mysql-test/r/lock.result

@@ -319,5 +319,27 @@ alter table t1 add column j int;
 unlock tables;
 drop table t1;
 #
+# Bug#45066 FLUSH TABLES WITH READ LOCK deadlocks against 
+#           LOCK TABLE 
+#
+DROP TABLE IF EXISTS t1;
+CREATE TABLE t1(a INT);
+LOCK TABLE t1 READ;
+FLUSH TABLES;
+ERROR HY000: Table 't1' was locked with a READ lock and can't be updated
+LOCK TABLE t1 WRITE;
+FLUSH TABLES;
+#
+# If you allow the next combination, you reintroduce bug Bug#45066
+# 
+LOCK TABLE t1 READ;
+FLUSH TABLES WITH READ LOCK;
+ERROR HY000: Can't execute the given command because you have active locked tables or an active transaction
+LOCK TABLE t1 WRITE;
+FLUSH TABLES WITH READ LOCK;
+ERROR HY000: Can't execute the given command because you have active locked tables or an active transaction
+UNLOCK TABLES;
+DROP TABLE t1;
+#
 # End of 6.0 tests.
 #

mysql-test/t/lock.test

@@ -385,6 +385,38 @@ alter table t1 add column j int;
 unlock tables;
 drop table t1;
 
+--echo #
+--echo # Bug#45066 FLUSH TABLES WITH READ LOCK deadlocks against 
+--echo #           LOCK TABLE 
+--echo #
+
+--disable_warnings
+DROP TABLE IF EXISTS t1;
+--enable_warnings
+
+CREATE TABLE t1(a INT);
+
+LOCK TABLE t1 READ;
+--error ER_TABLE_NOT_LOCKED_FOR_WRITE
+FLUSH TABLES;
+
+LOCK TABLE t1 WRITE;
+FLUSH TABLES;
+
+--echo #
+--echo # If you allow the next combination, you reintroduce bug Bug#45066
+--echo # 
+LOCK TABLE t1 READ;
+--error ER_LOCK_OR_ACTIVE_TRANSACTION
+FLUSH TABLES WITH READ LOCK;
+
+LOCK TABLE t1 WRITE;
+--error ER_LOCK_OR_ACTIVE_TRANSACTION
+FLUSH TABLES WITH READ LOCK;
+
+UNLOCK TABLES;
+DROP TABLE t1;
+
 --echo #
 --echo # End of 6.0 tests.
 --echo #