Record BACKUP and SCHEMA namespaces order

mysql-test/main/backup_lock_debug.result

@@ -26,3 +26,28 @@ disconnect con1;
 connection default;
 DROP TABLE t1;
 SET DEBUG_SYNC= 'RESET';
+#
+# Demonstrates a deadlock if BACKUP namespace is reorder after SCHEMA.
+# Culprit is ALTER TABLE taking SCHEMA lock on target database after
+# BACKUP lock was acquired.
+#
+CREATE DATABASE test2;
+CREATE TABLE t1(a INT) ENGINE=InnoDB;
+SET DEBUG_SYNC='alter_opened_table SIGNAL ready WAIT_FOR go';
+ALTER TABLE t1 RENAME TO test2.t1;
+connect  con1,localhost,root,,;
+SET DEBUG_SYNC='now WAIT_FOR ready';
+BACKUP STAGE START;
+SET DEBUG_SYNC='mdl_acquire_lock_wait SIGNAL ready1';
+BACKUP STAGE BLOCK_DDL;
+connect  con2,localhost,root,,;
+SET DEBUG_SYNC='now WAIT_FOR ready1';
+SET DEBUG_SYNC='mdl_acquire_lock_wait SIGNAL go';
+DROP DATABASE test2;
+connection default;
+connection con1;
+disconnect con1;
+connection con2;
+disconnect con2;
+connection default;
+SET DEBUG_SYNC='reset';

mysql-test/main/backup_lock_debug.test

@@ -3,6 +3,7 @@
 ########################################################################
 
 --source include/have_debug_sync.inc
+--source include/have_innodb.inc
 
 --echo #
 --echo # Make sure pending LOCK TABLES doesn't block BACKUP STAGE
@@ -38,3 +39,40 @@ disconnect con1;
 connection default;
 DROP TABLE t1;
 SET DEBUG_SYNC= 'RESET';
+
+
+--echo #
+--echo # Demonstrates a deadlock if BACKUP namespace is reorder after SCHEMA.
+--echo # Culprit is ALTER TABLE taking SCHEMA lock on target database after
+--echo # BACKUP lock was acquired.
+--echo #
+CREATE DATABASE test2;
+CREATE TABLE t1(a INT) ENGINE=InnoDB;
+
+SET DEBUG_SYNC='alter_opened_table SIGNAL ready WAIT_FOR go';
+send ALTER TABLE t1 RENAME TO test2.t1;
+
+connect (con1,localhost,root,,);
+SET DEBUG_SYNC='now WAIT_FOR ready';
+BACKUP STAGE START;
+SET DEBUG_SYNC='mdl_acquire_lock_wait SIGNAL ready1';
+send BACKUP STAGE BLOCK_DDL;
+
+connect (con2,localhost,root,,);
+SET DEBUG_SYNC='now WAIT_FOR ready1';
+SET DEBUG_SYNC='mdl_acquire_lock_wait SIGNAL go';
+send DROP DATABASE test2;
+
+connection default;
+reap;
+
+connection con1;
+reap;
+disconnect con1;
+
+connection con2;
+reap;
+disconnect con2;
+
+connection default;
+SET DEBUG_SYNC='reset';