Bug#19784790: ASSERTION `PART_SHARE->PARTITIONS_SHARE_REFS->NUM_PARTS

              >= M_TOT_PARTS' FAILED.

This patch is taken from MySQL, originally written by Mattias Jonsson
Here follows the original commit message:

Problem in handle_alter_part_error(),
result in altered partition_info object was still used
if table was under LOCK TABLES.

Solution was to always close and destroy all table
and table_share instances if exclusive mdl lock was
possible.
If not succeeding in get an exlusive lock (only possible
during rollback of DDL), at least close and destroy this
table instance.

rb#7361.
Approved by Mikael and Aditya.

mysql-test/suite/parts/r/partition_special_innodb.result

@@ -236,6 +236,7 @@ DROP TABLE t1;
 connect  con1,localhost,root,,;
 CREATE TABLE t1 ( i INT NOT NULL AUTO_INCREMENT PRIMARY KEY, f INT )
 ENGINE = InnoDB PARTITION BY HASH(i) PARTITIONS 2;
+INSERT INTO t1 VALUES (2, 2), (3, 3), (4, 4), (5, 5);
 connect  con2,localhost,root,,;
 SET lock_wait_timeout = 2;
 connection con1;
@@ -249,6 +250,19 @@ ERROR HY000: Lock wait timeout exceeded; try restarting transaction
 # Second attempt: says that partition already exists
 ALTER TABLE t1 ADD PARTITION PARTITIONS 2;
 ERROR HY000: Lock wait timeout exceeded; try restarting transaction
+# Check that we only can select, not insert/update/delete.
+INSERT INTO t1 VALUES (NULL, 6), (NULL, 7), (10, 10), (11, 11);
+ERROR HY000: Lock wait timeout exceeded; try restarting transaction
+UPDATE t1 SET i = 5 WHERE f = 2;
+ERROR HY000: Lock wait timeout exceeded; try restarting transaction
+DELETE FROM t1 WHERE i = 10;
+ERROR HY000: Lock wait timeout exceeded; try restarting transaction
+SELECT * FROM t1;
+i	f
+2	2
+3	3
+4	4
+5	5
 connection con1;
 # Connection 1 unlocks the table and locks it again:
 UNLOCK TABLES;
@@ -335,3 +349,30 @@ PARTITION BY RANGE(f1) (PARTITION p1 VALUES LESS THAN(10),
 PARTITION p2 VALUES LESS THAN (100));
 ALTER TABLE t1 convert to charset ascii collate ascii_bin, ALGORITHM=INSTANT;
 DROP TABLE t1;
+# Test WRITE LOCK.
+connect  con1,localhost,root,,;
+CREATE TABLE t1 ( i INT NOT NULL AUTO_INCREMENT PRIMARY KEY, f INT )
+ENGINE = InnoDB PARTITION BY HASH(i) PARTITIONS 2;
+INSERT INTO t1 VALUES (3, 3), (4, 4);
+connect  con2,localhost,root,,;
+SET lock_wait_timeout = 2;
+connection con1;
+#Connection 1 locks the table
+LOCK TABLE t1 WRITE;
+connection con2;
+# Check that we still can SELECT, but not insert/update/delete.
+# Check that we only can select, not insert/update/delete.
+INSERT INTO t1 VALUES (NULL, 1), (NULL, 2), (10, 10), (11, 11);
+ERROR HY000: Lock wait timeout exceeded; try restarting transaction
+UPDATE t1 SET i = 5 WHERE f = 2;
+ERROR HY000: Lock wait timeout exceeded; try restarting transaction
+DELETE FROM t1 WHERE i = 10;
+ERROR HY000: Lock wait timeout exceeded; try restarting transaction
+SELECT * FROM t1;
+ERROR HY000: Lock wait timeout exceeded; try restarting transaction
+connection con1;
+UNLOCK TABLES;
+connection con2;
+DROP TABLE t1;
+disconnect con1;
+connection default;

mysql-test/suite/parts/t/partition_special_innodb.test

@@ -83,6 +83,7 @@ DROP TABLE t1;
 --connect (con1,localhost,root,,)
 CREATE TABLE t1 ( i INT NOT NULL AUTO_INCREMENT PRIMARY KEY, f INT )
         ENGINE = InnoDB PARTITION BY HASH(i) PARTITIONS 2;
+INSERT INTO t1 VALUES (2, 2), (3, 3), (4, 4), (5, 5);
 
 --connect (con2,localhost,root,,)
 SET lock_wait_timeout = 2;
@@ -99,6 +100,15 @@ ALTER TABLE t1 ADD PARTITION PARTITIONS 2;
 --echo # Second attempt: says that partition already exists
 --error ER_LOCK_WAIT_TIMEOUT
 ALTER TABLE t1 ADD PARTITION PARTITIONS 2;
+--echo # Check that we only can select, not insert/update/delete.
+--error ER_LOCK_WAIT_TIMEOUT
+INSERT INTO t1 VALUES (NULL, 6), (NULL, 7), (10, 10), (11, 11);
+--error ER_LOCK_WAIT_TIMEOUT
+UPDATE t1 SET i = 5 WHERE f = 2;
+--error ER_LOCK_WAIT_TIMEOUT
+DELETE FROM t1 WHERE i = 10;
+--sorted_result
+SELECT * FROM t1;
 
 --connection con1
 --echo # Connection 1 unlocks the table and locks it again:
@@ -215,3 +225,37 @@ CREATE TABLE t1(
 				PARTITION p2 VALUES LESS THAN (100));
 ALTER TABLE t1 convert to charset ascii collate ascii_bin, ALGORITHM=INSTANT;
 DROP TABLE t1;
+
+--echo # Test WRITE LOCK.
+--connect (con1,localhost,root,,)
+CREATE TABLE t1 ( i INT NOT NULL AUTO_INCREMENT PRIMARY KEY, f INT )
+        ENGINE = InnoDB PARTITION BY HASH(i) PARTITIONS 2;
+INSERT INTO t1 VALUES (3, 3), (4, 4);
+
+--connect (con2,localhost,root,,)
+SET lock_wait_timeout = 2;
+
+--connection con1
+--echo #Connection 1 locks the table
+LOCK TABLE t1 WRITE;
+
+--connection con2
+--echo # Check that we still can SELECT, but not insert/update/delete.
+--echo # Check that we only can select, not insert/update/delete.
+--error ER_LOCK_WAIT_TIMEOUT
+INSERT INTO t1 VALUES (NULL, 1), (NULL, 2), (10, 10), (11, 11);
+--error ER_LOCK_WAIT_TIMEOUT
+UPDATE t1 SET i = 5 WHERE f = 2;
+--error ER_LOCK_WAIT_TIMEOUT
+DELETE FROM t1 WHERE i = 10;
+--error ER_LOCK_WAIT_TIMEOUT
+SELECT * FROM t1;
+
+--connection con1
+UNLOCK TABLES;
+
+--connection con2
+DROP TABLE t1;
+
+--disconnect con1
+--connection default