Merge from mysql-5.1-security to mysql-5.5-security

mysql-test/suite/innodb/r/innodb_bug57255.result

+create table A(id int not null primary key) engine=innodb;
+create table B(id int not null auto_increment primary key, f1 int not null, foreign key(f1) references A(id) on delete cascade) engine=innodb;
+create table C(id int not null auto_increment primary key, f1 int not null, foreign key(f1) references B(id) on delete cascade) engine=innodb;
+insert into A values(1), (2);
+DELETE FROM A where id = 1;
+DELETE FROM C where f1 = 2;
+DELETE FROM A where id = 1;
+DROP TABLE C;
+DROP TABLE B;
+DROP TABLE A;

mysql-test/suite/innodb/t/innodb_bug57255.test

+# Test Bug #57255. Cascade deletes that affect different rows should not
+# result in DB_FOREIGN_EXCEED_MAX_CASCADE error
+
+--source include/have_innodb.inc
+
+create table A(id int not null primary key) engine=innodb;
+
+create table B(id int not null auto_increment primary key, f1 int not null, foreign key(f1) references A(id) on delete cascade) engine=innodb;
+
+create table C(id int not null auto_increment primary key, f1 int not null, foreign key(f1) references B(id) on delete cascade) engine=innodb;
+
+insert into A values(1), (2);
+
+--disable_query_log
+let $i=257;
+while ($i)
+{
+insert into B(f1) values(1);
+dec $i;
+}
+let $i=486;
+while ($i)
+{
+insert into C(f1) values(2);
+dec $i;
+}
+--enable_query_log
+
+# Following Deletes should not report error
+DELETE FROM A where id = 1;
+DELETE FROM C where f1 = 2;
+DELETE FROM A where id = 1;
+
+DROP TABLE C;
+DROP TABLE B;
+DROP TABLE A;

storage/innobase/row/row0mysql.c

@@ -1652,6 +1652,9 @@ row_update_cascade_for_mysql(
 
 	trx = thr_get_trx(thr);
 
+	/* Increment fk_cascade_depth to record the recursive call depth on
+	a single update/delete that affects multiple tables chained
+	together with foreign key relations. */
 	thr->fk_cascade_depth++;
 
 	if (thr->fk_cascade_depth > FK_MAX_CASCADE_DEL) {
@@ -1663,6 +1666,12 @@ row_update_cascade_for_mysql(
 
 	row_upd_step(thr);
 
+	/* The recursive call for cascading update/delete happens
+	in above row_upd_step(), reset the counter once we come
+	out of the recursive call, so it does not accumulate for
+	different row deletes */
+	thr->fk_cascade_depth = 0;
+
 	err = trx->error_state;
 
 	/* Note that the cascade node is a subnode of another InnoDB