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MDEV-28956 Locking is broken if CREATE OR REPLACE fails under LOCK TABLES

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add_back_last_deleted_lock() was called when the lock was never
removed. Lock is removed in finalize_atomic_replace() in
close_all_tables_for_name(). finalize_atomic_replace() is done only
for successful operation.

In non-atomic codepath it drops the table first, if anything fails
later we don't need to return back the lock since there is no table
now. So the fix is required as well.
This commit is contained in:
Aleksey Midenkov
2022-08-31 11:55:05 +03:00
parent 24fff8267d
commit a228ec80e3
7 changed files with 112 additions and 17 deletions
Download Patch File Download Diff File Expand all files Collapse all files

16
mysql-test/main/create_or_replace.result
View File

@ -847,3 +847,19 @@ t2 CREATE TABLE `t2` (
`a` varchar(2300) DEFAULT NULL
) ENGINE=Aria DEFAULT CHARSET=latin1 PAGE_CHECKSUM=1
drop tables t2, t1;
#
# MDEV-28956 Locking is broken if CREATE OR REPLACE fails under LOCK TABLES
#
# Atomic CREATE OR REPLACE part:
#
create table t1 (pk int primary key) engine=innodb;
create or replace table t2 (a int primary key references t1 (pk)) engine=innodb;
lock tables t1 write, t2 write;
create or replace table t2 (c1 int not null, c1 varchar(255) ) engine=innodb;
ERROR 42S21: Duplicate column name 'c1'
select * from t1;
pk
select * from t2;
a
unlock tables;
drop tables t2, t1;

17
mysql-test/main/create_or_replace.test
View File

@ -638,3 +638,20 @@ create or replace table t2 engine aria select * from t1;
select * from t2;
show create table t2;
drop tables t2, t1;
--echo #
--echo # MDEV-28956 Locking is broken if CREATE OR REPLACE fails under LOCK TABLES
--echo #
--echo # Atomic CREATE OR REPLACE part:
--echo #
create table t1 (pk int primary key) engine=innodb;
create or replace table t2 (a int primary key references t1 (pk)) engine=innodb;
lock tables t1 write, t2 write;
--error ER_DUP_FIELDNAME
create or replace table t2 (c1 int not null, c1 varchar(255) ) engine=innodb;
select * from t1;
select * from t2;
unlock tables;
drop tables t2, t1;

19
mysql-test/main/create_or_replace2.result
View File

@ -72,3 +72,22 @@ ERROR 42000: Duplicate key name 'k'
create or replace table t1 (a int, b int, key k (a), key k (b));
ERROR 42000: Duplicate key name 'k'
drop table t1;
#
# MDEV-28956 Locking is broken if CREATE OR REPLACE fails under LOCK TABLES
#
# Non-atomic CREATE OR REPLACE part:
#
set @saved_debug_dbug= @@session.debug_dbug;
set @@debug_dbug="+d,ddl_log_expensive_rename";
create table t1 (pk int primary key) engine=innodb;
create or replace table t2 (a int primary key references t1 (pk)) engine=innodb;
lock tables t1 write, t2 write;
create or replace table t2 (c1 int not null, c1 varchar(255) ) engine=innodb;
ERROR 42S21: Duplicate column name 'c1'
select * from t1;
pk
select * from t2;
ERROR HY000: Table 't2' was not locked with LOCK TABLES
unlock tables;
drop tables t1;
set @@debug_dbug= @saved_debug_dbug;

21
mysql-test/main/create_or_replace2.test
View File

@ -65,3 +65,24 @@ create or replace table t1 (a int, b int, key k (a), key k (b));
--error ER_DUP_KEYNAME
create or replace table t1 (a int, b int, key k (a), key k (b));
drop table t1;
--echo #
--echo # MDEV-28956 Locking is broken if CREATE OR REPLACE fails under LOCK TABLES
--echo #
--echo # Non-atomic CREATE OR REPLACE part:
--echo #
set @saved_debug_dbug= @@session.debug_dbug;
set @@debug_dbug="+d,ddl_log_expensive_rename";
create table t1 (pk int primary key) engine=innodb;
create or replace table t2 (a int primary key references t1 (pk)) engine=innodb;
lock tables t1 write, t2 write;
--error ER_DUP_FIELDNAME
create or replace table t2 (c1 int not null, c1 varchar(255) ) engine=innodb;
select * from t1;
--error ER_TABLE_NOT_LOCKED
select * from t2;
unlock tables;
drop tables t1;
set @@debug_dbug= @saved_debug_dbug;

2
sql/handler.h
View File

@ -2382,7 +2382,7 @@ struct HA_CREATE_INFO: public Table_scope_and_contents_source_st,
}
bool finalize_atomic_replace(THD *thd, TABLE_LIST *orig_table);
void finalize_ddl(THD *thd, bool roll_back);
bool finalize_locked_tables(THD *thd);
bool finalize_locked_tables(THD *thd, bool operation_failed);
bool make_tmp_table_list(THD *thd, TABLE_LIST **create_table,
int *create_table_mode);
};

6
sql/sql_insert.cc
View File

@ -5414,7 +5414,8 @@ bool select_create::send_eof()
mysql_unlock_tables(thd, lock);
}
else if (atomic_replace && create_info->pos_in_locked_tables &&
create_info->finalize_locked_tables(thd))
/* send_eof() is done on success, passing false here */
create_info->finalize_locked_tables(thd, false))
DBUG_RETURN(true);
send_ok_packet();
@ -5526,6 +5527,7 @@ void select_create::abort_result_set()
thd->locked_tables_list.unlock_locked_table(thd, create_info->mdl_ticket);
}
else if (atomic_replace && create_info->pos_in_locked_tables)
(void) create_info->finalize_locked_tables(thd);
/* abort_result_set() is done on error, passing true here */
(void) create_info->finalize_locked_tables(thd, true);
DBUG_VOID_RETURN;
}

48
sql/sql_table.cc
View File

@ -4509,27 +4509,47 @@ void HA_CREATE_INFO::finalize_ddl(THD *thd, bool roll_back)
}
bool HA_CREATE_INFO::finalize_locked_tables(THD *thd)
/**
Finalize operation of LOCK TABLES mode for CREATE TABLE family of commands.
@param operation_failed Notify if the callee CREATE fails the operation
@return true on error, false on success
*/
bool HA_CREATE_INFO::finalize_locked_tables(THD *thd, bool operation_failed)
{
DBUG_ASSERT(pos_in_locked_tables);
DBUG_ASSERT(thd->locked_tables_mode);
DBUG_ASSERT(thd->variables.option_bits & OPTION_TABLE_LOCK);
/*
Add back the deleted table and re-created table as a locked table
This should always work as we have a meta lock on the table.
*/
thd->locked_tables_list.add_back_last_deleted_lock(pos_in_locked_tables);
if (!operation_failed)
{
/*
Add back the deleted table and re-created table as a locked table
This should always work as we have a meta lock on the table.
*/
thd->locked_tables_list.add_back_last_deleted_lock(pos_in_locked_tables);
}
if (thd->locked_tables_list.reopen_tables(thd, false))
{
thd->locked_tables_list.unlink_all_closed_tables(thd, NULL, 0);
return true;
}
/*
The lock was made exclusive in create_table_impl(). We have now
to bring it back to it's orginal state
*/
TABLE *table= pos_in_locked_tables->table;
table->mdl_ticket->downgrade_lock(MDL_SHARED_NO_READ_WRITE);
if (is_atomic_replace() || !operation_failed)
{
/*
The lock was made exclusive in create_table_impl(). We have now
to bring it back to it's orginal state.
*/
TABLE *table= pos_in_locked_tables->table;
table->mdl_ticket->downgrade_lock(MDL_SHARED_NO_READ_WRITE);
}
else
{
/*
In failed non-atomic we have nothing to downgrade:
original table was deleted and the lock was already removed.
*/
DBUG_ASSERT(!pos_in_locked_tables->table);
}
return false;
}
@ -5278,7 +5298,7 @@ err:
*/
if (thd->locked_tables_mode && pos_in_locked_tables &&
create_info->or_replace())
result|= (int) create_info->finalize_locked_tables(thd);
result|= (int) create_info->finalize_locked_tables(thd, result);
DBUG_RETURN(result);
}
@ -6023,7 +6043,7 @@ err:
*/
if (thd->locked_tables_mode && pos_in_locked_tables &&
create_info->or_replace())
res|= (int) local_create_info.finalize_locked_tables(thd);
res|= (int) local_create_info.finalize_locked_tables(thd, res);
DBUG_RETURN(res != 0);
}