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Fix for bug #12423 "Deadlock when doing FLUSH PRIVILEGES and GRANT in

multi-threaded environment".

To avoid deadlocks between several simultaneously run account management 
commands (particularly between FLUSH PRIVILEGES/SET PASSWORD and GRANT
commands) we should always take table and internal locks during their
execution in the same order. In other words we should first open and lock
privilege tables and only then obtain acl_cache::lock/LOCK_grant locks.


mysql-test/r/grant2.result:
  Added test for bug #12423 "Deadlock when doing FLUSH PRIVILEGES and GRANT in 
  multi-threaded environment".
mysql-test/t/grant2.test:
  Added test for bug #12423 "Deadlock when doing FLUSH PRIVILEGES and GRANT in 
  multi-threaded environment".
sql/mysqld.cc:
  acl_init/grant_init() are now used only at server start up so they always
  allocate temporary THD object and don't need argument for passing pointer
  to it.
sql/sql_acl.cc:
  To avoid deadlocks between several simultaneously run account management 
  commands (particularly between FLUSH PRIVILEGES/SET PASSWORD and GRANT
  commands) we should always take table and internal locks during their
  execution in the same order. In other words we should first open and lock
  privilege tables and only then obtain acl_cache::lock/LOCK_grant locks.
  
  Changed acl_reload()/grant_reload() and change_password()/update_user_table()
  in such way that they obey this principle. Now in acl_reload()/grant_reload()/
  change_password() we open and lock privilege tables, then obtain internal
  locks and then call acl_load()/grant_load()/update_user_table() functions to
  do actual loading or updating.
sql/sql_acl.h:
  acl_init/grant_init() are now used only at server start up so they always
  allocate temporary THD object and don't need argument for passing pointer
  to it. acl_reload()/grant_reload() now are able to report about their
  success or failure through return value.
sql/sql_parse.cc:
  If reload_acl_and_cache() is called from SIGHUP handler we have to
  allocate temporary THD for execution of acl_reload()/grant_reload().
This commit is contained in:
unknown
2005-09-01 16:52:59 +04:00
parent 9df32ec8f8
commit 2a64e9a2e8
6 changed files with 320 additions and 171 deletions

View File

@@ -134,8 +134,8 @@ public:
/* prototypes */
bool hostname_requires_resolving(const char *hostname);
my_bool acl_init(THD *thd, bool dont_read_acl_tables);
void acl_reload(THD *thd);
my_bool acl_init(bool dont_read_acl_tables);
my_bool acl_reload(THD *thd);
void acl_free(bool end=0);
ulong acl_get(const char *host, const char *ip,
const char *user, const char *db, my_bool db_is_pattern);
@@ -151,9 +151,9 @@ int mysql_grant(THD *thd, const char *db, List <LEX_USER> &user_list,
int mysql_table_grant(THD *thd, TABLE_LIST *table, List <LEX_USER> &user_list,
List <LEX_COLUMN> &column_list, ulong rights,
bool revoke);
my_bool grant_init(THD *thd);
my_bool grant_init();
void grant_free(void);
void grant_reload(THD *thd);
my_bool grant_reload(THD *thd);
bool check_grant(THD *thd, ulong want_access, TABLE_LIST *tables,
uint show_command, uint number, bool dont_print_error);
bool check_grant_column (THD *thd,TABLE *table, const char *name, uint length,