Backport of:

------------------------------------------------------------
revno: 2630.4.18
committer: Dmitry Lenev <dlenev@mysql.com>
branch nick: mysql-6.0-3726-w2
timestamp: Tue 2008-06-03 21:07:58 +0400
message:
  WL#3726 "DDL locking for all metadata objects".

  After review fixes in progress.

  Now during upgrading/downgrading metadata locks we deal with
  individual metadata lock requests rather than with all requests
  for this object in the context. This makes API a bit more clear
  and makes adjust_mdl_locks_upgradability() much nicer.


sql/lock.cc:
  lock_table_names():
    Set TABLE_LIST::mdl_lock_data when allocating new metadata
    lock request object for table list element.
sql/mdl.cc:
  Now during upgrading/downgrading metadata locks we deal with
  individual metadata lock requests rather than with all
  requests for this object in the context. Adjusted upgrade/
  downgrade functions accordingly.
  We also got rid of mdl_release_exclusive_locks() and
  now release locks individually. To simplify this process
  mdl_release_all_locks_for_name() was introduced.
sql/mdl.h:
  Now during upgrading/downgrading metadata locks we deal with
  individual metadata lock requests rather than with all
  requests for this object in the context. Adjusted upgrade/
  downgrade functions accordingly.
  We also got rid of mdl_release_exclusive_locks() and
  now release locks individually. To simplify this process
  mdl_release_all_locks_for_name() was introduced.
sql/sql_base.cc:
  Now during upgrading/downgrading metadata locks we deal with
  individual metadata lock requests rather than with all
  requests for this object in the context.
  We also got rid of mdl_release_exclusive_locks() and
  now release locks individually.
sql/sql_parse.cc:
  adjust_mdl_locks_upgradability() is much simplier now due to the
  fact that now during upgrading/downgrading metadata locks we
  deal with individual metadata lock requests rather than with
  all requests for this object in the context.
sql/sql_table.cc:
  Now during upgrading/downgrading metadata locks we deal with
  individual metadata lock requests rather than with all
  requests for this object in the context. Adjusted upgrade/
  downgrade functions accordingly.
  We also got rid of mdl_release_exclusive_locks() and
  now release locks individually. To simplify this process
  mdl_release_all_locks_for_name() was introduced.
sql/sql_trigger.cc:
  ow during upgrading/downgrading metadata locks we deal with
  individual metadata lock requests rather than with all
  requests for this object in the context.

1 files changed, 6 insertions, 4 deletions

diff --git a/sql/mdl.h b/sql/mdl.h
index 74c90c01730..12ce2bb9820 100644
--- a/sql/mdl.h
+++ b/sql/mdl.h
@@ -194,8 +194,8 @@ inline void mdl_set_upgradable(MDL_LOCK_DATA *lock_data)
 
 bool mdl_acquire_shared_lock(MDL_LOCK_DATA *lock_data, bool *retry);
 bool mdl_acquire_exclusive_locks(MDL_CONTEXT *context);
-bool mdl_upgrade_shared_lock_to_exclusive(MDL_CONTEXT *context, int type,
-                                          const char *db, const char *name);
+bool mdl_upgrade_shared_lock_to_exclusive(MDL_CONTEXT *context,
+                                          MDL_LOCK_DATA *lock_data);
 bool mdl_try_acquire_exclusive_lock(MDL_CONTEXT *context,
                                     MDL_LOCK_DATA *lock_data);
 bool mdl_acquire_global_shared_lock(MDL_CONTEXT *context);
@@ -203,9 +203,11 @@ bool mdl_acquire_global_shared_lock(MDL_CONTEXT *context);
 bool mdl_wait_for_locks(MDL_CONTEXT *context);
 
 void mdl_release_locks(MDL_CONTEXT *context);
-void mdl_release_exclusive_locks(MDL_CONTEXT *context);
+void mdl_release_all_locks_for_name(MDL_CONTEXT *context,
+                                    MDL_LOCK_DATA *lock_data);
 void mdl_release_lock(MDL_CONTEXT *context, MDL_LOCK_DATA *lock_data);
-void mdl_downgrade_exclusive_locks(MDL_CONTEXT *context);
+void mdl_downgrade_exclusive_lock(MDL_CONTEXT *context,
+                                  MDL_LOCK_DATA *lock_data);
 void mdl_release_global_shared_lock(MDL_CONTEXT *context);
 
 bool mdl_is_exclusive_lock_owner(MDL_CONTEXT *context, int type, const char *db,