Backport of:

------------------------------------------------------------
revno: 2630.4.14
committer: Dmitry Lenev <dlenev@mysql.com>
branch nick: mysql-6.0-3726-w
timestamp: Wed 2008-05-28 12:16:03 +0400
message:
  WL#3726 "DDL locking for all metadata objects".

  After review fixes in progress. Removed unused code and
  adjusted names of functions/methods to better reflect
  their current function.


sql/mysql_priv.h:
  Changed names of close_data_files_and_morph_locks() and
  close_handle_and_leave_table_as_lock() to better reflect
  their current function (locking is now responsibility
  of metadata locking subsystem).
sql/sql_base.cc:
  Changed names of close_data_files_and_morph_locks() and
  close_handle_and_leave_table_as_lock() to better reflect
  their current function (locking is now responsibility
  of metadata locking subsystem). Also adjusted comments
  describing these functions.
  Got rid of TABLE::open_placeholder since it is no longer
  used (its value is never read anywhere).
  TABLE::needs_reopen_or_name_lock() was renamed to needs_reopen()
  since we no longer use name-locks
sql/sql_handler.cc:
  TABLE::needs_reopen_or_name_lock() was renamed to needs_reopen()
  since we no longer use name-locks.
sql/sql_insert.cc:
  TABLE::needs_reopen_or_name_lock() was renamed to needs_reopen()
  since we no longer use name-locks
sql/sql_partition.cc:
  Changed name of close_data_files_and_morph_locks() to
  better reflect its current function (locking is now
  responsibility of metadata locking subsystem).
sql/sql_table.cc:
  Changed names of close_data_files_and_morph_locks() and
  close_handle_and_leave_table_as_lock() to better reflect
  their current function (locking is now responsibility
  of metadata locking subsystem).
  Got rid of TABLE::open_placeholder since it is no longer
  used.
sql/sql_trigger.cc:
  Changed name of close_data_files_and_morph_locks() to
  better reflect its current function (locking is now
  responsibility of metadata locking subsystem).
sql/table.h:
  Got rid of TABLE::open_placeholder which is no longer used
  altough its value was set in several places no code reads it).
  Removed unused TABLE::is_name_opened() method.
  Finally TABLE::needs_reopen_or_name_lock() was renamed to
  needs_reopen() since we no longer use name-locks.

sql/sql_handler.cc

@@ -801,7 +801,7 @@ void mysql_ha_flush(THD *thd)
     if (hash_tables->table &&
         (hash_tables->table->mdl_lock &&
          mdl_has_pending_conflicting_lock(hash_tables->table->mdl_lock) ||
-         hash_tables->table->needs_reopen_or_name_lock()))
+         hash_tables->table->needs_reopen()))
       mysql_ha_close_table(thd, hash_tables);
   }