Merge with 3.23 to get fix for deadlock when doing LOCK TABLES in one thread...

Merge with 3.23 to get fix for deadlock when doing LOCK TABLES in one thread and DROP TABLE in another thread

sql/lock.cc

@@ -487,11 +487,12 @@ int lock_table_name(THD *thd, TABLE_LIST *table_list)
 {
   TABLE *table;
   char  key[MAX_DBKEY_LENGTH];
+  char *db= table_list->db ? table_list->db : (thd->db ? thd->db : (char*) "");
   uint  key_length;
   DBUG_ENTER("lock_table_name");
   safe_mutex_assert_owner(&LOCK_open);
 
-  key_length=(uint) (strmov(strmov(key,table_list->db)+1,table_list->real_name)
+  key_length=(uint) (strmov(strmov(key,db)+1,table_list->real_name)
 		     -key)+ 1;
 
   /* Only insert the table if we haven't insert it already */
@@ -520,7 +521,7 @@ int lock_table_name(THD *thd, TABLE_LIST *table_list)
     my_free((gptr) table,MYF(0));
     DBUG_RETURN(-1);
   }
-  if (remove_table_from_cache(thd, table_list->db, table_list->real_name))
+  if (remove_table_from_cache(thd, db, table_list->real_name))
     DBUG_RETURN(1);					// Table is in use
   DBUG_RETURN(0);
 }
@@ -564,6 +565,77 @@ bool wait_for_locked_table_names(THD *thd, TABLE_LIST *table_list)
   DBUG_RETURN(result);
 }
 
+
+/*
+  Lock all tables in list with a name lock
+
+  SYNOPSIS
+    lock_table_names()
+    thd			Thread handle
+    table_list		Names of tables to lock
+
+  NOTES
+    One must have a lock on LOCK_open when calling this
+
+  RETURN
+    0	ok
+    1	Fatal error (end of memory ?)
+*/
+
+bool lock_table_names(THD *thd, TABLE_LIST *table_list)
+{
+  bool got_all_locks=1;
+  TABLE_LIST *lock_table;
+
+  for (lock_table=table_list ; lock_table ; lock_table=lock_table->next)
+  {
+    int got_lock;
+    if ((got_lock=lock_table_name(thd,lock_table)) < 0)
+      goto end;					// Fatal error
+    if (got_lock)
+      got_all_locks=0;				// Someone is using table
+  }
+
+  /* If some table was in use, wait until we got the lock */
+  if (!got_all_locks && wait_for_locked_table_names(thd, table_list))
+    goto end;
+  return 0;
+
+end:
+  unlock_table_names(thd, table_list, lock_table);
+  return 1;
+}
+
+
+/*
+  Unlock all tables in list with a name lock
+
+  SYNOPSIS
+    unlock_table_names()
+    thd			Thread handle
+    table_list		Names of tables to unlock
+    last_table		Don't unlock any tables after this one.
+			(default 0, which will unlock all tables)
+
+  NOTES
+    One must have a lock on LOCK_open when calling this
+    This function will send a COND_refresh signal to inform other threads
+    that the name locks are removed
+
+  RETURN
+    0	ok
+    1	Fatal error (end of memory ?)
+*/
+
+void unlock_table_names(THD *thd, TABLE_LIST *table_list,
+			TABLE_LIST *last_table)
+{
+  for (TABLE_LIST *table=table_list ; table != last_table ; table=table->next)
+    unlock_table_name(thd,table);
+  pthread_cond_broadcast(&COND_refresh);
+}
+
+
 static void print_lock_error(int error)
 {
   int textno;

sql/mysql_priv.h

@@ -723,6 +723,9 @@ int lock_and_wait_for_table_name(THD *thd, TABLE_LIST *table_list);
 int lock_table_name(THD *thd, TABLE_LIST *table_list);
 void unlock_table_name(THD *thd, TABLE_LIST *table_list);
 bool wait_for_locked_table_names(THD *thd, TABLE_LIST *table_list);
+bool lock_table_names(THD *thd, TABLE_LIST *table_list);
+void unlock_table_names(THD *thd, TABLE_LIST *table_list,
+			TABLE_LIST *last_table= 0);
 
 
 /* old unireg functions */

sql/sql_rename.cc

@@ -31,8 +31,8 @@ static TABLE_LIST *rename_tables(THD *thd, TABLE_LIST *table_list,
 
 bool mysql_rename_tables(THD *thd, TABLE_LIST *table_list)
 {
-  bool error=1,got_all_locks=1;
-  TABLE_LIST *lock_table,*ren_table=0;
+  bool error= 1;
+  TABLE_LIST *ren_table= 0;
   DBUG_ENTER("mysql_rename_tables");
 
   /*
@@ -47,23 +47,11 @@ bool mysql_rename_tables(THD *thd, TABLE_LIST *table_list)
   }
 
   VOID(pthread_mutex_lock(&LOCK_open));
-  for (lock_table=table_list ; lock_table ; lock_table=lock_table->next)
-  {
-    int got_lock;
-    if ((got_lock=lock_table_name(thd,lock_table)) < 0)
-      goto end;
-    if (got_lock)
-      got_all_locks=0;
-  }
-
-  if (!got_all_locks && wait_for_locked_table_names(thd,table_list))
-    goto end;
-
-  if (!(ren_table=rename_tables(thd,table_list,0)))
-    error=0;
-
-end:
-  if (ren_table)
+  if (lock_table_names(thd, table_list))
+    goto err;
+  
+  error=0;
+  if ((ren_table=rename_tables(thd,table_list,0)))
   {
     /* Rename didn't succeed;  rename back the tables in reverse order */
     TABLE_LIST *prev=0,*table;
@@ -85,7 +73,7 @@ end:
     table=table->next->next;			// Skip error table
     /* Revert to old names */
     rename_tables(thd, table, 1);
-    /* Note that lock_table == 0 here, so the unlock loop will work */
+    error= 1;
   }
 
   /* Lets hope this doesn't fail as the result will be messy */ 
@@ -100,9 +88,9 @@ end:
     send_ok(&thd->net);
   }
 
-  for (TABLE_LIST *table=table_list ; table != lock_table ; table=table->next)
-    unlock_table_name(thd,table);
-  pthread_cond_broadcast(&COND_refresh);
+  unlock_table_names(thd,table_list);
+
+err:
   pthread_mutex_unlock(&LOCK_open);
   DBUG_RETURN(error);
 }

sql/sql_table.cc

@@ -80,7 +80,7 @@ int mysql_rm_table(THD *thd,TABLE_LIST *tables, my_bool if_exists)
     {
       my_error(ER_TABLE_NOT_LOCKED_FOR_WRITE,MYF(0),
 	       tables->real_name);
-      error = 1;
+      error= 1;
       goto err;
     }
     while (global_read_lock && ! thd->killed)
@@ -93,7 +93,6 @@ int mysql_rm_table(THD *thd,TABLE_LIST *tables, my_bool if_exists)
 
  err:
   pthread_mutex_unlock(&LOCK_open);
-  VOID(pthread_cond_broadcast(&COND_refresh)); // Signal to refresh
 
   pthread_mutex_lock(&thd->mysys_var->mutex);
   thd->mysys_var->current_mutex= 0;
@@ -138,7 +137,6 @@ int mysql_rm_table_part2_with_lock(THD *thd,
   error=mysql_rm_table_part2(thd,tables, if_exists, dont_log_query);
 
   pthread_mutex_unlock(&LOCK_open);
-  VOID(pthread_cond_broadcast(&COND_refresh)); // Signal to refresh
 
   pthread_mutex_lock(&thd->mysys_var->mutex);
   thd->mysys_var->current_mutex= 0;
@@ -171,9 +169,12 @@ int mysql_rm_table_part2(THD *thd, TABLE_LIST *tables, bool if_exists,
   bool some_tables_deleted=0, tmp_table_deleted=0;
   DBUG_ENTER("mysql_rm_table_part2");
 
+  if (lock_table_names(thd, tables))
+    DBUG_RETURN(1);
+
   for (table=tables ; table ; table=table->next)
   {
-    char *db=table->db ? table->db : thd->db;
+    char *db=table->db;
     mysql_ha_closeall(thd, table);
     if (!close_temporary_table(thd, db, table->real_name))
     {
@@ -248,6 +249,8 @@ int mysql_rm_table_part2(THD *thd, TABLE_LIST *tables, bool if_exists,
     my_error(ER_BAD_TABLE_ERROR,MYF(0),wrong_tables.c_ptr());
     error=1;
   }
+  unlock_table_names(thd, tables);
+
   DBUG_RETURN(error);
 }