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:
  Auto merged
sql/mysql_priv.h:
  Auto merged
sql/sql_rename.cc:
  merge
sql/sql_table.cc:
  merge

4 files changed, 95 insertions, 29 deletions

diff --git a/sql/lock.cc b/sql/lock.cc
index 64456e6ec36..41a76007289 100644
--- a/sql/lock.cc
+++ b/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;
diff --git a/sql/mysql_priv.h b/sql/mysql_priv.h
index 7d830859fb2..c6e205f4729 100644
--- a/sql/mysql_priv.h
+++ b/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 */
diff --git a/sql/sql_rename.cc b/sql/sql_rename.cc
index 3eddd2646d5..d7e998264f3 100644
--- a/sql/sql_rename.cc
+++ b/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);
 }
diff --git a/sql/sql_table.cc b/sql/sql_table.cc
index 4c92c35632a..f84dd82ca65 100644
--- a/sql/sql_table.cc
+++ b/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);
 }