Sdditional fix-up for bug #26380: LOCK TABLES + FLUSH LOGS causes deadlock

FLUSH LOGS should ignore SET GLOBAL READ_ONLY.

sql/lock.cc

@@ -92,6 +92,7 @@ static void print_lock_error(int error, const char *);
     count                       The number of tables to lock.
     flags                       Options:
       MYSQL_LOCK_IGNORE_GLOBAL_READ_LOCK      Ignore a global read lock
+      MYSQL_LOCK_IGNORE_GLOBAL_READ_ONLY      Ignore SET GLOBAL READ_ONLY
       MYSQL_LOCK_IGNORE_FLUSH                 Ignore a flush tables.
       MYSQL_LOCK_NOTIFY_IF_NEED_REOPEN        Instead of reopening altered
                                               or dropped tables by itself,
@@ -150,11 +151,11 @@ MYSQL_LOCK *mysql_lock_tables(THD *thd, TABLE **tables, uint count,
       }
     }
 
-    if (   write_lock_used
-        && opt_readonly
-        && ! (thd->security_ctx->master_access & SUPER_ACL)
-        && ! thd->slave_thread
-       )
+    if (!(flags & MYSQL_LOCK_IGNORE_GLOBAL_READ_ONLY) &&
+        write_lock_used &&
+        opt_readonly &&
+        !(thd->security_ctx->master_access & SUPER_ACL) &&
+        !thd->slave_thread)
     {
       /*
 	Someone has issued SET GLOBAL READ_ONLY=1 and we want a write lock.

sql/mysql_priv.h

@@ -1765,6 +1765,7 @@ MYSQL_LOCK *mysql_lock_tables(THD *thd, TABLE **table, uint count,
 #define MYSQL_LOCK_IGNORE_FLUSH                 0x0002
 #define MYSQL_LOCK_NOTIFY_IF_NEED_REOPEN        0x0004
 #define MYSQL_OPEN_TEMPORARY_ONLY               0x0008
+#define MYSQL_LOCK_IGNORE_GLOBAL_READ_ONLY      0x0010
 
 void mysql_unlock_tables(THD *thd, MYSQL_LOCK *sql_lock);
 void mysql_unlock_read_tables(THD *thd, MYSQL_LOCK *sql_lock);

sql/sql_base.cc

@@ -4020,9 +4020,10 @@ int lock_tables(THD *thd, TABLE_LIST *tables, uint count, bool *need_reopen)
     TABLE **start,**ptr;
     uint lock_flag= MYSQL_LOCK_NOTIFY_IF_NEED_REOPEN;
     
-    /* Don't honor the GLOBAL READ LOCK if called from a logger */
+    /* Ignore GLOBAL READ LOCK and GLOBAL READ_ONLY if called from a logger */
     if (logger.is_privileged_thread(thd))
-      lock_flag|= MYSQL_LOCK_IGNORE_GLOBAL_READ_LOCK;
+      lock_flag|= (MYSQL_LOCK_IGNORE_GLOBAL_READ_LOCK |
+                   MYSQL_LOCK_IGNORE_GLOBAL_READ_ONLY);
 
     if (!(ptr=start=(TABLE**) thd->alloc(sizeof(TABLE*)*count)))
       DBUG_RETURN(-1);