MW-384 protect access to wsrep_ready variable with mutex

scripts/mysql_config.pl

 #!/usr/bin/perl
 # -*- cperl -*-
 #
-# Copyright (c) 2007, 2014, Oracle and/or its affiliates. All rights reserved.
+# Copyright (c) 2007, 2017, Oracle and/or its affiliates. All rights reserved.
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -53,7 +53,7 @@ my $cwd = cwd();
 my $basedir;
 
 my $socket  = '/tmp/mysql.sock';
-my $version = '5.5.38';
+my $version = '5.5.58';
 
 sub which
 {
@@ -204,7 +204,7 @@ $flags->{embedded_libs} =
   [@ldflags,@lib_e_opts,'','','','',''];
 
 $flags->{include} = ["-I$pkgincludedir"];
-$flags->{cflags}  = [@{$flags->{include}},split(" ",'-Wall  -DWITH_WSREP -DWSREP_PROC_INFO -DMYSQL_MAX_VARIABLE_VALUE_LEN=2048 -DWITH_INNODB_DISALLOW_WRITES -O2 -g -DNDEBUG -DDBUG_OFF')];
+$flags->{cflags}  = [@{$flags->{include}},split(" ",'')];
 
 # ----------------------------------------------------------------------
 # Remove some options that a client doesn't have to care about

sql/mysqld.cc

@@ -7929,7 +7929,7 @@ SHOW_VAR status_vars[]= {
 #endif
 #ifdef WITH_WSREP
   {"wsrep_connected",          (char*) &wsrep_connected,         SHOW_BOOL},
-  {"wsrep_ready",              (char*) &wsrep_ready,             SHOW_BOOL},
+  {"wsrep_ready",              (char*) &wsrep_show_ready,        SHOW_FUNC},
   {"wsrep_cluster_state_uuid", (char*) &wsrep_cluster_state_uuid,SHOW_CHAR_PTR},
   {"wsrep_cluster_conf_id",    (char*) &wsrep_cluster_conf_id,   SHOW_LONGLONG},
   {"wsrep_cluster_status",     (char*) &wsrep_cluster_status,    SHOW_CHAR_PTR},

sql/slave.cc

@@ -3794,7 +3794,7 @@ the slave SQL thread with \"SLAVE START\". We stopped at log \
   */
    if (wsrep_node_dropped && wsrep_restart_slave)
    {
-     if (wsrep_ready)
+     if (wsrep_ready_get())
      {
        WSREP_INFO("Slave error due to node temporarily non-primary"
 		  "SQL slave will continue");

sql/sql_parse.cc

@@ -851,7 +851,7 @@ bool do_command(THD *thd)
      * bail out if DB snapshot has not been installed. We however,
      * allow queries "SET" and "SHOW", they are trapped later in execute_command
      */
-    if (thd->variables.wsrep_on && !thd->wsrep_applier && !wsrep_ready &&
+    if (thd->variables.wsrep_on && !thd->wsrep_applier && !wsrep_ready_get() &&
         command != COM_QUERY        &&
         command != COM_PING         &&
         command != COM_QUIT         &&
@@ -2382,7 +2382,7 @@ mysql_execute_command(THD *thd)
       We additionally allow all other commands that do not change data in
       case wsrep_dirty_reads is enabled.
     */
-    if (thd->variables.wsrep_on && !thd->wsrep_applier && !wsrep_ready &&
+    if (thd->variables.wsrep_on && !thd->wsrep_applier && !wsrep_ready_get() &&
         lex->sql_command != SQLCOM_SET_OPTION &&
         !(thd->variables.wsrep_dirty_reads &&
          !is_update_query(lex->sql_command))  &&

sql/wsrep_mysqld.cc

@@ -13,6 +13,7 @@
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */
 
+#include <sql_plugin.h> // SHOW_MY_BOOL
 #include <mysqld.h>
 #include <sql_class.h>
 #include <sql_parse.h>
@@ -295,7 +296,7 @@ wsrep_view_handler_cb (void*                    app_ctx,
       // version change
       if (view->proto_ver != wsrep_protocol_version)
       {
-          my_bool wsrep_ready_saved= wsrep_ready;
+          my_bool wsrep_ready_saved= wsrep_ready_get();
           wsrep_ready_set(FALSE);
           WSREP_INFO("closing client connections for "
                      "protocol change %ld -> %d",
@@ -409,16 +410,34 @@ wsrep_view_handler_cb (void*                    app_ctx,
   return WSREP_CB_SUCCESS;
 }
 
-void wsrep_ready_set (my_bool x)
+my_bool wsrep_ready_set (my_bool x)
 {
   WSREP_DEBUG("Setting wsrep_ready to %d", x);
   if (mysql_mutex_lock (&LOCK_wsrep_ready)) abort();
-  if (wsrep_ready != x)
+  my_bool ret= (wsrep_ready != x);
+  if (ret)
   {
     wsrep_ready= x;
     mysql_cond_signal (&COND_wsrep_ready);
   }
   mysql_mutex_unlock (&LOCK_wsrep_ready);
+  return ret;
+}
+
+my_bool wsrep_ready_get (void)
+{
+  if (mysql_mutex_lock (&LOCK_wsrep_ready)) abort();
+  my_bool ret= wsrep_ready;
+  mysql_mutex_unlock (&LOCK_wsrep_ready);
+  return ret;
+}
+
+int wsrep_show_ready(THD *thd, SHOW_VAR *var, char *buff)
+{
+  var->type= SHOW_MY_BOOL;
+  var->value= buff;
+  *((my_bool *)buff)= wsrep_ready_get();
+  return 0;
 }
 
 // Wait until wsrep has reached ready state
@@ -437,17 +456,8 @@ void wsrep_ready_wait ()
 static void wsrep_synced_cb(void* app_ctx)
 {
   WSREP_INFO("Synchronized with group, ready for connections");
-  bool signal_main= false;
-  if (mysql_mutex_lock (&LOCK_wsrep_ready)) abort();
-  if (!wsrep_ready)
-  {
-    wsrep_ready= TRUE;
-    mysql_cond_signal (&COND_wsrep_ready);
-    signal_main= true;
-
-  }
+  my_bool signal_main= wsrep_ready_set(TRUE);
   local_status.set(WSREP_MEMBER_SYNCED);
-  mysql_mutex_unlock (&LOCK_wsrep_ready);
 
   if (signal_main)
   {

sql/wsrep_mysqld.h

@@ -115,7 +115,6 @@ enum enum_wsrep_sync_wait {
 
 // MySQL status variables
 extern my_bool     wsrep_connected;
-extern my_bool     wsrep_ready;
 extern const char* wsrep_cluster_state_uuid;
 extern long long   wsrep_cluster_conf_id;
 extern const char* wsrep_cluster_status;
@@ -130,6 +129,7 @@ extern const char* wsrep_provider_vendor;
 extern my_bool     wsrep_inited; // whether wsrep is initialized ?
 
 int  wsrep_show_status(THD *thd, SHOW_VAR *var, char *buff);
+int  wsrep_show_ready(THD *thd, SHOW_VAR *var, char *buff);
 void wsrep_free_status(THD *thd);
 
 /* Filters out --wsrep-new-cluster oprtion from argv[]
@@ -245,6 +245,7 @@ extern wsrep_seqno_t wsrep_locked_seqno;
 #define WSREP_PROVIDER_EXISTS                                                  \
   (wsrep_provider && strncasecmp(wsrep_provider, WSREP_NONE, FN_REFLEN))
 
+extern my_bool wsrep_ready_get();
 extern void wsrep_ready_wait();
 
 enum wsrep_trx_status {

sql/wsrep_priv.h

@@ -26,7 +26,7 @@
 #include <pthread.h>
 #include <cstdio>
 
-void    wsrep_ready_set (my_bool x);
+my_bool wsrep_ready_set (my_bool x);
 
 ssize_t wsrep_sst_prepare   (void** msg);
 wsrep_cb_status wsrep_sst_donate_cb (void* app_ctx,

sql/wsrep_sst.cc

@@ -1057,7 +1057,6 @@ wsrep_cb_status_t wsrep_sst_donate_cb (void* app_ctx, void* recv_ctx,
 {
   /* This will be reset when sync callback is called.
    * Should we set wsrep_ready to FALSE here too? */
-//  wsrep_notify_status(WSREP_MEMBER_DONOR);
   local_status.set(WSREP_MEMBER_DONOR);
 
   const char* method = (char*)msg;