--- a/sql/log.cc	2014-12-09 16:11:39.000000000 -0700
+++ b/sql/log.cc	2014-12-09 16:09:09.000000000 -0700
@@ -4916,6 +4916,8 @@

 int THD::binlog_setup_trx_data()
 {
+  char* tmpdir_to_use;
+
   DBUG_ENTER("THD::binlog_setup_trx_data");
   binlog_cache_mngr *cache_mngr=
     (binlog_cache_mngr*) thd_get_ha_data(this, binlog_hton);
@@ -4924,10 +4926,18 @@
     DBUG_RETURN(0);                             // Already set up

   cache_mngr= (binlog_cache_mngr*) my_malloc(sizeof(binlog_cache_mngr), MYF(MY_ZEROFILL));
+  if (!opt_mysql_binlog_tmpdir)
+  {
+    tmpdir_to_use= mysql_tmpdir;
+  }
+  else
+  {
+    tmpdir_to_use= opt_mysql_binlog_tmpdir;
+  }
   if (!cache_mngr ||
-      open_cached_file(&cache_mngr->stmt_cache.cache_log, mysql_tmpdir,
+      open_cached_file(&cache_mngr->stmt_cache.cache_log, tmpdir_to_use,
                        LOG_PREFIX, binlog_stmt_cache_size, MYF(MY_WME)) ||
-      open_cached_file(&cache_mngr->trx_cache.cache_log, mysql_tmpdir,
+      open_cached_file(&cache_mngr->trx_cache.cache_log, tmpdir_to_use,
                        LOG_PREFIX, binlog_cache_size, MYF(MY_WME)))
   {
     my_free(cache_mngr);
diff -ruN a/sql/mysqld.cc b/sql/mysqld.cc
--- a/sql/mysqld.cc	2014-12-08 16:01:37.000000000 -0700
+++ b/sql/mysqld.cc	2014-12-09 16:09:09.000000000 -0700
@@ -602,7 +602,7 @@
 char *mysql_data_home= const_cast<char*>(".");
 const char *mysql_real_data_home_ptr= mysql_real_data_home;
 char server_version[SERVER_VERSION_LENGTH];
-char *mysqld_unix_port, *opt_mysql_tmpdir;
+char *mysqld_unix_port, *opt_mysql_tmpdir, *opt_mysql_binlog_tmpdir;
 ulong thread_handling;

 /** name of reference on left expression in rewritten IN subquery */
diff -ruN a/sql/mysqld.h b/sql/mysqld.h
--- a/sql/mysqld.h	2014-12-08 16:01:37.000000000 -0700
+++ b/sql/mysqld.h	2014-12-09 16:09:09.000000000 -0700
@@ -212,6 +212,7 @@
 extern int cachedev_fd;
 extern time_t server_start_time, flush_status_time;
 extern char *opt_mysql_tmpdir, mysql_charsets_dir[];
+extern char *opt_mysql_binlog_tmpdir;
 extern int mysql_unpacked_real_data_home_len;
 extern MYSQL_PLUGIN_IMPORT MY_TMPDIR mysql_tmpdir_list;
 extern const char *first_keyword, *delayed_user, *binary_keyword;
diff -ruN a/sql/sys_vars.cc b/sql/sys_vars.cc
--- a/sql/sys_vars.cc	2014-12-09 16:11:39.000000000 -0700
+++ b/sql/sys_vars.cc	2014-12-09 16:09:10.000000000 -0700
@@ -1927,6 +1927,11 @@
        READ_ONLY GLOBAL_VAR(opt_mysql_tmpdir), CMD_LINE(REQUIRED_ARG, 't'),
        IN_FS_CHARSET, DEFAULT(0));

+static Sys_var_charptr Sys_binlog_tmpdir(
+       "binlog_tmpdir", "Path for binlog temporary files.",
+       READ_ONLY GLOBAL_VAR(opt_mysql_binlog_tmpdir), CMD_LINE(REQUIRED_ARG, 't'),
+       IN_FS_CHARSET, DEFAULT(0));
+
 static bool fix_trans_mem_root(sys_var *self, THD *thd, enum_var_type type)
 {
   if (type != OPT_GLOBAL)