Merge branch 'mysql/5.5' into 5.5

reverted about half of commits as either not applicable or
outright wrong

2 files changed, 18 insertions, 24 deletions

diff --git a/storage/innobase/buf/buf0flu.c b/storage/innobase/buf/buf0flu.c
index da58d8392cf..d15f2e4601e 100644
--- a/storage/innobase/buf/buf0flu.c
+++ b/storage/innobase/buf/buf0flu.c
@@ -1,6 +1,6 @@
 /*****************************************************************************
 
-Copyright (c) 1995, 2011, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 1995, 2016, 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 the Free Software
@@ -2103,12 +2103,7 @@ buf_flush_stat_update(void)
 	ib_uint64_t		lsn;
 	ulint			n_flushed;
 
-	lsn = log_get_lsn_nowait();
-
-	/* log_get_lsn_nowait tries to get log_sys->mutex with
-	mutex_enter_nowait, if this does not succeed function
-	returns 0, do not use that value to update stats. */
-	if (lsn == 0) {
+	if (!log_peek_lsn(&lsn)) {
 		return;
 	}
 
diff --git a/storage/innobase/srv/srv0srv.c b/storage/innobase/srv/srv0srv.c
index 49e5133df45..1cd21ac5a19 100644
--- a/storage/innobase/srv/srv0srv.c
+++ b/storage/innobase/srv/srv0srv.c
@@ -1,6 +1,6 @@
 /*****************************************************************************
 
-Copyright (c) 1995, 2013, Oracle and/or its affiliates. All Rights Reserved.
+Copyright (c) 1995, 2016, Oracle and/or its affiliates. All Rights Reserved.
 Copyright (c) 2008, 2009 Google Inc.
 Copyright (c) 2009, Percona Inc.
 Copyright (c) 2013, 2014, SkySQL Ab. All Rights Reserved.
@@ -2433,6 +2433,8 @@ exit_func:
 /*********************************************************************//**
 A thread which prints warnings about semaphore waits which have lasted
 too long. These can be used to track bugs which cause hangs.
+Note: In order to make sync_arr_wake_threads_if_sema_free work as expected,
+we should avoid waiting any mutexes in this function!
 @return	a dummy parameter */
 UNIV_INTERN
 os_thread_ret_t
@@ -2470,24 +2472,21 @@ loop:
 
 	/* Try to track a strange bug reported by Harald Fuchs and others,
 	where the lsn seems to decrease at times */
+	if (log_peek_lsn(&new_lsn)) {
+		if (new_lsn < old_lsn) {
+			ut_print_timestamp(stderr);
+			fprintf(stderr,
+				"  InnoDB: Error: old log sequence number %llu"
+				" was greater\n"
+				"InnoDB: than the new log sequence number %llu!\n"
+				"InnoDB: Please submit a bug report"
+				" to http://bugs.mysql.com\n",
+				old_lsn, new_lsn);
+			ut_ad(0);
+		}
 
-        /* We have to use nowait to ensure we don't block */
-	new_lsn= log_get_lsn_nowait();
-
-	if (new_lsn && new_lsn < old_lsn) {
-		ut_print_timestamp(stderr);
-		fprintf(stderr,
-			"  InnoDB: Error: old log sequence number %llu"
-			" was greater\n"
-			"InnoDB: than the new log sequence number %llu!\n"
-			"InnoDB: Please submit a bug report"
-			" to http://bugs.mysql.com\n",
-			old_lsn, new_lsn);
-		ut_ad(0);
-	}
-
-        if (new_lsn)
 		old_lsn = new_lsn;
+	}
 
 	if (difftime(time(NULL), srv_last_monitor_time) > 60) {
 		/* We referesh InnoDB Monitor values so that averages are