From 02afe9855a4d04fe56951a9e9ffd3e32537ff77e Mon Sep 17 00:00:00 2001
From: Kefu Chai <kchai@redhat.com>
Date: Mon, 10 Apr 2017 14:53:46 +0800
Subject: [PATCH] mon/MonClient: make get_mon_log_message() atomic

* LogClient: move reset_session() into get_mon_log_message() and add a
  "flush" param to the latter. so it can get_mon_log_message()
  atomically. otherwise another call changing the log queue could sneak
  in between reset_session() and get_mon_log_message().
* MonClient: add a "flush" param to do_send() so we can reset the
  LogClient session once we are connected to a monitor.

Fixes: http://tracker.ceph.com/issues/19427
Signed-off-by: Kefu Chai <kchai@redhat.com>
(cherry picked from commit 5215e291da2b527d85e129eda86043490843178e)

Conflicts:
	src/mon/MonClient.cc: handle_auth: replaced 'log_client->reset_session();
	send_log();' sequence with newly introduced 'send_log(true);' like
	the original patch does
---
 src/common/LogClient.cc | 12 +++++-------
 src/common/LogClient.h  |  3 +--
 src/mon/MonClient.cc    | 10 +++-------
 src/mon/MonClient.h     |  2 +-
 4 files changed, 10 insertions(+), 17 deletions(-)

diff --git a/src/common/LogClient.cc b/src/common/LogClient.cc
index f52912f7fccc4..e5c069fd7031b 100644
--- a/src/common/LogClient.cc
+++ b/src/common/LogClient.cc
@@ -264,15 +264,13 @@ void LogChannel::do_log(clog_type prio, const std::string& s)
   }
 }
 
-void LogClient::reset_session()
-{
-  Mutex::Locker l(log_lock);
-  last_log_sent = last_log - log_queue.size();
-}
-
-Message *LogClient::get_mon_log_message()
+Message *LogClient::get_mon_log_message(bool flush)
 {
   Mutex::Locker l(log_lock);
+  if (flush) {
+    // reset session
+    last_log_sent = last_log - log_queue.size();
+  }
   return _get_mon_log_message();
 }
 
diff --git a/src/common/LogClient.h b/src/common/LogClient.h
index bf70e39a80522..0e8a2578bf1d1 100644
--- a/src/common/LogClient.h
+++ b/src/common/LogClient.h
@@ -206,8 +206,7 @@ public:
   }
 
   bool handle_log_ack(MLogAck *m);
-  void reset_session();
-  Message *get_mon_log_message();
+  Message *get_mon_log_message(bool flush);
   bool are_pending();
 
   LogChannelRef create_channel() {
diff --git a/src/mon/MonClient.cc b/src/mon/MonClient.cc
index 3db182f6da283..6eaa395f40eba 100644
--- a/src/mon/MonClient.cc
+++ b/src/mon/MonClient.cc
@@ -302,10 +302,10 @@ bool MonClient::ms_dispatch(Message *m)
   return true;
 }
 
-void MonClient::send_log()
+void MonClient::send_log(bool flush)
 {
   if (log_client) {
-    Message *lm = log_client->get_mon_log_message();
+    Message *lm = log_client->get_mon_log_message(flush);
     if (lm)
       _send_mon_message(lm);
     more_log_pending = log_client->are_pending();
@@ -544,13 +544,9 @@ void MonClient::handle_auth(MAuthReply *m)
 	_send_mon_message(waiting_for_session.front());
 	waiting_for_session.pop_front();
       }
-
       _resend_mon_commands();
 
-      if (log_client) {
-	log_client->reset_session();
-	send_log();
-      }
+      send_log(true);
       if (session_established_context) {
         cb = session_established_context;
         session_established_context = NULL;
diff --git a/src/mon/MonClient.h b/src/mon/MonClient.h
index d2a29953ff4c5..0164cb3d3b97c 100644
--- a/src/mon/MonClient.h
+++ b/src/mon/MonClient.h
@@ -129,7 +129,7 @@ private:
   LogClient *log_client;
   bool more_log_pending;
 
-  void send_log();
+  void send_log(bool flush = false);
 
   AuthMethodList *auth_supported;
 
-- 
2.39.5