From 109f37f3abee0c12626d60763d7e8b5fa68b3381 Mon Sep 17 00:00:00 2001
From: Sage Weil <sage@newdream.net>
Date: Wed, 17 Feb 2010 21:47:18 -0800
Subject: [PATCH] workqueue: behave when multiple threads call drain()

Use a counter, not a bool.
---
 src/common/WorkQueue.cc | 4 ++--
 src/common/WorkQueue.h  | 6 ++++--
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/src/common/WorkQueue.cc b/src/common/WorkQueue.cc
index 62508125a8c90..22b8b75f19fe6 100644
--- a/src/common/WorkQueue.cc
+++ b/src/common/WorkQueue.cc
@@ -125,10 +125,10 @@ void ThreadPool::drain(_WorkQueue *wq)
 {
   dout(10) << "drain" << dendl;
   _lock.Lock();
-  _draining = true;
+  _draining++;
   while (processing || (wq != NULL && !wq->_empty()))
     _wait_cond.Wait(_lock);
-  _draining = false;
+  _draining--;
   _lock.Unlock();
 }
 
diff --git a/src/common/WorkQueue.h b/src/common/WorkQueue.h
index c24d32e2972f8..bd608a0c7bba2 100644
--- a/src/common/WorkQueue.h
+++ b/src/common/WorkQueue.h
@@ -23,7 +23,8 @@ class ThreadPool {
   string name;
   Mutex _lock;
   Cond _cond;
-  bool _stop, _pause, _draining;
+  bool _stop, _pause;
+  int _draining;
   Cond _wait_cond;
 
   struct _WorkQueue {
@@ -124,7 +125,8 @@ public:
     name(nm),
     _lock((new string(name + "::lock"))->c_str()),  // deliberately leak this
     _stop(false),
-    _pause(false), _draining(false),
+    _pause(false),
+    _draining(0),
     last_work_queue(0),
     processing(0) {
     set_num_threads(n);
-- 
2.39.5