diff --git a/versioning/BRM/extentmap.cpp b/versioning/BRM/extentmap.cpp
index 0a110fbc7..e0b7ba285 100644
--- a/versioning/BRM/extentmap.cpp
+++ b/versioning/BRM/extentmap.cpp
@@ -235,7 +235,7 @@ ExtentMapRBTreeImpl* ExtentMapRBTreeImpl::fInstance = nullptr;
 
 /*static*/
 ExtentMapRBTreeImpl* ExtentMapRBTreeImpl::makeExtentMapRBTreeImpl(unsigned key, off_t size, bool readOnly,
-                                                                  bool& emLocked,
+                                                                  std::atomic<bool>& emLocked,
                                                                   const MasterSegmentTable* emSegTable)
 {
   boost::mutex::scoped_lock lk(fInstanceMutex);
diff --git a/versioning/BRM/extentmap.h b/versioning/BRM/extentmap.h
index 39404e341..dc56d6b54 100644
--- a/versioning/BRM/extentmap.h
+++ b/versioning/BRM/extentmap.h
@@ -263,7 +263,8 @@ class ExtentMapRBTreeImpl
  public:
   ~ExtentMapRBTreeImpl() = default;
 
-  static ExtentMapRBTreeImpl* makeExtentMapRBTreeImpl(unsigned key, off_t size, bool readOnly, bool& emLocked,
+  static ExtentMapRBTreeImpl* makeExtentMapRBTreeImpl(unsigned key, off_t size, bool readOnly,
+                                                      std::atomic<bool>& emLocked,
                                                       const MasterSegmentTable* emSegTable = nullptr);
 
   static void refreshShmWithLock()