diff --git a/src/fuse_open.cpp b/src/fuse_open.cpp
index 97758549..6754265f 100644
--- a/src/fuse_open.cpp
+++ b/src/fuse_open.cpp
@@ -351,7 +351,7 @@ namespace FUSE
              {
                m = x_.second.mutex;
              });
-    m->lock();
+    const std::lock_guard<std::mutex> lock(*m);
 
     return open2(fusepath_,ffi_);
   }