librbd: silence -Wunused-variable warning

Signed-off-by: Kefu Chai <kchai@redhat.com>

diff --git a/src/librbd/librbd.cc b/src/librbd/librbd.cc
index 8094433ee5f035d23cfdb1fb5ec81a4de373b6a4..77d272283e5af2c26469c4d33b08450daf568a20 100644 (file)
--- a/src/librbd/librbd.cc
+++ b/src/librbd/librbd.cc
@@ -569,11 +569,13 @@ namespace librbd {
     tracepoint(librbd, trash_list_enter,
                io_ctx.get_pool_name().c_str(), io_ctx.get_id());
     int r = librbd::trash_list(io_ctx, entries);
+#ifdef WITH_LTTNG
     if (r >= 0) {
       for (const auto& entry : entries) {
        tracepoint(librbd, trash_list_entry, entry.id.c_str());
       }
     }
+#endif
     tracepoint(librbd, trash_list_exit, r, r);
     return r;
   }