librbd: wire up flush counter

Fixes: #5668
Signed-off-by: Sage Weil <sage@inktank.com>

diff --git a/src/librbd/internal.cc b/src/librbd/internal.cc
index b8a757ab3332793135605fa9b347615b3e1f771b..fdfc086e866bab61986d3d4e8733ca1866c350c3 100644 (file)
--- a/src/librbd/internal.cc
+++ b/src/librbd/internal.cc
@@ -2821,7 +2821,9 @@ reprotect_and_return_err:
       return r;
 
     ictx->user_flushed();
-    return _flush(ictx);
+    int r = _flush(ictx);
+    ictx->perfcounter->inc(l_librbd_flush);
+    return r;
   }
 
   int _flush(ImageCtx *ictx)