diff --git a/nbd.c b/nbd.c
index 0fd0583..f847940 100644
--- a/nbd.c
+++ b/nbd.c
@@ -882,6 +882,7 @@
     exp->nbdflags = nbdflags;
     exp->size = size == -1 ? bdrv_getlength(bs) : size;
     exp->close = close;
+    bdrv_ref(bs);
     return exp;
 }
 
@@ -928,6 +929,10 @@
     }
     nbd_export_set_name(exp, NULL);
     nbd_export_put(exp);
+    if (exp->bs) {
+        bdrv_unref(exp->bs);
+        exp->bs = NULL;
+    }
 }
 
 void nbd_export_get(NBDExport *exp)