+void periodic_mount_check(ev_source *ev_);
+
+#ifndef MOUNT_CHECK_INTERVAL
+# ifdef PATH_MTAB
+// statting a file is really cheap so check once a second
+# define MOUNT_CHECK_INTERVAL 1
+# else
+// hashing getfsstat() output could be more expensive so be less aggressive
+# define MOUNT_CHECK_INTERVAL 5
+# endif
+#endif
+