diff --git a/lib/libutil/flopen.c b/lib/libutil/flopen.c
index 92254cc1c3cf..b99055ea7bc1 100644
--- a/lib/libutil/flopen.c
+++ b/lib/libutil/flopen.c
@@ -63,7 +63,7 @@ flopen(const char *path, int flags, ...)
 		operation |= LOCK_NB;
 
 	truncate = (flags & O_TRUNC);
-	flags |= ~O_TRUNC;
+	flags &= ~O_TRUNC;
 
 	for (;;) {
 		if ((fd = open(path, flags, mode)) == -1)