diff --git a/src/libcephfs.cc b/src/libcephfs.cc
index d0463348411..87f365ed1b6 100644
--- a/src/libcephfs.cc
+++ b/src/libcephfs.cc
@@ -1319,7 +1319,7 @@ extern "C" int ceph_ll_lookup_root(struct ceph_mount_info *cmount,
   *parent = cmount->get_client()->get_root();
   if (*parent)
     return 0;
-  return EFAULT;
+  return -EFAULT;
 }
 
 extern "C" struct Inode *ceph_ll_get_inode(class ceph_mount_info *cmount,