diff --git a/src/conf/virdomainmomentobjlist.c b/src/conf/virdomainmomentobjlist.c
index e5cdd9a141..ea9850df8c 100644
--- a/src/conf/virdomainmomentobjlist.c
+++ b/src/conf/virdomainmomentobjlist.c
@@ -582,3 +582,20 @@ virDomainMomentFindLeaf(virDomainMomentObjList *list)
         return moment;
     return NULL;
 }
+
+
+/* Check if @moment is descendant of @ancestor. */
+bool
+virDomainMomentIsAncestor(virDomainMomentObj *moment,
+                          virDomainMomentObj *ancestor)
+{
+    if (moment == ancestor)
+        return false;
+
+    for (moment = moment->parent; moment; moment = moment->parent) {
+        if (moment == ancestor)
+            return true;
+    }
+
+    return false;
+}
diff --git a/src/conf/virdomainmomentobjlist.h b/src/conf/virdomainmomentobjlist.h
index d2ab3b46b1..2ea6b181c0 100644
--- a/src/conf/virdomainmomentobjlist.h
+++ b/src/conf/virdomainmomentobjlist.h
@@ -157,3 +157,7 @@ virDomainMomentCheckCycles(virDomainMomentObjList *list,
 
 virDomainMomentObj *
 virDomainMomentFindLeaf(virDomainMomentObjList *list);
+
+bool
+virDomainMomentIsAncestor(virDomainMomentObj *moment,
+                          virDomainMomentObj *ancestor);
diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index a75156f097..1cf40ba863 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -1221,6 +1221,7 @@ virDomainMomentDropChildren;
 virDomainMomentDropParent;
 virDomainMomentForEachChild;
 virDomainMomentForEachDescendant;
+virDomainMomentIsAncestor;
 virDomainMomentMoveChildren;
 virDomainMomentObjFree;
 virDomainMomentObjNew;