diff --git a/headers/private/kernel/disk_device_manager/KPartition.h b/headers/private/kernel/disk_device_manager/KPartition.h
index c05e280902..82e1b073e2 100644
--- a/headers/private/kernel/disk_device_manager/KPartition.h
+++ b/headers/private/kernel/disk_device_manager/KPartition.h
@@ -130,6 +130,7 @@ public:
 	bool RemoveAllChildren();
 	KPartition *ChildAt(int32 index) const;
 	int32 CountChildren() const;
+	int32 CountDescendants() const;
 
 	// Shadow Partition
 
diff --git a/src/kernel/core/disk_device_manager/KPartition.cpp b/src/kernel/core/disk_device_manager/KPartition.cpp
index 7ba762422f..011a3714f8 100644
--- a/src/kernel/core/disk_device_manager/KPartition.cpp
+++ b/src/kernel/core/disk_device_manager/KPartition.cpp
@@ -656,6 +656,16 @@ KPartition::CountChildren() const
 	return fPartitionData.child_count;
 }
 
+// CountDescendants
+int32
+KPartition::CountDescendants() const
+{
+	int32 count = 1;
+	for (int32 i = 0; KPartition *child = ChildAt(i); i++)
+		count += child->CountDescendants();
+	return count;
+}
+
 // CreateShadowPartition
 status_t
 KPartition::CreateShadowPartition()