diff --git a/src/backup/chunk_store.rs b/src/backup/chunk_store.rs
index 18a7285d..2975ee7a 100644
--- a/src/backup/chunk_store.rs
+++ b/src/backup/chunk_store.rs
@@ -163,6 +163,11 @@ impl ChunkStore {
         Ok(())
     }
 
+    pub fn sweep_used_chunks(&mut self) -> Result<(), Error> {
+
+        Ok(())
+    }
+
     pub fn insert_chunk(&mut self, chunk: &[u8]) -> Result<(bool, [u8; 32]), Error> {
 
         self.hasher.reset();
diff --git a/src/backup/datastore.rs b/src/backup/datastore.rs
index 6767f7be..86ab4434 100644
--- a/src/backup/datastore.rs
+++ b/src/backup/datastore.rs
@@ -61,11 +61,6 @@ impl DataStore {
         Ok(list)
     }
 
-    fn sweep_used_chunks(&mut self) -> Result<(), Error> {
-
-        Ok(())
-    }
-
     fn mark_used_chunks(&mut self) -> Result<(), Error> {
 
         let image_list = self.list_images()?;
@@ -81,7 +76,8 @@ impl DataStore {
     pub fn garbage_collection(&mut self) -> Result<(), Error> {
 
         self.mark_used_chunks()?;
-        self.sweep_used_chunks()?;
+
+        self.chunk_store.sweep_used_chunks()?;
 
         Ok(())
     }