diff --git a/src/storage/backend.rs b/src/storage/backend.rs
index 0b7dbe72..7c413b24 100644
--- a/src/storage/backend.rs
+++ b/src/storage/backend.rs
@@ -8,6 +8,7 @@ use std::vec::Vec;
 use std::fs::File as FSFile;
 use std::io::Read;
 use std::io::Write;
+use std::vec::IntoIter;
 
 use glob::glob;
 use glob::Paths;
@@ -61,6 +62,17 @@ impl StorageBackend {
         }
     }
 
+    pub fn iter_ids(&self, m: &Module) -> Option<IntoIter<FileID>>
+    {
+        glob(&self.prefix_of_files_for_module(m)[..]).and_then(|globlist| {
+            let v = globlist.filter_map(Result::ok)
+                            .map(|pbuf| from_pathbuf(&pbuf))
+                            .collect::<Vec<FileID>>()
+                            .into_iter();
+            Ok(v)
+        }).ok()
+    }
+
     /*
      * Write a file to disk.
      *