diff --git a/thin-provisioning/metadata.cc b/thin-provisioning/metadata.cc
index 723a813..77e0428 100644
--- a/thin-provisioning/metadata.cc
+++ b/thin-provisioning/metadata.cc
@@ -112,12 +112,14 @@ metadata::metadata(block_manager<>::ptr bm, open_type ot,
 	}
 }
 
-metadata::metadata(block_manager<>::ptr bm)
+metadata::metadata(block_manager<>::ptr bm, bool read_space_maps)
 {
 	tm_ = open_tm(bm);
 	sb_ = read_superblock(tm_->get_bm(), SUPERBLOCK_LOCATION);
 
-	open_space_maps();
+	if (read_space_maps)
+		open_space_maps();
+
 	open_btrees();
 }
 
diff --git a/thin-provisioning/metadata.h b/thin-provisioning/metadata.h
index d020542..0af2e38 100644
--- a/thin-provisioning/metadata.h
+++ b/thin-provisioning/metadata.h
@@ -74,7 +74,7 @@ namespace thin_provisioning {
 		// ii)  Read the metadata snap as given in the superblock
 		// iii) Read the metadata snap given on command line, checking it matches superblock.
 		//
-		metadata(block_manager<>::ptr bm); // (i)
+		metadata(block_manager<>::ptr bm, bool read_space_maps = true); // (i)
 		metadata(block_manager<>::ptr,
 			 boost::optional<block_address> metadata_snap); // (ii) and (iii)
 
diff --git a/thin-provisioning/thin_repair.cc b/thin-provisioning/thin_repair.cc
index abae4ca..194f431 100644
--- a/thin-provisioning/thin_repair.cc
+++ b/thin-provisioning/thin_repair.cc
@@ -23,7 +23,7 @@ namespace {
 			emitter::ptr e = create_restore_emitter(new_md);
 
 			block_manager<>::ptr old_bm = open_bm(old_path, block_manager<>::READ_ONLY);
-			metadata::ptr old_md(new metadata(old_bm));
+			metadata::ptr old_md(new metadata(old_bm, false)); // we don't need to read the space maps
 			metadata_dump(old_md, e, true);
 
 		} catch (std::exception &e) {