diff --git a/kmod/src/format.h b/kmod/src/format.h
index d0efbae4..ff1b69dd 100644
--- a/kmod/src/format.h
+++ b/kmod/src/format.h
@@ -22,7 +22,7 @@
 #define SCOUTFS_SEGMENT_SIZE (1 << SCOUTFS_SEGMENT_SHIFT)
 #define SCOUTFS_SEGMENT_MASK (SCOUTFS_SEGMENT_SIZE - 1)
 #define SCOUTFS_SEGMENT_PAGES (SCOUTFS_SEGMENT_SIZE / PAGE_SIZE)
-#define SCOUTFS_SEGMENT_BLOCKS (SCOUTFS_SEGMENT_SIZE / BLOCK_SIZE)
+#define SCOUTFS_SEGMENT_BLOCKS (SCOUTFS_SEGMENT_SIZE / SCOUTFS_BLOCK_SIZE)
 
 #define SCOUTFS_PAGES_PER_BLOCK (SCOUTFS_BLOCK_SIZE / PAGE_SIZE)
 #define SCOUTFS_BLOCK_PAGE_ORDER (SCOUTFS_BLOCK_SHIFT - PAGE_SHIFT)