diff --git a/include/lcnalloc.h b/include/lcnalloc.h
index cc5728a9..d4853dd7 100644
--- a/include/lcnalloc.h
+++ b/include/lcnalloc.h
@@ -27,7 +27,15 @@
 #include "runlist.h"
 #include "volume.h"
 
-extern runlist *ntfs_cluster_alloc(ntfs_volume *vol, s64 count, LCN start_lcn);
+typedef enum {
+	FIRST_ZONE	= 0,	/* For sanity checking. */
+	MFT_ZONE	= 0,	/* Allocate from $MFT zone. */
+	DATA_ZONE	= 1,	/* Allocate from $DATA zone. */
+	LAST_ZONE	= 1,	/* For sanity checking. */
+} NTFS_CLUSTER_ALLOCATION_ZONES;
+
+extern runlist *ntfs_cluster_alloc(ntfs_volume *vol, s64 count, LCN start_lcn,
+		const NTFS_CLUSTER_ALLOCATION_ZONES zone);
 
 extern int ntfs_cluster_free(ntfs_volume *vol, ntfs_attr *na, VCN start_vcn,
 		s64 count);