diff --git a/fs/9p/v9fs.h b/fs/9p/v9fs.h
index a8e127c..099c771 100644
--- a/fs/9p/v9fs.h
+++ b/fs/9p/v9fs.h
@@ -64,6 +64,7 @@
 
 enum p9_cache_modes {
 	CACHE_NONE,
+	CACHE_MMAP,
 	CACHE_LOOSE,
 	CACHE_FSCACHE,
 };