Re: [PATCH v3 09/16] index-helper: use watchman to avoid refreshing index with lstat()

diff --git a/read-cache.c b/read-cache.c
index 59d892e..b6e9244 100644
--- a/read-cache.c
+++ b/read-cache.c

@@ -1407,10 +1472,24 @@ static int read_watchman_ext(struct index_state *istate, const void *data,
 	ewah_each_bit(bitmap, mark_no_watchman, istate);
 	ewah_free(bitmap);
 
-	/*
-	 * TODO: update the untracked cache from the untracked data in this
-	 * extension.
-	 */
+	if (istate->untracked && istate->untracked->root) {
+		int i;
+		const char *untracked;
+
+		untracked = data + len + 8 + bitmap_size;