diff --git a/builtin/commit.c b/builtin/commit.c
index 5911447..41f481b 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -353,6 +353,13 @@
 
 		discard_cache();
 		read_cache_from(index_lock.filename);
+		if (update_main_cache_tree(WRITE_TREE_SILENT) == 0) {
+			if (reopen_lock_file(&index_lock) < 0)
+				die(_("unable to write index file"));
+			if (write_locked_index(&the_index, &index_lock, CLOSE_LOCK))
+				die(_("unable to update temporary index"));
+		} else
+			warning(_("Failed to update main cache tree"));
 
 		commit_style = COMMIT_NORMAL;
 		return index_lock.filename;
@@ -393,8 +400,12 @@
 	if (!only && !pathspec.nr) {
 		hold_locked_index(&index_lock, 1);
 		refresh_cache_or_die(refresh_flags);
-		if (active_cache_changed) {
+		if (active_cache_changed
+		    || !cache_tree_fully_valid(active_cache_tree)) {
 			update_main_cache_tree(WRITE_TREE_SILENT);
+			active_cache_changed = 1;
+		}
+		if (active_cache_changed) {
 			if (write_locked_index(&the_index, &index_lock,
 					       COMMIT_LOCK))
 				die(_("unable to write new_index file"));
@@ -444,6 +455,7 @@
 	hold_locked_index(&index_lock, 1);
 	add_remove_files(&partial);
 	refresh_cache(REFRESH_QUIET);
+	update_main_cache_tree(WRITE_TREE_SILENT);
 	if (write_locked_index(&the_index, &index_lock, CLOSE_LOCK))
 		die(_("unable to write new_index file"));