+static struct lock_file index_lock;
+
+static int update_paths(struct path_list *update)
+{
+ int i;
+ int fd = hold_locked_index(&index_lock, 0);
+ int status = 0;
+
+ if (fd < 0)
+ return -1;
+
+ for (i = 0; i < update->nr; i++) {
+ struct path_list_item *item = &update->items[i];
+ if (add_file_to_cache(item->path, ADD_CACHE_IGNORE_ERRORS))
+ status = -1;
+ }
+
+ if (!status && active_cache_changed) {
+ if (write_cache(fd, active_cache, active_nr) ||
+ commit_locked_index(&index_lock))
+ die("Unable to write new index file");
+ } else if (fd >= 0)
+ rollback_lock_file(&index_lock);
+ return status;
+}
+