vfs_open
error = vfs_open(real_path, f);
extern int vfs_open(const struct path *, struct file *);
error = vfs_open(&nd->path, file);
error = vfs_open(&path, file);
error = vfs_open(path, file);
error = vfs_open(path, f);
error = vfs_open(path, f);
error = vfs_open(path, f);