rem: err = EINVAL;
add: err = FS_EINVAL;
context: sys_readlink(bool kernel, int fd, const char *path, char *buf, size_t bufsize){    int             err;    vnode           *vn;    op_readlink     *op;    size_t          sz;    err = get_file_fd(kernel, fd, path, FALSE, &vn);    if (err)        goto error1;    op = vn->ns->fs->ops.readlink;    if (!op) {        err = EINVAL;        goto error2;    }    sz = bufsize;    err = (*op)(vn->ns->data, vn->data, buf, &sz);    if (err)        goto error2;    dec_vnode(vn, FALSE);    return sz;error2:    dec_vnode(vn, FALSE);error1:    return err;}