add condition is_singular()!!!

If you do not add the condition, the section pages or search results will also perform the redirection!

function me_spr_permalink_redirect($permalink) {
    global $post;
	if (is_singular() ){
		$url = get_post_meta($post->ID,'me_spr_post_redirect',true);
		if (!empty($url)) {
			wp_redirect($url,301);
			exit;
		}
	}
    return ;
}