nginx下不帶www跳轉到帶www

server
{
listen 80;
server_name m.bmw-szbaoxin.cn 0597seo.com;
index index.php index.html index.htm;
root /home/wwwroot/0597seo.com;
include /home/wwwroot/0597seo.com/.htaccess;

if ($host != 'm.bmw-szbaoxin.cn') {
rewrite ^/(.*)$ http://m.bmw-szbaoxin.cn/$1 permanent;
}

location ~ .*\.(php|php5)?$
{
fastcgi_pass 127.0.0.1:9000;
fastcgi_index index.php;
fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
fastcgi_param PHP_VALUE "open_basedir=/home/wwwroot/0597seo.com/:/tmp/:/proc/";
include fastcgi.conf;
}

location ~ .*\.(gif|jpg|jpeg|png|bmp|swf)$
{
expires 30d;
}

location ~ .*\.(js|css)?$
{
expires 12h;
}

location ~ /\.ht {
deny all;
}

}