Is it possible to extend M type, single entry with 30 days stay visa while staying in China?

I am from India and I intend to travel to Shanghai for commercial activities within Chinese division of our parent company. I had applied for 89 days visa but instead received M type single entry one with stay duration of 30 days. So is it possible to apply for extension of the entry permit while staying in China? Or I have to travel back to India and again apply for fresh entry permit.