My mum used to lock us in, first bt turning the handle upside down, then tying something heavy to it. I don't feel harmed by it but its not the method I would choose.
I tried cry it out with ds1, we had been on holiday and his normal routine was up the wall. It was back to work with me so needed sleep a naive 19 year old I took advice from my elders... Cry it out they said he will soon settle. After about two nights of sitting on the landing sobbing while ds screamed in his room I was horrified to get a knock on the door the following day. It was the police. One of my neighbours had reported me. I had to shoe them ds who was of course asleep in bed having been up all night. I never tried it again.
I co sleep with ds 2 and yep, I am shattered!