Lock Source file in Perforce while using Maven release plugin

I got an error in Hudson console out saying the build fail because Maven release plugin cannot update POM.xml version while there are still unresolved files. The problem is caused by other 开发者_运维知识库people updating the POM during the build.

Can any guru teach me how to solve the problem? I am think about a P4 lock, anyone can give me more details of using P4 lock with Maven and hudson?

If people aren't allowed to edit the POM.xml during the build, p4 lock would certainly be a good solution. The only other possibility I see is enabling maven to somehow merge the changes in, but it seems like the risk of conflicts might be high.