Overwriting copy functionality in filesystem

[Bharath Vedartham]

Hey everyone,

I was wondering how we can overwrite the copy functionality while
writing our own filesystem in linux. 
VFS does not offer any sort of API for copy. I think it calls create and
write when we execute the copy the file/dir.
I am interested in overwriting the way copy happens in my
filesystem(which I am writing for fun :p). 
Any ideas?

Thanks