Clean up parametrized buffers

[bhelabhav]

int doSomething(int h, char *buf);

We should only have to pass in a buf to: avoid recreating buffers everytime, or we need a return value in the buf.

We should consider removing some of the passed in buf parameters for readability. It does not affect our FS performance since that is measured in disk accesses, and not in the amount of virtual memory we consume.