Problem in understanding Lvm code

Hi,

For understanding the LVM and Snapshot module, I am going through the source code for solving some of my queries like
-How does it allocate space for creating snapshot?
-Does it create snapshot on the same volume?
-How does it copy the buffer to snapshot?

To move in further details I have compiled the LVM source code for debugging.
But after giving some of the printk statements in the code for understanding the flow the print statement of lvm.c get printed but the print statement in lvm-snap.c is not getting printed.

Can any one give some pointer to solve this or any other better approach to solve my above queries?

Mekhala