kernel beginner - ext3 hacking help

[Donato Capitella]

Hi there,
I just started hacking the linux kernel. I need to know how to do 2
things:

1) Given a virtual inode, how do I get the block list associated to it?
I tried to convert the inode to an ext3_inode_info using EXT3_I(), but I
can't find the block list there.

2) Given a block number, how do I write data to that block? Is there any
function like write_to_block(int block_n, char *buf, int bytes) or
something?

Thank you in advance, I'm young and this is my first approach to kernel
programming and don't know where to find documentation.

Donato Capitella