Which replica?

[James Cipar]

Is there any way to determine which replica of each chunk is read by a  
map-reduce program?  I've been looking through the hadoop code, and it  
seems like it tries to hide those kinds of details from the higher  
level API.  Ideally, I'd like the host the task was running on, the  
file name and chunk number, and the host the chunk was read from.