Hello all,

I'm currently trying to develop a Block Placement Policy in my research 
project. However, I'm having some problems. If anybody could hep me, I would 
really appreciate that. Below are my questions:

1) In the block placement policy, how can I get the name of the original file 
that the specific block belongs to? There's the srcPath parameter, and I can 
use this when I'm injecting the file to hdfs for the first time. But what about 
replicating the blocks that are under-replicated? In that case, how can I find 
the original filename?

2) When I want to delete a file, is blockplacementpolicy included in the 
process? Or chooseReplicaToDelete function only works for over-replicated 
blocks? I found out that blockManager class is handling this operation. But I 
couldn't really figure out where to look. The reason I want to understand is 
that I'm keeping specific information for every file/block that I'm writing to 
hdfs. Thus when I add or delete a file, I need to write the information to the 
datanodes that these files are affecting.

I appreciate your help in advance.

Best regards,
Engin Sozer

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