Hadoop which node will do split input data to multiple blocks?

Question

I am new to hadoop have few questions?

1. which node will do split input data to multiple blocks?
2. Find datanode based on shortpath . question is find shortpath between client vs datanode or datanode vs namenode?

Answer 1

The client writes the blocks directly to the datanodes after communicating with the namenode for allocating block locations

I don't understand the second part. The namenode must be contacted for any client to know where a block is located. Without the namenode, you cannot retrieve the file content as a whole