In the xv6 logging filesystem, filesystem operations are grouped into transactions, where each transaction consists of the following operations: 1. Write each modified block to the log area, along with its eventual destination. 2. Write a commit record. 3. For each entry in the log, copy the block to its final destination. 4. Clear the log. For each of these steps, describe what would happen if the system crashed during that step, saying what xv6 would do when it reboots and how this would guarantee that the transaction is carried out atomically (that is, every operation is carried out, or none of them are).