Q. How does NTFS handle data structures? How does NTFS recover from a system crash? What is guaranteed after a recovery takes place?

Answer: In NTFS all file-system data structure update are carry out inside transactions. Previous to a data structure is altered the transaction writes a log record containing redo as well as undoes information. A commit record is written to the log subsequent to a transaction has succeeded. Subsequent to a crash the file system can be restored to a consistent state by processing the log records first redoing operations for committed transactions as well as undoing operations for transactions that didn't successfully commit.

This scheme doesn't guarantee that user file contents are correct after a recovery however rather that the file-system data structures (file metadata) are undamaged and reflect a few consistent state that existed before the crash.