- * All the functions in this file are used to construct the log entries
- * to record transactions. They allocate * an intent log transaction
- * structure (itx_t) and save within it all the information necessary to
- * possibly replay the transaction. The itx is then assigned a sequence
- * number and inserted in the in-memory list anchored in the zilog.
+ * These zfs_log_* functions must be called within a dmu tx, in one
+ * of 2 contexts depending on zilog->z_replay:
+ *
+ * Non replay mode
+ * ---------------
+ * We need to record the transaction so that if it is committed to
+ * the Intent Log then it can be replayed. An intent log transaction
+ * structure (itx_t) is allocated and all the information necessary to
+ * possibly replay the transaction is saved in it. The itx is then assigned
+ * a sequence number and inserted in the in-memory list anchored in the zilog.
+ *
+ * Replay mode
+ * -----------
+ * We need to mark the intent log record as replayed in the log header.
+ * This is done in the same transaction as the replay so that they
+ * commit atomically.