+ /* change_count is increased with every operation which modifies the inode,
+ * and can be used to determine if cached data is still valid.
+ * change_commit is the value of change_count when the inode was last
+ * committed to stable storage. */
+ uint64_t change_count, change_commit;
+
+ /* Timestamp for controlling when modified data is flushed to stable
+ * storage. When an inode is first modified from a clean state, this is
+ * set to the current time. If the inode is clean, it is set to zero. */
+ int64_t change_time;
+
+ /* Additional state for tracking cache writeback status. */
+ uint64_t change_pending; /* change_count version currently being committed to storage */
+