+	/*
+	 * If inode has dirty timestamps and we need to write them, call
+	 * mark_inode_dirty_sync() to notify filesystem about it.
+	 */
+	if (inode->i_state & I_DIRTY_TIME &&
+	    (wbc->for_sync || wbc->sync_mode == WB_SYNC_ALL ||
+	     time_after(jiffies, inode->dirtied_time_when +
+			dirtytime_expire_interval * HZ))) {

If we're touching this area, it would be nice to split this condition
into a readable helper ala:

static inline bool inode_needs_timestamp_sync(struct writeback_control *wbc,
		struct inode *inode)
{
	if (!(inode->i_state & I_DIRTY_TIME))
		return false;
	if (wbc->for_sync || wbc->sync_mode == WB_SYNC_ALL)
		return true;
	return time_after(jiffies, inode->dirtied_time_when +
			  dirtytime_expire_interval * HZ);
}