f2fs: introduce cp_control structure

This patch add a new data structure to control checkpoint parameters.
Currently, it presents the reason of checkpoint such as is_umount and normal
sync.

Reviewed-by: Chao Yu <chao2.yu@samsung.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

fs/f2fs/recovery.c

@@ -542,8 +542,11 @@ out:
 		set_ckpt_flags(sbi->ckpt, CP_ERROR_FLAG);
 		mutex_unlock(&sbi->cp_mutex);
 	} else if (need_writecp) {
+		struct cp_control cpc = {
+			.reason = CP_SYNC,
+		};
 		mutex_unlock(&sbi->cp_mutex);
-		write_checkpoint(sbi, false);
+		write_checkpoint(sbi, &cpc);
 	} else {
 		mutex_unlock(&sbi->cp_mutex);
 	}