[PATCH] f2fs: including waf data in f2fs status information

[beomsu kim <beomsu7.kim@samsung.com>]

When evaluating in f2fs, it takes much time to obtain waf data.
This patch helps to obtain waf data without calcluation.

Signed-off-by: Beomsu Kim <beomsu7.kim@samsung.com>
---
 fs/f2fs/iostat.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/fs/f2fs/iostat.c b/fs/f2fs/iostat.c
index 3d5bfb1ad585..6ae9659d69e7 100644
--- a/fs/f2fs/iostat.c
+++ b/fs/f2fs/iostat.c
@@ -34,10 +34,22 @@ int __maybe_unused iostat_info_seq_show(struct seq_file *seq, void *offset)
 {
 	struct super_block *sb = seq->private;
 	struct f2fs_sb_info *sbi = F2FS_SB(sb);
+	struct f2fs_stat_info *si = F2FS_STAT(sbi);
+	int j;
+	unsigned long long waf = 0;
+	unsigned long long data_written_to_storage = 0, data_written_by_user = 0;
 
 	if (!sbi->iostat_enable)
 		return 0;
 
+	for (j = FS_DATA_IO; j <= FS_CP_META_IO; j++)
+		data_written_to_storage += si->sbi->iostat_bytes[j];
+	for (j = FS_DATA_IO; j <= FS_CDATA_IO; j++)
+		data_written_by_user += si->sbi->iostat_bytes[j];
+
+	if (data_written_by_user > 0)
+		waf = data_written_to_storage * 100 / data_written_by_user;
+
 	seq_printf(seq, "time:		%-16llu\n", ktime_get_real_seconds());
 	seq_printf(seq, "\t\t\t%-16s %-16s %-16s\n",
 				"io_bytes", "count", "avg_bytes");
@@ -81,6 +93,10 @@ int __maybe_unused iostat_info_seq_show(struct seq_file *seq, void *offset)
 	IOSTAT_INFO_SHOW("fs discard", FS_DISCARD_IO);
 	IOSTAT_INFO_SHOW("fs flush", FS_FLUSH_IO);
 
+	/* print waf */
+	seq_puts(seq, "[WAF]\n");
+	seq_printf(seq, "fs waf:		%llu.%02llu\n", waf / 100, waf % 100);
+
 	return 0;
 }
 
-- 
2.17.1