f2fs: introduce lifetime write IO statistics

This patch introduces lifetime IO write statistics exposed to the sysfs interface.
The write IO amount is obtained from block layer, accumulated in the file system and
stored in the hot node summary of checkpoint.

Signed-off-by: Shuoran Liu <liushuoran@huawei.com>
Signed-off-by: Pengyang Hou <houpengyang@huawei.com>
[Jaegeuk Kim: add sysfs documentation]
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

1 files changed, 13 insertions, 1 deletions

diff --git a/include/linux/f2fs_fs.h b/include/linux/f2fs_fs.h
index e59c3be92106..67aa01df777d 100644
--- a/include/linux/f2fs_fs.h
+++ b/include/linux/f2fs_fs.h
@@ -358,6 +358,12 @@ struct summary_footer {
 				sizeof(struct sit_journal_entry))
 #define SIT_JOURNAL_RESERVED	((SUM_JOURNAL_SIZE - 2) %\
 				sizeof(struct sit_journal_entry))
+
+/* Reserved area should make size of f2fs_extra_info equals to
+ * that of nat_journal and sit_journal.
+ */
+#define EXTRA_INFO_RESERVED	(SUM_JOURNAL_SIZE - 2 - 8)
+
 /*
  * frequently updated NAT/SIT entries can be stored in the spare area in
  * summary blocks
@@ -387,6 +393,11 @@ struct sit_journal {
 	__u8 reserved[SIT_JOURNAL_RESERVED];
 } __packed;
 
+struct f2fs_extra_info {
+	__le64 kbytes_written;
+	__u8 reserved[EXTRA_INFO_RESERVED];
+} __packed;
+
 /* 4KB-sized summary block structure */
 struct f2fs_summary_block {
 	struct f2fs_summary entries[ENTRIES_IN_SUM];
@@ -394,10 +405,11 @@ struct f2fs_summary_block {
 		__le16 n_nats;
 		__le16 n_sits;
 	};
-	/* spare area is used by NAT or SIT journals */
+	/* spare area is used by NAT or SIT journals or extra info */
 	union {
 		struct nat_journal nat_j;
 		struct sit_journal sit_j;
+		struct f2fs_extra_info info;
 	};
 	struct summary_footer footer;
 } __packed;