f2fs: add app/fs io stat

This patch enables inner app/fs io stats and introduces below virtual fs
nodes for exposing stats info:
/sys/fs/f2fs/<dev>/iostat_enable
/proc/fs/f2fs/<dev>/iostat_info

Signed-off-by: Chao Yu <yuchao0@huawei.com>
[Jaegeuk Kim: fix wrong stat assignment]
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

1 files changed, 26 insertions, 9 deletions

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index aefc2a5745d3..c43262dc36de 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1475,7 +1475,8 @@ out:
 }
 
 static int __write_data_page(struct page *page, bool *submitted,
-				struct writeback_control *wbc)
+				struct writeback_control *wbc,
+				enum iostat_type io_type)
 {
 	struct inode *inode = page->mapping->host;
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
@@ -1496,6 +1497,7 @@ static int __write_data_page(struct page *page, bool *submitted,
 		.encrypted_page = NULL,
 		.submitted = false,
 		.need_lock = LOCK_RETRY,
+		.io_type = io_type,
 	};
 
 	trace_f2fs_writepage(page, DATA);
@@ -1602,7 +1604,7 @@ redirty_out:
 static int f2fs_write_data_page(struct page *page,
 					struct writeback_control *wbc)
 {
-	return __write_data_page(page, NULL, wbc);
+	return __write_data_page(page, NULL, wbc, FS_DATA_IO);
 }
 
 /*
@@ -1611,7 +1613,8 @@ static int f2fs_write_data_page(struct page *page,
  * warm/hot data page.
  */
 static int f2fs_write_cache_pages(struct address_space *mapping,
-					struct writeback_control *wbc)
+					struct writeback_control *wbc,
+					enum iostat_type io_type)
 {
 	int ret = 0;
 	int done = 0;
@@ -1701,7 +1704,7 @@ continue_unlock:
 			if (!clear_page_dirty_for_io(page))
 				goto continue_unlock;
 
-			ret = __write_data_page(page, &submitted, wbc);
+			ret = __write_data_page(page, &submitted, wbc, io_type);
 			if (unlikely(ret)) {
 				/*
 				 * keep nr_to_write, since vfs uses this to
@@ -1756,8 +1759,9 @@ continue_unlock:
 	return ret;
 }
 
-static int f2fs_write_data_pages(struct address_space *mapping,
-			    struct writeback_control *wbc)
+int __f2fs_write_data_pages(struct address_space *mapping,
+						struct writeback_control *wbc,
+						enum iostat_type io_type)
 {
 	struct inode *inode = mapping->host;
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
@@ -1794,7 +1798,7 @@ static int f2fs_write_data_pages(struct address_space *mapping,
 		goto skip_write;
 
 	blk_start_plug(&plug);
-	ret = f2fs_write_cache_pages(mapping, wbc);
+	ret = f2fs_write_cache_pages(mapping, wbc, io_type);
 	blk_finish_plug(&plug);
 
 	if (wbc->sync_mode == WB_SYNC_ALL)
@@ -1813,6 +1817,16 @@ skip_write:
 	return 0;
 }
 
+static int f2fs_write_data_pages(struct address_space *mapping,
+			    struct writeback_control *wbc)
+{
+	struct inode *inode = mapping->host;
+
+	return __f2fs_write_data_pages(mapping, wbc,
+			F2FS_I(inode)->cp_task == current ?
+			FS_CP_DATA_IO : FS_DATA_IO);
+}
+
 static void f2fs_write_failed(struct address_space *mapping, loff_t to)
 {
 	struct inode *inode = mapping->host;
@@ -2079,10 +2093,13 @@ static ssize_t f2fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
 	up_read(&F2FS_I(inode)->dio_rwsem[rw]);
 
 	if (rw == WRITE) {
-		if (err > 0)
+		if (err > 0) {
+			f2fs_update_iostat(F2FS_I_SB(inode), APP_DIRECT_IO,
+									err);
 			set_inode_flag(inode, FI_UPDATE_WRITE);
-		else if (err < 0)
+		} else if (err < 0) {
 			f2fs_write_failed(mapping, offset + count);
+		}
 	}
 
 	trace_f2fs_direct_IO_exit(inode, offset, count, rw, err);