f2fs: account read IOs and use IO counts for is_idle

This patch adds issued read IO counts which is under block layer.

Chao modified a bit, since:

Below race can cause reversed reference on F2FS_RD_DATA, there is
the same issue in f2fs_submit_page_bio(), fix them by relocate
__submit_bio() and inc_page_count.

Thread A			Thread B
- f2fs_write_begin
 - f2fs_submit_page_read
 - __submit_bio
				- f2fs_read_end_io
				 - __read_end_io
				 - dec_page_count(, F2FS_RD_DATA)
 - inc_page_count(, F2FS_RD_DATA)

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

1 files changed, 22 insertions, 2 deletions

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 4b312b73d8a8..b5de10102775 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -52,6 +52,23 @@ static bool __is_cp_guaranteed(struct page *page)
 	return false;
 }
 
+static enum count_type __read_io_type(struct page *page)
+{
+	struct address_space *mapping = page->mapping;
+
+	if (mapping) {
+		struct inode *inode = mapping->host;
+		struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
+
+		if (inode->i_ino == F2FS_META_INO(sbi))
+			return F2FS_RD_META;
+
+		if (inode->i_ino == F2FS_NODE_INO(sbi))
+			return F2FS_RD_NODE;
+	}
+	return F2FS_RD_DATA;
+}
+
 /* postprocessing steps for read bios */
 enum bio_post_read_step {
 	STEP_INITIAL = 0,
@@ -82,6 +99,7 @@ static void __read_end_io(struct bio *bio)
 		} else {
 			SetPageUptodate(page);
 		}
+		dec_page_count(F2FS_P_SB(page), __read_io_type(page));
 		unlock_page(page);
 	}
 	if (bio->bi_private)
@@ -466,8 +484,8 @@ int f2fs_submit_page_bio(struct f2fs_io_info *fio)
 
 	bio_set_op_attrs(bio, fio->op, fio->op_flags);
 
-	if (!is_read_io(fio->op))
-		inc_page_count(fio->sbi, WB_DATA_TYPE(fio->page));
+	inc_page_count(fio->sbi, is_read_io(fio->op) ?
+			__read_io_type(page): WB_DATA_TYPE(fio->page));
 
 	__submit_bio(fio->sbi, bio, fio->type);
 	return 0;
@@ -598,6 +616,7 @@ static int f2fs_submit_page_read(struct inode *inode, struct page *page,
 		return -EFAULT;
 	}
 	ClearPageError(page);
+	inc_page_count(F2FS_I_SB(inode), F2FS_RD_DATA);
 	__submit_bio(F2FS_I_SB(inode), bio, DATA);
 	return 0;
 }
@@ -1586,6 +1605,7 @@ submit_and_realloc:
 		if (bio_add_page(bio, page, blocksize, 0) < blocksize)
 			goto submit_and_realloc;
 
+		inc_page_count(F2FS_I_SB(inode), F2FS_RD_DATA);
 		ClearPageError(page);
 		last_block_in_bio = block_nr;
 		goto next_page;