linux-kernel - [PATCH 4.19 195/361] f2fs: fix to account IO correctly

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Date:   Sun, 11 Nov 2018 14:19:02 -0800
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Chao Yu <yuchao0@...wei.com>,
        Jaegeuk Kim <jaegeuk@...nel.org>
Subject: [PATCH 4.19 195/361] f2fs: fix to account IO correctly

4.19-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Chao Yu <yuchao0@...wei.com>

commit 4c58ed076875f36dae0f240da1e25e99e5d4afb8 upstream.

Below race can cause reversed reference on dirty count, fix it by
relocating __submit_bio() and inc_page_count().

Thread A				Thread B
- f2fs_inplace_write_data
 - f2fs_submit_page_bio
  - __submit_bio
					- f2fs_write_end_io
					 - dec_page_count
  - inc_page_count

Cc: <stable@...r.kernel.org>
Fixes: d1b3e72d5490 ("f2fs: submit bio of in-place-update pages")
Signed-off-by: Chao Yu <yuchao0@...wei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 fs/f2fs/data.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -463,10 +463,10 @@ int f2fs_submit_page_bio(struct f2fs_io_
 
 	bio_set_op_attrs(bio, fio->op, fio->op_flags);
 
-	__submit_bio(fio->sbi, bio, fio->type);
-
 	if (!is_read_io(fio->op))
 		inc_page_count(fio->sbi, WB_DATA_TYPE(fio->page));
+
+	__submit_bio(fio->sbi, bio, fio->type);
 	return 0;
 }