linux-kernel - [PATCH AUTOSEL 5.7 04/24] f2fs: fix to check page dirty status before writeback

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Message-Id: <20200820000155.215089-4-sashal@kernel.org>
Date:   Wed, 19 Aug 2020 20:01:35 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Chao Yu <yuchao0@...wei.com>, Jaegeuk Kim <jaegeuk@...nel.org>,
        Sasha Levin <sashal@...nel.org>,
        linux-f2fs-devel@...ts.sourceforge.net
Subject: [PATCH AUTOSEL 5.7 04/24] f2fs: fix to check page dirty status before writeback

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

[ Upstream commit eb1353cfa9c1e9415b03dc117f8399969fa02102 ]

In f2fs_write_raw_pages(), we need to check page dirty status before
writeback, because there could be a racer (e.g. reclaimer) helps
writebacking the dirty page.

Signed-off-by: Chao Yu <yuchao0@...wei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 fs/f2fs/compress.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
index a5b2e72174bb1..a1504a7aecb19 100644
--- a/fs/f2fs/compress.c
+++ b/fs/f2fs/compress.c
@@ -1207,6 +1207,12 @@ static int f2fs_write_raw_pages(struct compress_ctx *cc,
 				congestion_wait(BLK_RW_ASYNC,
 						DEFAULT_IO_TIMEOUT);
 				lock_page(cc->rpages[i]);
+
+				if (!PageDirty(cc->rpages[i])) {
+					unlock_page(cc->rpages[i]);
+					continue;
+				}
+
 				clear_page_dirty_for_io(cc->rpages[i]);
 				goto retry_write;
 			}
-- 
2.25.1