linux-kernel - [PATCH] f2fs: fix to check page dirty status before writeback

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Date:   Fri, 19 Jun 2020 17:14:19 +0800
From:   Chao Yu <yuchao0@...wei.com>
To:     <jaegeuk@...nel.org>
CC:     <linux-f2fs-devel@...ts.sourceforge.net>,
        <linux-kernel@...r.kernel.org>, <chao@...nel.org>,
        Chao Yu <yuchao0@...wei.com>
Subject: [PATCH] f2fs: fix to check page dirty status before writeback

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>
---
 fs/f2fs/compress.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
index 5643aa2b8377..ce5645b5c833 100644
--- a/fs/f2fs/compress.c
+++ b/fs/f2fs/compress.c
@@ -1322,6 +1322,12 @@ 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;
 			}
-- 
2.26.2