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From:   Sasha Levin <Alexander.Levin@microsoft.com>
To:     "stable@vger.kernel.org" <stable@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
CC:     Chao Yu <yuchao0@huawei.com>, Yunlei He <heyunlei@huawei.com>,
        Jaegeuk Kim <jaegeuk@kernel.org>,
        Sasha Levin <Alexander.Levin@microsoft.com>
Subject: [PATCH AUTOSEL 4.18 081/131] f2fs: try grabbing node page lock
 aggressively in sync scenario
Thread-Topic: [PATCH AUTOSEL 4.18 081/131] f2fs: try grabbing node page lock
 aggressively in sync scenario
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Date:   Sun, 2 Sep 2018 13:04:46 +0000
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From: Chao Yu <yuchao0@huawei.com>

[ Upstream commit 4b270a8cc5047682f0a3f3f9af3b498408dbd2bc ]

In synchronous scenario, like in checkpoint(), we are going to flush
dirty node pages to device synchronously, we can easily failed
writebacking node page due to trylock_page() failure, especially in
condition of intensive lock competition, which can cause long latency
of checkpoint(). So let's use lock_page() in synchronous scenario to
avoid this issue.

Signed-off-by: Yunlei He <heyunlei@huawei.com>
Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
 fs/f2fs/node.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/fs/f2fs/node.c b/fs/f2fs/node.c
index 10643b11bd59..b949002e52a7 100644
--- a/fs/f2fs/node.c
+++ b/fs/f2fs/node.c
@@ -1633,7 +1633,9 @@ int f2fs_sync_node_pages(struct f2fs_sb_info *sbi,
 						!is_cold_node(page)))
 				continue;
 lock_node:
-			if (!trylock_page(page))
+			if (wbc->sync_mode =3D=3D WB_SYNC_ALL)
+				lock_page(page);
+			else if (!trylock_page(page))
 				continue;
=20
 			if (unlikely(page->mapping !=3D NODE_MAPPING(sbi))) {
--=20
2.17.1