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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Hyeongseok Kim <hyeongseok@gmail.com>,
        Sami Tolvanen <samitolvanen@google.com>,
        Mike Snitzer <snitzer@redhat.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.14 25/29] dm verity: skip verity work if I/O error when system is shutting down
Date:   Thu,  7 Jan 2021 15:31:40 +0100
Message-Id: <20210107143056.558164713@linuxfoundation.org>
In-Reply-To: <20210107143052.973437064@linuxfoundation.org>
References: <20210107143052.973437064@linuxfoundation.org>
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From: Hyeongseok Kim <hyeongseok@gmail.com>

[ Upstream commit 252bd1256396cebc6fc3526127fdb0b317601318 ]

If emergency system shutdown is called, like by thermal shutdown,
a dm device could be alive when the block device couldn't process
I/O requests anymore. In this state, the handling of I/O errors
by new dm I/O requests or by those already in-flight can lead to
a verity corruption state, which is a misjudgment.

So, skip verity work in response to I/O error when system is shutting
down.

Signed-off-by: Hyeongseok Kim <hyeongseok@gmail.com>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/md/dm-verity-target.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/md/dm-verity-target.c b/drivers/md/dm-verity-target.c
index e705799976c2c..2dae30713eb3d 100644
--- a/drivers/md/dm-verity-target.c
+++ b/drivers/md/dm-verity-target.c
@@ -551,6 +551,15 @@ static int verity_verify_io(struct dm_verity_io *io)
 	return 0;
 }
 
+/*
+ * Skip verity work in response to I/O error when system is shutting down.
+ */
+static inline bool verity_is_system_shutting_down(void)
+{
+	return system_state == SYSTEM_HALT || system_state == SYSTEM_POWER_OFF
+		|| system_state == SYSTEM_RESTART;
+}
+
 /*
  * End one "io" structure with a given error.
  */
@@ -578,7 +587,8 @@ static void verity_end_io(struct bio *bio)
 {
 	struct dm_verity_io *io = bio->bi_private;
 
-	if (bio->bi_status && !verity_fec_is_enabled(io->v)) {
+	if (bio->bi_status &&
+	    (!verity_fec_is_enabled(io->v) || verity_is_system_shutting_down())) {
 		verity_finish_io(io, bio->bi_status);
 		return;
 	}
-- 
2.27.0