[dm-devel] [PATCH AUTOSEL 4.19 10/10] dm verity: skip verity work if I/O error when system is shutting down

[Sasha Levin]

From: Hyeongseok Kim <hyeongseok at 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 at gmail.com>
Reviewed-by: Sami Tolvanen <samitolvanen at google.com>
Signed-off-by: Mike Snitzer <snitzer at redhat.com>
Signed-off-by: Sasha Levin <sashal at 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 e3599b43f9eb9..599be2d2b0ae9 100644
--- a/drivers/md/dm-verity-target.c
+++ b/drivers/md/dm-verity-target.c
@@ -533,6 +533,15 @@ 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.
  */
@@ -560,7 +569,8 @@ 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