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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, Keith Busch <kbusch@kernel.org>,
        Sagi Grimberg <sagi@grimberg.me>,
        Christoph Hellwig <hch@lst.de>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.4 41/65] nvme: fix identify error status silent ignore
Date:   Tue,  7 Jul 2020 17:17:20 +0200
Message-Id: <20200707145754.443602576@linuxfoundation.org>
In-Reply-To: <20200707145752.417212219@linuxfoundation.org>
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From: Sagi Grimberg <sagi@grimberg.me>

[ Upstream commit ea43d9709f727e728e933a8157a7a7ca1a868281 ]

Commit 59c7c3caaaf8 intended to only silently ignore non retry-able
errors (DNR bit set) such that we can still identify misbehaving
controllers, and in the other hand propagate retry-able errors (DNR bit
cleared) so we don't wrongly abandon a namespace just because it happens
to be temporarily inaccessible.

The goal remains the same as the original commit where this was
introduced but unfortunately had the logic backwards.

Fixes: 59c7c3caaaf8 ("nvme: fix possible hang when ns scanning fails during error recovery")
Reported-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/nvme/host/core.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index c44c00b9e1d85..d423515547237 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -1088,10 +1088,16 @@ static int nvme_identify_ns_descs(struct nvme_ctrl *ctrl, unsigned nsid,
 		dev_warn(ctrl->device,
 			"Identify Descriptors failed (%d)\n", status);
 		 /*
-		  * Don't treat an error as fatal, as we potentially already
-		  * have a NGUID or EUI-64.
+		  * Don't treat non-retryable errors as fatal, as we potentially
+		  * already have a NGUID or EUI-64.  If we failed with DNR set,
+		  * we want to silently ignore the error as we can still
+		  * identify the device, but if the status has DNR set, we want
+		  * to propagate the error back specifically for the disk
+		  * revalidation flow to make sure we don't abandon the
+		  * device just because of a temporal retry-able error (such
+		  * as path of transport errors).
 		  */
-		if (status > 0 && !(status & NVME_SC_DNR))
+		if (status > 0 && (status & NVME_SC_DNR))
 			status = 0;
 		goto free_data;
 	}
-- 
2.25.1