nvme: fix identify error status silent ignore

Commit 59c7c3c 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: 59c7c3c ("nvme: fix possible hang when ns scanning fails during error recovery")
Reported-by: Keith Busch <[email protected]>
Signed-off-by: Sagi Grimberg <[email protected]>
Reviewed-by: Keith Busch <[email protected]>
Signed-off-by: Christoph Hellwig <[email protected]>

Author: sagigrimberg

drivers/nvme/host/core.c

@@ -1116,10 +1116,16 @@ 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;
 	}