[PATCH] scsi: storvsc: Fix scsi_cmd error assignments in storvsc_handle_error

[PATCH] scsi: storvsc: Fix scsi_cmd error assignments in storvsc_handle_error

[Cathy Avery]

When an I/O is returned with an srb_status of SRB_STATUS_INVALID_LUN
which has zero good_bytes it must be assigned an error. Otherwise
the I/O will be continuously requeued and will cause a deadlock in the
case where disks are being hot added and removed. sd_probe_async will
wait forever for its I/O to complete while holding scsi_sd_probe_domain.

Also returning the default error of DID_TARGET_FAILURE causes
multipath to not retry the I/O resulting in applications receiving I/O
errors before a failover can occur.

Signed-off-by: Cathy Avery <cavery@redhat.com>
Signed-off-by: Long Li <longli@microsoft.com>
---
 drivers/scsi/storvsc_drv.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/storvsc_drv.c b/drivers/scsi/storvsc_drv.c
index 1b06cf0..3b3d1d0 100644
--- a/drivers/scsi/storvsc_drv.c
+++ b/drivers/scsi/storvsc_drv.c
@@ -953,10 +953,11 @@ static void storvsc_handle_error(struct vmscsi_request *vm_srb,
 		case TEST_UNIT_READY:
 			break;
 		default:
-			set_host_byte(scmnd, DID_TARGET_FAILURE);
+			set_host_byte(scmnd, DID_ERROR);
 		}
 		break;
 	case SRB_STATUS_INVALID_LUN:
+		set_host_byte(scmnd, DID_NO_CONNECT);
 		do_work = true;
 		process_err_fn = storvsc_remove_lun;
 		break;
-- 
2.5.0

Re: [PATCH] scsi: storvsc: Fix scsi_cmd error assignments in storvsc_handle_error

[Stephen Hemminger]

On Tue, 19 Dec 2017 13:32:48 -0500
Cathy Avery <cavery@redhat.com> wrote:

> When an I/O is returned with an srb_status of SRB_STATUS_INVALID_LUN
> which has zero good_bytes it must be assigned an error. Otherwise
> the I/O will be continuously requeued and will cause a deadlock in the
> case where disks are being hot added and removed. sd_probe_async will
> wait forever for its I/O to complete while holding scsi_sd_probe_domain.
> 
> Also returning the default error of DID_TARGET_FAILURE causes
> multipath to not retry the I/O resulting in applications receiving I/O
> errors before a failover can occur.
> 
> Signed-off-by: Cathy Avery <cavery@redhat.com>
> Signed-off-by: Long Li <longli@microsoft.com>

When working on the DVD probe issue I saw that error handling was
problematic. Thanks for fixing.

Reviewed-by: Stephen Hemminger <stephen@networkplumber.org>

Re: [PATCH] scsi: storvsc: Fix scsi_cmd error assignments in storvsc_handle_error

[Martin K. Petersen]

Cathy,

> When an I/O is returned with an srb_status of SRB_STATUS_INVALID_LUN
> which has zero good_bytes it must be assigned an error. Otherwise the
> I/O will be continuously requeued and will cause a deadlock in the
> case where disks are being hot added and removed. sd_probe_async will
> wait forever for its I/O to complete while holding
> scsi_sd_probe_domain.
>
> Also returning the default error of DID_TARGET_FAILURE causes
> multipath to not retry the I/O resulting in applications receiving I/O
> errors before a failover can occur.

Applied to 4.15/scsi-fixes. Thank you!

-- 
Martin K. Petersen	Oracle Linux Engineering