Fwd: [PATCH rfc v2 0/6] nvme controller reset and namespace scan work race conditions

[sagi@grimberg.me (Sagi Grimberg)]

> I have two complaints:
> 
> - FC is eliminated from this fix, as FC doesn't use 
> nvme_cancel_request() to terminate I/O's on resets/error recovery.

Becuase I didn't find nvme_cancel_request in fc I assumed that it
doesn't see the issue, but thanks for the extra hunk that is needed!

> - With this change, any error set by a transport must be either 
> NVME_SC_SUCCESS or NVME_SC_HOST_PATH_ERROR or it potentially misses the 
> fix. I'm not sure that I like that, although any error from the 
> transport is essentially a path error.? Do we lose anything by the loss 
> of error clarity ??? Looking at what's present, we don't have much 
> diversity when an error is set, so I guess it's ok.

The main objective is to avoid the issue if we have a transport related
error which means we cannot communicate the the device (hence we set
BLK_STS_TRANSPORT). If we have another transport related error we should
assign that as well to this path.

> Minimally, include the following fix for FC as well:
> 
> 
> Signed-off-by: James Smart <james.smart at broadcom.com>
> ---
>  ?fc.c.new |?? 35 +++++++++++++++++++++++++++++------
>  ?1 file changed, 29 insertions(+), 6 deletions(-)
> 
> --- fc.c.old??? 2019-08-05 10:55:51.318627945 -0700
> +++ fc.c.new??? 2019-08-05 11:01:46.278380191 -0700
> @@ -1608,9 +1608,13 @@ nvme_fc_fcpio_done(struct nvmefc_fcp_req
>  ???????????????? sizeof(op->rsp_iu), DMA_FROM_DEVICE);
> 
>  ???? if (opstate == FCPOP_STATE_ABORTED)
> -??????? status = cpu_to_le16(NVME_SC_ABORT_REQ << 1);
> -??? else if (freq->status)
> -??????? status = cpu_to_le16(NVME_SC_INTERNAL << 1);
> +??????? status = cpu_to_le16(NVME_SC_HOST_PATH_ERROR << 1);
> +??? else if (freq->status) {
> +??????? status = cpu_to_le16(NVME_SC_HOST_PATH_ERROR << 1);
> +??????? dev_info(ctrl->ctrl.device,
> +??????????? "NVME-FC{%d}: io failed due to lldd error %d\n",
> +??????????? ctrl->cnum, freq->status);
> +??? }
> 
>  ???? /*
>  ????? * For the linux implementation, if we have an unsuccesful
> @@ -1638,7 +1642,12 @@ nvme_fc_fcpio_done(struct nvmefc_fcp_req
>  ????????? */
>  ???????? if (freq->transferred_length !=
>  ???????????? be32_to_cpu(op->cmd_iu.data_len)) {
> -??????????? status = cpu_to_le16(NVME_SC_INTERNAL << 1);
> +??????????? status = cpu_to_le16(NVME_SC_HOST_PATH_ERROR << 1);
> +??????????? dev_info(ctrl->ctrl.device,
> +??????????????? "NVME-FC{%d}: io failed due to bad transfer "
> +??????????????? "length: %d vs expected %d\n",
> +??????????????? ctrl->cnum, freq->transferred_length,
> +??????????????? be32_to_cpu(op->cmd_iu.data_len));
>  ???????????? goto done;
>  ???????? }
>  ???????? result.u64 = 0;
> @@ -1655,7 +1664,17 @@ nvme_fc_fcpio_done(struct nvmefc_fcp_req
>  ???????????????????? freq->transferred_length ||
>  ????????????????? op->rsp_iu.status_code ||
>  ????????????????? sqe->common.command_id != cqe->command_id)) {
> -??????????? status = cpu_to_le16(NVME_SC_INTERNAL << 1);
> +??????????? status = cpu_to_le16(NVME_SC_HOST_PATH_ERROR << 1);
> +??????????? dev_info(ctrl->ctrl.device,
> +??????????????? "NVME-FC{%d}: io failed due to bad NVMe_ERSP: "
> +??????????????? "iu len %d, xfr len %d vs %d, status code "
> +??????????????? "%d, cmdid %d vs %d\n",
> +??????????????? ctrl->cnum, be16_to_cpu(op->rsp_iu.iu_len),
> +??????????????? be32_to_cpu(op->rsp_iu.xfrd_len),
> +??????????????? freq->transferred_length,
> +???????????????????? op->rsp_iu.status_code,
> +??????????????? sqe->common.command_id,
> +??????????????? cqe->command_id);
>  ???????????? goto done;
>  ???????? }
>  ???????? result = cqe->result;
> @@ -1663,7 +1682,11 @@ nvme_fc_fcpio_done(struct nvmefc_fcp_req
>  ???????? break;
> 
>  ???? default:
> -??????? status = cpu_to_le16(NVME_SC_INTERNAL << 1);
> +??????? status = cpu_to_le16(NVME_SC_HOST_PATH_ERROR << 1);
> +??????? dev_info(ctrl->ctrl.device,
> +??????????? "NVME-FC{%d}: io failed due to odd NVMe_xRSP iu "
> +??????????? "len %d\n",
> +??????????? ctrl->cnum, freq->rcv_rsplen);
>  ???????? goto done;
>  ???? }
> 

I will, thanks!