Re: [Qemu-devel] [PATCH 1/2] iscsi: Translate scsi sense into error code

[Peter Lieven <pl@kamp.de>]

Am 22.10.2015 um 10:17 schrieb Fam Zheng:
> Previously we return -EIO blindly when anything goes wrong. Add a helper
> function to parse sense fields and try to make the return code more
> meaningful.
>
> Signed-off-by: Fam Zheng <famz@redhat.com>
> ---
>   block/iscsi.c | 56 +++++++++++++++++++++++++++++++++++++++++++++++++++++++-
>   1 file changed, 55 insertions(+), 1 deletion(-)
>
> diff --git a/block/iscsi.c b/block/iscsi.c
> index 93f1ee4..f3e20ae 100644
> --- a/block/iscsi.c
> +++ b/block/iscsi.c
> @@ -84,6 +84,7 @@ typedef struct IscsiTask {
>       IscsiLun *iscsilun;
>       QEMUTimer retry_timer;
>       bool force_next_flush;
> +    int err_code;
>   } IscsiTask;
>   
>   typedef struct IscsiAIOCB {
> @@ -182,6 +183,58 @@ static inline unsigned exp_random(double mean)
>   #define QEMU_SCSI_STATUS_TIMEOUT        SCSI_STATUS_TIMEOUT
>   #endif
>   
> +static int iscsi_translate_sense(struct scsi_sense *sense)
> +{
> +    int ret = 0;
> +
> +    switch (sense->key) {
> +    case SCSI_SENSE_NO_SENSE:
> +        return 0;
> +        break;
> +    case SCSI_SENSE_NOT_READY:
> +        return -EBUSY;
> +        break;
> +    case SCSI_SENSE_DATA_PROTECTION:
> +        return -EACCES;
> +        break;
> +    case SCSI_SENSE_COMMAND_ABORTED:
> +        return -ECANCELED;
> +        break;
> +    case SCSI_SENSE_ILLEGAL_REQUEST:
> +        /* Parse ASCQ */
> +        break;
> +    default:
> +        return -EIO;
> +        break;
> +    }
> +    switch (sense->ascq) {
> +    case SCSI_SENSE_ASCQ_PARAMETER_LIST_LENGTH_ERROR:
> +    case SCSI_SENSE_ASCQ_INVALID_OPERATION_CODE:
> +    case SCSI_SENSE_ASCQ_INVALID_FIELD_IN_CDB:
> +    case SCSI_SENSE_ASCQ_INVALID_FIELD_IN_PARAMETER_LIST:
> +        ret = -EINVAL;
> +        break;
> +    case SCSI_SENSE_ASCQ_LBA_OUT_OF_RANGE:
> +        ret = -ERANGE;
> +        break;
> +    case SCSI_SENSE_ASCQ_LOGICAL_UNIT_NOT_SUPPORTED:
> +        ret = -ENOTSUP;
> +        break;
> +    case SCSI_SENSE_ASCQ_WRITE_PROTECTED:
> +        ret = -EACCES;
> +        break;
> +    case SCSI_SENSE_ASCQ_MEDIUM_NOT_PRESENT:
> +    case SCSI_SENSE_ASCQ_MEDIUM_NOT_PRESENT_TRAY_CLOSED:
> +    case SCSI_SENSE_ASCQ_MEDIUM_NOT_PRESENT_TRAY_OPEN:
> +        ret = -ENOMEDIUM;
> +        break;
> +    default:
> +        ret = -EIO;
> +        break;
> +    }
> +    return ret;
> +}
> +
>   static void
>   iscsi_co_generic_cb(struct iscsi_context *iscsi, int status,
>                           void *command_data, void *opaque)
> @@ -226,6 +279,7 @@ iscsi_co_generic_cb(struct iscsi_context *iscsi, int status,
>                   return;
>               }
>           }
> +        iTask->err_code = iscsi_translate_sense(&task->sense);
>           error_report("iSCSI Failure: %s", iscsi_get_error(iscsi));
>       } else {
>           iTask->iscsilun->force_next_flush |= iTask->force_next_flush;
> @@ -455,7 +509,7 @@ retry:
>       }
>   
>       if (iTask.status != SCSI_STATUS_GOOD) {
> -        return -EIO;
> +        return iTask.err_code;
>       }

why do you only use that translated error code for writev? Other calls could benefit from it as well.

Peter