SCSI Add support for STATUS_BUSY

Add support for BUSY status coide from the target and just pass this
back to the application as is (instead of converting it to _ERROR).

This allows the application to trap task->status==SCSI_STATUS_BUSY and
decide what/how to proceed.

include/iscsi.h

@@ -264,6 +264,7 @@ EXTERN int iscsi_is_logged_in(struct iscsi_context *iscsi);
 enum scsi_status {
 	SCSI_STATUS_GOOD                 = 0,
 	SCSI_STATUS_CHECK_CONDITION      = 2,
+	SCSI_STATUS_BUSY                 = 8,
 	SCSI_STATUS_RESERVATION_CONFLICT = 0x18,
 	SCSI_STATUS_REDIRECT             = 0x101,
 	SCSI_STATUS_CANCELLED            = 0x0f000000,

lib/iscsi-command.c

@@ -40,6 +40,7 @@ iscsi_scsi_response_cb(struct iscsi_context *iscsi, int status,
 	case SCSI_STATUS_RESERVATION_CONFLICT:
 	case SCSI_STATUS_CHECK_CONDITION:
 	case SCSI_STATUS_GOOD:
+	case SCSI_STATUS_BUSY:
 	case SCSI_STATUS_ERROR:
 	case SCSI_STATUS_CANCELLED:
 		scsi_cbdata->callback(iscsi, status, scsi_cbdata->task,
@@ -395,6 +396,11 @@ iscsi_process_scsi_reply(struct iscsi_context *iscsi, struct iscsi_pdu *pdu,
 		pdu->callback(iscsi, SCSI_STATUS_RESERVATION_CONFLICT,
 			task, pdu->private_data);
 		break;
+	case SCSI_STATUS_BUSY:
+		iscsi_set_error(iscsi, "BUSY");
+		pdu->callback(iscsi, SCSI_STATUS_BUSY,
+			task, pdu->private_data);
+		break;
 	default:
 		iscsi_set_error(iscsi, "Unknown SCSI status :%d.", status);