static void iscsi_readcapacity_sync(IscsiLun *iscsilun, Error **errp)
{
    struct scsi_task *task = NULL;
    struct scsi_readcapacity10 *rc10 = NULL;
    struct scsi_readcapacity16 *rc16 = NULL;
    int retries = ISCSI_CMD_RETRIES; 

    do {
        if (task != NULL) {
            scsi_free_scsi_task(task);
            task = NULL;
        }

        switch (iscsilun->type) {
        case TYPE_DISK:
            task = iscsi_readcapacity16_sync(iscsilun->iscsi, iscsilun->lun);
            if (task != NULL && task->status == SCSI_STATUS_GOOD) {
                rc16 = scsi_datain_unmarshall(task);
                if (rc16 == NULL) {
                    error_setg(errp, "iSCSI: Failed to unmarshall readcapacity16 data.");
                } else {
                    iscsilun->block_size = rc16->block_length;
                    iscsilun->num_blocks = rc16->returned_lba + 1;
                    iscsilun->lbpme = !!rc16->lbpme;
                    iscsilun->lbprz = !!rc16->lbprz;
                    iscsilun->use_16_for_rw = (rc16->returned_lba > 0xffffffff);
                }
                break;
            }
            if (task != NULL && task->status == SCSI_STATUS_CHECK_CONDITION
                && task->sense.key == SCSI_SENSE_UNIT_ATTENTION) {
                break;
            }
            /* Fall through and try READ CAPACITY(10) instead.  */
        case TYPE_ROM:
            task = iscsi_readcapacity10_sync(iscsilun->iscsi, iscsilun->lun, 0, 0);
            if (task != NULL && task->status == SCSI_STATUS_GOOD) {
                rc10 = scsi_datain_unmarshall(task);
                if (rc10 == NULL) {
                    error_setg(errp, "iSCSI: Failed to unmarshall readcapacity10 data.");
                } else {
                    iscsilun->block_size = rc10->block_size;
                    if (rc10->lba == 0) {
                        /* blank disk loaded */
                        iscsilun->num_blocks = 0;
                    } else {
                        iscsilun->num_blocks = rc10->lba + 1;
                    }
                }
            }
            break;
        default:
            return;
        }
    } while (task != NULL && task->status == SCSI_STATUS_CHECK_CONDITION
             && task->sense.key == SCSI_SENSE_UNIT_ATTENTION
             && retries-- > 0);

    if (task == NULL || task->status != SCSI_STATUS_GOOD) {
        error_setg(errp, "iSCSI: failed to send readcapacity10/16 command");
    } else if (!iscsilun->block_size ||
               iscsilun->block_size % BDRV_SECTOR_SIZE) {
        error_setg(errp, "iSCSI: the target returned an invalid "
                   "block size of %d.", iscsilun->block_size);
    }
    if (task) {
        scsi_free_scsi_task(task);
    }
}
Unknown