+ /**
+ * check whether this OSC device is available for non-delay read,
+ * fast switching mirror if we haven't tried all mirrors.
+ */
+ if (ios->cis_io->ci_type == CIT_READ && ios->cis_io->ci_ndelay &&
+ !ios->cis_io->ci_tried_all_mirrors && osc_import_not_healthy(imp)) {
+ rc = -EWOULDBLOCK;
+ } else if (likely(!imp->imp_invalid)) {