CORTX-33577: Fixed panic in degraded read, replaced assert with error code

* It might possible that in degraded mode we may land up in a situation
  where there are more than K failure and read_verify_is not true. In this
  case ideally, we should return proper error code (-EIO) instead of assert.

Signed-off-by: Yatin Mahajan <[email protected]>

Author: yatin-mahajan

motr/io_nw_xfer.c

@@ -1928,8 +1928,14 @@ static int nw_xfer_req_dispatch(struct nw_xfer_request *xfer)
 		 *    The units needed for recvoery are ready.
 		 */
 		M0_ASSERT(ioreq_sm_state(ioo) == IRS_DEGRADED_READING);
-		M0_ASSERT(op->op_code == M0_OC_READ &&
-			  instance->m0c_config->mc_is_read_verify);
+		if (op->op_code == M0_OC_READ &&
+		    instance->m0c_config->mc_is_read_verify) {
+			M0_LOG(M0_DEBUG, "As per design in Read verify mode");
+		} else {
+			M0_LOG(M0_ERROR, "More than K targets are offline");
+			rc = -EIO;
+		}
+
 		ioreq_sm_state_set_locked(ioo, IRS_READ_COMPLETE);
 	} else if (rc == 0)
 		xfer->nxr_state = NXS_INFLIGHT;