target: Make EXTENDED_COPY 0xe4 failure return COPY TARGET DEVICE NOT REACHABLE

This patch addresses a bug where EXTENDED_COPY across multiple LUNs
results in a CHECK_CONDITION when the source + destination are not
located on the same physical node.

ESX Host environments expect sense COPY_ABORTED w/ COPY TARGET DEVICE
NOT REACHABLE to be returned when this occurs, in order to signal
fallback to local copy method.

As described in section 6.3.3 of spc4r22:

"If it is not possible to complete processing of a segment because the
copy manager is unable to establish communications with a copy target
device, because the copy target device does not respond to INQUIRY,
or because the data returned in response to INQUIRY indicates
an unsupported logical unit, then the EXTENDED COPY command shall be
terminated with CHECK CONDITION status, with the sense key set to
COPY ABORTED, and the additional sense code set to COPY TARGET DEVICE
NOT REACHABLE."

Tested on v4.1.y with ESX v5.5u2+ with BlockCopy across multiple nodes.

Reported-by: Nixon Vincent <[e-mail]>
Tested-by: Nixon Vincent <[e-mail]>
Cc: Nixon Vincent <[e-mail]>
Tested-by: Dinesh Israni <[e-mail]>
Signed-off-by: Dinesh Israni <[e-mail]>
Cc: Dinesh Israni <[e-mail]>
Cc: [e-mail] # 3.14+
Signed-off-by: Nicholas Bellinger <[e-mail]>

drivers/target/target_core_transport.c

···
 	case TCM_LOGICAL_BLOCK_GUARD_CHECK_FAILED:
 	case TCM_LOGICAL_BLOCK_APP_TAG_CHECK_FAILED:
 	case TCM_LOGICAL_BLOCK_REF_TAG_CHECK_FAILED:
+	case TCM_COPY_TARGET_DEVICE_NOT_REACHABLE:
 		break;
 	case TCM_OUT_OF_RESOURCES:
 		sense_reason = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
···
 		.asc = 0x10,
 		.ascq = 0x03, /* LOGICAL BLOCK REFERENCE TAG CHECK FAILED */
 		.add_sector_info = true,
+	},
+	[TCM_COPY_TARGET_DEVICE_NOT_REACHABLE] = {
+		.key = COPY_ABORTED,
+		.asc = 0x0d,
+		.ascq = 0x02, /* COPY TARGET DEVICE NOT REACHABLE */
+
 	},
 	[TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE] = {
 		/*

drivers/target/target_core_xcopy.c

···
 	}
 	mutex_unlock(&g_device_mutex);
 
-	pr_err("Unable to locate 0xe4 descriptor for EXTENDED_COPY\n");
+	pr_debug_ratelimited("Unable to locate 0xe4 descriptor for EXTENDED_COPY\n");
 	return -EINVAL;
 }
 
···
 
 static int target_xcopy_parse_target_descriptors(struct se_cmd *se_cmd,
 				struct xcopy_op *xop, unsigned char *p,
-				unsigned short tdll)
+				unsigned short tdll, sense_reason_t *sense_ret)
 {
 	struct se_device *local_dev = se_cmd->se_dev;
 	unsigned char *desc = p;
 	int offset = tdll % XCOPY_TARGET_DESC_LEN, rc, ret = 0;
 	unsigned short start = 0;
 	bool src = true;
+
+	*sense_ret = TCM_INVALID_PARAMETER_LIST;
 
 	if (offset != 0) {
 		pr_err("XCOPY target descriptor list length is not"
···
 		rc = target_xcopy_locate_se_dev_e4(se_cmd, xop, true);
 	else
 		rc = target_xcopy_locate_se_dev_e4(se_cmd, xop, false);
-
-	if (rc < 0)
+	/*
+	 * If a matching IEEE NAA 0x83 descriptor for the requested device
+	 * is not located on this node, return COPY_ABORTED with ASQ/ASQC
+	 * 0x0d/0x02 - COPY_TARGET_DEVICE_NOT_REACHABLE to request the
+	 * initiator to fall back to normal copy method.
+	 */
+	if (rc < 0) {
+		*sense_ret = TCM_COPY_TARGET_DEVICE_NOT_REACHABLE;
 		goto out;
+	}
 
 	pr_debug("XCOPY TGT desc: Source dev: %p NAA IEEE WWN: 0x%16phN\n",
 		 xop->src_dev, &xop->src_tid_wwn[0]);
···
 	xcopy_pt_undepend_remotedev(xop);
 	kfree(xop);
 
-	pr_warn("target_xcopy_do_work: Setting X-COPY CHECK_CONDITION -> sending response\n");
+	pr_warn_ratelimited("target_xcopy_do_work: rc: %d, Setting X-COPY CHECK_CONDITION"
+			    " -> sending response\n", rc);
 	ec_cmd->scsi_status = SAM_STAT_CHECK_CONDITION;
 	target_complete_cmd(ec_cmd, SAM_STAT_CHECK_CONDITION);
 }
···
 		" tdll: %hu sdll: %u inline_dl: %u\n", list_id, list_id_usage,
 		tdll, sdll, inline_dl);
 
-	rc = target_xcopy_parse_target_descriptors(se_cmd, xop, &p[16], tdll);
+	rc = target_xcopy_parse_target_descriptors(se_cmd, xop, &p[16], tdll, &ret);
 	if (rc <= 0)
 		goto out;
 

include/target/target_core_base.h

···
 	TCM_LOGICAL_BLOCK_GUARD_CHECK_FAILED	= R(0x15),
 	TCM_LOGICAL_BLOCK_APP_TAG_CHECK_FAILED	= R(0x16),
 	TCM_LOGICAL_BLOCK_REF_TAG_CHECK_FAILED	= R(0x17),
+	TCM_COPY_TARGET_DEVICE_NOT_REACHABLE	= R(0x18),
 #undef R
 };