test: add prout_preempt() helper function

Issue a Persistent Reservation Out PREEMPT request, with keys and type
provided.
PREEMPT allows for the removal of registrations, and replacement of
reservations.

Signed-off-by: David Disseldorp <ddiss@suse.de>

test-tool/iscsi-support.c

@@ -1022,6 +1022,58 @@ prout_clear(struct scsi_device *sdev, unsigned long long key)
 	return ret;
 }
 
+int
+prout_preempt(struct scsi_device *sdev,
+	      unsigned long long sark, unsigned long long rk,
+	      enum scsi_persistent_out_type pr_type)
+{
+	struct scsi_persistent_reserve_out_basic poc;
+	struct scsi_task *task;
+	int ret = 0;
+
+	/* reserve the target using specified reservation type */
+	logging(LOG_VERBOSE,
+		"Send PROUT/PREEMPT to preempt reservation and/or "
+		"registration");
+
+	if (!data_loss) {
+		printf("--dataloss flag is not set in. Skipping PROUT\n");
+		return -1;
+	}
+
+	memset(&poc, 0, sizeof (poc));
+	poc.reservation_key = rk;
+	poc.service_action_reservation_key = sark;
+	task = scsi_cdb_persistent_reserve_out(
+	    SCSI_PERSISTENT_RESERVE_PREEMPT,
+	    SCSI_PERSISTENT_RESERVE_SCOPE_LU,
+	    pr_type, &poc);
+	assert(task != NULL);
+
+	task = send_scsi_command(sdev, task, NULL);
+	if (task == NULL) {
+		logging(LOG_NORMAL,
+		    "[FAILED] Failed to send PROUT command: %s",
+		    iscsi_get_error(sdev->iscsi_ctx));
+		return -1;
+	}
+	if (status_is_invalid_opcode(task)) {
+		scsi_free_scsi_task(task);
+		logging(LOG_NORMAL, "[SKIPPED] PERSISTENT RESERVE OUT is not implemented.");
+		return -2;
+	}
+
+	if (task->status != SCSI_STATUS_GOOD) {
+		logging(LOG_NORMAL,
+		    "[FAILED] PROUT command: failed with sense. %s",
+		    iscsi_get_error(sdev->iscsi_ctx));
+		ret = -1;
+	}
+
+	scsi_free_scsi_task(task);
+	return ret;
+}
+
 int
 prin_verify_reserved_as(struct scsi_device *sdev,
     unsigned long long key, enum scsi_persistent_out_type pr_type)

test-tool/iscsi-support.h

@@ -274,6 +274,9 @@ int prout_reserve(struct scsi_device *sdev,
 int prout_release(struct scsi_device *sdev,
     unsigned long long key, enum scsi_persistent_out_type pr_type);
 int prout_clear(struct scsi_device *sdev, unsigned long long key);
+int prout_preempt(struct scsi_device *sdev,
+		  unsigned long long sark, unsigned long long rk,
+		  enum scsi_persistent_out_type pr_type);
 int prin_verify_not_reserved(struct scsi_device *sdev);
 int prin_verify_reserved_as(struct scsi_device *sdev,
     unsigned long long key, enum scsi_persistent_out_type pr_type);