From d58bb4614c60cb3b6b634ed821f39de22a368665 Mon Sep 17 00:00:00 2001

From: David Disseldorp <ddiss@suse.de>

Date: Fri, 11 Sep 2015 11:57:46 +0200

Subject: [PATCH] target/rbd: SCSI3 check conflict support

Patch-mainline: Not yet, SES2 clustered LIO/RBD

References: fate#318836

Check for existing SCSI3 persistent reservations prior to SCSI command

execution.

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

---

 drivers/target/target_core_rbd.c |   96 +++++++++++++++++++++++++++++++++++++++

 1 file changed, 96 insertions(+)

--- a/drivers/target/target_core_rbd.c

+++ b/drivers/target/target_core_rbd.c

@@ -2447,7 +2447,103 @@ tcm_rbd_execute_pr_register_and_move(str

 	return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;

 }

+static sense_reason_t

+tcm_rbd_execute_pr_check_scsi3_conflict(struct se_cmd *cmd,

+					struct tcm_rbd_pr_info *pr_info,

+					char *it_nexus)

+{

+	struct tcm_rbd_pr_rsv *rsv;

+	struct tcm_rbd_pr_reg *reg;

+	bool registered_nexus;

+	int rc;

+

+	if (!pr_info->rsv) {

+		dout("no SCSI3 persistent reservation\n");

+		return TCM_NO_SENSE;

+	}

+

+	rsv = pr_info->rsv;

+	dout("PR reservation holder: %s, us: %s\n", rsv->it_nexus, it_nexus);

+

+	if (!strncmp(rsv->it_nexus, it_nexus, ARRAY_SIZE(rsv->it_nexus))) {

+		dout("cmd is from reservation holder\n");

+		return TCM_NO_SENSE;

+	}

+

+	registered_nexus = false;

+	list_for_each_entry(reg, &pr_info->regs, regs_node) {

+		if (!strncmp(reg->it_nexus, it_nexus,

+						ARRAY_SIZE(reg->it_nexus))) {

+			dout("cmd is from PR registrant: %s\n", it_nexus);

+			registered_nexus = true;

+			break;

+		}

+	}

+	rc = core_scsi3_pr_seq_non_holder(cmd, rsv->type, it_nexus,

+					  registered_nexus);

+	if (rc == 1) {

+		dout("SCSI3 reservation conflict\n");

+		return TCM_RESERVATION_CONFLICT;

+	} else if (rc < 0) {

+		pr_warn("SCSI3 PR non-holder check failed\n");

+		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;

+	}

+

+	return TCM_NO_SENSE;

+}

+

+static sense_reason_t

+tcm_rbd_execute_pr_check_conflict(struct se_cmd *cmd,

+				  enum target_pr_check_type type)

+{

+	struct se_device *dev = cmd->se_dev;

+	struct tcm_rbd_dev *tcm_rbd_dev = TCM_RBD_DEV(dev);

+	struct tcm_rbd_pr_info *pr_info;

+	char nexus_buf[TCM_RBD_PR_IT_NEXUS_MAXLEN];

+	int rc;

+	sense_reason_t ret;

+

+	switch (cmd->t_task_cdb[0]) {

+	case INQUIRY:

+	case RELEASE:

+	case RELEASE_10:

+		/* always allow cdb execution */

+		return TCM_NO_SENSE;

+	default:

+		break;

+	}

+

+	rc = tcm_rbd_pr_info_get(tcm_rbd_dev, &pr_info, NULL, NULL);

+	if (rc == -ENODATA) {

+		dout("no PR info, can't conflict\n");

+		return TCM_NO_SENSE;

+	}

+	if (rc < 0) {

+		/* existing registration required for reservation */

+		pr_err("failed to obtain PR info\n");

+		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;

+	}

+

+	rc = tcm_rbd_gen_it_nexus(cmd->se_sess, nexus_buf,

+				  ARRAY_SIZE(nexus_buf));

+	if (rc < 0) {

+		ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;

+		goto out_info_free;

+	}

+

+	ret = tcm_rbd_execute_pr_check_scsi3_conflict(cmd, pr_info, nexus_buf);

+	if (ret)

+		goto out_info_free;

+

+	ret = TCM_NO_SENSE;

+out_info_free:

+	kfree(pr_info);

+	return ret;

+}

+

 static struct target_pr_ops tcm_rbd_pr_ops = {

+	.check_conflict		= tcm_rbd_execute_pr_check_conflict,

+

 	.pr_read_keys		= tcm_rbd_execute_pr_read_keys,

 	.pr_read_reservation	= tcm_rbd_execute_pr_read_reservation,

 	.pr_report_capabilities	= tcm_rbd_execute_pr_report_capabilities,