From 423f49601e2eea96ee4711b590a034b8e098acfc Mon Sep 17 00:00:00 2001
From: David Disseldorp <ddiss@suse.de>
Date: Thu, 27 Aug 2015 17:46:39 +0200
Subject: [PATCH] target/rbd: add pr_clear support
Patch-mainline: Not yet, SES2 clustered LIO/RBD
References: fate#318836
Add a tcm_rbd_pr_ops handler for PR CLEAR requests, that removes any
reservation and all existing registrations.
Signed-off-by: David Disseldorp <ddiss@suse.de>
---
drivers/target/target_core_rbd.c | 108 +++++++++++++++++++++++++++++++++++++++
1 file changed, 108 insertions(+)
--- a/drivers/target/target_core_rbd.c
+++ b/drivers/target/target_core_rbd.c
@@ -2061,6 +2061,113 @@ err_info_free:
return ret;
}
+static sense_reason_t
+tcm_rbd_execute_pr_clear(struct se_cmd *cmd, u64 key)
+{
+ struct se_device *dev = cmd->se_dev;
+ struct tcm_rbd_dev *tcm_rbd_dev = TCM_RBD_DEV(dev);
+ char nexus_buf[TCM_RBD_PR_IT_NEXUS_MAXLEN];
+ struct tcm_rbd_pr_info *pr_info;
+ struct tcm_rbd_pr_reg *reg;
+ struct tcm_rbd_pr_reg *existing_reg;
+ char *pr_xattr;
+ int pr_xattr_len;
+ int rc;
+ sense_reason_t ret;
+ int retries = 0;
+
+ if (!cmd->se_sess || !cmd->se_lun) {
+ pr_err("SPC-3 PR: se_sess || struct se_lun is NULL!\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)
+ return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+
+retry:
+ pr_info = NULL;
+ pr_xattr = NULL;
+ pr_xattr_len = 0;
+ rc = tcm_rbd_pr_info_get(tcm_rbd_dev, &pr_info, &pr_xattr,
+ &pr_xattr_len);
+ if (rc < 0) {
+ /* existing registration required for clear */
+ pr_err("failed to obtain PR info\n");
+ return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+ }
+
+ /* check for an existing registration */
+ existing_reg = NULL;
+ list_for_each_entry(reg, &pr_info->regs, regs_node) {
+ if (!strncmp(reg->it_nexus, nexus_buf, ARRAY_SIZE(nexus_buf))) {
+ dout("found existing PR reg for %s\n", nexus_buf);
+ existing_reg = reg;
+ break;
+ }
+ }
+
+ if (!existing_reg) {
+ pr_err("SPC-3 PR: Unable to locate registration for CLEAR\n");
+ return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+ }
+
+ if (key != existing_reg->key) {
+ pr_err("SPC-3 PR CLEAR: Received res_key: 0x%016Lx"
+ " does not match existing SA REGISTER res_key:"
+ " 0x%016Lx\n", key, existing_reg->key);
+ ret = TCM_RESERVATION_CONFLICT;
+ goto err_info_free;
+ }
+
+ /* release the persistent reservation, if any */
+ if (pr_info->rsv)
+ tcm_rbd_pr_info_rsv_clear(pr_info);
+
+ /* remove all registrations */
+ list_for_each_entry_safe(existing_reg, reg, &pr_info->regs, regs_node) {
+ tcm_rbd_pr_info_clear_reg(pr_info, existing_reg);
+ }
+
+ /*
+ * TODO:
+ * e) Establish a unit attention condition for the initiator
+ * port associated with every registered I_T nexus other
+ * than the I_T nexus on which the PERSISTENT RESERVE OUT
+ * command with CLEAR service action was received, with the
+ * additional sense code set to RESERVATIONS PREEMPTED.
+ */
+
+ /* PR generation must be incremented on successful CLEAR */
+ pr_info->gen++;
+
+ rc = tcm_rbd_pr_info_replace(tcm_rbd_dev, pr_xattr, pr_xattr_len,
+ pr_info);
+ if (rc == -ECANCELED) {
+ pr_warn("atomic PR info update failed due to parallel "
+ "change, expected(%d) %s. Retrying...\n",
+ pr_xattr_len, pr_xattr);
+ retries++;
+ if (retries <= TCM_RBD_PR_REG_MAX_RETRIES) {
+ tcm_rbd_pr_info_free(pr_info);
+ kfree(pr_xattr);
+ goto retry;
+ }
+ }
+ if (rc < 0) {
+ pr_err("atomic PR info update failed: %d\n", rc);
+ ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+ goto err_info_free;
+ }
+
+ ret = TCM_NO_SENSE;
+err_info_free:
+ tcm_rbd_pr_info_free(pr_info);
+ kfree(pr_xattr);
+ return ret;
+}
+
static struct target_pr_ops tcm_rbd_pr_ops = {
.pr_read_keys = tcm_rbd_execute_pr_read_keys,
.pr_read_reservation = tcm_rbd_execute_pr_read_reservation,
@@ -2068,6 +2175,7 @@ static struct target_pr_ops tcm_rbd_pr_o
.pr_register = tcm_rbd_execute_pr_register,
.pr_reserve = tcm_rbd_execute_pr_reserve,
.pr_release = tcm_rbd_execute_pr_release,
+ .pr_clear = tcm_rbd_execute_pr_clear,
};
static const struct target_backend_ops tcm_rbd_ops = {