From b8ed821ba05f3d06ebcd302cb595a06fbe6a1d73 Mon Sep 17 00:00:00 2001
From: David Disseldorp <ddiss@suse.de>
Date: Wed, 26 Aug 2015 21:54:07 +0200
Subject: [PATCH] target/rbd: add pr_release support
Patch-mainline: Not yet, SES2 clustered LIO/RBD
References: fate#318836
Add a tcm_rbd_pr_ops handler for PR RELEASE requests.
This change also ensures that deregistration with reservation results in
an implicit RELEASE.
Signed-off-by: David Disseldorp <ddiss@suse.de>
---
drivers/target/target_core_rbd.c | 154 +++++++++++++++++++++++++++++++++++++--
1 file changed, 147 insertions(+), 7 deletions(-)
--- a/drivers/target/target_core_rbd.c
+++ b/drivers/target/target_core_rbd.c
@@ -844,6 +844,15 @@ tcm_rbd_pr_info_rsv_set(struct tcm_rbd_p
return 0;
}
+static void
+tcm_rbd_pr_info_rsv_clear(struct tcm_rbd_pr_info *pr_info)
+{
+ kfree(pr_info->rsv);
+ pr_info->rsv = NULL;
+
+ dout("pr_info rsv cleared\n");
+}
+
static int
tcm_rbd_pr_info_append_reg(struct tcm_rbd_pr_info *pr_info, char *nexus,
u64 key)
@@ -882,13 +891,24 @@ static int
tcm_rbd_pr_info_unregister_reg(struct tcm_rbd_pr_info *pr_info,
struct tcm_rbd_pr_reg *reg)
{
- /*
- * TODO
- * If the I_T nexus is a reservation holder, the persistent reservation
- * is of an all registrants type, and the I_T nexus is the last
- * remaining registered I_T nexus, then the device server shall also
- * release the persistent reservation.
- */
+ struct tcm_rbd_pr_rsv *rsv;
+ bool all_reg = false;
+
+ rsv = pr_info->rsv;
+ if (rsv && tcm_rbd_is_rsv_holder(rsv, reg, &all_reg)) {
+ /*
+ * If the persistent reservation holder is more than one I_T
+ * nexus, the reservation shall not be released until the
+ * registrations for all persistent reservation holder I_T
+ * nexuses are removed.
+ */
+ if (!all_reg || (pr_info->num_regs == 1)) {
+ pr_warn("implicitly releasing PR of type %d on "
+ "unregister from %s\n",
+ rsv->type, reg->it_nexus);
+ tcm_rbd_pr_info_rsv_clear(pr_info);
+ }
+ }
tcm_rbd_pr_info_clear_reg(pr_info, reg);
@@ -1846,11 +1866,131 @@ err_info_free:
return ret;
}
+static sense_reason_t
+tcm_rbd_execute_pr_release(struct se_cmd *cmd, int type, 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 release */
+ pr_err("failed to obtain PR info\n");
+ return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+ }
+
+ if (!pr_info->rsv) {
+ /* no persistent reservation, return GOOD status */
+ goto done;
+ }
+
+ /* 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 RELEASE\n");
+ return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+ }
+
+ if (!tcm_rbd_is_rsv_holder(pr_info->rsv, existing_reg, NULL)) {
+ /* registered but not a persistent reservation holder */
+ goto done;
+ }
+
+ if (key != existing_reg->key) {
+ pr_err("SPC-3 PR RELEASE: 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;
+ }
+
+ if (pr_info->rsv->type != type) {
+ pr_err("SPC-3 PR: Attempted RELEASE from %s with different "
+ "TYPE, returning RESERVATION_CONFLICT\n",
+ existing_reg->it_nexus);
+ ret = TCM_RESERVATION_CONFLICT;
+ goto err_info_free;
+ }
+
+ /* release the persistent reservation */
+ tcm_rbd_pr_info_rsv_clear(pr_info);
+
+ /*
+ * TODO:
+ * c) If the released persistent reservation is a registrants only type
+ * or all registrants type persistent reservation,
+ * the device server shall establish a unit attention condition for
+ * the initiator port associated with every regis-
+ * tered I_T nexus other than I_T nexus on which the PERSISTENT
+ * RESERVE OUT command with RELEASE service action was received,
+ * with the additional sense code set to RESERVATIONS RELEASED
+ */
+
+ 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;
+ }
+
+done:
+ 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_register = tcm_rbd_execute_pr_register,
.pr_reserve = tcm_rbd_execute_pr_reserve,
+ .pr_release = tcm_rbd_execute_pr_release,
};
static const struct target_backend_ops tcm_rbd_ops = {