This patch added functions to handle Persistent Reservation
Reserve against TCMU devices.
Function tcm_rbd_pr_info_rsv_set() will help set PR information
in struct tcmu_pr_info, function tcmu_execute_pr_reserve() will
help handle PR reserve requests against TCMU devices.
Signed-off-by: Zhu Lingshan <lszhu@xxxxxxxx>
---
drivers/target/target_core_user.c | 162 ++++++++++++++++++++++++++++++
1 file changed, 162 insertions(+)
diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c
index bde325888477..8390b1d37873 100644
--- a/drivers/target/target_core_user.c
+++ b/drivers/target/target_core_user.c
@@ -2970,6 +2970,167 @@ static int is_passthrough_pr_supportive_dev(struct tcmu_dev *udev)
return ret;
}
+
+
+static int tcm_rbd_pr_info_rsv_set(struct tcmu_pr_info *pr_info, u64 key,
+ char *nexus, int type)
+{
+ struct tcmu_pr_rsv *rsv;
+
+ if (pr_info->rsv != NULL) {
+ pr_debug("rsv_set called with existing reservation\n");
+ return -EINVAL;
+ }
+
+ rsv = kmalloc(sizeof(*rsv), GFP_KERNEL);
+ if (!rsv)
+ return -ENOMEM;
+
+ rsv->key = key;
+ strlcpy(rsv->it_nexus, nexus, ARRAY_SIZE(rsv->it_nexus));
+ rsv->type = type;
+ pr_info->rsv = rsv;
+ pr_debug("pr_info rsv set: 0x%llx %s %d\n", key, nexus, type);
+
+ return 0;
+}
+
+
+static sense_reason_t
+tcmu_execute_pr_reserve(struct se_cmd *cmd, int type, u64 key)
+{
+ struct se_device *dev = cmd->se_dev;
+ struct tcmu_dev *udev = TCMU_DEV(dev);
+ char nexus_buf[TCMU_PR_IT_NEXUS_MAXLEN];
+ struct tcmu_pr_info *pr_info;
+ struct tcmu_pr_reg *reg;
+ struct tcmu_pr_reg *existing_reg;
+ char *pr_xattr;
+ int pr_xattr_len;
+ int rc;
+ sense_reason_t ret;
+ int retries = 0;
+
+ udev->pr_info.pr_info_buf = kzalloc(TCMU_PR_INFO_XATTR_MAX_SIZE,
+ GFP_KERNEL);
+ if (!udev->pr_info.pr_info_buf)
+ return TCM_OUT_OF_RESOURCES;
+
+ if (!cmd->se_sess || !cmd->se_lun) {
+ pr_err("SPC-3 PR: se_sess || struct se_lun is NULL!\n");
+ ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+ goto err_info_free;
+ }
+
+ rc = tcmu_gen_it_nexus(cmd->se_sess, nexus_buf,
+ ARRAY_SIZE(nexus_buf));
+ if (rc < 0) {
+ ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+ goto err_info_free;
+ }
+
+retry:
+ pr_info = NULL;
+ pr_xattr = NULL;
+ pr_xattr_len = 0;
+ rc = tcmu_pr_info_get(udev, &pr_info, &pr_xattr,
+ &pr_xattr_len);
+ if (rc < 0) {
+ /* existing registration required for reservation */
+ pr_err("failed to obtain PR info\n");
+ ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+ goto err_info_free;
+ }
+
+ /* 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))) {
+ pr_debug("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 RESERVE\n");
+ ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
+ goto err_info_free;
+ }
+
+ if (key != existing_reg->key) {
+ pr_err("SPC-3 PR RESERVE: Received res_key: 0x%016llx ", key);
+ pr_err("does not match existing SA REGISTER res_key: ");
+ pr_err("0x%016llx\n", existing_reg->key);
+ ret = TCM_RESERVATION_CONFLICT;
+ goto err_info_free;
+ }
+
+ if (pr_info->rsv) {
+ if (!tcmu_is_rsv_holder(pr_info->rsv, existing_reg, NULL)) {
+ pr_err("SPC-3 PR: Attempted RESERVE from %s while ",
+ nexus_buf);
+ pr_err("reservation already held by %s, ",
+ pr_info->rsv->it_nexus);
+ pr_err("returning RESERVATION_CONFLICT\n");
+ ret = TCM_RESERVATION_CONFLICT;
+ goto err_info_free;
+ }
+
+ if (pr_info->rsv->type != type) {
+ /* scope already checked */
+ pr_err("SPC-3 PR: Attempted RESERVE from %s ",
+ existing_reg->it_nexus);
+ pr_err("trying to change TYPE, ");
+ pr_err("returning RESERVATION_CONFLICT\n");
+ ret = TCM_RESERVATION_CONFLICT;
+ goto err_info_free;
+ }
+
+ pr_debug("reserve matches existing reservation, ");
+ pr_debug("nothing to do\n");
+ goto done;
+ }
+
+ /* new reservation */
+ rc = tcm_rbd_pr_info_rsv_set(pr_info, key, nexus_buf, type);
+ if (rc < 0) {
+ pr_err("failed to set PR info reservation\n");
+ ret = TCM_OUT_OF_RESOURCES;
+ goto err_info_free;
+ }
+
+ rc = tcmu_pr_info_replace(udev, pr_xattr, pr_xattr_len,
+ pr_info);
+ if (rc == -ECANCELED) {
+ pr_warn("atomic PR info update failed due to parallel ");
+ pr_warn("change, expected(%d) %s. Retrying...\n",
+ pr_xattr_len, pr_xattr);
+ retries++;
+ if (retries <= TCMU_PR_REG_MAX_RETRIES) {
+ tcmu_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:
+ tcmu_pr_info_free(pr_info);
+ kfree(pr_xattr);
+ kfree(udev->pr_info.pr_info_buf);
+ return ret;
+}
+
+
static int tcmu_configure_device(struct se_device *dev)
{
struct tcmu_dev *udev = TCMU_DEV(dev);
@@ -3724,6 +3885,7 @@ static struct configfs_attribute *tcmu_action_attrs[] = {
static struct target_pr_ops tcmu_pr_ops = {
.pr_read_keys = tcmu_execute_pr_read_keys,
.pr_register = tcmu_execute_pr_register,
+ .pr_reserve = tcmu_execute_pr_reserve,
};
static struct target_backend_ops tcmu_ops = {
--
2.17.1
--
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