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Commit 6c3c9baa authored by Nicholas Bellinger's avatar Nicholas Bellinger
Browse files

target: Avoid dropping AllRegistrants reservation during unregister 



This patch fixes an issue with AllRegistrants reservations where
an unregister operation by the I_T nexus reservation holder would
incorrectly drop the reservation, instead of waiting until the
last active I_T nexus is unregistered as per SPC-4.

This includes updating __core_scsi3_complete_pro_release() to reset
dev->dev_pr_res_holder with another pr_reg for this special case,
as well as a new 'unreg' parameter to determine when the release
is occuring from an implicit unregister, vs. explicit RELEASE.

It also adds special handling in core_scsi3_free_pr_reg_from_nacl()
to release the left-over pr_res_holder, now that pr_reg is deleted
from pr_reg_list within __core_scsi3_complete_pro_release().

Reported-by: default avatarIlias Tsitsimpis <i.tsitsimpis@gmail.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
parent d16ca7c5

drivers/target/target_core_pr.c

+65 −22
Original line number Diff line number Diff line
@@ -76,7 +76,7 @@ enum preempt_type { 
};



static void __core_scsi3_complete_pro_release(struct se_device *, struct se_node_acl *,

			struct t10_pr_registration *, int);

					      struct t10_pr_registration *, int, int);



static sense_reason_t

target_scsi2_reservation_check(struct se_cmd *cmd)
@@ -1177,7 +1177,7 @@ static int core_scsi3_check_implicit_release( 
		 *    service action with the SERVICE ACTION RESERVATION KEY

		 *    field set to zero (see 5.7.11.3).

		 */

		__core_scsi3_complete_pro_release(dev, nacl, pr_reg, 0);

		__core_scsi3_complete_pro_release(dev, nacl, pr_reg, 0, 1);

		ret = 1;

		/*

		 * For 'All Registrants' reservation types, all existing
@@ -1219,6 +1219,7 @@ static void __core_scsi3_free_registration( 


	pr_reg->pr_reg_deve->def_pr_registered = 0;

	pr_reg->pr_reg_deve->pr_res_key = 0;

	if (!list_empty(&pr_reg->pr_reg_list))

		list_del(&pr_reg->pr_reg_list);

	/*

	 * Caller accessing *pr_reg using core_scsi3_locate_pr_reg(),
@@ -1271,6 +1272,7 @@ void core_scsi3_free_pr_reg_from_nacl( 
{

	struct t10_reservation *pr_tmpl = &dev->t10_pr;

	struct t10_pr_registration *pr_reg, *pr_reg_tmp, *pr_res_holder;

	bool free_reg = false;

	/*

	 * If the passed se_node_acl matches the reservation holder,

	 * release the reservation.
@@ -1278,13 +1280,18 @@ void core_scsi3_free_pr_reg_from_nacl( 
	spin_lock(&dev->dev_reservation_lock);

	pr_res_holder = dev->dev_pr_res_holder;

	if ((pr_res_holder != NULL) &&

	    (pr_res_holder->pr_reg_nacl == nacl))

		__core_scsi3_complete_pro_release(dev, nacl, pr_res_holder, 0);

	    (pr_res_holder->pr_reg_nacl == nacl)) {

		__core_scsi3_complete_pro_release(dev, nacl, pr_res_holder, 0, 1);

		free_reg = true;

	}

	spin_unlock(&dev->dev_reservation_lock);

	/*

	 * Release any registration associated with the struct se_node_acl.

	 */

	spin_lock(&pr_tmpl->registration_lock);

	if (pr_res_holder && free_reg)

		__core_scsi3_free_registration(dev, pr_res_holder, NULL, 0);



	list_for_each_entry_safe(pr_reg, pr_reg_tmp,

			&pr_tmpl->registration_list, pr_reg_list) {
@@ -1307,7 +1314,7 @@ void core_scsi3_free_all_registrations( 
	if (pr_res_holder != NULL) {

		struct se_node_acl *pr_res_nacl = pr_res_holder->pr_reg_nacl;

		__core_scsi3_complete_pro_release(dev, pr_res_nacl,

				pr_res_holder, 0);

						  pr_res_holder, 0, 0);

	}

	spin_unlock(&dev->dev_reservation_lock);
@@ -2103,13 +2110,13 @@ core_scsi3_emulate_pro_register(struct se_cmd *cmd, u64 res_key, u64 sa_res_key, 
		/*

		 * sa_res_key=0 Unregister Reservation Key for registered I_T Nexus.

		 */

		pr_holder = core_scsi3_check_implicit_release(

				cmd->se_dev, pr_reg);

		type = pr_reg->pr_res_type;

		pr_holder = core_scsi3_check_implicit_release(cmd->se_dev,

							      pr_reg);

		if (pr_holder < 0) {

			ret = TCM_RESERVATION_CONFLICT;

			goto out;

		}

		type = pr_reg->pr_res_type;



		spin_lock(&pr_tmpl->registration_lock);

		/*
@@ -2383,23 +2390,59 @@ static void __core_scsi3_complete_pro_release( 
	struct se_device *dev,

	struct se_node_acl *se_nacl,

	struct t10_pr_registration *pr_reg,

	int explicit)

	int explicit,

	int unreg)

{

	struct target_core_fabric_ops *tfo = se_nacl->se_tpg->se_tpg_tfo;

	char i_buf[PR_REG_ISID_ID_LEN];

	int pr_res_type = 0, pr_res_scope = 0;



	memset(i_buf, 0, PR_REG_ISID_ID_LEN);

	core_pr_dump_initiator_port(pr_reg, i_buf, PR_REG_ISID_ID_LEN);

	/*

	 * Go ahead and release the current PR reservation holder.

	 * If an All Registrants reservation is currently active and

	 * a unregister operation is requested, replace the current

	 * dev_pr_res_holder with another active registration.

	 */

	if (dev->dev_pr_res_holder) {

		pr_res_type = dev->dev_pr_res_holder->pr_res_type;

		pr_res_scope = dev->dev_pr_res_holder->pr_res_scope;

		dev->dev_pr_res_holder->pr_res_type = 0;

		dev->dev_pr_res_holder->pr_res_scope = 0;

		dev->dev_pr_res_holder->pr_res_holder = 0;

		dev->dev_pr_res_holder = NULL;

	}

	if (!unreg)

		goto out;



	spin_lock(&dev->t10_pr.registration_lock);

	list_del_init(&pr_reg->pr_reg_list);

	/*

	 * 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.

	 */

	if (!list_empty(&dev->t10_pr.registration_list) &&

	    ((pr_res_type == PR_TYPE_WRITE_EXCLUSIVE_ALLREG) ||

	     (pr_res_type == PR_TYPE_EXCLUSIVE_ACCESS_ALLREG))) {

		dev->dev_pr_res_holder =

			list_entry(dev->t10_pr.registration_list.next,

				   struct t10_pr_registration, pr_reg_list);

		dev->dev_pr_res_holder->pr_res_type = pr_res_type;

		dev->dev_pr_res_holder->pr_res_scope = pr_res_scope;

		dev->dev_pr_res_holder->pr_res_holder = 1;

	}

	spin_unlock(&dev->t10_pr.registration_lock);

out:

	if (!dev->dev_pr_res_holder) {

		pr_debug("SPC-3 PR [%s] Service Action: %s RELEASE cleared"

			" reservation holder TYPE: %s ALL_TG_PT: %d\n",

		tfo->get_fabric_name(), (explicit) ? "explicit" : "implicit",

		core_scsi3_pr_dump_type(pr_reg->pr_res_type),

			tfo->get_fabric_name(), (explicit) ? "explicit" :

			"implicit", core_scsi3_pr_dump_type(pr_res_type),

			(pr_reg->pr_reg_all_tg_pt) ? 1 : 0);

	}

	pr_debug("SPC-3 PR [%s] RELEASE Node: %s%s\n",

		tfo->get_fabric_name(), se_nacl->initiatorname,

		i_buf);
@@ -2530,7 +2573,7 @@ core_scsi3_emulate_pro_release(struct se_cmd *cmd, int type, int scope, 
	 *    server shall not establish a unit attention condition.

	 */

	__core_scsi3_complete_pro_release(dev, se_sess->se_node_acl,

			pr_reg, 1);

					  pr_reg, 1, 0);



	spin_unlock(&dev->dev_reservation_lock);
@@ -2618,7 +2661,7 @@ core_scsi3_emulate_pro_clear(struct se_cmd *cmd, u64 res_key) 
	if (pr_res_holder) {

		struct se_node_acl *pr_res_nacl = pr_res_holder->pr_reg_nacl;

		__core_scsi3_complete_pro_release(dev, pr_res_nacl,

			pr_res_holder, 0);

						  pr_res_holder, 0, 0);

	}

	spin_unlock(&dev->dev_reservation_lock);

	/*
@@ -2677,7 +2720,7 @@ static void __core_scsi3_complete_pro_preempt( 
	 */

	if (dev->dev_pr_res_holder)

		__core_scsi3_complete_pro_release(dev, nacl,

				dev->dev_pr_res_holder, 0);

						  dev->dev_pr_res_holder, 0, 0);



	dev->dev_pr_res_holder = pr_reg;

	pr_reg->pr_res_holder = 1;
@@ -2923,7 +2966,7 @@ core_scsi3_pro_preempt(struct se_cmd *cmd, int type, int scope, u64 res_key, 
	if (pr_reg_n != pr_res_holder)

		__core_scsi3_complete_pro_release(dev,

						  pr_res_holder->pr_reg_nacl,

				dev->dev_pr_res_holder, 0);

						  dev->dev_pr_res_holder, 0, 0);

	/*

	 * b) Remove the registrations for all I_T nexuses identified

	 *    by the SERVICE ACTION RESERVATION KEY field, except the
@@ -3386,7 +3429,7 @@ core_scsi3_emulate_pro_register_and_move(struct se_cmd *cmd, u64 res_key, 
	 *    holder (i.e., the I_T nexus on which the

	 */

	__core_scsi3_complete_pro_release(dev, pr_res_nacl,

			dev->dev_pr_res_holder, 0);

					  dev->dev_pr_res_holder, 0, 0);

	/*

	 * g) Move the persistent reservation to the specified I_T nexus using

	 *    the same scope and type as the persistent reservation released in