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target: Avoid dropping AllRegistrants reservation during unregister

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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: Ilias Tsitsimpis <i.tsitsimpis@gmail.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This commit is contained in:
Nicholas Bellinger 2014-12-15 11:50:26 -08:00
parent d16ca7c519
commit 6c3c9baa0d
1 changed files with 65 additions and 22 deletions
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87
drivers/target/target_core_pr.c
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@ -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
@ -1219,7 +1219,8 @@ static void __core_scsi3_free_registration(
pr_reg->pr_reg_deve->def_pr_registered = 0;
pr_reg->pr_reg_deve->pr_res_key = 0;
list_del(&pr_reg->pr_reg_list);
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(),
* so call core_scsi3_put_pr_reg() to decrement our reference.
@ -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.
*/
dev->dev_pr_res_holder = NULL;
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;
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),
(pr_reg->pr_reg_all_tg_pt) ? 1 : 0);
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_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;
@ -2922,8 +2965,8 @@ 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);
pr_res_holder->pr_reg_nacl,
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 @@ after_iport_check:
* 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