[ 40/53] target: Fix SPC-2 RELEASE bug for multi-session iSCSI client setups

3.2.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Bernhard Kohl <redacted>

commit edc318d9fea6854df752ec8c645b960b0d5a1d23 upstream.

This patch addresses a bug in a special case for target core SPC-2 RELEASE
logic where the same physical client (eg: iSCSI InitiatorName) with
differing iSCSI session identifiers (ISID) is allowed to incorrectly release
the same client's SPC-2 reservation from the non reservation holding path.

Note this bug is specific to iscsi-target w/ SPC-2 reservations, and
with the default enforce_pr_isids=1 device attr setting in target-core
controls if a InitiatorName + different ISID reservations are handled
the same as a single iSCSI client entity.

Signed-off-by: Bernhard Kohl <redacted>
Signed-off-by: Nicholas Bellinger <redacted>
Signed-off-by: Ben Hutchings <redacted>
---
 drivers/target/target_core_pr.c |    3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/target/target_core_pr.c b/drivers/target/target_core_pr.c
index 86f0c3b..c3148b1 100644
--- a/drivers/target/target_core_pr.c
+++ b/drivers/target/target_core_pr.c

@@ -220,6 +220,9 @@ int target_scsi2_reservation_release(struct se_task *task)
 	if (dev->dev_reserved_node_acl != sess->se_node_acl)
 		goto out_unlock;
 
+	if (dev->dev_res_bin_isid != sess->sess_bin_isid)
+		goto out_unlock;
+
 	dev->dev_reserved_node_acl = NULL;
 	dev->dev_flags &= ~DF_SPC2_RESERVATIONS;
 	if (dev->dev_flags & DF_SPC2_RESERVATIONS_WITH_ISID) {

-- 
1.7.10