target: Fix compatible reservation handling (CRH=1) with legacy RESERVE/RELEASE

This patch addresses a bug with target_check_scsi2_reservation_conflict()
return checking in target_scsi2_reservation_[reserve,release]() that was
preventing CRH=1 operation from silently succeeding in the two special
cases defined by SPC-3, and not failing with reservation conflict status
when dealing with legacy RESERVE/RELEASE + active SPC-3 PR logic.

Also explictly set cmd->scsi_status = SAM_STAT_RESERVATION_CONFLICT during
the early non reservation holder failure from pr_ops->t10_seq_non_holder()
check in transport_generic_cmd_sequencer() for fabrics that already expect
it to be set.

This bug was originally introduced in mainline commit:

commit eacac00ce5bfde8086cd0615fb53c986f7f970fe
Author: Christoph Hellwig <hch@infradead.org>
Date:   Thu Nov 3 17:50:40 2011 -0400

    target: split core_scsi2_emulate_crh

Reported-by: Martin Svec <martin.svec@zoner.cz>
Cc: Martin Svec <martin.svec@zoner.cz>
Cc: Christoph Hellwig <hch@lst.de>
Cc: stable@vger.kernel.org
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

1 files changed, 22 insertions, 12 deletions

diff --git a/drivers/target/target_core_pr.c b/drivers/target/target_core_pr.c
index b7c779389eea..63e703bb6ac9 100644
--- a/drivers/target/target_core_pr.c
+++ b/drivers/target/target_core_pr.c
@@ -117,7 +117,7 @@ static struct t10_pr_registration *core_scsi3_locate_pr_reg(struct se_device *,
                                         struct se_node_acl *, struct se_session *);
 static void core_scsi3_put_pr_reg(struct t10_pr_registration *);
 
-static int target_check_scsi2_reservation_conflict(struct se_cmd *cmd, int *ret)
+static int target_check_scsi2_reservation_conflict(struct se_cmd *cmd)
 {
         struct se_session *se_sess = cmd->se_sess;
         struct se_subsystem_dev *su_dev = cmd->se_dev->se_sub_dev;
@@ -127,7 +127,7 @@ static int target_check_scsi2_reservation_conflict(struct se_cmd *cmd, int *ret)
         int conflict = 0;
 
         if (!crh)
-                return false;
+                return -EINVAL;
 
         pr_reg = core_scsi3_locate_pr_reg(cmd->se_dev, se_sess->se_node_acl,
                         se_sess);
@@ -155,16 +155,14 @@ static int target_check_scsi2_reservation_conflict(struct se_cmd *cmd, int *ret)
                  */
                 if (pr_reg->pr_res_holder) {
                         core_scsi3_put_pr_reg(pr_reg);
-                        *ret = 0;
-                        return false;
+                        return 1;
                 }
                 if ((pr_reg->pr_res_type == PR_TYPE_WRITE_EXCLUSIVE_REGONLY) ||
                     (pr_reg->pr_res_type == PR_TYPE_EXCLUSIVE_ACCESS_REGONLY) ||
                     (pr_reg->pr_res_type == PR_TYPE_WRITE_EXCLUSIVE_ALLREG) ||
                     (pr_reg->pr_res_type == PR_TYPE_EXCLUSIVE_ACCESS_ALLREG)) {
                         core_scsi3_put_pr_reg(pr_reg);
-                        *ret = 0;
-                        return true;
+                        return 1;
                 }
                 core_scsi3_put_pr_reg(pr_reg);
                 conflict = 1;
@@ -189,10 +187,10 @@ static int target_check_scsi2_reservation_conflict(struct se_cmd *cmd, int *ret)
                         " while active SPC-3 registrations exist,"
                         " returning RESERVATION_CONFLICT\n");
                 cmd->scsi_sense_reason = TCM_RESERVATION_CONFLICT;
-                return true;
+                return -EBUSY;
         }
 
-        return false;
+        return 0;
 }
 
 int target_scsi2_reservation_release(struct se_task *task)
@@ -201,12 +199,18 @@ int target_scsi2_reservation_release(struct se_task *task)
         struct se_device *dev = cmd->se_dev;
         struct se_session *sess = cmd->se_sess;
         struct se_portal_group *tpg = sess->se_tpg;
-        int ret = 0;
+        int ret = 0, rc;
 
         if (!sess || !tpg)
                 goto out;
-        if (target_check_scsi2_reservation_conflict(cmd, &ret))
+        rc = target_check_scsi2_reservation_conflict(cmd);
+        if (rc == 1)
+                goto out;
+        else if (rc < 0) {
+                cmd->scsi_sense_reason = TCM_RESERVATION_CONFLICT;
+                ret = -EINVAL;
                 goto out;
+        }
 
         ret = 0;
         spin_lock(&dev->dev_reservation_lock);
@@ -243,7 +247,7 @@ int target_scsi2_reservation_reserve(struct se_task *task)
         struct se_device *dev = cmd->se_dev;
         struct se_session *sess = cmd->se_sess;
         struct se_portal_group *tpg = sess->se_tpg;
-        int ret = 0;
+        int ret = 0, rc;
 
         if ((cmd->t_task_cdb[1] & 0x01) &&
             (cmd->t_task_cdb[1] & 0x02)) {
@@ -259,8 +263,14 @@ int target_scsi2_reservation_reserve(struct se_task *task)
          */
         if (!sess || !tpg)
                 goto out;
-        if (target_check_scsi2_reservation_conflict(cmd, &ret))
+        rc = target_check_scsi2_reservation_conflict(cmd);
+        if (rc == 1)
                 goto out;
+        else if (rc < 0) {
+                cmd->scsi_sense_reason = TCM_RESERVATION_CONFLICT;
+                ret = -EINVAL;
+                goto out;
+        }
 
         ret = 0;
         spin_lock(&dev->dev_reservation_lock);