[Devel] [PATCH RHEL7 COMMIT] ms/target: Don't override EXTENDED_COPY xcopy_pt_cmd SCSI status code

[Konstantin Khorenko]

The commit is pushed to "branch-rh7-3.10.0-693.21.1.vz7.46.x-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh7-3.10.0-693.21.1.vz7.46.2
------>
commit f03b7c21a02e2426416abbcd85b1cdba93c0e1c0
Author: Dinesh Israni <ddi at datera.io>
Date:   Mon Apr 2 17:28:22 2018 +0300

    ms/target: Don't override EXTENDED_COPY xcopy_pt_cmd SCSI status code
    
    ML: 926317de33998c112c5510301868ea9aa34097e2
    
    This patch addresses a bug where a local EXTENDED_COPY WRITE or READ
    backend I/O request would always return SAM_STAT_CHECK_CONDITION,
    even if underlying xcopy_pt_cmd->se_cmd generated a different
    SCSI status code.
    
    ESX host environments expect to hit SAM_STAT_RESERVATION_CONFLICT
    for certain scenarios, and SAM_STAT_CHECK_CONDITION results in
    non-retriable status for these cases.
    
    Tested on v4.1.y with ESX v5.5u2+ with local IBLOCK backend copy.
    
    Reported-by: Nixon Vincent <nixon.vincent at calsoftinc.com>
    Tested-by: Nixon Vincent <nixon.vincent at calsoftinc.com>
    Cc: Nixon Vincent <nixon.vincent at calsoftinc.com>
    Tested-by: Dinesh Israni <ddi at datera.io>
    Signed-off-by: Dinesh Israni <ddi at datera.io>
    Cc: Dinesh Israni <ddi at datera.io>
    Cc: stable at vger.kernel.org # 3.14+
    Signed-off-by: Nicholas Bellinger <nab at linux-iscsi.org>
    Signed-off-by: Andrei Vagin <avagin at openvz.org>
---
 drivers/target/target_core_xcopy.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/target/target_core_xcopy.c b/drivers/target/target_core_xcopy.c
index 5cfb3829c2d6..9f5a002bfa04 100644
--- a/drivers/target/target_core_xcopy.c
+++ b/drivers/target/target_core_xcopy.c
@@ -707,6 +707,7 @@ static int target_xcopy_read_source(
 	rc = target_xcopy_setup_pt_cmd(xpt_cmd, xop, src_dev, &cdb[0],
 				remote_port, true);
 	if (rc < 0) {
+		ec_cmd->scsi_status = xpt_cmd->se_cmd.scsi_status;
 		transport_generic_free_cmd(se_cmd, 0);
 		return rc;
 	}
@@ -718,6 +719,7 @@ static int target_xcopy_read_source(
 
 	rc = target_xcopy_issue_pt_cmd(xpt_cmd);
 	if (rc < 0) {
+		ec_cmd->scsi_status = xpt_cmd->se_cmd.scsi_status;
 		transport_generic_free_cmd(se_cmd, 0);
 		return rc;
 	}
@@ -768,6 +770,7 @@ static int target_xcopy_write_destination(
 				remote_port, false);
 	if (rc < 0) {
 		struct se_cmd *src_cmd = &xop->src_pt_cmd->se_cmd;
+		ec_cmd->scsi_status = xpt_cmd->se_cmd.scsi_status;
 		/*
 		 * If the failure happened before the t_mem_list hand-off in
 		 * target_xcopy_setup_pt_cmd(), Reset memory + clear flag so that
@@ -783,6 +786,7 @@ static int target_xcopy_write_destination(
 
 	rc = target_xcopy_issue_pt_cmd(xpt_cmd);
 	if (rc < 0) {
+		ec_cmd->scsi_status = xpt_cmd->se_cmd.scsi_status;
 		se_cmd->se_cmd_flags &= ~SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC;
 		transport_generic_free_cmd(se_cmd, 0);
 		return rc;
@@ -869,10 +873,14 @@ static void target_xcopy_do_work(struct work_struct *work)
 out:
 	xcopy_pt_undepend_remotedev(xop);
 	kfree(xop);
-
-	pr_warn_ratelimited("target_xcopy_do_work: rc: %d, Setting X-COPY CHECK_CONDITION"
-			    " -> sending response\n", rc);
-	ec_cmd->scsi_status = SAM_STAT_CHECK_CONDITION;
+	/*
+	 * Don't override an error scsi status if it has already been set
+	 */
+	if (ec_cmd->scsi_status == SAM_STAT_GOOD) {
+		pr_warn_ratelimited("target_xcopy_do_work: rc: %d, Setting X-COPY"
+			" CHECK_CONDITION -> sending response\n", rc);
+		ec_cmd->scsi_status = SAM_STAT_CHECK_CONDITION;
+	}
 	target_complete_cmd(ec_cmd, SAM_STAT_CHECK_CONDITION);
 }