!34 fence_scsi: fix registration handling if ISID conflict

From: @xiangbudaomz 
Reviewed-by: @bixiaoyan1 
Signed-off-by: @bixiaoyan1

fence-agents.spec

@@ -6,12 +6,13 @@
 Name: fence-agents
 Summary: Set of unified programs capable of host isolation ("fencing")
 Version: 4.12.1
-Release: 4
+Release: 5
 License: GPLv2+ and LGPLv2+
 Group: System Environment/Base
 URL: https://github.com/ClusterLabs/fence-agents
 Source0: https://github.com/ClusterLabs/fence-agents/archive//v%{version}/%{name}-%{version}.tar.gz
 Patch0: fence_ipmilan-fix-typo-in-description.patch
+Patch1: fence_scsi-fix-registration-handling-if-ISID-conflic.patch
 
 # skipped: pve, raritan, rcd-serial, virsh
 %global allfenceagents %(cat <<EOF
@@ -1127,6 +1128,9 @@ are located on corosync cluster nodes.
 %{_libdir}/fence-virt/cpg.so
 
 %changelog
+* Fri Apr 26 2024 zouzhimin <zouzhimin@kylinos.cn> - 4.12.1-5
+- fence_scsi: fix registration handling if ISID conflict
+
 * Thu Apr 18 2024 zouzhimin <zouzhimin@kylinos.cn> - 4.12.1-4
 - fence_ipmilan: fix typo in description
 

fence_scsi-fix-registration-handling-if-ISID-conflic.patch

@@ -0,0 +1,71 @@
+From 9d0d0d013c7edae43a4ebc5f46bf2e7a4f127654 Mon Sep 17 00:00:00 2001
+From: "sreejit.mohanan" <sreejit.mohanan@nutanix.com>
+Date: Fri, 17 Feb 2023 18:04:03 -0800
+Subject: [PATCH] fence_scsi: fix registration handling if ISID conflicts ISID
+ (Initiator Session ID) belonging to I_T Nexus changes for RHEL based on the
+ session ID. This means that the connection to the device can be set up with
+ different ISID on reconnects.
+
+fence_scsi treats same key as a tip to ignore issuing registration
+to the device but if the device was registered using a different
+ISID, the key would be the same but the I_T Nexus (new ISID) would
+not have access to the device.
+
+Fixing this by preempting the old key and replacing with the current
+one.
+---
+ agents/scsi/fence_scsi.py | 35 ++++++++++++++++++++++++++++++++---
+ 1 file changed, 32 insertions(+), 3 deletions(-)
+
+diff --git a/agents/scsi/fence_scsi.py b/agents/scsi/fence_scsi.py
+index f9e6823b..85e4f29e 100644
+--- a/agents/scsi/fence_scsi.py
++++ b/agents/scsi/fence_scsi.py
+@@ -137,12 +137,41 @@ def register_dev(options, dev):
+ 		for slave in get_mpath_slaves(dev):
+ 			register_dev(options, slave)
+ 		return True
+-	if get_reservation_key(options, dev, False) == options["--key"]:
+-		return True
++
++	# Check if any registration exists for the key already. We track this in
++	# order to decide whether the existing registration needs to be cleared.
++	# This is needed since the previous registration could be for a
++	# different I_T nexus (different ISID).
++	registration_key_exists = False
++	if options["--key"] in get_registration_keys(options, dev):
++		registration_key_exists = True
++	if not register_helper(options, options["--key"], dev):
++		return False
++
++	if registration_key_exists:
++		# If key matches, make sure it matches with the connection that
++		# exists right now. To do this, we can issue a preempt with same key
++		# which should replace the old invalid entries from the target.
++		if not preempt(options, options["--key"], dev):
++			return False
++
++		# If there was no reservation, we need to issue another registration
++		# since the previous preempt would clear registration made above.
++		if get_reservation_key(options, dev, False) != options["--key"]:
++			return register_helper(options, options["--key"], dev)
++	return True
++
++# cancel registration without aborting tasks
++def preempt(options, host, dev):
++	reset_dev(options,dev)
++	cmd = options["--sg_persist-path"] + " -n -o -P -T 5 -K " + host + " -S " + options["--key"] + " -d " + dev
++	return not bool(run_cmd(options, cmd)["rc"])
++
++# helper function to send the register command
++def register_helper(options, host, dev):
+ 	reset_dev(options, dev)
+ 	cmd = options["--sg_persist-path"] + " -n -o -I -S " + options["--key"] + " -d " + dev
+ 	cmd += " -Z" if "--aptpl" in options else ""
+-	#cmd return code != 0 but registration can be successful
+ 	return not bool(run_cmd(options, cmd)["rc"])
+ 
+ 
+-- 
+2.25.1
+