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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 f9e6823b2..85e4f29e6 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"])
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