From f0150c225e93c123a97837e308a85296cac8e7cc Mon Sep 17 00:00:00 2001
From: Kevin Adams <kevin.adams@ksatechnologies.com>
Date: Mon, 8 Jun 2026 12:48:39 -0400
Subject: [PATCH] fix: delegate qemu_blockdev_options to Plugin.pm for
 host_device path
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TrueNAS.pm::qemu_blockdev_options returns an iscsi:// blockdev — wrong for
multipath where path() returns /dev/mapper/<wwid>. Simply removing the override
caused the parent's iscsi driver to be inherited instead.

Fix: explicitly call PVE::Storage::Plugin::qemu_blockdev_options (the
grandparent). It calls path(), sees /dev/mapper/<wwid> starts with '/',
stats it as S_ISBLK, and returns { driver => 'host_device', filename => ... }.
QEMU receives: "driver":"host_device","filename":"/dev/mapper/<wwid>"

Tested: VM 103 started with multipath disk (vm-103-disk-0 on TrueNAS-Scale01-MP).
QEMU confirmed using host_device driver on /dev/mapper/36589cfc000000ad...

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
---
 perl5/PVE/Storage/Custom/TrueNASMultipath.pm | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/perl5/PVE/Storage/Custom/TrueNASMultipath.pm b/perl5/PVE/Storage/Custom/TrueNASMultipath.pm
index 6259593..d7da0b9 100644
--- a/perl5/PVE/Storage/Custom/TrueNASMultipath.pm
+++ b/perl5/PVE/Storage/Custom/TrueNASMultipath.pm
@@ -104,11 +104,19 @@ sub path {
     return ("/dev/mapper/$wwid", $ext->{lun_id}, $storeid);
 }
 
-# ── qemu_blockdev_options — not used (path returns a block device) ────────────
+# ── qemu_blockdev_options — delegate to Plugin.pm (host_device for /dev/mapper) ─
 
-# The base class qemu_blockdev_options builds an iscsi:// blockdev.
-# For multipath we return undef so PVE uses path() instead.
-sub qemu_blockdev_options { return; }
+# TrueNAS.pm overrides qemu_blockdev_options to return an iscsi:// blockdev —
+# that's wrong for multipath where path() returns /dev/mapper/<wwid>.
+# We skip the parent and call the grandparent (PVE::Storage::Plugin) directly.
+# Plugin.pm calls path(), sees /dev/mapper/<wwid> starts with '/', stats it as a
+# block device (S_ISBLK), and returns { driver => 'host_device', filename => ... }.
+# QEMU then accesses the dm-multipath block device directly.
+sub qemu_blockdev_options {
+    my ($class, $scfg, $storeid, $volname, $machine_version, $options) = @_;
+    return PVE::Storage::Plugin::qemu_blockdev_options(
+        $class, $scfg, $storeid, $volname, $machine_version, $options // {});
+}
 
 # ── activate_volume — login via all portals, wait for mapper device ───────────