feat: implement volume_resize for truenas and truenas-multipath (#294)

Without an override the base Plugin.pm resize dies "can't resize this
image format", which blocked qm disk resize, the GUI and Terraform's
cloud-image provisioning. Grows the zvol via pool/dataset update
(1 MiB-aligned, integer volsize for SCALE's Pydantic). The WebSocket
transport gains the PUT -> pool.dataset.update mapping it needs.

Multipath additionally rescans the target's kernel sessions and runs
multipathd resize map when the device is active on this node, since
QMP block_resize on a host_device can't grow past the stale dm size.

Backport note: release/3.x is REST-only, so the WebSocket PUT ->
pool.dataset.update mapping from the original commit is dropped.

(cherry picked from commit 312cfa8)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

README.md

@@ -35,6 +35,7 @@ This plugin is a native `PVE::Storage::Custom` type — Proxmox discovers it aut
 - Bearer Token (API key) authentication — no username/password, no SSH keys
 - Per-VM iSCSI targets (`proxmox-vm-<vmid>`) — removing one disk never affects other VMs
 - Automatic rollback when operations fail (no dangling iSCSI extents)
+- Disk resize, including on a running VM. Cloud-init drives are supported (v4.0.2+).
 - Supports TrueNAS CORE 13.x and TrueNAS SCALE 24.10–25.10
 
 ---
@@ -607,6 +608,18 @@ If you see iSCSI extents in TrueNAS that are not associated with any target, the
 perl -MPVE::Storage -e 'PVE::Storage::vdisk_free(PVE::Storage::config(), "STORAGE:vm-101-disk-0")'
 ```
 
+### Resize, disk info or cloud-init operations fail on 4.0.1 and earlier
+
+These errors come from plugin gaps that are **fixed in v4.0.2** ([#294](https://github.com/TheGrandWazoo/freenas-proxmox/issues/294)):
+
+| Error | Cause | Workaround before upgrading |
+|---|---|---|
+| `can't resize this image format` (`qm disk resize`, GUI Resize, Terraform) | No `volume_resize` | Grow the zvol in TrueNAS (Datasets → zvol → Edit → Size). Then run `qm rescan --vmid <id>` so Proxmox picks up the new size. |
+| `volume_size_info on '<volid>' failed - no format` (content API, `bpg/proxmox` Terraform refresh) | `volume_size_info` returned only a size | None. Upgrade. |
+| `unable to parse TrueNAS volume name 'vm-<id>-cloudinit'` (`qm destroy`, cloud-init regenerate) | `parse_volname` rejected cloud-init names | Remove the cloud-init drive from the VM. Then delete `vm-<id>-cloudinit` in TrueNAS along with its iSCSI extent (and the `proxmox-vm-<id>` target if it's now empty). |
+
+Resizing only grows the disk. You still need to grow the partition and filesystem inside the guest yourself (cloud-init's `growpart` does this on next boot).
+
 ### `qm destroy` left multipath disks behind on TrueNAS
 
 **Symptom:** you destroy a VM whose disks are on a `truenas-multipath` storage. The task reports `OK`, but the zvols, extents and the `proxmox-vm-<id>` target are still on TrueNAS. The journal has no `free_image` line for those disks.

perl5/PVE/Storage/Custom/TrueNAS.pm

@@ -634,6 +634,33 @@ sub volume_size_info {
     return wantarray ? ($size, $format, $used, $parent) : $size;
 }
 
+# Grows the zvol. Without this override the base Plugin.pm version dies with
+# "can't resize this image format" (#294). For a running VM, qemu-server then
+# issues QMP block_resize, which makes libiscsi re-read the LUN capacity —
+# TrueNAS resizes the LUN with the zvol, so no iSCSI-side call is needed here.
+sub volume_resize {
+    my ($class, $scfg, $storeid, $volname, $size, $running, $snapname) = @_;
+    _resolve_token($storeid, $scfg);
+
+    die "resizing a snapshot is not supported\n" if $snapname;
+    $class->parse_volname($volname);    # dies on names we don't own
+
+    # Align to 1 MiB like ZFSPoolPlugin, so volsize is always a multiple of
+    # the zvol's volblocksize (TrueNAS rejects anything else).
+    my $new_kb = int($size / 1024);
+    $new_kb += (1024 - $new_kb % 1024) % 1024;
+
+    my $zvol = _zvol_prefix($scfg) . "/$volname";
+    my $enc  = uri_escape($zvol, "^A-Za-z0-9\\-_.~");
+
+    _log('info', "volume_resize: $zvol to ${new_kb}K");
+
+    # int() for a fresh IV: SCALE 25.10 Pydantic rejects string-typed integers.
+    _api($scfg, 'PUT', "/pool/dataset/id/$enc", { volsize => int($new_kb * 1024) });
+
+    return $new_kb;
+}
+
 sub path {
     my ($class, $scfg, $volname, $storeid, $snapname) = @_;
     _resolve_token($storeid, $scfg);

perl5/PVE/Storage/Custom/TrueNASMultipath.pm

@@ -116,6 +116,36 @@ sub path {
     return ("/dev/mapper/$wwid", $ds_vmid, $vtype);
 }
 
+# ── volume_resize — grow zvol, then refresh kernel view of the LUN ────────────
+
+# The base class grows the zvol. If the volume is active on this node, the
+# kernel iSCSI sessions and the dm map still report the old size, and
+# qemu-server's QMP block_resize on the host_device would fail. Rescan every
+# session to the target, then have multipathd resize the map.
+sub volume_resize {
+    my ($class, $scfg, $storeid, $volname, $size, $running, $snapname) = @_;
+
+    my $new_kb = $class->SUPER::volume_resize($scfg, $storeid, $volname, $size, $running, $snapname);
+
+    my $ext  = PVE::Storage::Custom::TrueNAS::_find_extent($scfg, $volname);
+    my $wwid = $ext ? _naa_to_wwid($ext->{naa}) : undef;
+    return $new_kb unless $wwid && -b "/dev/mapper/$wwid" && defined $ext->{target_id};
+
+    my $t   = PVE::Storage::Custom::TrueNAS::_api($scfg, 'GET',
+                  "/iscsi/target/id/$ext->{target_id}") // {};
+    my $iqn = PVE::Storage::Custom::TrueNAS::_basename($scfg) . ":$t->{name}";
+
+    my ($rc, $out) = _iscsiadm('-m', 'node', '-T', $iqn, '-R');
+    die "iscsiadm rescan of $iqn failed (rc=$rc): $out\n" if $rc;
+
+    my $multipathd = -x '/usr/sbin/multipathd' ? '/usr/sbin/multipathd' : '/sbin/multipathd';
+    system($multipathd, 'resize', 'map', $wwid) == 0
+        or die "multipathd resize map $wwid failed (rc=" . ($? >> 8) . ")\n";
+
+    PVE::Storage::Custom::TrueNAS::_log('info', "multipath resize: $wwid rescanned and resized");
+    return $new_kb;
+}
+
 # ── qemu_blockdev_options — delegate to Plugin.pm (host_device for /dev/mapper) ─
 
 # TrueNAS.pm overrides qemu_blockdev_options to return an iscsi:// blockdev —

t/lib/MockTrueNAS.pm

@@ -66,7 +66,7 @@ sub _route {
         }
     }
 
-    return if $method eq 'DELETE' || $method eq 'POST';
+    return if $method eq 'DELETE' || $method eq 'POST' || $method eq 'PUT';
 
     die "MockTrueNAS: unhandled $method $path\n";
 }

t/resize.t

@@ -0,0 +1,77 @@
+#!/usr/bin/perl
+# volume_resize (#294): grows the zvol via PUT /pool/dataset/id/<zvol> with a
+# 1 MiB-aligned integer volsize, returns the new size in KiB (ZFSPoolPlugin
+# convention), and refuses snapshots / foreign volume names.
+
+use strict;
+use warnings;
+
+use FindBin;
+use lib "$FindBin::Bin/lib", "$FindBin::Bin/../perl5";
+
+use Test::More;
+use JSON ();
+
+use MockTrueNAS;
+use PVE::Storage::Custom::TrueNAS;
+use PVE::Storage::Custom::TrueNASMultipath;
+
+my $TN = 'PVE::Storage::Custom::TrueNAS';
+my $MP = 'PVE::Storage::Custom::TrueNASMultipath';
+my $GiB = 1024 ** 3;
+
+sub puts { my ($api) = @_; return grep { $_->[0] eq 'PUT' } @{ $api->calls }; }
+
+subtest 'grows zvol to the requested size' => sub {
+    my $api = MockTrueNAS->install();
+    my $kb  = $TN->volume_resize(MockTrueNAS::scfg(), 'store', 'vm-100-disk-0', 40 * $GiB, 0);
+    is($kb, 40 * 1024 * 1024, 'returns new size in KiB');
+
+    my @p = puts($api);
+    is(scalar @p, 1, 'one PUT');
+    is($p[0][1], '/pool/dataset/id/tank%2Fvm%2Fvm-100-disk-0', 'targets the zvol');
+    is($p[0][2]{volsize}, 40 * $GiB, 'volsize in bytes');
+    is(JSON->new->canonical->encode($p[0][2]), '{"volsize":' . (40 * $GiB) . '}',
+       'volsize encodes as a JSON integer, not a string');
+};
+
+subtest 'rounds up to a 1 MiB boundary' => sub {
+    my $api = MockTrueNAS->install();
+    my $kb  = $TN->volume_resize(MockTrueNAS::scfg(), 'store', 'vm-100-disk-0', 10 * $GiB + 1536, 0);
+    is($kb, 10 * 1024 * 1024 + 1024, 'next whole MiB');
+    is((puts($api))[0][2]{volsize} % (1024 * 1024), 0, 'volsize is MiB-aligned');
+};
+
+subtest 'cloud-init drive can be resized' => sub {
+    my $api = MockTrueNAS->install();
+    $TN->volume_resize(MockTrueNAS::scfg(), 'store', 'vm-100-cloudinit', 8 * 1024 * 1024, 0);
+    is(scalar(puts($api)), 1, 'PUT issued');
+};
+
+subtest 'snapshot resize refused' => sub {
+    my $api = MockTrueNAS->install();
+    eval { $TN->volume_resize(MockTrueNAS::scfg(), 'store', 'vm-100-disk-0', $GiB, 0, 'snap1') };
+    like($@, qr/snapshot/, 'dies');
+    is(scalar(puts($api)), 0, 'no API write');
+};
+
+subtest 'foreign volume name refused before any API write' => sub {
+    my $api = MockTrueNAS->install();
+    eval { $TN->volume_resize(MockTrueNAS::scfg(), 'store', '../other-zvol', $GiB, 0) };
+    like($@, qr/unable to parse/, 'dies');
+    is(scalar(puts($api)), 0, 'no API write');
+};
+
+subtest 'multipath: inactive volume only grows the zvol' => sub {
+    my $api = MockTrueNAS->install(
+        extents       => [ { id => 3, name => 'vm-100-disk-0', naa => '0x6589cfc000000abc' } ],
+        targetextents => [ { id => 5, extent => 3, target => 7, lunid => 0 } ],
+        targets       => [ { id => 7, name => 'proxmox-vm-100' } ],
+    );
+    # /dev/mapper/36589cfc000000abc does not exist here, so no rescan is attempted.
+    my $kb = $MP->volume_resize(MockTrueNAS::scfg(), 'store', 'vm-100-disk-0', 20 * $GiB, 0);
+    is($kb, 20 * 1024 * 1024, 'returns new size in KiB');
+    is(scalar(puts($api)), 1, 'zvol PUT issued');
+};
+
+done_testing();