From: Fiona Ebner <f.ebner@proxmox.com>
To: pve-devel@lists.proxmox.com
Subject: [pve-devel] [PATCH storage v4 05/49] plugin: add method to get qemu blockdevice options for volume
Date: Tue, 1 Jul 2025 17:40:25 +0200 [thread overview]
Message-ID: <20250701154117.434512-6-f.ebner@proxmox.com> (raw)
In-Reply-To: <20250701154117.434512-1-f.ebner@proxmox.com>
This is in preparation to switch qemu-server from using '-drive' to
the modern '-blockdev' in the QEMU commandline options as well as for
the qemu-storage-daemon, which only supports '-blockdev'. The plugins
know best what driver and options are needed to access an image, so
a dedicated plugin method returning the necessary parameters for
'-blockdev' is the most straight-forward.
There intentionally is only handling for absolute paths in the default
plugin implementation. Any plugin requiring more needs to implement
the method itself. With PVE 9 being a major release and most popular
plugins not using special protocols like 'rbd://', this seems
acceptable.
For NBD, etc. qemu-server should construct the blockdev object.
Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
---
Changes in v4:
* More compact POD.
src/PVE/Storage.pm | 17 ++++++++++++
src/PVE/Storage/Plugin.pm | 56 +++++++++++++++++++++++++++++++++++++++
2 files changed, 73 insertions(+)
diff --git a/src/PVE/Storage.pm b/src/PVE/Storage.pm
index 69eb435..ec8b753 100755
--- a/src/PVE/Storage.pm
+++ b/src/PVE/Storage.pm
@@ -719,6 +719,23 @@ sub abs_filesystem_path {
return $path;
}
+# see the documentation for the plugin method
+sub qemu_blockdev_options {
+ my ($cfg, $volid) = @_;
+
+ my ($storeid, $volname) = parse_volume_id($volid);
+
+ my $scfg = storage_config($cfg, $storeid);
+
+ my $plugin = PVE::Storage::Plugin->lookup($scfg->{type});
+
+ my ($vtype) = $plugin->parse_volname($volname);
+ die "cannot use volume of type '$vtype' as a QEMU blockdevice\n"
+ if $vtype ne 'images' && $vtype ne 'iso' && $vtype ne 'import';
+
+ return $plugin->qemu_blockdev_options($scfg, $storeid, $volname);
+}
+
# used as last resort to adapt volnames when migrating
my $volname_for_storage = sub {
my ($cfg, $storeid, $name, $vmid, $format) = @_;
diff --git a/src/PVE/Storage/Plugin.pm b/src/PVE/Storage/Plugin.pm
index 53b9848..680bb6b 100644
--- a/src/PVE/Storage/Plugin.pm
+++ b/src/PVE/Storage/Plugin.pm
@@ -1961,6 +1961,62 @@ sub rename_volume {
return "${storeid}:${base}${target_vmid}/${target_volname}";
}
+=pod
+
+=head3 qemu_blockdev_options
+
+ $blockdev = $plugin->qemu_blockdev_options($scfg, $storeid, $volname)
+
+Returns a hash reference with the basic options needed to open the volume via QEMU's C<-blockdev>
+API. This at least requires a C<< $blockdev->{driver} >> and a reference to the image, e.g.
+C<< $blockdev->{filename} >> for the C<file> driver. For files, the C<file> driver can be used. For
+host block devices, the C<host_device> driver can be used. The plugin must not set options like
+C<cache> or C<aio>. Those are managed by qemu-server and will be overwritten. For other available
+drivers and the exact specification of the options, see
+L<https://qemu.readthedocs.io/en/master/interop/qemu-qmp-ref.html#object-QMP-block-core.BlockdevOptions>
+
+While Perl does not have explicit types, the result will need to be converted to JSON later and
+match the QMP specification (see link above), so implicit types are important. In the return value,
+use C<JSON::true> and C<JSON::false> for booleans, C<"$value"> for strings, and C<int($value)> for
+integers.
+
+The volume is activated before the function is called.
+
+Arguments:
+
+=over
+
+=item C<$scfg>: The hash reference with the storage configuration.
+
+=item C<$storeid>: The storage ID.
+
+=item C<$volume>: The volume name.
+
+=back
+
+=cut
+
+sub qemu_blockdev_options {
+ my ($class, $scfg, $storeid, $volname) = @_;
+
+ my $blockdev = {};
+
+ my ($path) = $class->filesystem_path($scfg, $volname);
+
+ if ($path =~ m|^/|) {
+ # The 'file' driver only works for regular files. The check below is taken from
+ # block/file-posix.c:hdev_probe_device() in QEMU. Do not bother with detecting 'host_cdrom'
+ # devices here, those are not managed by the storage layer.
+ my $st = File::stat::stat($path) or die "stat for '$path' failed - $!\n";
+ my $driver = (S_ISCHR($st->mode) || S_ISBLK($st->mode)) ? 'host_device' : 'file';
+ $blockdev = { driver => $driver, filename => $path };
+ } else {
+ die "storage plugin doesn't implement qemu_blockdev_options() method\n";
+ }
+
+ return $blockdev;
+}
+
# Used by storage plugins for external backup providers. See PVE::BackupProvider::Plugin for the API
# the provider needs to implement.
#
--
2.47.2
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next prev parent reply other threads:[~2025-07-01 15:44 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-07-01 15:40 [pve-devel] [PATCH-SERIES qemu/storage/qemu-server v2 00/49] let's switch to blockdev, blockdev, blockdev, part four (final) Fiona Ebner
2025-07-01 15:40 ` [pve-devel] [PATCH qemu v2 01/49] PVE backup: prepare for the switch to using blockdev rather than drive Fiona Ebner
2025-07-01 15:40 ` [pve-devel] [PATCH qemu v2 02/49] block/zeroinit: support using as blockdev driver Fiona Ebner
2025-07-01 15:40 ` [pve-devel] [PATCH qemu v2 03/49] block/alloc-track: " Fiona Ebner
2025-07-01 15:40 ` [pve-devel] [PATCH qemu v2 04/49] block: include child references in block device info Fiona Ebner
2025-07-01 15:40 ` Fiona Ebner [this message]
2025-07-01 15:40 ` [pve-devel] [PATCH storage v4 06/49] iscsi direct plugin: implement method to get qemu blockdevice options Fiona Ebner
2025-07-01 15:40 ` [pve-devel] [PATCH storage v4 07/49] zfs iscsi plugin: implement new " Fiona Ebner
2025-07-01 15:40 ` [pve-devel] [PATCH storage v4 08/49] zfs pool plugin: implement " Fiona Ebner
2025-07-01 15:40 ` [pve-devel] [PATCH storage v4 09/49] ceph/rbd: set 'keyring' in ceph configuration for externally managed RBD storages Fiona Ebner
2025-07-01 15:40 ` [pve-devel] [PATCH storage v4 10/49] rbd plugin: implement new method to get qemu blockdevice options Fiona Ebner
2025-07-01 15:40 ` [pve-devel] [PATCH storage v4 11/49] plugin: qemu block device: add hints option and EFI disk hint Fiona Ebner
2025-07-01 15:40 ` [pve-devel] [PATCH storage v4 12/49] plugin: qemu block device: add support for snapshot option Fiona Ebner
2025-07-01 15:40 ` [pve-devel] [PATCH storage v4 13/49] plugin: add machine version to qemu_blockdev_options() interface Fiona Ebner
2025-07-01 15:40 ` [pve-devel] [PATCH storage v4 14/49] plugin api: bump api version and age Fiona Ebner
2025-07-01 15:40 ` [pve-devel] [PATCH qemu-server v2 15/49] mirror: code style: avoid masking earlier declaration of $op Fiona Ebner
2025-07-01 15:40 ` [pve-devel] [PATCH qemu-server v2 16/49] test: collect mocked functions for QemuServer module Fiona Ebner
2025-07-01 15:40 ` [pve-devel] [PATCH qemu-server v2 17/49] drive: add helper to parse drive interface Fiona Ebner
2025-07-01 15:40 ` [pve-devel] [PATCH qemu-server v2 18/49] drive: drop invalid export of get_scsi_devicetype Fiona Ebner
2025-07-01 15:40 ` [pve-devel] [PATCH qemu-server v2 19/49] blockdev: add and use throttle_group_id() helper Fiona Ebner
2025-07-01 15:40 ` [pve-devel] [PATCH qemu-server v2 20/49] blockdev: introduce top_node_name() and parse_top_node_name() helpers Fiona Ebner
2025-07-01 15:40 ` [pve-devel] [PATCH qemu-server v2 21/49] blockdev: add helpers for attaching and detaching block devices Fiona Ebner
2025-07-01 15:40 ` [pve-devel] [PATCH qemu-server v2 22/49] blockdev: add missing include for JSON module Fiona Ebner
2025-07-01 15:40 ` [pve-devel] [PATCH qemu-server v2 23/49] backup: use blockdev for fleecing images Fiona Ebner
2025-07-01 15:40 ` [pve-devel] [PATCH qemu-server v2 24/49] backup: use blockdev for TPM state file Fiona Ebner
2025-07-01 15:40 ` [pve-devel] [PATCH qemu-server v2 25/49] blockdev: introduce qdev_id_to_drive_id() helper Fiona Ebner
2025-07-01 15:40 ` [pve-devel] [PATCH qemu-server v2 26/49] blockdev: introduce and use get_block_info() helper Fiona Ebner
2025-07-01 15:40 ` [pve-devel] [PATCH qemu-server v2 27/49] blockdev: move helper for resize into module Fiona Ebner
2025-07-01 15:40 ` [pve-devel] [PATCH qemu-server v2 28/49] blockdev: add helper to get node below throttle node Fiona Ebner
2025-07-01 15:40 ` [pve-devel] [PATCH qemu-server v2 29/49] blockdev: resize: query and use node name for resize operation Fiona Ebner
2025-07-01 15:40 ` [pve-devel] [PATCH qemu-server v2 30/49] blockdev: support using zeroinit filter Fiona Ebner
2025-07-01 15:40 ` [pve-devel] [PATCH qemu-server v2 31/49] blockdev: make some functions private Fiona Ebner
2025-07-01 15:40 ` [pve-devel] [PATCH qemu-server v2 32/49] blockdev: add 'no-throttle' option to skip generationg throttle top node Fiona Ebner
2025-07-01 15:40 ` [pve-devel] [PATCH qemu-server v2 33/49] block job: allow specifying a block node that should be detached upon completion Fiona Ebner
2025-07-01 15:40 ` [pve-devel] [PATCH qemu-server v2 34/49] block job: add blockdev mirror Fiona Ebner
2025-07-01 15:40 ` [pve-devel] [PATCH qemu-server v2 35/49] blockdev: add change_medium() helper Fiona Ebner
2025-07-01 15:40 ` [pve-devel] [PATCH qemu-server v2 36/49] blockdev: add blockdev_change_medium() helper Fiona Ebner
2025-07-01 15:40 ` [pve-devel] [PATCH qemu-server v2 37/49] blockdev: move helper for configuring throttle limits to module Fiona Ebner
2025-07-01 15:40 ` [pve-devel] [PATCH qemu-server v2 38/49] clone disk: skip check for aio=default (io_uring) compatibility starting with machine version 10.0 Fiona Ebner
2025-07-01 15:40 ` [pve-devel] [PATCH qemu-server v2 39/49] print drive device: don't reference any drive for 'none' " Fiona Ebner
2025-07-01 15:41 ` [pve-devel] [PATCH qemu-server v2 40/49] blockdev: add support for NBD paths Fiona Ebner
2025-07-01 15:41 ` [pve-devel] [PATCH qemu-server v2 41/49] blockdev: add helper to generate PBS block device for live restore Fiona Ebner
2025-07-01 15:41 ` [pve-devel] [PATCH qemu-server v2 42/49] blockdev: support alloc-track driver for live-{import, restore} Fiona Ebner
2025-07-01 15:41 ` [pve-devel] [PATCH qemu-server v2 43/49] live import: also record volid information Fiona Ebner
2025-07-01 15:41 ` [pve-devel] [PATCH qemu-server v2 44/49] live import/restore: query which node to use for operation Fiona Ebner
2025-07-01 15:41 ` [pve-devel] [PATCH qemu-server v2 45/49] live import/restore: use Blockdev::detach helper Fiona Ebner
2025-07-01 15:41 ` [pve-devel] [PATCH qemu-server v2 46/49] command line: switch to blockdev starting with machine version 10.0 Fiona Ebner
2025-07-01 15:41 ` [pve-devel] [PATCH qemu-server v2 47/49] test: migration: update running machine to 10.0 Fiona Ebner
2025-07-01 15:41 ` [pve-devel] [PATCH qemu-server v2 48/49] partially fix #3227: ensure that target image for mirror has the same size for EFI disks Fiona Ebner
2025-07-01 15:41 ` [pve-devel] [PATCH qemu-server v2 49/49] blockdev: pass along machine version to storage layer Fiona Ebner
2025-07-02 8:20 ` [pve-devel] [PATCH-SERIES qemu/storage/qemu-server v2 00/49] let's switch to blockdev, blockdev, blockdev, part four (final) DERUMIER, Alexandre via pve-devel
2025-07-02 8:36 ` Fiona Ebner
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