From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from firstgate.proxmox.com (firstgate.proxmox.com [IPv6:2a01:7e0:0:424::9]) by lore.proxmox.com (Postfix) with ESMTPS id 2D8CB1FF16B for ; Tue, 1 Jul 2025 17:44:02 +0200 (CEST) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id 828F9A29C; Tue, 1 Jul 2025 17:41:57 +0200 (CEST) From: Fiona Ebner To: pve-devel@lists.proxmox.com Date: Tue, 1 Jul 2025 17:40:25 +0200 Message-ID: <20250701154117.434512-6-f.ebner@proxmox.com> X-Mailer: git-send-email 2.47.2 In-Reply-To: <20250701154117.434512-1-f.ebner@proxmox.com> References: <20250701154117.434512-1-f.ebner@proxmox.com> MIME-Version: 1.0 X-SPAM-LEVEL: Spam detection results: 0 AWL -0.029 Adjusted score from AWL reputation of From: address BAYES_00 -1.9 Bayes spam probability is 0 to 1% DMARC_MISSING 0.1 Missing DMARC policy KAM_DMARC_STATUS 0.01 Test Rule for DKIM or SPF Failure with Strict Alignment SPF_HELO_NONE 0.001 SPF: HELO does not publish an SPF Record SPF_PASS -0.001 SPF: sender matches SPF record Subject: [pve-devel] [PATCH storage v4 05/49] plugin: add method to get qemu blockdevice options for volume X-BeenThere: pve-devel@lists.proxmox.com X-Mailman-Version: 2.1.29 Precedence: list List-Id: Proxmox VE development discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Proxmox VE development discussion Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: pve-devel-bounces@lists.proxmox.com Sender: "pve-devel" 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 --- 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<< $blockdev->{filename} >> for the C driver. For files, the C driver can be used. For +host block devices, the C driver can be used. The plugin must not set options like +C or C. Those are managed by qemu-server and will be overwritten. For other available +drivers and the exact specification of the options, see +L + +While Perl does not have explicit types, the result will need to be converted to JSON later and +match the QMP specification (see link above), so implicit types are important. In the return value, +use C and C for booleans, C<"$value"> for strings, and C 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 _______________________________________________ pve-devel mailing list pve-devel@lists.proxmox.com https://lists.proxmox.com/cgi-bin/mailman/listinfo/pve-devel