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 C01BE1FF183 for ; Wed, 18 Jun 2025 15:04:22 +0200 (CEST) Received: from firstgate.proxmox.com (localhost [127.0.0.1]) by firstgate.proxmox.com (Proxmox) with ESMTP id E05711290C; Wed, 18 Jun 2025 15:02:31 +0200 (CEST) From: Fiona Ebner To: pve-devel@lists.proxmox.com Date: Wed, 18 Jun 2025 15:02:07 +0200 Message-Id: <20250618130209.90649-31-f.ebner@proxmox.com> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250618130209.90649-1-f.ebner@proxmox.com> References: <20250618130209.90649-1-f.ebner@proxmox.com> MIME-Version: 1.0 X-SPAM-LEVEL: Spam detection results: 0 AWL -0.031 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 qemu-server v2 30/32] blockdev: add helpers to generate blockdev commandline 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" The drive device and node structure is: front-end device {ide-hd,scsi-hd,virtio-blk-pci} (id=$drive_id) - throttle node (node-name=$drive_id) - format node (node-name=f$encoded-info) - file node (node-name=e$encoded-info) The node-name can only be 31 characters long and needs to start with a letter. The throttle node will stay inserted below the front-end device. The other nodes might change however, because of drive mirroring and similar. There currently are no good helpers to query/walk the block graph via QMP, x-debug-query-block-graph is experimental and for debugging only. Therefore, necessary information is encoded in the node name to be able to find it again. In particular, this is the volume ID, the drive ID and optionally a snapshot name. As long as the configuration file matches with the running instance, this is enough to find the correct node for block operations like mirror and resize. The 'snapshot' option, for QEMU's snapshot mode, i.e. writes are only temporary, is not yet supported. Originally-by: Alexandre Derumier [FE: split up patch expand commit message explicitly test for drivers with aio setting improve readonly handling improve CD-ROM handling fix failure for storage named 'nbd' by always using full regex improve node name generation fail when drive->{snapshot} is set] Signed-off-by: Fiona Ebner --- Changes in v2: * Use json_bool helper. * Coerce some additional strings by quoting for JSON, just to be sure. src/PVE/QemuServer/Blockdev.pm | 171 ++++++++++++++++++++++++++++++++- 1 file changed, 170 insertions(+), 1 deletion(-) diff --git a/src/PVE/QemuServer/Blockdev.pm b/src/PVE/QemuServer/Blockdev.pm index 4d1266b8..76a00383 100644 --- a/src/PVE/QemuServer/Blockdev.pm +++ b/src/PVE/QemuServer/Blockdev.pm @@ -3,7 +3,41 @@ package PVE::QemuServer::Blockdev; use strict; use warnings; -use PVE::QemuServer::Drive; +use Digest::SHA; +use Fcntl qw(S_ISBLK S_ISCHR); +use File::stat; + +use PVE::JSONSchema qw(json_bool); +use PVE::Storage; + +use PVE::QemuServer::Drive qw(drive_is_cdrom); + +my sub get_node_name { + my ($type, $drive_id, $volid, $snap) = @_; + + my $info = "drive=$drive_id,"; + $info .= "snap=$snap," if defined($snap); + $info .= "volid=$volid"; + + my $hash = substr(Digest::SHA::sha256_hex($info), 0, 30); + + my $prefix = ""; + if ($type eq 'fmt') { + $prefix = 'f'; + } elsif ($type eq 'file') { + $prefix = 'e'; + } else { + die "unknown node type '$type'"; + } + # node-name must start with an alphabetical character + return "${prefix}${hash}"; +} + +my sub read_only_json_option { + my ($drive, $options) = @_; + + return json_bool($drive->{ro} || drive_is_cdrom($drive) || $options->{'read-only'}); +} sub generate_throttle_group { my ($drive) = @_; @@ -41,4 +75,139 @@ sub generate_throttle_group { }; } +sub generate_blockdev_drive_cache { + my ($drive, $scfg) = @_; + + my $cache_direct = PVE::QemuServer::Drive::drive_uses_cache_direct($drive, $scfg); + return { + direct => json_bool($cache_direct), + 'no-flush' => json_bool($drive->{cache} && $drive->{cache} eq 'unsafe'), + }; +} + +sub generate_file_blockdev { + my ($storecfg, $drive, $options) = @_; + + my $blockdev = {}; + my $scfg = undef; + + die "generate_file_blockdev called without volid/path\n" if !$drive->{file}; + die "generate_file_blockdev called with 'none'\n" if $drive->{file} eq 'none'; + # FIXME use overlay and new config option to define storage for temp write device + die "'snapshot' option is not yet supported for '-blockdev'\n" if $drive->{snapshot}; + + my $drive_id = PVE::QemuServer::Drive::get_drive_id($drive); + + if ($drive->{file} eq 'cdrom') { + my $path = PVE::QemuServer::Drive::get_iso_path($storecfg, $drive->{file}); + $blockdev = { driver => 'host_cdrom', filename => "$path" }; + } elsif ($drive->{file} =~ m|^/|) { + my $path = $drive->{file}; + # The 'file' driver only works for regular files. The check below is taken from + # block/file-posix.c:hdev_probe_device() in QEMU. To detect CD-ROM host devices, QEMU issues + # an ioctl, while the code here relies on the media=cdrom flag instead. + my $st = File::stat::stat($path) or die "stat for '$path' failed - $!\n"; + my $driver = 'file'; + if (S_ISCHR($st->mode) || S_ISBLK($st->mode)) { + $driver = drive_is_cdrom($drive) ? 'host_cdrom' : 'host_device'; + } + $blockdev = { driver => "$driver", filename => "$path" }; + } else { + my $volid = $drive->{file}; + my ($storeid) = PVE::Storage::parse_volume_id($volid); + + my $vtype = (PVE::Storage::parse_volname($storecfg, $drive->{file}))[0]; + die "$drive_id: explicit media parameter is required for iso images\n" + if !defined($drive->{media}) && defined($vtype) && $vtype eq 'iso'; + + my $storage_opts = { hints => {} }; + $storage_opts->{hints}->{'efi-disk'} = 1 if $drive->{interface} eq 'efidisk'; + $storage_opts->{'snapshot-name'} = $options->{'snapshot-name'} + if defined($options->{'snapshot-name'}); + $blockdev = PVE::Storage::qemu_blockdev_options($storecfg, $volid, $storage_opts); + $scfg = PVE::Storage::storage_config($storecfg, $storeid); + } + + $blockdev->{cache} = generate_blockdev_drive_cache($drive, $scfg); + + my $driver = $blockdev->{driver}; + # only certain drivers have the aio setting + if ($driver eq 'file' || $driver eq 'host_cdrom' || $driver eq 'host_device') { + $blockdev->{aio} = + PVE::QemuServer::Drive::aio_cmdline_option($scfg, $drive, $blockdev->{cache}->{direct}); + } + + if (!drive_is_cdrom($drive)) { + $blockdev->{discard} = $drive->{discard} && $drive->{discard} eq 'on' ? 'unmap' : 'ignore'; + $blockdev->{'detect-zeroes'} = PVE::QemuServer::Drive::detect_zeroes_cmdline_option($drive); + } + + $blockdev->{'node-name'} = + get_node_name('file', $drive_id, $drive->{file}, $options->{'snapshot-name'}); + + $blockdev->{'read-only'} = read_only_json_option($drive, $options); + + return $blockdev; +} + +sub generate_format_blockdev { + my ($storecfg, $drive, $child, $options) = @_; + + die "generate_format_blockdev called without volid/path\n" if !$drive->{file}; + die "generate_format_blockdev called with 'none'\n" if $drive->{file} eq 'none'; + + my $scfg; + my $format; + my $volid = $drive->{file}; + my $drive_id = PVE::QemuServer::Drive::get_drive_id($drive); + my ($storeid) = PVE::Storage::parse_volume_id($volid, 1); + + # For PVE-managed volumes, use the format from the storage layer and prevent overrides via the + # drive's 'format' option. For unmanaged volumes, fallback to 'raw' to avoid auto-detection by + # QEMU. + if ($storeid) { + $scfg = PVE::Storage::storage_config($storecfg, $storeid); + $format = PVE::QemuServer::Drive::checked_volume_format($storecfg, $volid); + if ($drive->{format} && $drive->{format} ne $format) { + die "drive '$drive->{interface}$drive->{index}' - volume '$volid'" + . " - 'format=$drive->{format}' option different from storage format '$format'\n"; + } + } else { + $format = $drive->{format} // 'raw'; + } + + # define cache option on both format && file node like libvirt does + my $cache = generate_blockdev_drive_cache($drive, $scfg); + + my $node_name = get_node_name('fmt', $drive_id, $drive->{file}, $options->{'snapshot-name'}); + + return { + 'node-name' => "$node_name", + driver => "$format", + file => $child, + cache => $cache, + 'read-only' => read_only_json_option($drive, $options), + }; +} + +sub generate_drive_blockdev { + my ($storecfg, $drive, $options) = @_; + + my $drive_id = PVE::QemuServer::Drive::get_drive_id($drive); + + die "generate_drive_blockdev called without volid/path\n" if !$drive->{file}; + die "generate_drive_blockdev called with 'none'\n" if $drive->{file} eq 'none'; + + my $child = generate_file_blockdev($storecfg, $drive, $options); + $child = generate_format_blockdev($storecfg, $drive, $child, $options); + + # this is the top filter entry point, use $drive-drive_id as nodename + return { + driver => "throttle", + 'node-name' => "drive-$drive_id", + 'throttle-group' => "throttle-drive-$drive_id", + file => $child, + }; +} + 1; -- 2.39.5 _______________________________________________ pve-devel mailing list pve-devel@lists.proxmox.com https://lists.proxmox.com/cgi-bin/mailman/listinfo/pve-devel