> Alexandre Derumier via pve-devel <pve-devel@lists.proxmox.com> hat am
> 11.03.2025 11:28 CET geschrieben:
same here - please add some description about why things are implemented how
they are.. else we have to dive through multiple threads of review discussions
in 2 years when we want to find out ;)
> Signed-off-by: Alexandre Derumier <alexandre.derum...@groupe-cyllene.com>
> ---
> src/PVE/Storage/LVMPlugin.pm | 228 ++++++++++++++++++++++++++++++++---
> 1 file changed, 210 insertions(+), 18 deletions(-)
>
> diff --git a/src/PVE/Storage/LVMPlugin.pm b/src/PVE/Storage/LVMPlugin.pm
> index 38f7fa1..19dbd7e 100644
> --- a/src/PVE/Storage/LVMPlugin.pm
> +++ b/src/PVE/Storage/LVMPlugin.pm
> @@ -4,6 +4,7 @@ use strict;
> use warnings;
>
> use IO::File;
> +use POSIX qw/ceil/;
>
> use PVE::Tools qw(run_command trim);
> use PVE::Storage::Plugin;
> @@ -218,6 +219,7 @@ sub type {
> sub plugindata {
> return {
> content => [ {images => 1, rootdir => 1}, { images => 1 }],
> + format => [ { raw => 1, qcow2 => 1 } , 'raw' ],
> };
> }
>
> @@ -293,7 +295,10 @@ sub parse_volname {
> PVE::Storage::Plugin::parse_lvm_name($volname);
>
> if ($volname =~ m/^(vm-(\d+)-\S+)$/) {
> - return ('images', $1, $2, undef, undef, undef, 'raw');
> + my $name = $1;
> + my $vmid = $2;
> + my $format = $volname =~ m/\.qcow2$/ ? 'qcow2' : 'raw';
this is really tricky and I am afraid there are still pitfalls/bugs here unless
we add additional checks in places that a requested $format and the one in the
name match..
> + return ('images', $name, $vmid, undef, undef, undef, $format);
> }
>
> die "unable to parse lvm volume name '$volname'\n";
> @@ -302,11 +307,13 @@ sub parse_volname {
> sub filesystem_path {
> my ($class, $scfg, $volname, $snapname) = @_;
>
> - die "lvm snapshot is not implemented"if defined($snapname);
> + my ($vtype, $name, $vmid, $basename, $basevmid, $isBase, $format) =
> + $class->parse_volname($volname);
>
> - my ($vtype, $name, $vmid) = $class->parse_volname($volname);
> + die "snapshot is working with qcow2 format only" if defined($snapname)
> && $format ne 'qcow2';
>
> my $vg = $scfg->{vgname};
> + $name = $class->get_snap_volname($volname, $snapname) if $snapname;
>
> my $path = "/dev/$vg/$name";
>
> @@ -334,7 +341,9 @@ sub find_free_diskname {
>
> my $disk_list = [ keys %{$lvs->{$vg}} ];
>
> - return PVE::Storage::Plugin::get_next_vm_diskname($disk_list, $storeid,
> $vmid, undef, $scfg);
> + $add_fmt_suffix = $fmt eq 'qcow2' ? 1 : undef;
> +
> + return PVE::Storage::Plugin::get_next_vm_diskname($disk_list, $storeid,
> $vmid, $fmt, $scfg, $add_fmt_suffix);
> }
>
> sub lvcreate {
> @@ -363,9 +372,9 @@ sub lvrename {
> }
>
> sub alloc_image {
> - my ($class, $storeid, $scfg, $vmid, $fmt, $name, $size) = @_;
> + my ($class, $storeid, $scfg, $vmid, $fmt, $name, $size, $backing) = @_;
same as for the dir-based one - $backing as arbitrary path is not a good idea..
this should either be a snapshot $volname, or just the $snapname itself?
>
> - die "unsupported format '$fmt'" if $fmt ne 'raw';
> + die "unsupported format '$fmt'" if $fmt !~ m/(raw|qcow2)/;
>
> die "illegal name '$name' - should be 'vm-$vmid-*'\n"
> if $name && $name !~ m/^vm-$vmid-/;
> @@ -378,12 +387,36 @@ sub alloc_image {
>
> my $free = int($vgs->{$vg}->{free});
>
> +
> + #add extra space for qcow2 metadatas
> + #without sub-allocated clusters : For 1TB storage : l2_size = disk_size
> × 8 / cluster_size
> + #with sub-allocated clusters : For 1TB storage : l2_size = disk_size × 8
> / cluster_size / 16
are these formulas valid for all disk sizes, or just for 1TB?
> + #4MB overhead for 1TB with extented l2
> clustersize=128k
so this means 1TB x 8 / 128K / 16 = 1GB / 256 = 4MB
if the formula is generic, that means 1 GB of storage == 4KB of overhead, or
1MB of storage == 4 bytes of overhead?
> +
> + #can't use qemu-img measure, because it's not possible to define options
> like clustersize && extended_l2
> + #verification has been done with : qemu-img create -f qcow2 -o
> extended_l2=on,cluster_size=128k test.img 1G
> +
> + my $qcow2_overhead = ceil($size/1024/1024/1024) * 4096;
above you say 4MB for 1TB, but here you go down to KB and then multiply by 4K?
why not go down to MB and multiply by 4?
> +
> + my $lvmsize = $size;
> + $lvmsize += $qcow2_overhead if $fmt eq 'qcow2';
> +
> die "not enough free space ($free < $size)\n" if $free < $size;
>
> - $name = $class->find_free_diskname($storeid, $scfg, $vmid)
> + $name = $class->find_free_diskname($storeid, $scfg, $vmid, $fmt)
> if !$name;
>
> - lvcreate($vg, $name, $size, ["pve-vm-$vmid"]);
> + my $tags = ["pve-vm-$vmid"];
> + #tags all snapshots volumes with the main volume tag for easier
> activation of the whole group
> + push @$tags, "\@pve-$name" if $fmt eq 'qcow2';
> + lvcreate($vg, $name, $lvmsize, $tags);
> +
> + if ($fmt eq 'qcow2') {
> + #format the lvm volume with qcow2 format
> + $class->activate_volume($storeid, $scfg, $name, undef, {});
the last two parameters are not needed..
> + my $path = $class->path($scfg, $name, $storeid);
> + PVE::Storage::Plugin::qemu_img_create($scfg, $fmt, $size, $path,
> $backing);
> + }
>
> return $name;
> }
> @@ -538,6 +571,12 @@ sub activate_volume {
>
> my $lvm_activate_mode = 'ey';
>
> + #activate volume && all snapshots volumes by tag
> + my ($vtype, $name, $vmid, $basename, $basevmid, $isBase, $format) =
> + $class->parse_volname($volname);
> +
> + $path = "\@pve-$name" if $format eq 'qcow2';
> +
> my $cmd = ['/sbin/lvchange', "-a$lvm_activate_mode", $path];
> run_command($cmd, errmsg => "can't activate LV '$path'");
> $cmd = ['/sbin/lvchange', '--refresh', $path];
> @@ -550,6 +589,10 @@ sub deactivate_volume {
> my $path = $class->path($scfg, $volname, $storeid, $snapname);
> return if ! -b $path;
>
> + my ($vtype, $name, $vmid, $basename, $basevmid, $isBase, $format) =
> + $class->parse_volname($volname);
> + $path = "\@pve-$name" if $format eq 'qcow2';
> +
> my $cmd = ['/sbin/lvchange', '-aln', $path];
> run_command($cmd, errmsg => "can't deactivate LV '$path'");
> }
> @@ -557,15 +600,27 @@ sub deactivate_volume {
> sub volume_resize {
> my ($class, $scfg, $storeid, $volname, $size, $running) = @_;
>
> - $size = ($size/1024/1024) . "M";
> + my ($vtype, $name, $vmid, $basename, $basevmid, $isBase, $format) =
> + $class->parse_volname($volname);
> +
> + my $lvmsize = $size / 1024;
I don't really get this, see comments above for alloc_image
> + my $qcow2_overhead = ceil($size/1024/1024/1024/1024) * 4096;
> + $lvmsize += $qcow2_overhead if $format eq 'qcow2';
we definitely don't want to have this twice..
> + $lvmsize = "${lvmsize}k";
>
> my $path = $class->path($scfg, $volname);
> - my $cmd = ['/sbin/lvextend', '-L', $size, $path];
> + my $cmd = ['/sbin/lvextend', '-L', $lvmsize, $path];
>
> $class->cluster_lock_storage($storeid, $scfg->{shared}, undef, sub {
> run_command($cmd, errmsg => "error resizing volume '$path'");
> });
>
> + if(!$running && $format eq 'qcow2') {
> + my $prealloc_opt =
> PVE::Storage::Plugin::preallocation_cmd_option($scfg, $format);
> + my $cmd = ['/usr/bin/qemu-img', 'resize', "--$prealloc_opt", '-f',
> $format, $path , $size];
> + run_command($cmd, timeout => 10);
> + }
> +
> return 1;
> }
>
> @@ -587,30 +642,159 @@ sub volume_size_info {
> sub volume_snapshot {
> my ($class, $scfg, $storeid, $volname, $snap) = @_;
>
> - die "lvm snapshot is not implemented";
> + my ($vtype, $name, $vmid, $basename, $basevmid, $isBase, $format) =
> + $class->parse_volname($volname);
> +
> + die "can't snapshot this image format\n" if $format ne 'qcow2';
> +
> + $class->activate_volume($storeid, $scfg, $volname, undef, {});
last two not needed
> +
> + my $snap_volname = $class->get_snap_volname($volname, $snap);
> + my $snap_path = $class->path($scfg, $volname, $storeid, $snap);
see above..
> +
> + my $size = $class->volume_size_info($scfg, $storeid, $volname, 5);
> +
> + #rename current lvm volume to snap volume
> + my $vg = $scfg->{vgname};
> + print"rename $volname to $snap_volname\n";
> + eval { lvrename($vg, $volname, $snap_volname); };
> + if ($@) {
> + die "can't rename lvm volume from $volname to $snap_volname: $@ \n";
> + }
> +
> + eval { $class->alloc_image($storeid, $scfg, $vmid, 'qcow2', $volname,
> $size/1024, $snap_path); };
> + if ($@) {
> + eval { $class->free_image($storeid, $scfg, $volname, 0) };
missing error handling, this needs to rename back? also, this might return a
code-reference that needs to be executed..
> + warn $@ if $@;
> + }
> }
>
> +sub volume_rollback_is_possible {
> + my ($class, $scfg, $storeid, $volname, $snap, $blockers) = @_;
> +
> + my $snap_path = $class->path($scfg, $volname, $storeid, $snap);
> +
> + $class->activate_volume($storeid, $scfg, $volname, undef, {});
> + my $snapshots = $class->volume_snapshot_info($scfg, $storeid, $volname);
> + my $parent_snap = $snapshots->{current}->{parent};
wouldn't it be enough to check that this equals $snap?
> +
> + return 1 if $snapshots->{$parent_snap}->{file} eq $snap_path;
> + die "can't rollback, '$snap' is not most recent snapshot on
> '$volname'\n";
> +
> + return 1;
> +}
> +
> +
> sub volume_snapshot_rollback {
> my ($class, $scfg, $storeid, $volname, $snap) = @_;
>
> - die "lvm snapshot rollback is not implemented";
> + die "can't rollback snapshot for this image format\n" if $volname !~
> m/\.(qcow2)$/;
this should go below parse_volname and use the format it returns..
> +
> + my ($vtype, $name, $vmid, $basename, $basevmid, $isBase, $format) =
> + $class->parse_volname($volname);
> +
> + $class->activate_volume($storeid, $scfg, $volname, undef, {});
two unneeded parameters
> + my $size = $class->volume_size_info($scfg, $storeid, $volname, 5);
> + my $snap_path = $class->path($scfg, $volname, $storeid, $snap);
> +
> + #simply delete the current snapshot and recreate it
> + eval { $class->free_image($storeid, $scfg, $volname, 0) };
might return a code reference that needs to be executed..
> + if ($@) {
> + die "can't delete old volume $volname: $@\n";
> + }
> +
> + eval { $class->alloc_image($storeid, $scfg, $vmid, 'qcow2', $volname,
> $size/1024, $snap_path) };
> + if ($@) {
> + die "can't allocate new volume $volname: $@\n";
> + }
> +
> + return undef;
> }
>
> sub volume_snapshot_delete {
> - my ($class, $scfg, $storeid, $volname, $snap) = @_;
> + my ($class, $scfg, $storeid, $volname, $snap, $running) = @_;
> +
> + die "can't delete snapshot for this image format\n" if $volname !~
> m/\.(qcow2)$/;
this should parse the volname and use the returned format!
> +
> + return 1 if $running;
> +
> + my $cmd = "";
> + my $path = $class->filesystem_path($scfg, $volname);
> +
> + my $snapshots = $class->volume_snapshot_info($scfg, $storeid, $volname);
> + my $snap_path = $snapshots->{$snap}->{file};
> + my $snap_volname = $snapshots->{$snap}->{volname};
> + die "volume $snap_path is missing" if !-e $snap_path;
>
> - die "lvm snapshot delete is not implemented";
> + my $parent_snap = $snapshots->{$snap}->{parent};
> + my $child_snap = $snapshots->{$snap}->{child};
> +
> + my $parent_path = $snapshots->{$parent_snap}->{file} if $parent_snap;
> + my $child_path = $snapshots->{$child_snap}->{file} if $child_snap;
> + my $child_volname = $snapshots->{$child_snap}->{volname} if $child_snap;
same as in the Plugin.pm patch, this is not allowed code style!
> +
> + #if first snapshot,as it should be bigger, we merge child, and rename
> the snapshot to child
> + if(!$parent_snap) {
> + print"commit $child_path\n";
> + $cmd = ['/usr/bin/qemu-img', 'commit', $child_path];
could use `-d`, since we don't use $child_path afterwards anyway
> + eval { run_command($cmd) };
> + if ($@) {
> + die "error commiting $child_path to $parent_path: $@\n";
> + }
> + print"delete $child_volname\n";
> + eval { $class->free_image($storeid, $scfg, $child_volname, 0) };
might return a code reference that needs to be executed..
> + if ($@) {
> + die "error delete old snapshot volume $child_volname: $@\n";
> + }
> + print"rename $snap_volname to $child_volname\n";
> + my $vg = $scfg->{vgname};
> + eval { lvrename($vg, $snap_volname, $child_volname) };
> + if ($@) {
> + die "error renaming snapshot: $@\n";
> + }
> + } else {
> + #we rebase the child image on the parent as new backing image
> + die "missing parentsnap snapshot to rebase child $child_path\n" if
> !$parent_path;
how would this happen?
> + print "link $child_snap to $parent_snap\n";
> + $cmd = ['/usr/bin/qemu-img', 'rebase', '-b', $parent_path, '-F',
> 'qcow2', '-f', 'qcow2', $child_path];
> + eval { run_command($cmd) };
> + if ($@) {
> + die "error rebase $child_path with $parent_path; $@\n";
> + }
> + #delete the snapshot
> + eval { $class->free_image($storeid, $scfg, $snap_volname, 0); };
might return a code reference that needs to be executed..
> + if ($@) {
> + die "error delete old snapshot volume $snap_volname: $@\n";
> + }
> + }
> }
>
> sub volume_has_feature {
> my ($class, $scfg, $feature, $storeid, $volname, $snapname, $running) =
> @_;
>
> my $features = {
> - copy => { base => 1, current => 1},
> - rename => {current => 1},
> + copy => {
> + base => { qcow2 => 1, raw => 1},
> + current => { qcow2 => 1, raw => 1},
> + snap => { qcow2 => 1 },
did you actually test this? AFAICT this would still fall back to internal qcow2
snapshots?
> + },
> + 'rename' => {
> + current => { qcow2 => 1, raw => 1},
how does this interact with snapshots?
> + },
> + snapshot => {
> + current => { qcow2 => 1 },
> + snap => { qcow2 => 1 },
> + },
> + template => {
> + current => { qcow2 => 1, raw => 1},
see below..
> + },
> + clone => {
> + base => { qcow2 => 1, raw => 1 },
how can we do linked clones of raw volumes? how can we do linked clones of
qcow2 volumes if we don't allow creating base volumes?
> + },
> };
>
> - my ($vtype, $name, $vmid, $basename, $basevmid, $isBase) =
> +
> + my ($vtype, $name, $vmid, $basename, $basevmid, $isBase, $format) =
> $class->parse_volname($volname);
>
> my $key = undef;
> @@ -619,7 +803,7 @@ sub volume_has_feature {
> }else{
> $key = $isBase ? 'base' : 'current';
> }
> - return 1 if $features->{$feature}->{$key};
> + return 1 if defined($features->{$feature}->{$key}->{$format});
why the defined?
>
> return undef;
> }
> @@ -740,4 +924,12 @@ sub rename_volume {
> return "${storeid}:${target_volname}";
> }
>
> +sub get_snap_volname {
> + my ($class, $volname, $snapname) = @_;
> +
> + my ($vtype, $name, $vmid, $basename, $basevmid, $isBase, $format) =
> $class->parse_volname($volname);
> + $name = !$snapname || $snapname eq 'current' ? $volname :
> "snap-$snapname-$name";
see above..
> + return $name;
> +}
> +
> 1;
> --
> 2.39.5
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