On 4/29/25 13:36, Friedrich Weber wrote:
> When discovering a new volume group (VG), for example on boot, LVM
> triggers autoactivation. With the default settings, this activates all
> logical volumes (LVs) in the VG. Activating an LV creates a
> device-mapper device and a block device under /dev/mapper.
>
> Autoactivation is problematic for shared LVM storages, see #4997 [1].
> For the inherently local LVM-thin storage it is less problematic, but
> it still makes sense to avoid unnecessarily activating LVs and thus
> making them visible on the host at boot.
>
> Hence, disable autoactivation after creating new LVs. As lvcreate
> doesn't accept the --setautoactivation flag for thin LVs, this is done
> with an additional lvchange command. With this setting, LVM
> autoactivation will not activate these LVs, and the storage stack will
> take care of activating/deactivating LVs when needed.
>
> [1] https://bugzilla.proxmox.com/show_bug.cgi?id=4997
>
> Signed-off-by: Friedrich Weber <f.we...@proxmox.com>
> ---
>
> Notes:
> - would be great to get your opinion on whether we should consider
> LVM-thin storages in this series or not.
>
> - passing --setautoactivation n to lvcreate for a thin volume says:
>
> Option --setautoactivation is unsupported with thins.
>
> But lvchange --setautoactivation seems to work on thin LVs, so the
> fact that lvcreate doesn't accept it may be a bug. I reported it
> upstream [1].
>
> new in v3
>
> [1] https://gitlab.com/lvmteam/lvm2/-/issues/32
Since the upstream issue has not been addressed yet and the change to
LVM-thin does, AFAICT, not mitigate problems like in #4997 (or am I
missing something here?), but is mostly done to streamline behavior,
could the changes for LVM-thin be held back until it's clear that
lvcreate not supporting --setautoactivation for LVM-thin is not on purpose?
>
> src/PVE/Storage/LvmThinPlugin.pm | 18 +++++++++++++++++-
> 1 file changed, 17 insertions(+), 1 deletion(-)
>
> diff --git a/src/PVE/Storage/LvmThinPlugin.pm
> b/src/PVE/Storage/LvmThinPlugin.pm
> index 49a4dcb..3f75ba1 100644
> --- a/src/PVE/Storage/LvmThinPlugin.pm
> +++ b/src/PVE/Storage/LvmThinPlugin.pm
> @@ -82,6 +82,19 @@ sub filesystem_path {
> return wantarray ? ($path, $vmid, $vtype) : $path;
> }
>
> +# lvcreate refuses --setautoactivation for thin volumes, so set it via
> lvchange
> +my $set_lv_autoactivation = sub {
> + my ($vg, $lv, $autoactivation) = @_;
> +
> + my $cmd = [
> + '/sbin/lvchange',
> + '--setautoactivation', $autoactivation ? 'y' : 'n',
> + "$vg/$lv"
> + ];
> + eval { run_command($cmd); };
> + warn "could not set autoactivation: $@" if $@;
> +};
> +
> sub alloc_image {
> my ($class, $storeid, $scfg, $vmid, $fmt, $name, $size) = @_;
>
> @@ -103,6 +116,7 @@ sub alloc_image {
> '--thinpool', "$vg/$scfg->{thinpool}" ];
>
> run_command($cmd, errmsg => "lvcreate '$vg/$name' error");
> + $set_lv_autoactivation->($vg, $name, 0);
>
> return $name;
> }
> @@ -283,6 +297,7 @@ sub clone_image {
>
> my $cmd = ['/sbin/lvcreate', '-n', $name, '-prw', '-kn', '-s', $lv];
> run_command($cmd, errmsg => "clone image '$lv' error");
> + $set_lv_autoactivation->($vg, $name, 0);
>
> return $name;
> }
> @@ -332,7 +347,7 @@ sub volume_snapshot {
>
> my $cmd = ['/sbin/lvcreate', '-n', $snapvol, '-pr', '-s',
> "$vg/$volname"];
> run_command($cmd, errmsg => "lvcreate snapshot '$vg/$snapvol' error");
> -
> + # disabling autoactivation not needed, as -s defaults to
> --setautoactivationskip y
> }
>
> sub volume_snapshot_rollback {
> @@ -346,6 +361,7 @@ sub volume_snapshot_rollback {
>
> $cmd = ['/sbin/lvcreate', '-kn', '-n', $volname, '-s', "$vg/$snapvol"];
> run_command($cmd, errmsg => "lvm rollback '$vg/$snapvol' error");
> + $set_lv_autoactivation->($vg, $volname, 0);
> }
>
> sub volume_snapshot_delete {
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