[pve-devel] [PATCH qemu-server 1/3] fix #2816: restore: remove timeout when allocating disks
Dominik Csapak
d.csapak at proxmox.com
Wed Sep 20 13:23:26 CEST 2023
comment inline:
On 9/12/23 11:16, Fiona Ebner wrote:
> 10 minutes is not long enough when disks are large and/or network
> storages are used when preallocation is not disabled. The default is
> metadata preallocation for qcow2, so there are still reports of the
> issue [0][1]. If allocation really does not finish like the comment
> describing the timeout feared, just let the user cancel it.
>
> Also note that when restoring a PBS backup, there is no timeout for
> disk allocation, and there don't seem to be any user complaints yet.
>
> The 5 second timeout for receiving the config from vma is kept,
> because certain corruptions in the VMA header can lead to the
> operation hanging there.
>
> There is no need for the $tmp variable before setting back the old
> timeout, because that is at least one second, so we'll always be able
> to set the $oldtimeout variable to undef in time in practice.
> Currently, there shouldn't even be an outer timeout in the first
> place, because the only call path leading to here is via the create
> API (also used by qmrestore), both of which don't set a timeout.
>
> [0]: https://forum.proxmox.com/threads/126825/
> [1]: https://forum.proxmox.com/threads/128093/
>
> Signed-off-by: Fiona Ebner <f.ebner at proxmox.com>
> ---
> PVE/QemuServer.pm | 9 +++------
> 1 file changed, 3 insertions(+), 6 deletions(-)
>
> diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm
> index bf1de179..05283562 100644
> --- a/PVE/QemuServer.pm
> +++ b/PVE/QemuServer.pm
> @@ -7483,14 +7483,11 @@ sub restore_vma_archive {
> $devinfo->{$devname} = { size => $size, dev_id => $dev_id };
> } elsif ($line =~ m/^CTIME: /) {
> # we correctly received the vma config, so we can disable
> - # the timeout now for disk allocation (set to 10 minutes, so
> - # that we always timeout if something goes wrong)
> - alarm(600);
> + # the timeout now for disk allocation
> + alarm($oldtimeout || 0);
> + $oldtimeout = undef;
this part looks wrong to me, because AFAIU you want to disable the timeout
(by canceling the alarm), but what you do here is to set it to $oldtimeout
if that was set before?
i guess what we want to do here is:
----
alarm(0);
<... do stuff ...>
alarm($oldtimeout || 0);
$oldtimeout = undef;
----
?
> &$print_devmap();
> print $fifofh "done\n";
> - my $tmp = $oldtimeout || 0;
> - $oldtimeout = undef;
> - alarm($tmp);
> close($fifofh);
> $fifofh = undef;
> }
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