[pve-devel] [PATCH qemu-server 14/16] introduce QSD module for qemu-storage-daemon functionality

[Daniel Kral]

On Tue Oct 14, 2025 at 4:39 PM CEST, Fiona Ebner wrote:
> diff --git a/src/PVE/QemuServer/Helpers.pm b/src/PVE/QemuServer/Helpers.pm
> index 2c78a7b4..ab8aa389 100644
> --- a/src/PVE/QemuServer/Helpers.pm
> +++ b/src/PVE/QemuServer/Helpers.pm
> @@ -89,6 +89,24 @@ sub qsd_pidfile_name {
>      return "${var_run_tmpdir}/qsd-${vmid}.pid";
>  }
>  
> +sub qsd_fuse_export_cleanup_files {
> +    my ($vmid) = @_;
> +
> +    PVE::Tools::dir_glob_foreach(
> +        $var_run_tmpdir,
> +        "qsd-${vmid}-.*.fuse",
> +        sub {
> +            my ($file) = @_;
> +            unlink "${var_run_tmpdir}/${file}";

This could fail if the exported fuse fs wasn't cleaned up by qsd
correctly, see more below.

> +        },
> +    );
> +}
> +
> +sub qsd_fuse_export_path {
> +    my ($vmid, $export_name) = @_;
> +    return "${var_run_tmpdir}/qsd-${vmid}-${export_name}.fuse";
> +}
> +

--- [ snip ] ---

> +=head3 quit
> +
> +    PVE::QemuServer::QSD::quit($vmid);
> +
> +Shut down the QEMU storage daemon associated to VM C<$vmid> and cleans up its PID file and socket.
> +Waits for 60 seconds for clean shutdown, then sends SIGTERM and waits an additional 10 seconds
> +before sending SIGKILL.
> +
> +=cut
> +
> +sub quit($vmid) {
> +    eval { PVE::QemuServer::Monitor::qsd_cmd($vmid, 'quit'); };
> +    my $qmp_err = $@;
> +    warn "QEMU storage daemon for $vmid failed to handle 'quit' - $qmp_err" if $qmp_err;
> +
> +    my $count = $qmp_err ? 60 : 0; # can't wait for QMP 'quit' to terminate the process if it failed
> +    my $pid = PVE::QemuServer::Helpers::qsd_running_locally($vmid);
> +    while ($pid) {
> +        if ($count == 60) {
> +            warn "QEMU storage daemon for $vmid still running with PID $pid"
> +                . " - terminating now with SIGTERM\n";
> +            kill 15, $pid;
> +        } elsif ($count == 70) {
> +            warn "QEMU storage daemon for $vmid still running with PID $pid"
> +                . " - terminating now with SIGKILL\n";
> +            kill 9, $pid;
> +            last;

SIGKILL will leave the exported fuse export in an unremovable state
since the qsd couldn't clean it up. I could only reproduce this by doing
it manually with `kill -SIGKILL ...`, which resulted in the VM not being
startable anymore.

Might be worth to add an `umount /run/qemu-server/qsd-....fuse` if
unlink fails or if we can stat -f that the file is still the
FUSE-exported image?

> +        }
> +
> +        sleep 1;
> +        $count++;
> +        $pid = PVE::QemuServer::Helpers::qsd_running_locally($vmid);
> +    }
> +
> +    unlink PVE::QemuServer::Helpers::qsd_pidfile_name($vmid);
> +    unlink PVE::QemuServer::Helpers::qmp_socket({ vmid => $vmid, type => 'qsd' });
> +
> +    PVE::QemuServer::Helpers::qsd_fuse_export_cleanup_files($vmid);
> +
> +    return;
> +}
> +
> +1;