first functional version of extend lv

blockdev: set write threshold

src/PVE/QemuServer.pm

@@ -5822,6 +5822,28 @@ sub vm_start_nolock {
         warn $@ if $@;
     }
 
+    # set write threshold for LVM thin provisioning disks
+    PVE::QemuConfig->foreach_volume(
+        $conf,
+        sub {
+            my ($ds, $drive) = @_;
+            return if PVE::QemuServer::drive_is_cdrom($drive, 1);
+            my $volid = $drive->{file};
+            if ( $volid ne 'none') {
+                my $drive_id = PVE::QemuServer::Drive::get_drive_id($drive);
+                my $snapshots = PVE::Storage::volume_snapshot_info($storecfg, $volid);
+                my $parentid = $snapshots->{'current'}->{parent};
+                # for now only set write_threshold for volumes that have snapshots
+                # FIX: Change to only thin drives
+                if ($parentid) {
+                    PVE::QemuServer::Blockdev::set_write_threshold(
+                        $storecfg, $vmid, $drive_id, $volid
+                    );
+                }
+            }
+        },
+    );
+
     #start nbd server for storage migration
     if (my $nbd = $migrate_opts->{nbd}) {
 

src/PVE/QemuServer/Blockdev.pm

@@ -111,6 +111,21 @@ sub get_block_info {
     return $block_info;
 }
 
+sub get_block_stats {
+    my ($vmid) = @_;
+
+    my $block_stats = {};
+
+    my $qmp_block_stats = mon_cmd($vmid, "query-blockstats");
+    for my $info ($qmp_block_stats->@*) {
+        my $qdev_id = $info->{qdev} or next;
+        my $drive_id = qdev_id_to_drive_id($qdev_id);
+        $block_stats->{$drive_id} = $info;
+    }
+
+    return $block_stats;
+}
+
 my sub get_node_name {
     my ($type, $drive_id, $volid, $options) = @_;
 
@@ -700,6 +715,24 @@ sub resize {
     );
 }
 
+sub underlay_resize {
+    my ($storecfg, $vmid, $drive_id, $volid) = @_;
+
+    my $running = PVE::QemuServer::Helpers::vm_running_locally($vmid);
+
+    # get backing_snap
+    my $snapshots = PVE::Storage::volume_snapshot_info($storecfg, $volid);
+    my $backing_snap = $snapshots->{current}->{parent};
+    my $size = PVE::Storage::volume_underlay_resize($storecfg, $volid, $backing_snap);
+
+    return if !$running;
+    my $block_info = get_block_info($vmid);
+    my $inserted = $block_info->{$drive_id}->{inserted}
+        or die "no block node inserted for drive '$drive_id'\n";
+
+    set_write_threshold($storecfg, $vmid, $drive_id, $volid);
+}
+
 my sub blockdev_change_medium {
     my ($storecfg, $vmid, $qdev_id, $drive) = @_;
 
@@ -820,6 +853,49 @@ sub set_io_throttle {
     }
 }
 
+sub block_set_write_threshold {
+    my ($vmid, $nodename, $threshold) = @_;
+
+    print "set threshold $nodename $threshold\n";
+
+    PVE::QemuServer::mon_cmd(
+        $vmid,
+        "block-set-write-threshold",
+        'node-name' => $nodename,
+        'write-threshold' => int($threshold),
+    );
+}
+
+sub compute_write_threshold {
+    my ($storecfg, $scfg, $volid) = @_;
+
+    my $lv_size = PVE::Storage::volume_underlay_size_info($storecfg, $volid, 5);
+
+    my $write_threshold = $lv_size - $scfg->{chunksize} * (1 - $scfg->{'chunk-percentage'});
+
+    return $write_threshold;
+}
+
+sub set_write_threshold {
+    my ($storecfg, $vmid, $drive_id, $volid, $options) = @_;
+
+    my ($storeid) = PVE::Storage::parse_volume_id($volid);
+    my $scfg = PVE::Storage::storage_config($storecfg, $storeid);
+    my $support_qemu_snapshots = PVE::Storage::volume_qemu_snapshot_method($storecfg, $volid);
+
+    # set write threshold is only supported for lvm storage using
+    # qcow2+external snapshots
+    return if $scfg->{type} ne 'lvm' || $support_qemu_snapshots ne 'mixed';
+    # return if drive is not set as thin
+    # return if !$drive->{thin};
+
+    my $nodename = get_node_name('file', $drive_id, $volid, $options);
+    my $write_threshold = compute_write_threshold($storecfg, $scfg, $volid);
+
+    print "setting threshold for $volid from $storeid\n";
+    block_set_write_threshold($vmid, $nodename, $write_threshold);
+}
+
 sub blockdev_external_snapshot {
     my ($storecfg, $vmid, $machine_version, $deviceid, $drive, $snap, $parent_snap) = @_;
 
@@ -868,6 +944,10 @@ sub blockdev_external_snapshot {
         node => $snap_fmt_blockdev->{'node-name'},
         overlay => $new_fmt_blockdev->{'node-name'},
     );
+
+    # FIX: only if thin
+    my $drive_id = PVE::QemuServer::Drive::get_drive_id($drive);
+    set_write_threshold($storecfg, $vmid, $drive_id, $volid);
 }
 
 sub blockdev_delete {

src/PVE/QemuServer/Drive.pm

@@ -254,6 +254,13 @@ my %drivedesc_base = (
         optional => 1,
         default => 0,
     },
+    thin => {
+        type => 'boolean',
+        description =>
+            'Controls whether a drive should be thin provisioned',
+        optional => 1,
+        default => 0,
+    },
 );
 
 my %iothread_fmt = (

src/qmeventd/qmeventd.c

@@ -43,7 +43,7 @@
 
 #define DEFAULT_KILL_TIMEOUT 60
 
-static int verbose = 0;
+static int verbose = 1;
 static int kill_timeout = DEFAULT_KILL_TIMEOUT;
 static int epoll_fd = 0;
 static const char *progname;
@@ -209,6 +209,25 @@ void handle_qmp_event(struct Client *client, struct json_object *obj) {
 
         // check if a backup is running and kill QEMU process if not
         terminate_check(client);
+    } else if (!strcmp(json_object_get_string(event), "BLOCK_WRITE_THRESHOLD")) {
+        struct json_object *data;
+        struct json_object *nodename;
+        if (json_object_object_get_ex(obj, "data", &data) &&
+            json_object_object_get_ex(data, "node-name", &nodename)) {
+
+            // needs concurrency control
+            char extend_queue_path[] = "/etc/pve/extend-queue";
+            FILE *p_extend_queue = fopen(extend_queue_path, "a");
+            if (p_extend_queue == NULL) {
+                VERBOSE_PRINT(
+                    "%s: Couldn't open extend queue file %s", client->qemu.vmid, extend_queue_path
+                );
+            } else {
+                const char *nodename_string = json_object_get_string(nodename);
+                fprintf(p_extend_queue, "%s: %s\n", client->qemu.vmid, nodename_string);
+            }
+            fclose(p_extend_queue);
+        }
     }
 }