[pve-devel] [PATCH v5 qemu-server 3/10] migration: only migrate disks used by the guest

[Aaron Lauterer]

When scanning all configured storages for disk images belonging to the
VM, the migration could easily fail if a storage is not available, but
enabled. That storage might not even be used by the VM at all.

By not scanning all storages and only looking at the disk images
referenced in the VM config, we can avoid unnecessary failures.
Some information that used to be provided by the storage scanning needs
to be fetched explicilty (size, format).

Behaviorally the biggest change is that unreferenced disk images will
not be migrated anymore. Only images referenced in the config will be
migrated.

The tests have been adapted accordingly.

Signed-off-by: Aaron Lauterer <a.lauterer at proxmox.com>
---
changes since v4:
- reordered
- kept check if snaphots on qcow2 exist
- fixed return values in mock volume_size_info()
- removed missed fixme in tests that doesn't apply anymore

 PVE/QemuMigrate.pm                    | 52 +++++----------------------
 test/MigrationTest/QemuMigrateMock.pm | 10 ++++++
 test/run_qemu_migrate_tests.pl        | 12 +++----
 3 files changed, 25 insertions(+), 49 deletions(-)

diff --git a/PVE/QemuMigrate.pm b/PVE/QemuMigrate.pm
index b10a515..4f6ab64 100644
--- a/PVE/QemuMigrate.pm
+++ b/PVE/QemuMigrate.pm
@@ -317,49 +317,6 @@ sub scan_local_volumes {
 	    $abort = 1;
 	};
 
-	my @sids = PVE::Storage::storage_ids($storecfg);
-	foreach my $storeid (@sids) {
-	    my $scfg = PVE::Storage::storage_config($storecfg, $storeid);
-	    next if $scfg->{shared} && !$self->{opts}->{remote};
-	    next if !PVE::Storage::storage_check_enabled($storecfg, $storeid, undef, 1);
-
-	    # get list from PVE::Storage (for unused volumes)
-	    my $dl = PVE::Storage::vdisk_list($storecfg, $storeid, $vmid, undef, 'images');
-
-	    next if @{$dl->{$storeid}} == 0;
-
-	    my $targetsid = PVE::JSONSchema::map_id($self->{opts}->{storagemap}, $storeid);
-	    if (!$self->{opts}->{remote}) {
-		# check if storage is available on target node
-		my $target_scfg = PVE::Storage::storage_check_enabled(
-		    $storecfg,
-		    $targetsid,
-		    $self->{node},
-		);
-
-		die "content type 'images' is not available on storage '$targetsid'\n"
-		    if !$target_scfg->{content}->{images};
-
-	    }
-
-	    my $bwlimit = $self->get_bwlimit($storeid, $targetsid);
-
-	    PVE::Storage::foreach_volid($dl, sub {
-		my ($volid, $sid, $volinfo) = @_;
-
-		$local_volumes->{$volid}->{ref} = 'storage';
-		$local_volumes->{$volid}->{size} = $volinfo->{size};
-		$local_volumes->{$volid}->{targetsid} = $targetsid;
-		$local_volumes->{$volid}->{bwlimit} = $bwlimit;
-
-		# If with_snapshots is not set for storage migrate, it tries to use
-		# a raw+size stream, but on-the-fly conversion from qcow2 to raw+size
-		# back to qcow2 is currently not possible.
-		$local_volumes->{$volid}->{snapshots} = ($volinfo->{format} =~ /^(?:qcow2|vmdk)$/);
-		$local_volumes->{$volid}->{format} = $volinfo->{format};
-	    });
-	}
-
 	my $replicatable_volumes = !$self->{replication_jobcfg} ? {}
 	    : PVE::QemuConfig->get_replicatable_volumes($storecfg, $vmid, $conf, 0, 1);
 	foreach my $volid (keys %{$replicatable_volumes}) {
@@ -408,6 +365,11 @@ sub scan_local_volumes {
 	    $local_volumes->{$volid}->{ref} = 'storage' if $attr->{is_unused};
 	    $local_volumes->{$volid}->{ref} = 'generated' if $attr->{is_tpmstate};
 
+	    $local_volumes->{$volid}->{bwlimit} = $self->get_bwlimit($sid, $targetsid);
+	    $local_volumes->{$volid}->{targetsid} = $targetsid;
+
+	    $local_volumes->{$volid}->@{qw(size format)} = PVE::Storage::volume_size_info($storecfg, $volid);
+
 	    $local_volumes->{$volid}->{is_vmstate} = $attr->{is_vmstate} ? 1 : 0;
 
 	    $local_volumes->{$volid}->{drivename} = $attr->{drivename}
@@ -420,6 +382,10 @@ sub scan_local_volumes {
 		}
 		die "local cdrom image\n";
 	    }
+	    # If with_snapshots is not set for storage migrate, it tries to use
+	    # a raw+size stream, but on-the-fly conversion from qcow2 to raw+size
+	    # back to qcow2 is currently not possible.
+	    $local_volumes->{$volid}->{snapshots} = ($local_volumes->{$volid}->{format} =~ /^(?:qcow2|vmdk)$/);
 
 	    my ($path, $owner) = PVE::Storage::path($storecfg, $volid);
 
diff --git a/test/MigrationTest/QemuMigrateMock.pm b/test/MigrationTest/QemuMigrateMock.pm
index 94fe686..1efabe2 100644
--- a/test/MigrationTest/QemuMigrateMock.pm
+++ b/test/MigrationTest/QemuMigrateMock.pm
@@ -240,6 +240,16 @@ $MigrationTest::Shared::storage_module->mock(
 
 	delete $source_volids->{$volid};
     },
+    volume_size_info => sub {
+	my ($scfg, $volid) = @_;
+	my ($storeid, $volname) = PVE::Storage::parse_volume_id($volid);
+
+	for my $v ($source_vdisks->{$storeid}->@*) {
+	    return wantarray ? ($v->{size}, $v->{format}, $v->{used}, $v->{parent}) : $v->{size}
+		if $v->{volid} eq $volid;
+	}
+	die "could not find '$volid' in mock 'source_vdisks'\n";
+    },
 );
 
 $MigrationTest::Shared::tools_module->mock(
diff --git a/test/run_qemu_migrate_tests.pl b/test/run_qemu_migrate_tests.pl
index 090449f..fedbc32 100755
--- a/test/run_qemu_migrate_tests.pl
+++ b/test/run_qemu_migrate_tests.pl
@@ -708,7 +708,6 @@ my $tests = [
 	},
     },
     {
-	# FIXME: Maybe add orphaned drives as unused?
 	name => '149_running_orphaned_disk_targetstorage_zfs',
 	target => 'pve1',
 	vmid => 149,
@@ -729,10 +728,11 @@ my $tests = [
 	},
 	expected_calls => $default_expected_calls_online,
 	expected => {
-	    source_volids => {},
+	    source_volids => {
+		'local-dir:149/vm-149-disk-0.qcow2' => 1,
+	    },
 	    target_volids => {
 		'local-zfs:vm-149-disk-10' => 1,
-		'local-zfs:vm-149-disk-0' => 1,
 	    },
 	    vm_config => get_patched_config(149, {
 		scsi0 => 'local-zfs:vm-149-disk-10,format=raw,size=4G',
@@ -745,7 +745,6 @@ my $tests = [
 	},
     },
     {
-	# FIXME: Maybe add orphaned drives as unused?
 	name => '149_running_orphaned_disk',
 	target => 'pve1',
 	vmid => 149,
@@ -765,10 +764,11 @@ my $tests = [
 	},
 	expected_calls => $default_expected_calls_online,
 	expected => {
-	    source_volids => {},
+	    source_volids => {
+		'local-dir:149/vm-149-disk-0.qcow2' => 1,
+	    },
 	    target_volids => {
 		'local-lvm:vm-149-disk-10' => 1,
-		'local-dir:149/vm-149-disk-0.qcow2' => 1,
 	    },
 	    vm_config => get_patched_config(149, {
 		scsi0 => 'local-lvm:vm-149-disk-10,format=raw,size=4G',
-- 
2.39.2