[pve-devel] [PATCH storage v7 5/9] introduce $vtype+meta export formats

[Filip Schauer <f.schauer@proxmox.com>]

These new export formats include a JSON metadata header containing the
vtype and the format. This allows for future extensibility without
breaking backward compatibility when adding additional metadata.

Signed-off-by: Filip Schauer <f.schauer@proxmox.com>
---
 src/PVE/Storage.pm        | 16 ++++++-
 src/PVE/Storage/Plugin.pm | 94 +++++++++++++++++++++++++++++++++------
 2 files changed, 95 insertions(+), 15 deletions(-)

diff --git a/src/PVE/Storage.pm b/src/PVE/Storage.pm
index 88e4e6d..cfadcc4 100755
--- a/src/PVE/Storage.pm
+++ b/src/PVE/Storage.pm
@@ -48,7 +48,21 @@ use constant APIVER => 10;
 # see https://www.gnu.org/software/libtool/manual/html_node/Libtool-versioning.html
 use constant APIAGE => 1;
 
-our $KNOWN_EXPORT_FORMATS = ['raw+size', 'tar+size', 'qcow2+size', 'vmdk+size', 'zfs', 'btrfs'];
+our $KNOWN_EXPORT_FORMATS = [
+    'raw+size',
+    'tar+size',
+    'qcow2+size',
+    'vmdk+size',
+    'zfs',
+    'btrfs',
+    'images+meta',
+    'rootdir+meta',
+    'iso+meta',
+    'vztmpl+meta',
+    'backup+meta',
+    'snippets+meta',
+    'import+meta'
+];
 
 # load standard plugins
 PVE::Storage::DirPlugin->register();
diff --git a/src/PVE/Storage/Plugin.pm b/src/PVE/Storage/Plugin.pm
index a97f449..34f26a3 100644
--- a/src/PVE/Storage/Plugin.pm
+++ b/src/PVE/Storage/Plugin.pm
@@ -1693,6 +1693,25 @@ sub read_common_header($) {
     return $size;
 }
 
+sub write_meta_header($$) {
+    my ($fh, $meta) = @_;
+    my $meta_json = JSON::encode_json($meta);
+    $meta_json = Encode::encode('utf8', $meta_json);
+    syswrite($fh, pack("Q<", length($meta_json)), 8);
+    syswrite($fh, $meta_json, length($meta_json));
+}
+
+sub read_meta_header($) {
+    my ($fh) = @_;
+    sysread($fh, my $meta_size, 8);
+    $meta_size = unpack('Q<', $meta_size);
+    die "import: no meta size found in export header, aborting.\n" if !defined($meta_size);
+    sysread($fh, my $meta_json, $meta_size);
+    $meta_json = Encode::decode('utf8', $meta_json);
+    my $meta = JSON::decode_json($meta_json);
+    return $meta;
+}
+
 # Export a volume into a file handle as a stream of desired format.
 sub volume_export {
     my ($class, $scfg, $storeid, $fh, $volname, $format, $snapshot, $base_snapshot, $with_snapshots) = @_;
@@ -1700,7 +1719,7 @@ sub volume_export {
     my $err_msg = "volume export format $format not available for $class\n";
     if ($scfg->{path} && !defined($snapshot) && !defined($base_snapshot)) {
 	my ($file) = $class->path($scfg, $volname, $storeid) or die $err_msg;
-	my $file_format = ($class->parse_volname($volname))[6];
+	my ($vtype, $file_format) = ($class->parse_volname($volname))[0, 6];
 	my $size = file_size_info($file, undef, $file_format);
 
 	if ($format eq 'raw+size') {
@@ -1723,7 +1742,44 @@ sub volume_export {
 	    die $err_msg if $file_format ne 'subvol';
 	    write_common_header($fh, $size);
 	    run_command(['tar', @COMMON_TAR_FLAGS, '-cf', '-', '-C', $file, '.'],
-	                output => '>&'.fileno($fh));
+			output => '>&'.fileno($fh));
+	    return;
+	} elsif ($format eq "$vtype+meta") {
+	    die "format $file_format cannot be exported without snapshots\n"
+		if !$with_snapshots && $file_format =~ /^qcow2|vmdk$/;
+	    die "format $file_format cannot be exported with snapshots\n"
+		if $with_snapshots && $file_format =~ /^raw|subvol$/;
+
+	    my $data_format;
+	    if ($file_format eq 'subvol') {
+		$data_format = 'tar';
+	    } else {
+		$data_format = $file_format;
+	    }
+
+	    my $meta = {
+		vtype => $vtype,
+		format => $data_format,
+	    };
+
+	    write_meta_header($fh, $meta);
+	    write_common_header($fh, $size);
+	    if ($data_format =~ /^(raw|ova|ovf|qcow2|vmdk)$/) {
+		run_command(
+		    ['dd', "if=$file", "bs=4k", "status=progress"],
+		    output => '>&'.fileno($fh)
+		);
+	    } elsif ($data_format eq 'tar') {
+		run_command(
+		    ['tar', @COMMON_TAR_FLAGS, '-cf', '-', '-C', $file, '.'],
+		    output => '>&'.fileno($fh)
+		);
+	    } else {
+		run_command(
+		    ['qemu-img', 'convert', '-f', $file_format, '-O', 'raw', $file, '/dev/stdout'],
+		    output => '>&'.fileno($fh)
+		);
+	    }
 	    return;
 	}
     }
@@ -1738,11 +1794,11 @@ sub volume_export_formats {
 	my ($vtype, $format) = ($class->parse_volname($volname))[0, 6];
 
 	if ($with_snapshots) {
-	    return ($format.'+size') if ($format eq 'qcow2' || $format eq 'vmdk');
+	    return ("$vtype+meta", $format.'+size') if $format =~ /^(qcow2|vmdk)$/;
 	    return ();
 	}
-	return ('tar+size') if $format eq 'subvol';
-	return ('raw+size') if $vtype =~ /^(iso|snippets|vztmpl|import)$/;
+	return ("$vtype+meta", 'tar+size') if $format eq 'subvol';
+	return ("$vtype+meta", 'raw+size') if $vtype =~ /^(iso|snippets|vztmpl|import)$/;
     }
     return ();
 }
@@ -1751,18 +1807,28 @@ sub volume_export_formats {
 sub volume_import {
     my ($class, $scfg, $storeid, $fh, $volname, $format, $snapshot, $base_snapshot, $with_snapshots, $allow_rename) = @_;
 
-    die "volume import format '$format' not available for $class\n"
-	if $format !~ /^(raw|tar|qcow2|vmdk)\+size$/;
-    my $data_format = $1;
+    my ($vtype, $name, $vmid, $basename, $basevmid, $isBase, $file_format) =
+	$class->parse_volname($volname);
+
+    my $meta;
+    my $data_format;
+
+    if ($format =~ /^(images|rootdir|iso|vztmpl|backup|snippets|import)\+meta$/) {
+	die "volume type does not match import format\n" if $1 ne $vtype;
+	$meta = read_meta_header($fh);
+	die "volume type does not match metadata header\n" if $meta->{vtype} ne $vtype;
+	$data_format = $meta->{format};
+    } elsif ($format =~ /^(raw|tar|qcow2|vmdk)\+size$/) {
+	$data_format = $1;
+    } else {
+	die "volume import format '$format' not available for $class\n";
+    }
 
     die "format $format cannot be imported without snapshots\n"
 	if !$with_snapshots && ($data_format eq 'qcow2' || $data_format eq 'vmdk');
     die "format $format cannot be imported with snapshots\n"
 	if $with_snapshots && ($data_format eq 'raw' || $data_format eq 'tar');
 
-    my ($vtype, $name, $vmid, $basename, $basevmid, $isBase, $file_format) =
-	$class->parse_volname($volname);
-
     # XXX: Should we bother with conversion routines at this level? This won't
     # happen without manual CLI usage, so for now we just error out...
     if (
@@ -1835,11 +1901,11 @@ sub volume_import_formats {
 	my ($vtype, $format) = ($class->parse_volname($volname))[0, 6];
 
 	if ($with_snapshots) {
-	    return ($format.'+size') if ($format eq 'qcow2' || $format eq 'vmdk');
+	    return ("$vtype+meta", $format.'+size') if $format =~ /^(qcow2|vmdk)$/;
 	    return ();
 	}
-	return ('tar+size') if $format eq 'subvol';
-	return ('raw+size') if $vtype =~ /^(iso|snippets|vztmpl|import)$/;
+	return ("$vtype+meta", 'tar+size') if $format eq 'subvol';
+	return ("$vtype+meta", 'raw+size') if $vtype =~ /^(iso|snippets|vztmpl|import)$/;
     }
     return ();
 }
-- 
2.39.5



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