[pve-devel] [PATCH storage 3/4] update import/export storage API

[Wolfgang Bumiller <w.bumiller@proxmox.com>]

This bumps APIVER, but also APIAGE, see below.

The import methods (volume_import, volume_import_formats):
  This additionally gets the '$snapshot' parameter which is
  already present on the export side as an informational
  piece to know which of the snapshots is the *current* one.
  The current "disk" state will be set to this snapshot.
  This, too, is required for our btrfs implementation.
    `volume_import_formats` can obviously not make much
  *use* of this parameter, but it'll still be useful to know
  that the information is actually available in the import
  call, so its presence will be checked in the btrfs
  implementation.

Currently this is intended to be used for btrfs send/recv
support, which in theory could also get additional metadata
similar to how we do the "tar+size" format, however, we
currently only really use this within this repository in
storage_migrate() which has this information readily
available anyway.

On the export side (volume_export, volume_export_formats):
  The `$with_snapshots` option can now also be an ordered
  array of snapshots to include, as a hint for storages
  which need this. (As of the next commit this is only
  btrfs, and only when also specifying a base snapshot,
  which is a case we can currently not run into except on
  the command line interface.)
    The current providers of the `with_snapshot` option will
  still treat it as a boolean (since eg. for ZFS you cannot
  really "skip" snapshots AFAIK).
    This is mainly intended for storages which do not have a
  strong association between snapshots and the originals, or
  an ordering (eg. btrfs and lvm-thin allow creating
  arbitrary snapshot trees, and with btrfs you can even
  create a "circular" connection between subvolumes, also we
  could consider reflink based copies snapshots on xfs in
  the future maybe?)

While `import_formats` and `export_formats` now take the same
parameters, I appended the `$snapshot` parameter to the end of
`import_formats` to the end for compatibility.
Therefore we also bump APIAGE, as apart from the btrfs
storage, none of our other storages need the new parameter.

Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>
---
 PVE/CLI/pvesm.pm | 23 +++++++++++++++++++++--
 PVE/Storage.pm   | 48 ++++++++++++++++++++++++++++++++----------------
 2 files changed, 53 insertions(+), 18 deletions(-)

diff --git a/PVE/CLI/pvesm.pm b/PVE/CLI/pvesm.pm
index d28f1ba..b22f759 100755
--- a/PVE/CLI/pvesm.pm
+++ b/PVE/CLI/pvesm.pm
@@ -276,12 +276,23 @@ __PACKAGE__->register_method ({
 		optional => 1,
 		default => 0,
 	    },
+	    'snapshot-list' => {
+		description => "Ordered list of snapshots to transfer",
+		type => 'string',
+		format => 'string-list',
+		optional => 1,
+	    },
 	},
     },
     returns => { type => 'null' },
     code => sub {
 	my ($param) = @_;
 
+	my $with_snapshots = $param->{'with-snapshots'};
+	if (defined(my $list = $param->{'snapshot-list'})) {
+	    $with_snapshots = PVE::Tools::split_list($list);
+	}
+
 	my $filename = $param->{filename};
 
 	my $outfh;
@@ -295,7 +306,7 @@ __PACKAGE__->register_method ({
 	eval {
 	    my $cfg = PVE::Storage::config();
 	    PVE::Storage::volume_export($cfg, $outfh, $param->{volume}, $param->{format},
-		$param->{snapshot}, $param->{base}, $param->{'with-snapshots'});
+		$param->{snapshot}, $param->{base}, $with_snapshots);
 	};
 	my $err = $@;
 	if ($filename ne '-') {
@@ -361,6 +372,13 @@ __PACKAGE__->register_method ({
 		optional => 1,
 		default => 0,
 	    },
+	    snapshot => {
+		description => "The current-state snapshot if the stream contains snapshots",
+		type => 'string',
+		pattern => qr/[a-z0-9_\-]{1,40}/i,
+		maxLength => 40,
+		optional => 1,
+	    },
 	},
     },
     returns => { type => 'string' },
@@ -436,7 +454,8 @@ __PACKAGE__->register_method ({
 	my $volume = $param->{volume};
 	my $delete = $param->{'delete-snapshot'};
 	my $imported_volid = PVE::Storage::volume_import($cfg, $infh, $volume, $param->{format},
-	    $param->{base}, $param->{'with-snapshots'}, $param->{'allow-rename'});
+	    $param->{base}, $param->{'with-snapshots'}, $param->{'allow-rename'},
+	    $param->{snapshot});
 	PVE::Storage::volume_snapshot_delete($cfg, $imported_volid, $delete)
 	    if defined($delete);
 	return $imported_volid;
diff --git a/PVE/Storage.pm b/PVE/Storage.pm
index f9f8d16..15fcedf 100755
--- a/PVE/Storage.pm
+++ b/PVE/Storage.pm
@@ -41,11 +41,11 @@ use PVE::Storage::PBSPlugin;
 use PVE::Storage::BTRFSPlugin;
 
 # Storage API version. Increment it on changes in storage API interface.
-use constant APIVER => 8;
+use constant APIVER => 9;
 # Age is the number of versions we're backward compatible with.
 # This is like having 'current=APIVER' and age='APIAGE' in libtool,
 # see https://www.gnu.org/software/libtool/manual/html_node/Libtool-versioning.html
-use constant APIAGE => 7;
+use constant APIAGE => 8;
 
 # load standard plugins
 PVE::Storage::DirPlugin->register();
@@ -716,7 +716,8 @@ sub storage_migrate {
     my $send = ['pvesm', 'export', $volid, $format, '-', '-with-snapshots', $with_snapshots];
     my $recv = [@$ssh, '--', 'pvesm', 'import', $target_volid, $format, $import_fn, '-with-snapshots', $with_snapshots];
     if (defined($snapshot)) {
-	push @$send, '-snapshot', $snapshot
+	push @$send, '-snapshot', $snapshot;
+	push @$recv, '-snapshot', $snapshot;
     }
     if ($migration_snapshot) {
 	push @$recv, '-delete-snapshot', $snapshot;
@@ -1716,7 +1717,7 @@ sub prune_mark_backup_group {
     }
 }
 
-sub volume_export {
+sub volume_export : prototype($$$$$$$) {
     my ($cfg, $fh, $volid, $format, $snapshot, $base_snapshot, $with_snapshots) = @_;
 
     my ($storeid, $volname) = parse_volume_id($volid, 1);
@@ -1727,18 +1728,27 @@ sub volume_export {
                                   $snapshot, $base_snapshot, $with_snapshots);
 }
 
-sub volume_import {
-    my ($cfg, $fh, $volid, $format, $base_snapshot, $with_snapshots, $allow_rename) = @_;
+sub volume_import : prototype($$$$$$$$) {
+    my ($cfg, $fh, $volid, $format, $base_snapshot, $with_snapshots, $allow_rename, $snapshot) = @_;
 
     my ($storeid, $volname) = parse_volume_id($volid, 1);
     die "cannot import into volume '$volid'\n" if !$storeid;
     my $scfg = storage_config($cfg, $storeid);
     my $plugin = PVE::Storage::Plugin->lookup($scfg->{type});
-    return $plugin->volume_import($scfg, $storeid, $fh, $volname, $format,
-                                  $base_snapshot, $with_snapshots, $allow_rename) // $volid;
-}
-
-sub volume_export_formats {
+    return $plugin->volume_import(
+	$scfg,
+	$storeid,
+	$fh,
+	$volname,
+	$format,
+	$base_snapshot,
+	$with_snapshots,
+	$allow_rename,
+	$snapshot,
+    ) // $volid;
+}
+
+sub volume_export_formats : prototype($$$$$) {
     my ($cfg, $volid, $snapshot, $base_snapshot, $with_snapshots) = @_;
 
     my ($storeid, $volname) = parse_volume_id($volid, 1);
@@ -1750,21 +1760,27 @@ sub volume_export_formats {
                                           $with_snapshots);
 }
 
-sub volume_import_formats {
-    my ($cfg, $volid, $base_snapshot, $with_snapshots) = @_;
+sub volume_import_formats : prototype($$$$$) {
+    my ($cfg, $volid, $base_snapshot, $with_snapshots, $snapshot) = @_;
 
     my ($storeid, $volname) = parse_volume_id($volid, 1);
     return if !$storeid;
     my $scfg = storage_config($cfg, $storeid);
     my $plugin = PVE::Storage::Plugin->lookup($scfg->{type});
-    return $plugin->volume_import_formats($scfg, $storeid, $volname,
-                                          $base_snapshot, $with_snapshots);
+    return $plugin->volume_import_formats(
+	$scfg,
+	$storeid,
+	$volname,
+	$base_snapshot,
+	$with_snapshots,
+	$snapshot,
+    );
 }
 
 sub volume_transfer_formats {
     my ($cfg, $src_volid, $dst_volid, $snapshot, $base_snapshot, $with_snapshots) = @_;
     my @export_formats = volume_export_formats($cfg, $src_volid, $snapshot, $base_snapshot, $with_snapshots);
-    my @import_formats = volume_import_formats($cfg, $dst_volid, $base_snapshot, $with_snapshots);
+    my @import_formats = volume_import_formats($cfg, $dst_volid, $base_snapshot, $with_snapshots, $snapshot);
     my %import_hash = map { $_ => 1 } @import_formats;
     my @common = grep { $import_hash{$_} } @export_formats;
     return @common;
-- 
2.30.2