Add support for multiple reloads in loadinfo, as for deltas. Download and

create lvm for each image in the list, adding back pointers in the metadata
to the parent so that we can reconstruct the chain later when a container
uses an image. When creating the disk, add loop over image deltas after we
load the base disk image.

clientside/tmcc/linux/xen/libvnode_xen.pm

@@ -277,6 +277,7 @@ sub InitializeRouteTable();
 sub AllocateRouteTable($);
 sub LookupRouteTable($);
 sub FreeRouteTable($);
+sub downloadOneImage($$);
 
 sub getXenInfo()
 {
@@ -2332,6 +2333,23 @@ sub createRootDisk($)
 sub CreatePrimaryDisk($$$$)
 {
     my ($lvname, $imagemetadata, $target, $extrafs) = @_;
+
+    #
+    # If this image is a delta, we have to go back to the base and start
+    # with it. Then lay down each delta on top if it. 
+    #
+    my @deltas = ();
+    if (exists($imagemetadata->{'PARENTIMAGE'})) {
+	while (exists($imagemetadata->{'PARENTIMAGE'})) {
+	    my $parent = $imagemetadata->{'PARENTIMAGE'};
+	    my $parent_metadata;
+	    LoadImageMetadata($parent, \$parent_metadata);
+
+	    push(@deltas, $imagemetadata);
+	    $imagemetadata = $parent_metadata;
+	}
+	$lvname = "image+" . $imagemetadata->{'IMAGENAME'};
+    }
     my $basedisk   = lvmVolumePath($lvname);
     my $rootvndisk = lvmVolumePath($target);
     my $loadslice  = $imagemetadata->{'PART'};
@@ -2500,6 +2518,25 @@ sub CreatePrimaryDisk($$$$)
 	    mysystem2("nice dd if=$basedisk bs=1M count=$chunks | ".
 		      "nice $IMAGEUNZIP -s $loadslice -f -o ".
 		      "                 -W 164 - $rootvndisk");
+	    return -1
+		if ($?);
+
+	    #
+	    # Lay down the deltas.
+	    #
+	    while (@deltas) {
+		my $delta_metadata = pop(@deltas);
+		$lvname   = "image+" . $delta_metadata->{'IMAGENAME'};
+		$basedisk = lvmVolumePath($lvname);
+		$chunks   = $delta_metadata->{'IMAGECHUNKS'};
+	    
+		mysystem2("nice dd if=$basedisk bs=1M count=$chunks | ".
+			  "nice $IMAGEUNZIP -s $loadslice -f -o ".
+			  "                 -W 164 - $rootvndisk");
+
+		return -1
+		    if ($?);
+	    }
 	}
     }
     else {
@@ -2530,31 +2567,93 @@ sub createAuxDisk($$)
 #
 # Create a logical volume for the image if it doesn't already exist.
 #
+# The reload info is now a list, so as to support deltas. The first
+# image is the base, provides the full chunksize of the image; the
+# chunksize of the deltas is really small. The last image is what is
+# the boot image, and its timestamp is the one we care about. Note
+# that we never do deltas for "packaged" images.
+#
 sub createImageDisk($$$)
 {
     my ($image,$vnode_id,$raref) = @_;
+    my $imagelockname = ImageLockName($image);
+
+    #
+    # Drop the shared lock the caller has. We are going to take an exclusive
+    # lock in the function below. We will take the shared lock again
+    # before returning.
+    #
+    TBScriptUnlock();
+
+    #
+    # Process each image in the list.
+    #
+    foreach my $ref (@{$raref}) {
+	goto bad
+	    if (downloadOneImage($vnode_id, $ref));
+    }
+
+    #
+    # To recreate the image later, we have to add parent pointers
+    # to the metadata so we can load each delta on top of the base.
+    #
+    my @images = @{$raref};
+    my $child  = pop(@images);
+    my $child_metadata;
+    LoadImageMetadata($child->{'IMAGENAME'}, \$child_metadata);
+    while (@images) {
+	my $parent = pop(@images);
+	my $parent_metadata;
+	LoadImageMetadata($parent->{'IMAGENAME'}, \$parent_metadata);
+
+	$child_metadata->{'PARENTIMAGE'} = $parent->{'IMAGENAME'};
+	StoreImageMetadata($child->{'IMAGENAME'}, $child_metadata);
+
+	$child = $parent;
+	$child_metadata = $parent_metadata;
+    }
+    
+    # And back to a shared lock.
+    if (TBScriptLock($imagelockname, TBSCRIPTLOCK_SHAREDLOCK(), 1800)
+	!= TBSCRIPTLOCK_OKAY()) {
+	print STDERR "Could not get $imagelockname lock back ".
+	    "after a long time!\n";
+	return -1;
+    }
+    #
+    # XXX note that we don ot declare RELOADDONE here since we have not
+    # actually created the vnode disk yet. That is the caller's
+    # responsibility.
+    #    
+    return 0;
+  bad:
+    return -1;
+}
+
+#
+# Download and create an LVM for a single compressed image.
+#
+sub downloadOneImage($$)
+{
+    my ($vnode_id, $raref) = @_;
+    my $image = $raref->{'IMAGENAME'};
+    my $imagelockname = ImageLockName($image);
     my $tstamp = $raref->{'IMAGEMTIME'};
     my $lvname = "image+" . $image;
     my $lvmpath = lvmVolumePath($lvname);
     my $imagedatepath = "$METAFS/${image}.date";
     my $imagemetapath = "$METAFS/${image}.metadata";
-    my $imagelockname = ImageLockName($image);
     my $imagepath = $lvmpath;
     my $unpack = 0;
     my $nochunks = 0;
     my $lv_size;
 
-    #
-    # We are locked by the caller with a shared lock.
-    #
-    # Need to promote to an exclusive lock.
-    #
-    TBScriptUnlock();
     if (TBScriptLock($imagelockname, undef, 1800) != TBSCRIPTLOCK_OKAY()) {
 	print STDERR "Could not get $imagelockname write lock".
 	    "after a long time!\n";
 	return -1;
     }
+    
     # Ick.
     if (exists($raref->{'MBRVERS'}) && $raref->{'MBRVERS'} == 99) {
 	$unpack = 1;
@@ -2562,9 +2661,7 @@ sub createImageDisk($$$)
     
     #
     # Do we have the right image file already? No need to download it
-    # again if the timestamp matches. Note that we are using the mod
-    # time on the lvm volume path for this, which we set below when
-    # the image is downloaded.
+    # again if the timestamp matches. 
     #
     if (findLVMLogicalVolume($lvname)) {
 	if (-e $imagedatepath) {
@@ -2614,7 +2711,7 @@ sub createImageDisk($$$)
     #
     # XXX Using MBRVERS for now, need something else.
     #
-    if (exists($raref->{'MBRVERS'}) && $raref->{'MBRVERS'} == 99) {
+    if ($unpack) {
 	$lv_size = 6 * 1024;
     }
     elsif (!exists($raref->{'IMAGECHUNKS'})) {
@@ -2633,7 +2730,8 @@ sub createImageDisk($$$)
 	# tmcd may also tell us the sector range of the uncompressed data.
 	# Extract useful tidbits from that.
 	#
-	if (exists($raref->{'IMAGELOW'}) && exists($raref->{'IMAGEHIGH'})) {
+	if (exists($raref->{'IMAGELOW'}) &&
+	    exists($raref->{'IMAGEHIGH'})) {
 	    $raref->{'LVSIZE'} =
 		$raref->{'IMAGEHIGH'} - $raref->{'IMAGELOW'} + 1;
 	}
@@ -2665,7 +2763,16 @@ sub createImageDisk($$$)
 	$imagepath = "$EXTRAFS/${image}.ndz";
     }
 
+    #
     # Now we just download the file, then let create do its normal thing
+    #
+    # Note that raref can be an array now, but downloadImage deals
+    # with that. When it returns, all parts have been loaded into
+    # LVM. We might improve things by putting each part into its
+    # own LVM, so we have them for other images, but if the deltas are
+    # small and the branching limited, it is not worth the effort.
+    # Lets see how it goes ...
+    #
     if (libvnode::downloadImage($imagepath, $unpack, $vnode_id, $raref)) {
 	print STDERR "libvnode_xen: could not download image $image\n";
 	goto bad;
@@ -2733,20 +2840,7 @@ sub createImageDisk($$$)
     StoreImageMetadata($image, $raref);
 
   okay:
-    # And back to a shared lock.
     TBScriptUnlock();
-    if (TBScriptLock($imagelockname, TBSCRIPTLOCK_SHAREDLOCK(), 1800)
-	!= TBSCRIPTLOCK_OKAY()) {
-	print STDERR "Could not get $imagelockname lock back ".
-	    "after a long time!\n";
-	return -1;
-    }
-
-    #
-    # XXX note that we don't declare RELOADDONE here since we haven't
-    # actually created the vnode shadow disk yet.  That is the caller's
-    # responsibility.
-    #
     return 0;
   bad:
     TBScriptUnlock();