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Fix in the calculation of a volume's physical size #13286

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77fbaba
Fix the calculation of a volume's physical size
Sep 11, 2026
01ea312
Add missing HashSet import in LibvirtStorageAdaptor
Sep 11, 2026
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4 changes: 4 additions & 0 deletions ...ervisors/kvm/src/main/java/com/cloud/hypervisor/kvm/resource/LibvirtStorageVolumeDef.java
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Original file line number Diff line number Diff line change
Expand Up @@ -83,6 +83,10 @@ public VolumeFormat getFormat() {
return this._volFormat;
}

public Long getVolSize() {
return _volSize;
}

@Override
public String toString() {
StringBuilder storageVolBuilder = new StringBuilder();
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31 changes: 31 additions & 0 deletions ...rs/kvm/src/main/java/com/cloud/hypervisor/kvm/resource/LibvirtStorageVolumeXMLParser.java
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Original file line number Diff line number Diff line change
Expand Up @@ -22,6 +22,7 @@
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.ParserConfigurationException;

import com.cloud.utils.StringUtils;
import org.apache.cloudstack.utils.security.ParserUtils;
import org.apache.logging.log4j.Logger;
import org.apache.logging.log4j.LogManager;
Expand All @@ -35,6 +36,35 @@
public class LibvirtStorageVolumeXMLParser {
protected Logger logger = LogManager.getLogger(getClass());

public String getBackingFileNameIfExists(String volXML) {
try {
DocumentBuilder builder = ParserUtils.getSaferDocumentBuilderFactory().newDocumentBuilder();

InputSource is = new InputSource();
is.setCharacterStream(new StringReader(volXML));
Document doc = builder.parse(is);

Element rootElement = doc.getDocumentElement();
NodeList backingStores = rootElement.getElementsByTagName("backingStore");
if (backingStores.getLength() > 0) {
Element backingStore = (Element) backingStores.item(0);
NodeList pathNodes = backingStore.getElementsByTagName("path");
if (pathNodes.getLength() > 0) {
String path = pathNodes.item(0).getTextContent();
if (StringUtils.isBlank(path)) {
return null;
}
path = path.trim();
int lastSlash = path.lastIndexOf('/');
return lastSlash >= 0 ? path.substring(lastSlash + 1) : path;
}
}
} catch (ParserConfigurationException | SAXException | IOException e) {
logger.error(e.toString(), e);
}
return null;
}

public LibvirtStorageVolumeDef parseStorageVolumeXML(String volXML) {
DocumentBuilder builder;
try {
Expand All @@ -50,6 +80,7 @@ public LibvirtStorageVolumeDef parseStorageVolumeXML(String volXML) {
Element target = (Element)rootElement.getElementsByTagName("target").item(0);
String format = getAttrValue("type", "format", target);
Long capacity = Long.parseLong(getTagValue("capacity", rootElement));

return new LibvirtStorageVolumeDef(VolName, capacity, LibvirtStorageVolumeDef.VolumeFormat.getFormat(format), null, null);
} catch (ParserConfigurationException e) {
logger.debug(e.toString());
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32 changes: 31 additions & 1 deletion ...hypervisors/kvm/src/main/java/com/cloud/hypervisor/kvm/storage/LibvirtStorageAdaptor.java
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Original file line number Diff line number Diff line change
Expand Up @@ -27,6 +27,7 @@
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.HashSet;
import java.util.UUID;
import java.util.concurrent.ConcurrentHashMap;
import java.util.stream.Collectors;
Expand Down Expand Up @@ -505,6 +506,12 @@ public LibvirtStoragePoolDef getStoragePoolDef(Connect conn, StoragePool pool) t
return parser.parseStoragePoolXML(poolDefXML);
}

private String getBackingFileOfVolumeIfExists(StorageVol vol) throws LibvirtException {
String volDefXML = vol.getXMLDesc(0);
LibvirtStorageVolumeXMLParser parser = new LibvirtStorageVolumeXMLParser();
return parser.getBackingFileNameIfExists(volDefXML);
}

public LibvirtStorageVolumeDef getStorageVolumeDef(Connect conn, StorageVol vol) throws LibvirtException {
String volDefXML = vol.getXMLDesc(0);
LibvirtStorageVolumeXMLParser parser = new LibvirtStorageVolumeXMLParser();
Expand Down Expand Up @@ -655,6 +662,28 @@ public KVMStoragePool getStoragePool(String uuid, boolean refreshInfo) {
}
}

private Long getBackingFileSizes(StoragePool pool, StorageVol vol) throws LibvirtException {
long total = 0L;
Set<String> visited = new HashSet<>();
StorageVol current = vol;

while (current != null) {
total += current.getInfo().allocation;
String backingName = getBackingFileOfVolumeIfExists(current);
if (StringUtils.isBlank(backingName) || !visited.add(backingName)) {
break;
}
try {
current = getVolume(pool, backingName);

@Damans227 Damans227 Oct 13, 2026

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what happens when the backing file isnt found in this pool? looks like each miss refreshes the whole pool, and this runs for every volume on each stats pass

@JoaoJandre JoaoJandre Oct 13, 2026

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If the backing file is not on the pool. Then the VM is inconsistent and likely corrupt. This should never happen currently.

@Damans227 Damans227 Oct 19, 2026

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ok, so the refresh only runs on a broken volume. that covers it

} catch (CloudRuntimeException e) {
logger.error("Unable to resolve backing volume {} in pool {}: {}", backingName, pool.getName(), e.getMessage());
break;
}
}

return total;
}

@Override
public KVMPhysicalDisk getPhysicalDisk(String volumeUuid, KVMStoragePool pool) {
LibvirtStoragePool libvirtPool = (LibvirtStoragePool)pool;
Expand All @@ -663,8 +692,9 @@ public KVMPhysicalDisk getPhysicalDisk(String volumeUuid, KVMStoragePool pool) {
StorageVol vol = getVolume(libvirtPool.getPool(), volumeUuid);
KVMPhysicalDisk disk;
LibvirtStorageVolumeDef voldef = getStorageVolumeDef(libvirtPool.getPool().getConnect(), vol);
Long allSizes = getBackingFileSizes(libvirtPool.getPool(), vol);
disk = new KVMPhysicalDisk(vol.getPath(), vol.getName(), pool);
disk.setSize(vol.getInfo().allocation);
disk.setSize(allSizes);

@Damans227 Damans227 Oct 13, 2026

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wont every volume made from the same template now count the whole template too? adding up the volumes on a pool would count it many times

@JoaoJandre JoaoJandre Oct 13, 2026

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I'm not sure I understood your question. But yes, volumes with linked clone templates will also account for the template size in the volume size. Which is congruent with what would be seen from inside the VM.

@Damans227 Damans227 Oct 19, 2026

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makes sense if its meant to match what the vm sees. that covers it

disk.setVirtualSize(vol.getInfo().capacity);

/**
Expand Down
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