linstor/kvm: Workaround a qemu bug and IDE bus discard enabled. (#9859)

qemu has a bug versions prior 7.0 with discard enabled and using the IDE bus.
It would crash the qemu process and kill the virtual machine,
this is most noticeable on installing a windows guest from the
Windows ISO installer.

plugins/hypervisors/kvm/src/main/java/com/cloud/hypervisor/kvm/resource/LibvirtComputingResource.java

@@ -375,6 +375,7 @@ public class LibvirtComputingResource extends ServerResourceBase implements Serv
     protected static final String DEFAULT_TUNGSTEN_VIF_DRIVER_CLASS_NAME = "com.cloud.hypervisor.kvm.resource.VRouterVifDriver";
     private final static long HYPERVISOR_LIBVIRT_VERSION_SUPPORTS_IO_URING = 6003000;
     private final static long HYPERVISOR_QEMU_VERSION_SUPPORTS_IO_URING = 5000000;
+    private final static long HYPERVISOR_QEMU_VERSION_IDE_DISCARD_FIXED = 7000000;
 
     protected HypervisorType hypervisorType;
     protected String hypervisorURI;
@@ -3033,7 +3034,7 @@ public class LibvirtComputingResource extends ServerResourceBase implements Serv
                 }
             } else if (volume.getType() != Volume.Type.ISO) {
                 final PrimaryDataStoreTO store = (PrimaryDataStoreTO)data.getDataStore();
-                physicalDisk = storagePoolManager.getPhysicalDisk(store.getPoolType(), store.getUuid(), data.getPath());
+                physicalDisk = getStoragePoolMgr().getPhysicalDisk(store.getPoolType(), store.getUuid(), data.getPath());
                 pool = physicalDisk.getPool();
             }
 
@@ -3128,7 +3129,7 @@ public class LibvirtComputingResource extends ServerResourceBase implements Serv
                     else {
                         disk.defBlockBasedDisk(physicalDisk.getPath(), devId, diskBusType);
                     }
-                    if (pool.getType() == StoragePoolType.Linstor) {
+                    if (pool.getType() == StoragePoolType.Linstor && isQemuDiscardBugFree(diskBusType)) {
                         disk.setDiscard(DiscardType.UNMAP);
                     }
                 } else {
@@ -3275,6 +3276,16 @@ public class LibvirtComputingResource extends ServerResourceBase implements Serv
         return isUbuntuHost() || isIoUringSupportedByQemu();
     }
 
+    /**
+     * Qemu has a bug with discard enabled on IDE bus devices if qemu version < 7.0.
+     * <a href="https://bugzilla.redhat.com/show_bug.cgi?id=2029980">redhat bug entry</a>
+     * @param diskBus used for the disk
+     * @return true if it is safe to enable discard, otherwise false.
+     */
+    public boolean isQemuDiscardBugFree(DiskDef.DiskBus diskBus) {
+        return diskBus != DiskDef.DiskBus.IDE || getHypervisorQemuVersion() >= HYPERVISOR_QEMU_VERSION_IDE_DISCARD_FIXED;
+    }
+
     public boolean isUbuntuHost() {
         Map<String, String> versionString = getVersionStrings();
         String hostKey = "Host.OS";

plugins/hypervisors/kvm/src/main/java/com/cloud/hypervisor/kvm/storage/KVMStorageProcessor.java

@@ -1444,7 +1444,7 @@ public class KVMStorageProcessor implements StorageProcessor {
                     diskdef.defFileBasedDisk(attachingDisk.getPath(), devId, busT, DiskDef.DiskFmtType.QCOW2);
                 } else if (attachingDisk.getFormat() == PhysicalDiskFormat.RAW) {
                     diskdef.defBlockBasedDisk(attachingDisk.getPath(), devId, busT);
-                    if (attachingPool.getType() == StoragePoolType.Linstor) {
+                    if (attachingPool.getType() == StoragePoolType.Linstor && resource.isQemuDiscardBugFree(busT)) {
                         diskdef.setDiscard(DiscardType.UNMAP);
                     }
                 }

plugins/hypervisors/kvm/src/test/java/com/cloud/hypervisor/kvm/resource/LibvirtComputingResourceTest.java

@@ -58,9 +58,12 @@ import javax.xml.xpath.XPathFactory;
 
 import com.cloud.utils.net.NetUtils;
 
+import com.cloud.vm.VmDetailConstants;
 import org.apache.cloudstack.api.ApiConstants.IoDriverPolicy;
 import org.apache.cloudstack.storage.command.AttachAnswer;
 import org.apache.cloudstack.storage.command.AttachCommand;
+import org.apache.cloudstack.storage.to.PrimaryDataStoreTO;
+import org.apache.cloudstack.storage.to.VolumeObjectTO;
 import org.apache.cloudstack.utils.bytescale.ByteScaleUtils;
 import org.apache.cloudstack.utils.linux.CPUStat;
 import org.apache.cloudstack.utils.linux.MemStat;
@@ -6295,4 +6298,114 @@ public class LibvirtComputingResourceTest {
             Assert.assertEquals(expectedShares, libvirtComputingResourceSpy.getHostCpuMaxCapacity());
         }
     }
+
+    @Test
+    public void createLinstorVdb() throws LibvirtException, InternalErrorException, URISyntaxException {
+        final Connect connect = Mockito.mock(Connect.class);
+
+        final int id = random.nextInt(65534);
+        final String name = "test-instance-1";
+
+        final int cpus = 2;
+        final int speed = 1024;
+        final int minRam = 256 * 1024;
+        final int maxRam = 512 * 1024;
+        final String os = "Ubuntu";
+        final String vncPassword = "mySuperSecretPassword";
+
+        final VirtualMachineTO to = new VirtualMachineTO(id, name, VirtualMachine.Type.User, cpus, speed, minRam,
+                maxRam, BootloaderType.HVM, os, false, false, vncPassword);
+        to.setVncAddr("");
+        to.setArch("x86_64");
+        to.setUuid("b0f0a72d-7efb-3cad-a8ff-70ebf30b3af9");
+        to.setVcpuMaxLimit(cpus + 1);
+        final HashMap<String, String> vmToDetails = new HashMap<>();
+        to.setDetails(vmToDetails);
+
+        String diskLinPath = "9ebe53c1-3d35-46e5-b7aa-6fc223ba0fcf";
+        final DiskTO diskTO = new DiskTO();
+        diskTO.setDiskSeq(1L);
+        diskTO.setType(Volume.Type.ROOT);
+        diskTO.setDetails(new HashMap<>());
+        diskTO.setPath(diskLinPath);
+
+        final PrimaryDataStoreTO primaryDataStoreTO = Mockito.mock(PrimaryDataStoreTO.class);
+        String pDSTOUUID = "9ebe53c1-3d35-46e5-b7aa-6fc223ac4fcf";
+        when(primaryDataStoreTO.getPoolType()).thenReturn(StoragePoolType.Linstor);
+        when(primaryDataStoreTO.getUuid()).thenReturn(pDSTOUUID);
+
+        VolumeObjectTO dataTO = new VolumeObjectTO();
+
+        dataTO.setUuid("12be53c1-3d35-46e5-b7aa-6fc223ba0f34");
+        dataTO.setPath(diskTO.getPath());
+        dataTO.setDataStore(primaryDataStoreTO);
+        diskTO.setData(dataTO);
+        to.setDisks(new DiskTO[]{diskTO});
+
+        String path = "/dev/drbd1020";
+        final KVMStoragePoolManager storagePoolMgr = Mockito.mock(KVMStoragePoolManager.class);
+        final KVMStoragePool storagePool = Mockito.mock(KVMStoragePool.class);
+        final KVMPhysicalDisk vol = Mockito.mock(KVMPhysicalDisk.class);
+
+        when(libvirtComputingResourceSpy.getStoragePoolMgr()).thenReturn(storagePoolMgr);
+        when(storagePool.getType()).thenReturn(StoragePoolType.Linstor);
+        when(storagePoolMgr.getPhysicalDisk(StoragePoolType.Linstor, pDSTOUUID, diskLinPath)).thenReturn(vol);
+        when(vol.getPath()).thenReturn(path);
+        when(vol.getPool()).thenReturn(storagePool);
+        when(vol.getFormat()).thenReturn(PhysicalDiskFormat.RAW);
+
+        // 1. test Bus: IDE and broken qemu version -> NO discard
+        when(libvirtComputingResourceSpy.getHypervisorQemuVersion()).thenReturn(6000000L);
+        vmToDetails.put(VmDetailConstants.ROOT_DISK_CONTROLLER, DiskDef.DiskBus.IDE.name());
+        {
+            LibvirtVMDef vm = new LibvirtVMDef();
+            vm.addComp(new DevicesDef());
+            libvirtComputingResourceSpy.createVbd(connect, to, name, vm);
+
+            DiskDef rootDisk = vm.getDevices().getDisks().get(0);
+            assertEquals(DiskDef.DiskType.BLOCK, rootDisk.getDiskType());
+            assertEquals(DiskDef.DiskBus.IDE, rootDisk.getBusType());
+            assertEquals(DiskDef.DiscardType.IGNORE, rootDisk.getDiscard());
+        }
+
+        // 2. test Bus: VIRTIO and broken qemu version -> discard unmap
+        vmToDetails.put(VmDetailConstants.ROOT_DISK_CONTROLLER, DiskDef.DiskBus.VIRTIO.name());
+        {
+            LibvirtVMDef vm = new LibvirtVMDef();
+            vm.addComp(new DevicesDef());
+            libvirtComputingResourceSpy.createVbd(connect, to, name, vm);
+
+            DiskDef rootDisk = vm.getDevices().getDisks().get(0);
+            assertEquals(DiskDef.DiskType.BLOCK, rootDisk.getDiskType());
+            assertEquals(DiskDef.DiskBus.VIRTIO, rootDisk.getBusType());
+            assertEquals(DiskDef.DiscardType.UNMAP, rootDisk.getDiscard());
+        }
+
+        // 3. test Bus; IDE and "good" qemu version -> discard unmap
+        vmToDetails.put(VmDetailConstants.ROOT_DISK_CONTROLLER, DiskDef.DiskBus.IDE.name());
+        when(libvirtComputingResourceSpy.getHypervisorQemuVersion()).thenReturn(7000000L);
+        {
+            LibvirtVMDef vm = new LibvirtVMDef();
+            vm.addComp(new DevicesDef());
+            libvirtComputingResourceSpy.createVbd(connect, to, name, vm);
+
+            DiskDef rootDisk = vm.getDevices().getDisks().get(0);
+            assertEquals(DiskDef.DiskType.BLOCK, rootDisk.getDiskType());
+            assertEquals(DiskDef.DiskBus.IDE, rootDisk.getBusType());
+            assertEquals(DiskDef.DiscardType.UNMAP, rootDisk.getDiscard());
+        }
+
+        // 4. test Bus: VIRTIO and "good" qemu version -> discard unmap
+        vmToDetails.put(VmDetailConstants.ROOT_DISK_CONTROLLER, DiskDef.DiskBus.VIRTIO.name());
+        {
+            LibvirtVMDef vm = new LibvirtVMDef();
+            vm.addComp(new DevicesDef());
+            libvirtComputingResourceSpy.createVbd(connect, to, name, vm);
+
+            DiskDef rootDisk = vm.getDevices().getDisks().get(0);
+            assertEquals(DiskDef.DiskType.BLOCK, rootDisk.getDiskType());
+            assertEquals(DiskDef.DiskBus.VIRTIO, rootDisk.getBusType());
+            assertEquals(DiskDef.DiscardType.UNMAP, rootDisk.getDiscard());
+        }
+    }
 }

plugins/storage/volume/linstor/CHANGELOG.md

@@ -5,6 +5,13 @@ All notable changes to Linstor CloudStack plugin will be documented in this file
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [2024-10-28]
+
+### Fixed
+
+- Disable discard="unmap" for ide devices and qemu < 7.0
+  https://bugzilla.redhat.com/show_bug.cgi?id=2029980
+
 ## [2024-10-04]
 
 ### Added