linstor: Support VM-Instance Disk snapshots

This adds VM-Instance disk snapshot support for
Linstor primary storage. Instance snapshots are stored on
the used Linstor storage pool backend and can be converted
into regular volume snapshots and also reverted.

Instance VM snapshots are not fully atomic but with the
create multi snapshot feature as good as it gets.
Snapshots are done over multiple volumes in the same devicemanager run.

plugins/storage/volume/linstor/src/main/java/org/apache/cloudstack/storage/datastore/driver/LinstorPrimaryDataStoreDriverImpl.java

@@ -101,6 +101,7 @@
 import org.apache.cloudstack.storage.datastore.db.StoragePoolVO;
 import org.apache.cloudstack.storage.datastore.util.LinstorConfigurationManager;
 import org.apache.cloudstack.storage.datastore.util.LinstorUtil;
+import org.apache.cloudstack.storage.snapshot.SnapshotObject;
 import org.apache.cloudstack.storage.to.SnapshotObjectTO;
 import org.apache.cloudstack.storage.volume.VolumeObject;
 import org.apache.log4j.Logger;
@@ -970,25 +971,29 @@ private Answer copyTemplate(DataObject srcData, DataObject dstData) {
      * @param api Linstor Developer api object
      * @param pool StoragePool this resource resides on
      * @param rscName rscName of the snapshotted resource
-     * @param snapshotInfo snapshot info of the snapshot
+     * @param snapshotName Name of the snapshot to copy from
+     * @param snapshotObject snapshot object of the origCmd, so the path can be modified
      * @param origCmd original LinstorBackupSnapshotCommand that needs to have a patched path
      * @return answer from agent operation
      * @throws ApiException if any Linstor api operation fails
      */
     private Answer copyFromTemporaryResource(
-            DevelopersApi api, StoragePoolVO pool, String rscName, SnapshotInfo snapshotInfo, CopyCommand origCmd)
+            DevelopersApi api,
+            StoragePoolVO pool,
+            String rscName,
+            String snapshotName,
+            SnapshotObject snapshotObject,
+            CopyCommand origCmd)
             throws ApiException {
         Answer answer;
         String restoreName = rscName + "-rst";
-        String snapshotName = LinstorUtil.RSC_PREFIX + snapshotInfo.getUuid();
         String devName = restoreResourceFromSnapshot(api, pool, rscName, snapshotName, restoreName);
 
         Optional<RemoteHostEndPoint> optEPAny = getLinstorEP(api, restoreName);
         if (optEPAny.isPresent()) {
             // patch the src device path to the temporary linstor resource
-            SnapshotObjectTO soTO = (SnapshotObjectTO)snapshotInfo.getTO();
-            soTO.setPath(devName);
-            origCmd.setSrcTO(soTO);
+            snapshotObject.setPath(devName);
+            origCmd.setSrcTO(snapshotObject.getTO());
             answer = optEPAny.get().sendMessage(origCmd);
         } else{
             answer = new Answer(origCmd, false, "Unable to get matching Linstor endpoint.");
@@ -998,13 +1003,36 @@ private Answer copyFromTemporaryResource(
         return answer;
     }
 
+    /**
+     * vmsnapshots don't have our typical snapshot path set
+     * instead the path is the internal snapshot name e.g.: {vm}_VS_{datestr}
+     * we have to find out and modify the path here before
+     * @return the original snapshotObject.getPath()
+     */
+    private String setCorrectSnapshotPath(DevelopersApi api, String rscName, SnapshotObject snapshotObject)
+            throws ApiException {
+        String originalPath = LinstorUtil.RSC_PREFIX + snapshotObject.getUuid();
+        if (!(snapshotObject.getPath().startsWith("/dev/mapper/") ||
+                snapshotObject.getPath().startsWith("zfs://"))) {
+            originalPath = snapshotObject.getPath();
+            com.linbit.linstor.api.model.StoragePool linStoragePool =
+                    LinstorUtil.getDiskfulStoragePool(api, rscName);
+            if (linStoragePool == null) {
+                throw new CloudRuntimeException("Linstor: Unable to find storage pool for resource " + rscName);
+            }
+            final String path = LinstorUtil.getSnapshotPath(linStoragePool, rscName, snapshotObject.getPath());
+            snapshotObject.setPath(path);
+        }
+        return originalPath;
+    }
+
     protected Answer copySnapshot(DataObject srcData, DataObject destData) {
         String value = _configDao.getValue(Config.BackupSnapshotWait.toString());
         int _backupsnapshotwait = NumbersUtil.parseInt(
             value, Integer.parseInt(Config.BackupSnapshotWait.getDefaultValue()));
 
-        SnapshotInfo snapshotInfo = (SnapshotInfo)srcData;
-        Boolean snapshotFullBackup = snapshotInfo.getFullBackup();
+        SnapshotObject snapshotObject = (SnapshotObject)srcData;
+        Boolean snapshotFullBackup = snapshotObject.getFullBackup();
         final StoragePoolVO pool = _storagePoolDao.findById(srcData.getDataStore().getId());
         final DevelopersApi api = LinstorUtil.getLinstorAPI(pool.getHostAddress());
         boolean fullSnapshot = true;
@@ -1015,29 +1043,31 @@ protected Answer copySnapshot(DataObject srcData, DataObject destData) {
         options.put("fullSnapshot", fullSnapshot + "");
         options.put(SnapshotInfo.BackupSnapshotAfterTakingSnapshot.key(),
             String.valueOf(SnapshotInfo.BackupSnapshotAfterTakingSnapshot.value()));
-        options.put("volumeSize", snapshotInfo.getBaseVolume().getSize() + "");
+        options.put("volumeSize", snapshotObject.getBaseVolume().getSize() + "");
 
         try {
+            final String rscName = LinstorUtil.RSC_PREFIX + snapshotObject.getBaseVolume().getUuid();
+            String snapshotName = setCorrectSnapshotPath(api, rscName, snapshotObject);
+
             CopyCommand cmd = new LinstorBackupSnapshotCommand(
-                srcData.getTO(),
+                snapshotObject.getTO(),
                 destData.getTO(),
                 _backupsnapshotwait,
                 VirtualMachineManager.ExecuteInSequence.value());
             cmd.setOptions(options);
 
-            String rscName = LinstorUtil.RSC_PREFIX + snapshotInfo.getBaseVolume().getUuid();
             Optional<RemoteHostEndPoint> optEP = getDiskfullEP(api, rscName);
             Answer answer;
             if (optEP.isPresent()) {
                 answer = optEP.get().sendMessage(cmd);
             } else {
                 s_logger.debug("No diskfull endpoint found to copy image, creating diskless endpoint");
-                answer = copyFromTemporaryResource(api, pool, rscName, snapshotInfo, cmd);
+                answer = copyFromTemporaryResource(api, pool, rscName, snapshotName, snapshotObject, cmd);
             }
             return answer;
         } catch (Exception e) {
             s_logger.debug("copy snapshot failed: ", e);
-            throw new CloudRuntimeException(e.toString());
+            throw new CloudRuntimeException("Copy snapshot failed, please cleanup snapshot manually: " + e);
         }
 
     }