linstor: backupsnapshot improve logging

Author: rp-

plugins/storage/volume/linstor/src/main/java/com/cloud/hypervisor/kvm/resource/wrapper/LinstorBackupSnapshotCommandWrapper.java

@@ -90,18 +90,23 @@ private String convertImageToQCow2(
         // NOTE: the qemu img will also contain the drbd metadata at the end
         final QemuImg qemu = new QemuImg(waitMilliSeconds);
         qemu.convert(srcFile, dstFile);
-        s_logger.info("Backup snapshot " + srcFile + " to " + dstPath);
+        s_logger.info(String.format("Backup snapshot '%s' to '%s'", srcPath, dstPath));
         return dstPath;
     }
 
     private SnapshotObjectTO setCorrectSnapshotSize(final SnapshotObjectTO dst, final String dstPath) {
         final File snapFile = new File(dstPath);
-        final long size = snapFile.exists() ? snapFile.length() : 0;
+        long size;
+        if (snapFile.exists()) {
+            size = snapFile.length();
+        } else {
+            s_logger.warn(String.format("Snapshot file %s does not exist. Reporting size 0", dstPath));
+            size = 0;
+        }
 
-        final SnapshotObjectTO snapshot = new SnapshotObjectTO();
-        snapshot.setPath(dst.getPath() + File.separator + dst.getName());
-        snapshot.setPhysicalSize(size);
-        return snapshot;
+        dst.setPath(dst.getPath() + File.separator + dst.getName());
+        dst.setPhysicalSize(size);
+        return dst;
     }
 
     @Override
@@ -151,6 +156,7 @@ public CopyCmdAnswer execute(LinstorBackupSnapshotCommand cmd, LibvirtComputingR
             s_logger.info("Backup shrunk " + dstPath + " to actual size " + src.getVolume().getSize());
 
             SnapshotObjectTO snapshot = setCorrectSnapshotSize(dst, dstPath);
+            s_logger.info(String.format("Actual file size for '%s' is %d", dstPath, snapshot.getPhysicalSize()));
             return new CopyCmdAnswer(snapshot);
         } catch (final Exception e) {
             final String error = String.format("Failed to backup snapshot with id [%s] with a pool %s, due to %s",