We saw a case where the recovery stats reported `recovered_bytes` greater than `length_in_bytes` for one file:

```
GET /_recovery?detailed

200 OK
...
{
  "name": "_buk.fdt",
  "length_in_bytes": 26891307173,
  "reused": false,
  "recovered_in_bytes": 35324928266,
  "recovered_from_snapshot_in_bytes": 8433621093
}
...
```

NB `35324928266 == 26891307173 + 8433621093`

This causes Elasticsearch to compute a negative value for the reserved space on the target node of this recovery, which prevents stats APIs from working. This appears to be caused by a network-level failure which triggers a retry without first cancelling an ongoing download of a different file with the same name from the snapshot repository.

---

### Workaround

Restart the target node to clear these stats.
x-pack/plugin/snapshot-based-recoveries/src/internalClusterTest/java/org/elasticsearch/xpack/snapshotbasedrecoveries/recovery/SnapshotBasedIndexRecoveryIT.java
import org.elasticsearch.indices.recovery.DelayRecoveryException;
import org.elasticsearch.indices.recovery.PeerRecoverySourceService;
import org.elasticsearch.indices.recovery.PeerRecoveryTargetService;
import org.elasticsearch.indices.recovery.RecoverySettings;
import org.elasticsearch.indices.recovery.RecoverySnapshotFileRequest;
import org.elasticsearch.indices.recovery.RecoverySourceHandler;
import org.elasticsearch.indices.recovery.RecoveryState;
import org.elasticsearch.plugins.Plugin;
import org.elasticsearch.plugins.RepositoryPlugin;
import org.elasticsearch.repositories.IndexId;
import org.elasticsearch.repositories.RepositoriesService;
import org.elasticsearch.repositories.Repository;
import org.elasticsearch.repositories.blobstore.BlobStoreRepository;
import org.elasticsearch.repositories.fs.FsRepository;
import org.elasticsearch.search.SearchHit;
import org.elasticsearch.search.sort.SortOrder;
import org.elasticsearch.snapshots.AbstractSnapshotIntegTestCase;
import org.elasticsearch.snapshots.RestoreInfo;
import org.elasticsearch.snapshots.SnapshotInfo;
import org.elasticsearch.test.ESIntegTestCase;
import org.elasticsearch.test.InternalSettingsPlugin;
import org.elasticsearch.test.MockLogAppender;
import org.elasticsearch.test.junit.annotations.TestLogging;
import org.elasticsearch.test.transport.MockTransportService;
import org.elasticsearch.transport.Transport;
import org.elasticsearch.transport.TransportChannel;
import org.elasticsearch.transport.TransportService;
import org.elasticsearch.xcontent.NamedXContentRegistry;
import java.io.FilterInputStream;
import java.io.IOException;