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.
server/src/main/java/org/elasticsearch/indices/recovery/RecoveryState.java
}
    public RecoverySource getRecoverySource() {
        return recoverySource;
    }
    /**
     * Returns recovery source node (only non-null if peer recovery)
     */
    @Nullable
    public DiscoveryNode getSourceNode() {
        return sourceNode;
    }
    public DiscoveryNode getTargetNode() {
        return targetNode;
    }
    public boolean getPrimary() {
        return primary;
    }
    public static RecoveryState readRecoveryState(StreamInput in) throws IOException {
        return new RecoveryState(in);
    }
    @Override
    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
        builder.field(Fields.ID, shardId.id());
        builder.field(Fields.TYPE, recoverySource.getType());
        builder.field(Fields.STAGE, stage.toString());
        builder.field(Fields.PRIMARY, primary);
        builder.timeField(Fields.START_TIME_IN_MILLIS, Fields.START_TIME, timer.startTime);
        if (timer.stopTime > 0) {
            builder.timeField(Fields.STOP_TIME_IN_MILLIS, Fields.STOP_TIME, timer.stopTime);
        }