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
static final String ID = "id";
        static final String TYPE = "type";
        static final String STAGE = "stage";
        static final String PRIMARY = "primary";
        static final String START_TIME = "start_time";
        static final String START_TIME_IN_MILLIS = "start_time_in_millis";
        static final String STOP_TIME = "stop_time";
        static final String STOP_TIME_IN_MILLIS = "stop_time_in_millis";
        static final String TOTAL_TIME = "total_time";
        static final String TOTAL_TIME_IN_MILLIS = "total_time_in_millis";
        static final String SOURCE = "source";
        static final String HOST = "host";