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/index/shard/IndexShard.java
/**
     * Returns the current {@link RecoveryState} if this shard is recovering or has been recovering.
     * Returns null if the recovery has not yet started or shard was not recovered (created via an API).
     */
    @Override
    public RecoveryState recoveryState() {
        return this.recoveryState;
    }
    @Override
    public ShardLongFieldRange getTimestampRange() {
        if (mapperService() == null) {
            return ShardLongFieldRange.UNKNOWN; 
        }
        final MappedFieldType mappedFieldType = mapperService().fieldType(DataStream.TimestampField.FIXED_TIMESTAMP_FIELD);
        if (mappedFieldType instanceof DateFieldMapper.DateFieldType == false) {
            return ShardLongFieldRange.UNKNOWN; 
        }
        if (mappedFieldType.isIndexed() == false) {
            return ShardLongFieldRange.UNKNOWN; 
        }
        final ShardLongFieldRange rawTimestampFieldRange;
        try {
            rawTimestampFieldRange = getEngine().getRawFieldRange(DataStream.TimestampField.FIXED_TIMESTAMP_FIELD);
        } catch (IOException | AlreadyClosedException e) {
            logger.debug("exception obtaining range for timestamp field", e);
            return ShardLongFieldRange.UNKNOWN;
        }
        if (rawTimestampFieldRange == ShardLongFieldRange.UNKNOWN) {
            return ShardLongFieldRange.UNKNOWN;
        }