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
}
        return engine.getMergeStats();
    }
    public SegmentsStats segmentStats(boolean includeSegmentFileSizes, boolean includeUnloadedSegments) {
        SegmentsStats segmentsStats = getEngine().segmentsStats(includeSegmentFileSizes, includeUnloadedSegments);
        segmentsStats.addBitsetMemoryInBytes(shardBitsetFilterCache.getMemorySizeInBytes());
        return segmentsStats;
    }
    public WarmerStats warmerStats() {
        return shardWarmerService.stats();
    }
    public FieldDataStats fieldDataStats(String... fields) {
        return shardFieldData.stats(fields);
    }
    public TranslogStats translogStats() {
        return getEngine().getTranslogStats();
    }
    public CompletionStats completionStats(String... fields) {
        readAllowed();
        return getEngine().completionStats(fields);
    }
    public BulkStats bulkStats() {
        return bulkOperationListener.stats();
    }
    /**
     * Executes the given flush request against the engine.
     *
     * @param request the flush request
     * @return <code>false</code> if <code>waitIfOngoing==false</code> and an ongoing request is detected, else <code>true</code>.
     *         If <code>false</code> is returned, no flush happened.