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
SnapshotInfo.IndexSnapshotDetails indexSnapshotDetails = snapshotInfo.indexSnapshotDetails().get(index);
            assertThat(indexSnapshotDetails, is(notNullValue()));
            return indexSnapshotDetails.getSize().getBytes();
        }
        return -1;
    }
    private void indexDocs(String indexName, int docIdOffset, int docCount) throws Exception {
        IndexRequestBuilder[] builders = new IndexRequestBuilder[docCount];
        for (int i = 0; i < builders.length; i++) {
            int docId = i + docIdOffset;
            builders[i] = client().prepareIndex(indexName)
                .setId(Integer.toString(docId))
                .setSource("field", docId, "field2", "Some text " + docId);
        }
        indexRandom(true, builders);
        
        assertBusy(() -> {
            ShardStats stats = client().admin()
                .indices()
                .prepareStats(indexName)
                .clear()
                .get()
                .asMap()
                .entrySet()
                .stream()
                .filter(e -> e.getKey().shardId().getId() == 0)
                .map(Map.Entry::getValue)
                .findFirst()
                .orElse(null);
            assertThat(stats, is(notNullValue()));