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
String indexName = randomAlphaOfLength(10).toLowerCase(Locale.ROOT);
        createIndex(
            indexName,
            Settings.builder()
                .put(IndexMetadata.SETTING_NUMBER_OF_SHARDS, 1)
                .put(IndexMetadata.SETTING_NUMBER_OF_REPLICAS, 0)
                .put(IndexService.GLOBAL_CHECKPOINT_SYNC_INTERVAL_SETTING.getKey(), "1s")
                .put("index.routing.allocation.require._name", sourceNode)
                .build()
        );
        int numDocs = randomIntBetween(300, 1000);
        indexDocs(indexName, 0, numDocs);
        String repoName = "repo";
        createRepo(repoName, TestRepositoryPlugin.INSTRUMENTED_TYPE);
        createSnapshot(repoName, "snap", Collections.singletonList(indexName));
        int docsIndexedAfterSnapshot = randomIntBetween(1, 2000);
        indexDocs(indexName, numDocs, docsIndexedAfterSnapshot);
        forceMerge();
        String targetNode = internalCluster().startDataOnlyNode();
        assertAcked(
            client().admin()
                .indices()
                .prepareUpdateSettings(indexName)
                .setSettings(Settings.builder().put("index.routing.allocation.require._name", targetNode))
                .get()
        );
        ensureGreen();
        RecoveryState recoveryState = getLatestPeerRecoveryStateForShard(indexName, 0);
        assertPeerRecoveryWasSuccessful(recoveryState, sourceNode, targetNode);
        InstrumentedRepo repository = getRepositoryOnNode(repoName, targetNode);