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
assertThat(restoredIndexDataNodes.contains(sourceNode), is(equalTo(true)));
        assertThat(restoredIndexDataNodes.contains(targetNode), is(equalTo(true)));
        assertPeerRecoveryWasSuccessful(recoveryState, sourceNode, targetNode);
        
        
        InstrumentedRepo sourceRepo = getRepositoryOnNode(repoName, sourceNode);
        InstrumentedRepo targetRepo = getRepositoryOnNode(repoName, targetNode);
        assertThat(sourceRepo.totalBytesRead.get(), is(equalTo(targetRepo.totalBytesRead.get())));
        long snapshotSizeForIndex = getSnapshotSizeForIndex(repoName, "snap", indexName);
        assertThat(sourceRepo.totalBytesRead.get(), is(greaterThan(0L)));
        assertThat(sourceRepo.totalBytesRead.get(), is(lessThanOrEqualTo(snapshotSizeForIndex)));
    }
    public void testReplicaRecoveryUsesSnapshots() throws Exception {
        List<String> dataNodes = internalCluster().startDataOnlyNodes(3);
        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(MergePolicyConfig.INDEX_MERGE_ENABLED, false)
                .put(IndexService.GLOBAL_CHECKPOINT_SYNC_INTERVAL_SETTING.getKey(), "1s")
                .put("index.routing.allocation.include._name", String.join(",", dataNodes))
                .build()
        );
        int numDocs = randomIntBetween(300, 1000);
        indexDocs(indexName, 0, numDocs);
        String repoName = "repo";
        createRepo(repoName, TestRepositoryPlugin.INSTRUMENTED_TYPE);
        createSnapshot(repoName, "snap", Collections.singletonList(indexName));