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
MockTransportService targetMockTransportService,
            List<RecoverySnapshotFileRequest> recoverySnapshotFileRequests,
            CheckedRunnable<Exception> awaitForRecoverSnapshotFileRequestReceived,
            Runnable respondToRecoverSnapshotFile
        ) throws Exception;
    }
    private void assertPeerRecoveryUsedSnapshots(String indexName, String sourceNode, String targetNode) {
        RecoveryState recoveryStateIndexRecoveredFromPeer = getLatestPeerRecoveryStateForShard(indexName, 0);
        assertPeerRecoveryWasSuccessful(recoveryStateIndexRecoveredFromPeer, sourceNode, targetNode);
        assertThat(recoveryStateIndexRecoveredFromPeer.getIndex().recoveredFromSnapshotBytes(), is(greaterThan(0L)));
    }
    private void assertPeerRecoveryDidNotUseSnapshots(String indexName, String sourceNode, String targetNode) {
        RecoveryState recoveryStateIndexRecoveredFromPeer = getLatestPeerRecoveryStateForShard(indexName, 0);
        assertPeerRecoveryWasSuccessful(recoveryStateIndexRecoveredFromPeer, sourceNode, targetNode);
        assertThat(recoveryStateIndexRecoveredFromPeer.getIndex().recoveredFromSnapshotBytes(), is(equalTo(0L)));
    }
    private Store.MetadataSnapshot getMetadataSnapshot(String nodeName, String indexName) throws IOException {
        ClusterState clusterState = client().admin().cluster().prepareState().get().getState();
        IndicesService indicesService = internalCluster().getInstance(IndicesService.class, nodeName);
        IndexService indexService = indicesService.indexService(clusterState.metadata().index(indexName).getIndex());
        IndexShard shard = indexService.getShard(0);
        try (Engine.IndexCommitRef indexCommitRef = shard.acquireSafeIndexCommit()) {
            IndexCommit safeCommit = indexCommitRef.getIndexCommit();
            assertThat(safeCommit, is(notNullValue()));
            return shard.store().getMetadata(safeCommit);
        }
    }
    private long getSnapshotSizeForIndex(String repository, String snapshot, String index) {
        GetSnapshotsResponse getSnapshotsResponse = client().admin().cluster().prepareGetSnapshots(repository).addSnapshots(snapshot).get();
        for (SnapshotInfo snapshotInfo : getSnapshotsResponse.getSnapshots()) {