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
public void addRefreshListener(long checkpoint, ActionListener<Void> listener) {
        final boolean readAllowed;
        if (isReadAllowed()) {
            readAllowed = true;
        } else {
            
            
            
            synchronized (postRecoveryMutex) {
                readAllowed = isReadAllowed();
            }
        }
        if (readAllowed) {
            refreshListeners.addOrNotify(checkpoint, listener);
        } else {
            
            listener.onFailure(new IllegalIndexShardStateException(shardId, state, "Read not allowed on IndexShard"));
        }
    }
    private static class RefreshMetricUpdater implements ReferenceManager.RefreshListener {
        private final MeanMetric refreshMetric;
        private long currentRefreshStartTime;
        private Thread callingThread = null;
        private RefreshMetricUpdater(MeanMetric refreshMetric) {
            this.refreshMetric = refreshMetric;
        }
        @Override
        public void beforeRefresh() throws IOException {
            if (Assertions.ENABLED) {
                assert callingThread == null