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
if (pendingLocation == null || pendingLocation.compareTo(lastWriteLocation) <= 0) {
                        return null;
                    } else {
                        return pendingLocation;
                    }
                });
            }
        }
    }
    /**
     * Registers the given listener and invokes it once the shard is active again and all
     * pending refresh translog location has been refreshed. If there is no pending refresh location registered the listener will be
     * invoked immediately.
     * @param listener the listener to invoke once the pending refresh location is visible. The listener will be called with
     *                 <code>true</code> if the listener was registered to wait for a refresh.
     */
    public final void awaitShardSearchActive(Consumer<Boolean> listener) {
        markSearcherAccessed(); 
        final Translog.Location location = pendingRefreshLocation.get();
        if (location != null) {
            addRefreshListener(location, (b) -> {
                pendingRefreshLocation.compareAndSet(location, null);
                listener.accept(true);
            });
        } else {
            listener.accept(false);
        }
    }
    /**
     * Add a listener for refreshes.