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/indices/recovery/RecoveryTarget.java
return false;
    }
    /**
     * cancel the recovery. calling this method will clean temporary files and release the store
     * unless this object is in use (in which case it will be cleaned once all ongoing users call
     * {@link #decRef()}
     * <p>
     * if {@link #cancellableThreads()} was used, the threads will be interrupted.
     */
    public void cancel(String reason) {
        if (finished.compareAndSet(false, true)) {
            try {
                logger.debug("recovery canceled (reason: [{}])", reason);
                cancellableThreads.cancel(reason);
            } finally {
                
                decRef();
            }
        }
    }
    /**
     * fail the recovery and call listener
     *
     * @param e                exception that encapsulating the failure
     * @param sendShardFailure indicates whether to notify the master of the shard failure
     */
    public void fail(RecoveryFailedException e, boolean sendShardFailure) {
        if (finished.compareAndSet(false, true)) {
            try {
                notifyListener(e, sendShardFailure);