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 boolean isSystem() {
        return indexSettings.getIndexMetadata().isSystem();
    }
    /**
     * USE THIS METHOD WITH CARE!
     * Returns the primary term the index shard is supposed to be on. In case of primary promotion or when a replica learns about
     * a new term due to a new primary, the term that's exposed here will not be the term that the shard internally uses to assign
     * to operations. The shard will auto-correct its internal operation term, but this might take time.
     * See {@link org.elasticsearch.cluster.metadata.IndexMetadata#primaryTerm(int)}
     */
    public long getPendingPrimaryTerm() {
        return this.pendingPrimaryTerm;
    }
    
    public long getOperationPrimaryTerm() {
        return replicationTracker.getOperationPrimaryTerm();
    }
    /**
     * Returns a unique UUID that identifies this IndexShard instance
     */
    public String getShardUuid() {
        return shardUuid;
    }
    /**
     * Returns the timestamp at which this IndexShard instance was created
     */
    public long getShardCreationTime() {
        return shardCreationTime;
    }