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/RecoveryState.java
public synchronized int recoveredOperations() {
            return recovered;
        }
        /**
         * returns the total number of translog operations needed to be recovered at this moment.
         * Note that this can change as the number of operations grows during recovery.
         * <p>
         * A value of -1 ({@link RecoveryState.Translog#UNKNOWN} is return if this is unknown (typically a gateway recovery)
         */
        public synchronized int totalOperations() {
            return total;
        }
        public synchronized void totalOperations(int total) {
            this.total = totalLocal == UNKNOWN ? total : totalLocal + total;
            assert total == UNKNOWN || this.total >= recovered
                : "total, if known, should be > recovered. total [" + total + "], recovered [" + recovered + "]";
        }
        /**
         * returns the total number of translog operations to recovered, on the start of the recovery. Unlike {@link #totalOperations}
         * this does change during recovery.
         * <p>
         * A value of -1 ({@link RecoveryState.Translog#UNKNOWN} is return if this is unknown (typically a gateway recovery)
         */
        public synchronized int totalOperationsOnStart() {
            return this.totalOnStart;
        }
        public synchronized void totalOperationsOnStart(int total) {
            this.totalOnStart = totalLocal == UNKNOWN ? total : totalLocal + total;
        }
        /**