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
shardRoutings.add(routingTable.shard(copy));
            }
            shardRoutings.addAll(routingTable.assignedShards()); 
            if (shardRoutings.stream()
                .allMatch(
                    shr -> shr.assignedToNode() && retentionLeases.contains(ReplicationTracker.getPeerRecoveryRetentionLeaseId(shr))
                )) {
                useRetentionLeasesInPeerRecovery = true;
            }
        }
    }
    /**
     * Marks the shard as recovering based on a recovery state, fails with exception is recovering is not allowed to be set.
     */
    public IndexShardState markAsRecovering(String reason, RecoveryState recoveryState) throws IndexShardStartedException,
        IndexShardRelocatedException, IndexShardRecoveringException, IndexShardClosedException {
        synchronized (mutex) {
            if (state == IndexShardState.CLOSED) {
                throw new IndexShardClosedException(shardId);
            }
            if (state == IndexShardState.STARTED) {
                throw new IndexShardStartedException(shardId);
            }
            if (state == IndexShardState.RECOVERING) {
                throw new IndexShardRecoveringException(shardId);
            }
            if (state == IndexShardState.POST_RECOVERY) {
                throw new IndexShardRecoveringException(shardId);
            }
            this.recoveryState = recoveryState;