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
final ShardRouting newRouting,
        final @Nullable ShardRouting currentRouting,
        final Logger logger
    ) throws IOException {
        assert newRouting != null : "newRouting must not be null";
        
        final ShardId shardId = newRouting.shardId();
        if (currentRouting == null
            || currentRouting.primary() != newRouting.primary()
            || currentRouting.allocationId().equals(newRouting.allocationId()) == false) {
            assert currentRouting == null || currentRouting.isSameAllocation(newRouting);
            if (logger.isTraceEnabled()) {
                final String writeReason;
                if (currentRouting == null) {
                    writeReason = "initial state with allocation id [" + newRouting.allocationId() + "]";
                } else {
                    writeReason = "routing changed from " + currentRouting + " to " + newRouting;
                }
                logger.trace("{} writing shard state, reason [{}]", shardId, writeReason);
            }
            final ShardStateMetadata newShardStateMetadata = new ShardStateMetadata(
                newRouting.primary(),
                indexSettings.getUUID(),
                newRouting.allocationId()
            );
            ShardStateMetadata.FORMAT.writeAndCleanup(newShardStateMetadata, shardPath.getShardStatePath());
        } else {
            logger.trace("{} skip writing shard state, has been written before", shardId);
        }
    }