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
} else {
                    assert indexShard.assertRetentionLeasesPersisted();
                }
                indexShard.maybeCheckIndex();
                state().setRemoteTranslogStage();
            } catch (CorruptIndexException | IndexFormatTooNewException | IndexFormatTooOldException ex) {
                
                
                
                
                
                try {
                    try {
                        store.removeCorruptionMarker();
                    } finally {
                        Lucene.cleanLuceneIndex(store.directory()); 
                    }
                } catch (Exception e) {
                    logger.debug("Failed to clean lucene index", e);
                    ex.addSuppressed(e);
                }
                RecoveryFailedException rfe = new RecoveryFailedException(state(), "failed to clean after recovery", ex);
                fail(rfe, true);
                throw rfe;
            } catch (Exception ex) {
                RecoveryFailedException rfe = new RecoveryFailedException(state(), "failed to clean after recovery", ex);
                fail(rfe, true);
                throw rfe;
            } finally {
                store.decRef();