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.
x-pack/plugin/searchable-snapshots/src/main/java/org/elasticsearch/xpack/searchablesnapshots/recovery/SearchableSnapshotRecoveryState.java
super.start();
        }
        private synchronized void addFileToIgnore(String name) {
            filesToIgnore.add(name);
        }
        @Override
        public synchronized void addFileDetail(String name, long length, boolean reused) {
            if (filesToIgnore.contains(name)) {
                return;
            }
            super.addFileDetail(name, length, reused);
        }
        private synchronized void markFileAsReused(String name) {
            ((SearchableSnapshotRecoveryFilesDetails) fileDetails).markFileAsReused(name);
        }
        
        @Override
        public synchronized void start() {}
        @Override
        public synchronized void stop() {}
        @Override
        public synchronized void reset() {}
        private synchronized void stopTimer() {
            super.stop();
        }
    }
    private static class SearchableSnapshotRecoveryFilesDetails extends RecoveryFilesDetails {
        @Override
        public void addFileDetails(String name, long length, boolean reused) {