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
*/
    public final void sync(Translog.Location location, Consumer<Exception> syncListener) {
        verifyNotClosed();
        translogSyncProcessor.put(location, syncListener);
    }
    public void sync() throws IOException {
        verifyNotClosed();
        getEngine().syncTranslog();
    }
    /**
     * Checks if the underlying storage sync is required.
     */
    public boolean isSyncNeeded() {
        return getEngine().isTranslogSyncNeeded();
    }
    /**
     * Returns the current translog durability mode
     */
    public Translog.Durability getTranslogDurability() {
        return indexSettings.getTranslogDurability();
    }
    
    private final AtomicBoolean flushOrRollRunning = new AtomicBoolean();
    /**
     * Schedules a flush or translog generation roll if needed but will not schedule more than one concurrently. The operation will be
     * executed asynchronously on the flush thread pool.
     */
    public void afterWriteOperation() {
        if (shouldPeriodicallyFlush() || shouldRollTranslogGeneration()) {
            if (flushOrRollRunning.compareAndSet(false, true)) {