Ceph » rgw

I think i have this problem:
RGW Dynamic bucket index resharding keeps resharding all buckets - https://tracker.ceph.com/issues/24551?next_issue_id=24546&prev_issue_id=24562

I think RGW was resharding buckets over and over again but in my case this reproduced on versioning disabled buckets:

radosgw-admin reshard list
...
   {
        "time": "2018-07-17 11:08:20.336354Z",
        "tenant": "",
        "bucket_name": "bucket-name",
        "bucket_id": "default.32785769.2",
        "new_instance_id": "",
        "old_num_shards": 1,
        "new_num_shards": 161
    },
...

radosgw-admin bucket limit check
... 
           {
                "bucket": "bucket-name",
                "tenant": "",
                "num_objects": 20840702,
                "num_shards": 161,
                "objects_per_shard": 129445,
                "fill_status": "OVER 100.000000%" 
            },
...

This may be related to the problem addressed by http://tracker.ceph.com/issues/27219 . The problem there was that due to high load, resharding could not complete before the resharding lock expired. This PR does a number of things to address this, including renewing the lock periodically to allow resharding to complete.