rgw: remove rgw_data_log_obj_prefix

The evaluation based on rgw_data_log_obj_prefix had a logical error
not considering the value and always were returning "data_log".
As the config was having the dev level and apparantly it was useless
and fixing the logic could break the existing clusters (if they don't
adopt before upgrade), it was decided to remove the config.

Fixes: https://tracker.ceph.com/issues/67861
Signed-off-by: Seena Fallah <seenafallah@gmail.com>

doc/radosgw/config-ref.rst

@@ -149,7 +149,6 @@ file under each ``[client.radosgw.{instance-name}]`` instance.
 .. confval:: rgw_run_sync_thread
 .. confval:: rgw_data_log_window
 .. confval:: rgw_data_log_changes_size
-.. confval:: rgw_data_log_obj_prefix
 .. confval:: rgw_data_log_num_shards
 .. confval:: rgw_md_log_max_shards
 .. confval:: rgw_data_sync_poll_interval

src/common/options/rgw.yaml.in

@@ -2066,14 +2066,6 @@ options:
   services:
   - rgw
   with_legacy: true
-- name: rgw_data_log_obj_prefix
-  type: str
-  level: dev
-  default: data_log
-  fmt_desc: The object name prefix for the data log.
-  services:
-  - rgw
-  with_legacy: true
 - name: rgw_data_sync_poll_interval
   type: int
   level: dev

src/rgw/driver/rados/rgw_datalog.h

@@ -241,10 +241,7 @@ class RGWDataChangesLog {
   std::unique_ptr<DataLogBackends> bes;
 
   const int num_shards;
-  std::string get_prefix() {
-    auto prefix = cct->_conf->rgw_data_log_obj_prefix;
-    return prefix.empty() ? prefix : "data_log";
-  }
+  std::string get_prefix() { return "data_log"; }
   std::string metadata_log_oid() {
     return get_prefix() + "generations_metadata";
   }