* write path should ideally tolerate any fragment pattern, but only generate a fixed layout (since the tunable may be changed over time).
* rocksdb: use db_paths (db/ and db.bulk/ ?)
* rocksdb: auto-detect use_fsync option when not xfs or btrfs
- * hobject sorting
- - backfill
- - scrub
- - pgnls
- - tiering agent position
- - ObjectStore::collection_list_range
- - ObjectStore::collection_list_partial
- - DBObjectMap::clone lock ordering
- - HashIndex::get_path_contents_by_hash
- - HashIndex::list_by_hash
* avoid mtime updates when doing open-by-handle
* fid xattr backpointer
- * kill collection_list_range
* inline first fsync_item in TransContext to void allocation?
* refcounted fragments (for efficient clone)