In class IDiskRemote, all metadata file system operations use os file system api directly.
There is little extendiability if we want store the metadata of HDFS or S3 into distributed file system.
So I suggest change this way by using DiskPtr and will propose a pull request.

In addition, metadata of HDFS or S3 only store local FS which is not sharable.

namespace DB
{
struct DiskS3Settings
{
    DiskS3Settings(
        const std::shared_ptr<Aws::S3::S3Client> & client_,
        size_t s3_max_single_read_retries_,
        size_t s3_min_upload_part_size_,
        size_t s3_max_single_part_upload_size_,
        size_t min_bytes_for_seek_,
        bool send_metadata_,
        int thread_pool_size_,
        int list_object_keys_size_,
        int objects_chunk_size_to_delete_);
    std::shared_ptr<Aws::S3::S3Client> client;
    size_t s3_max_single_read_retries;
    size_t s3_min_upload_part_size;
    size_t s3_max_single_part_upload_size;
    size_t min_bytes_for_seek;
    bool send_metadata;
    int thread_pool_size;
    int list_object_keys_size;
    int objects_chunk_size_to_delete;
};
/**
 * Storage for persisting data in S3 and metadata on the local disk.
 * Files are represented by file in local filesystem (clickhouse_root/disks/disk_name/path/to/file)
 * that contains S3 object key with actual data.
 */
class DiskS3 final : public IDiskRemote