bool FileWriter::syncFileRange()

in util/FileWriter.cpp [140:196]

• 53 lines of code
• 8 McCabe index (conditional complexity)

bool FileWriter::syncFileRange(int64_t written, bool forced) {
#ifdef HAS_SYNC_FILE_RANGE
  const WdtOptions &options = threadCtx_.getOptions();
  if (options.disk_sync_interval_mb < 0) {
    return true;
  }
  const int64_t syncIntervalBytes = options.disk_sync_interval_mb * 1024 * 1024;
  writtenSinceLastSync_ += written;
  if (writtenSinceLastSync_ == 0) {
    // no need to sync
    WVLOG(1) << "skipping syncFileRange for " << blockDetails_->fileName
             << ". Data written " << written
             << " sync forced = " << std::boolalpha << forced;
    return true;
  }
  if (forced || writtenSinceLastSync_ > syncIntervalBytes) {
    // sync_file_range with flag SYNC_FILE_RANGE_WRITE is an asynchronous
    // operation. So, this is not that costly. Source :
    // http://yoshinorimatsunobu.blogspot.com/2014/03/how-syncfilerange-really-works.html
    int status;
    {
      PerfStatCollector statCollector(threadCtx_,
                                      PerfStatReport::SYNC_FILE_RANGE);
      status = sync_file_range(fd_, nextSyncOffset_, writtenSinceLastSync_,
                               SYNC_FILE_RANGE_WRITE);
    }
    if (status != 0) {
      WPLOG(ERROR) << "sync_file_range() failed for " << blockDetails_->fileName
                   << "fd " << fd_;
      return false;
    }
#ifdef HAS_POSIX_FADVISE
    int ret;
    if (!options.skip_fadvise) {
      {
        PerfStatCollector statCollector(threadCtx_, PerfStatReport::FADVISE);
        ret = posix_fadvise(fd_, nextSyncOffset_, writtenSinceLastSync_,
                            POSIX_FADV_DONTNEED);
      }
      if (ret != 0) {
        WPLOG(ERROR) << "posix_fadvise failed for "
                     << blockDetails_->fileName
                     << " " << nextSyncOffset_ << " "
                     << writtenSinceLastSync_;
        return false;
      }
    }
#endif
    WVLOG(1) << "file range [" << nextSyncOffset_ << " "
             << writtenSinceLastSync_ << "] synced for file "
             << blockDetails_->fileName;
    nextSyncOffset_ += writtenSinceLastSync_;
    writtenSinceLastSync_ = 0;
  }
#endif
  return true;
}