whole_func_string: function _zero(_arg, _cb) {
          if (!_arg.create) {
              _cb();
              return;
          }
  
          // We need to stub this out now since we won't write the file to manta
          // until writeback runs on this file.
          var now = new Date().toUTCString();
          var info = {
              extension: 'bin',
              type: 'application/octet-stream',
              parent: path.dirname(p),
              size: 0,
              headers: {
                  'last-modified': now
              }
          };
  
          var opts = {};
          if (_arg.exclusive) {
              // exclusive applies only to the local file in the cache
              opts.flag = 'wx';
          } else {
              opts.flag = 'w';
          }
  
          self._stat(p, info, function (s_err, stats) {
              if (s_err) {
                  _cb(s_err);
                  return;
              }
  
              fs.writeFile(stats._cacheFile, new Buffer(0), opts, function (err) {
                  if (err) {
                      _cb(err);
                      return;
                  }
  
                  // mark file as dirty in the cache
                  self.cache.dirty(p, stats._fhandle, function (d_err) {
                      if (d_err) {
                          log.warn(d_err, 'dirty(%s): failed', p);
                          _cb(d_err);
                      } else {
                          self.cache.add_to_pdir(p, _cb);
                      }
                  });
              });
          });
      }
func_code_string: function _zero(_arg, _cb) {
          if (!_arg.create) {
              _cb();
              return;
          }
  
          // We need to stub this out now since we won't write the file to manta
          // until writeback runs on this file.
          var now = new Date().toUTCString();
          var info = {
              extension: 'bin',
              type: 'application/octet-stream',
              parent: path.dirname(p),
              size: 0,
              headers: {
                  'last-modified': now
              }
          };
  
          var opts = {};
          if (_arg.exclusive) {
              // exclusive applies only to the local file in the cache
              opts.flag = 'wx';
          } else {
              opts.flag = 'w';
          }
  
          self._stat(p, info, function (s_err, stats) {
              if (s_err) {
                  _cb(s_err);
                  return;
              }
  
              fs.writeFile(stats._cacheFile, new Buffer(0), opts, function (err) {
                  if (err) {
                      _cb(err);
                      return;
                  }
  
                  // mark file as dirty in the cache
                  self.cache.dirty(p, stats._fhandle, function (d_err) {
                      if (d_err) {
                          log.warn(d_err, 'dirty(%s): failed', p);
                          _cb(d_err);
                      } else {
                          self.cache.add_to_pdir(p, _cb);
                      }
                  });
              });
          });
      }
func_documentation_string: When creating use _stat to save the zero-size new file info into the cache and create an empty local file.