我对“rws”和“rwd”模式之间的区别感到困惑.

这是docs的状态：

“rws” Open for reading and writing,as with “rw”,and also require
that every update to the file’s content or Metadata be written
synchronously to the underlying storage device.

“rwd” Open for reading and writing,and also require
that every update to the file’s content be written synchronously to
the underlying storage device.

[…]

The “rwd” mode can be used to reduce the number of I/O operations
performed. Using “rwd” only requires updates to the file’s content to
be written to storage; using “rws” requires updates to both the file’s
content and its Metadata to be written,which generally requires at
least one more low-level I/O operation.

…并没有解释什么元数据的意思.这是否意味着“rws”会更新文件系统上最后修改的时间戳,而“rwd”不会更新？