Passive -> active:
If the file metadata has already been committed, using
"for the same purpose" is a little unclear. How about
can be more efficient than .Fn fsync .
Either remove the "The" at the beginning of this sentence, or add a word before "fail" to say what they are:
"fsync and fdatasync fail if:"
Wouldn't it clutter the tag line ? Some changes are synced, which are is described in the main text.
fdatasync(2) cannot be a default choice, it requires careful consideration if used.