Re: 2.4.18 no timestamp update on modified mmapped files

[Andrew Morton <akpm@zip.com.au>]

Keith Owens wrote:
> 
> On Mon, 10 Jun 2002 23:49:02 -0700,
> Andrew Morton <akpm@zip.com.au> wrote:
> >Keith Owens wrote:
> >> On Mon, 10 Jun 2002 23:17:27 -0700,
> >> Andrew Morton <akpm@zip.com.au> wrote:
> >> >     The st_ctime and st_mtime fields of a file that is mapped with MAP_SHARED
> >> >     and PROT_WRITE shall be marked for update at some point in the interval
> >> >     between a write reference to the mapped region and the next call to msync() with
> >> >     MS_ASYNC or MS_SYNC for that portion of the file by any process. If there is
> >> >     no such call and if the underlying file is modified as a result of a write reference,
> >> >     then these fields shall be marked for update at some time after the write reference.
> >>
> >> That says nothing about a file where the only updates are via mmap.  My
> >> file had grown to its final size so there were no more writes, only
> >> pages being dirtied via mmap.
> >
> >It is specifically referring to updates via mmap!  "a write reference
> >to the mapped region".  This is the mmap documentation.
> 
> I saw "write reference" and my brain translated that to "write()".  I
> blame the long weekend.

That'll be a left-brain/write-brain thing.

I think it's too late to fix this in 2.4.  If we did, a person
could develop and test an application on 2.4.21, ship it, then
find that it fails on millions of 2.4.17 machines.

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