PATCH: Forcible delaying of UFS (soft)updates

[Terry Lambert]

Chris Dillon wrote:
> As for atimes, if you're expecting all writes to be delayed, and you
> still want atimes to be updated, you'll surely take into account that
> the atime updates will be delayed as well.  This is all purely
> optional behaviour, remember, so you should understand which bits of
> your foot you're likely to shoot off when you turn it on.  It's not
> really foot-shooting in that case, either, as long as you're not
> relying on your atimes for anything important.

POSIX sometimes says "SHALL be updated"; but mostly, it says
"SHALL be marked for update".  Probably you can delay those
indefinitely, as long as the timestamp is set at the time you
mark, so it matches what would have been there.  It's probably
OK to coelesce them to the most recent one, as well.

The atime is actually one of the things I had to "POSIX lawyer"
in a project back around 1994.  8-).

-- Terry