futimens/utimensat (was: Re: Change default VFS timestamp precision?)

[Baptiste Daroussin]

January 3 2015 5:13 PM, "Jilles Tjoelker" <jilles at stack.nl> wrote: 
> On Fri, Dec 19, 2014 at 03:12:01PM -0500, Garrett Wollman wrote:
> 
>> In article <20141219194800.GA29107 at stack.nl>, jilles at stack.nl writes:
>> 
>>> Because there is no API to set timestamps with nanosecond resolution,
>>> and therefore a cp -p copy of a file will appear older than the original
>>> with 99.9% probability. I think that is undesirable.
>> 
>> But that's something we can easily fix -- and should have done, years
>> ago. Why don't we just *do* that?
>> 
>> Of course, in the case of NFS clients, where this issue is most
>> severe, the RPCs are already defined. The underlying VOP_SETATTR has
>> no trouble with nanoseconds, either. It's just a matter of providing
>> a standard library interface (and associated system call(s)) to do it,
>> and since Linux has already implemented this, we can just implement
>> that interface and applications will get it "for free".
> 
> OK, I dusted off the old patch from pluknet@ and added many necessary
> things.
> 
> Please review at https://reviews.freebsd.org/D1426
> 
> I added a compatibility wrapper, mainly to save portmgr some work. Of
> course, this does not add to the old kernel a version of lutimes() that
> works relative to a file descriptor.
> 
> I also have changes for cp, mv and more utilities, but that's a
> different patch. There is also contrib code that either only supports
> old calls or is explicitly configured to use only old calls.
> 

When you have the final version of the patch and willing to commit please send portmgr a heads up.
FYI committing Thursday such patches is a good idea as it gives portmgr almost a week to upgrade the builders :)

Best regards,
Bapt