Re: [RFC][PATCH 0/6] Enhanced file stat system call

[Arnd Bergmann <arnd@arndb.de>]

On Thursday 05 May 2016 21:00:18 Steve French wrote:
> On Thu, May 5, 2016 at 5:54 PM, Steve French <smfrench@gmail.com> wrote:
> > On Wed, May 4, 2016 at 8:46 AM, Arnd Bergmann <arnd@arndb.de> wrote:
> >> On Friday 29 April 2016 13:57:36 David Howells wrote:
> >>> struct statx *buffer);
> >>>
> >>> This is an enhanced file stat function that provides a number of useful
> >>> features, in summary:
> >>>
> >>> (1) More information: creation time, data version number, inode
> >>> generation
> >>> number and flags. A subset of these is available through a number of
> >>> filesystems (such as CIFS, NFS, AFS, Ext4 and BTRFS).
> >>>
> >>
> >> I have a question about birthtime/creationtime: As we are gaining a way
> >> to read this, should we also provide a way to update it using a new
> >> variant
> >> of the utimensat syscall in order to have 'cp -a' create an identical
> >> copy,
> >> or is the idea that this is defined as the time that is particular copy
> >> of the inode was created?
> >>
> >> I've discussed this with Deepa in the past, as she is driving the
> >> convertion of the inode timestamps to timespec64 now, and we will
> >> need a new version of utimensat for her work as well. I can see good
> >> reasons either way (allowing updates of btime or disallowing them).
> >
> It would help interop with Windows (and presumably Mac) if birth time can be
> updated

Ok, thanks. That is certainly a good reason in favor.

If nothing else comes up, I guess we can prepare a patch for a new
utimensat variant to do this and wait for more comments on that.

	Arnd