Re: [RFC][PATCH] xfs: extended timestamp range

Arnd Bergmann
2019-11-19T13:38:17Z

On Tue, Nov 19, 2019 at 6:36 AM Darrick J. Wong <darrick.wong@oracle.com> wrote:
> On Mon, Nov 18, 2019 at 11:30:58AM +0200, Amir Goldstein wrote:
> > I am assuming you are working on the patch.
> > If you would like me to re-post my patch with the decided
> > on-disk formats for inode and a quota patch let me know.
>
> Still working on it. In the meantime, I have a question for you and
> Arnd: I've started writing more fstests. How does userspace query the
> kernel to find out the supported range of timestamps? fstests currently
> hardcodes it, but yuck. XFS could find an ioctl/sysfs knob to export
> that info, but it really belongs in statvfs or something.

David Howells has gone through 15 revisions of his fsinfo syscall,
the most recent post was this summer:

https://lwn.net/Articles/792628/
https://lore.kernel.org/lkml/156173661696.14042.17822154531324224780.stgit@warthog.procyon.org.uk/

I don't know whether he has a timeline for completing the work.

The last version was waiting on the new mount API, which has gone into
v5.2, so maybe the patches just need to be refreshed on top of v5.4.

We had previously discussed adding a generic ioctl in do_vfs_ioctl
or using up the last 128 bits of padding in struct statfs, but I think the
fsinfo() syscall would be best.

Arnd