Re: [PATCH 5/5] xfs: allow linkat() on O_TMPFILE files

[Dave Chinner]

On Sat, Dec 14, 2013 at 01:36:47AM +0800, Zhi Yong Wu wrote:
> On Sat, Dec 14, 2013 at 12:41 AM, Christoph Hellwig <hch@xxxxxxxxxxxxx> wrote:
> > On Fri, Dec 13, 2013 at 10:27:53PM +0800, Zhi Yong Wu wrote:
> >> From: Zhi Yong Wu <wuzhy@xxxxxxxxxxxxxxxxxx>
> >>
> >> Enable O_TMPFILE support in linkat().
> >> For more info, please refer to:
> >>   http://oss.sgi.com/archives/xfs/2013-08/msg00341.html
> >
> > Generall you should provide all reasonable information in the changelog
> > instead of linking to it.
> will apply this, thanks.
> >
> >> +     if (sip->i_d.di_nlink == 0)
> >> +             tres = &M_RES(mp)->tr_link_tmpfile;
> >> +     else
> >> +             tres = &M_RES(mp)->tr_link;
> >
> > As mentioned before I think Dave wanted you to always use the same
> > reservation, but I'll leave that discussion to him.
> If as you said, when some tons of regular files are created, it won't
> waste some disk space? e.g. some files want to reserve some space, but
> get NOSPACE due to other files reserving additional space?

This is a log space reservation, not a disk space reservation. End
either way, what is unused by the transaction is returned to the
free space pool at the end of the transaction. So for simplicity,
we should just use the one reservation for the link transaction -
take whichever is larger at calculation time.

Cheers,

Dave.
-- 
Dave Chinner
david@xxxxxxxxxxxxx
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/