Re: [PATCH 05/25] vfs: avoid problematic remapping requests into partial EOF block

Darrick J. Wong
2018-11-02T17:42:29Z

On Fri, Nov 02, 2018 at 12:04:39PM +0000, Filipe Manana wrote:
> On Mon, Oct 15, 2018 at 1:31 AM Dave Chinner <david@fromorbit.com> wrote:
> >
> > On Fri, Oct 12, 2018 at 09:22:18PM +0100, Filipe Manana wrote:
> > > On Thu, Oct 11, 2018 at 5:13 AM Darrick J. Wong <darrick.wong@oracle.com> wrote:
> > > >
> > > > From: Darrick J. Wong <darrick.wong@oracle.com>
> > > >
> > > > A deduplication data corruption is exposed by fstests generic/505 on
> > > > XFS.
> > >
> > > (and btrfs)
> > >
> > > Btw, the generic test I wrote was indeed numbered 505, however it was
> > > never committed and there's now a generic/505 which has nothing to do
> > > with deduplication.
> > > So you should update the changelog to avoid confusion.
> >
> > What test is it now? And if it hasn't been committed, are you going
> > to update it and repost as it clearly had value....
>
> Sorry, I lost track of this.
>
> So what was the conclusion of the thread where discussion about this
> problem started?
> It wasn't clear to me if a consensus was reached and got lost on that
> long user space dedupe tools discussion between you and Zygo.
>
> The test assumed a fix of rounding down the range and deduping less
> bytes then requested (which ended up included in 4.19 for btrfs).
>
> From this vfs patch it seems it was decided to return errno -EDADE instead.
> Is this the final decision?

No, I reworked the whole mess to match btrfs-4.19 behavior of deduping
fewer bytes than requested.

--D

> >
> > Cheers,
> >
> > Dave.
> > --
> > Dave Chinner
> > david@fromorbit.com
>
>
>
> --
> Filipe David Manana,
>
> “Whether you think you can, or you think you can't — you're right.”