Re: [git pull] device mapper fix for 4.18-rc6

[Mike Snitzer <snitzer@redhat.com>]

On Fri, Jul 20 2018 at  5:25pm -0400,
Linus Torvalds <torvalds@linux-foundation.org> wrote:

> On Fri, Jul 20, 2018 at 12:14 PM Mike Snitzer <snitzer@redhat.com> wrote:
> >
> >   Fix DM writecache target to allow an optional offset to the start of
> >   the data and metadata area.  This allows userspace tools (e.g. LVM2)
> >   to place a header and metadata at the front of the writecache device
> >   for its use.
> 
> "fix"?
> 
> Not really.

I hold it to be a "fix" because it was an embarassing oversight on my
part.  Without this, userspace support cannot be properly added.  LVM2
developers raised their inability to put their metadata anywhere and I
was like "oh shit".

Not much point releasing the DM kernel code if it cannot be properly
tied into a volume manager for persistent use across boots, etc.

> But I'm a softie, and I took it. Don't do it again.

Considering dm-writecache was merged for 4.18 I think it important to
get it right.  So thankfully you've chosen wisely ;)

But I certainly sat on this change for a couple rc releases, should've
gotten it to you a couple weeks ago.

Thanks,
Mike