Re: [RFC PATCH 0/3] xfs: forced extent alignment

[Dave Chinner <david@fromorbit.com>]

On Wed, Mar 06, 2024 at 11:46:38AM +0000, John Garry wrote:
> On 06/03/2024 05:20, Dave Chinner wrote:
> > Hi Garry,
> > 
> > I figured that it was simpler just to write the forced extent
> > alignment allocator patches that to make you struggle through them
> > and require lots of round trips to understand all the weird corner
> > cases.
> 
> I appreciate that.
> 
> > 
> > The following 3 patches:
> > 
> > - rework the setup and extent allocation logic a bit to make force
> >    aligned allocation much easier to implement and understand
> > - move all the alignment adjustments into the setup logic
> > - rework the alignment slop calculations and greatly simplify the
> >    the exact EOF block allocation case
> > - add a XFS_ALLOC_FORCEALIGN flag so that the inode config only
> >    needs to be checked once at setup. This also allows other
> >    allocation types (e.g. inode clusters) use forced alignment
> >    allocation semantics in future.
> > - clearly document when we are turning off allocation alignment and
> >    abort FORCEALIGN allocation at that point rather than doing
> >    unaligned allocation.
> > 
> > I've run this through fstests once so it doesn't let the smoke out,
> > but I haven't actually tested it against a stripe aligned filesystem
> > config yet, nor tested the forcealign functionality so it may not be
> > exactly right yet.
> > 
> > Is this sufficiently complete for you to take from here into the
> > forcealign series?
> > 
> 
> I'll try it out.
> 
> What baseline are these against? Mine were against v6.8-rc5, but I guess
> that you develop against an XFS integration tree. Maybe they apply and build
> cleanly against v6.8-rc5 ...

6.8-rc7 + linux-xfs/for-next + some other local patches to other
parts of XFS that shouldn't overlap with this patch set. I don't
think there's anything in for-next overlapping this code, so it
might just apply cleanly to your tree....

-Dave.
-- 
Dave Chinner
david@fromorbit.com