Re: [PATCH 4/5] xfs: speed up directory bestfree block scanning

Christoph Hellwig
2018-10-26T20:33:12Z

On Fri, Oct 26, 2018 at 09:58:42PM +1100, Dave Chinner wrote:
> > The only case where we have a fbp here is if we had a fblk passed in,
> > but it it did have the index set to -1. But as far as I can tell
> > searching that again doesn't make any sense at all, so I'd apply
> > something like this in top of your patch (some of this also seems
> > to be in your next patch, so independent of the logic change might
> > be worth moving over here):
>
> So you've done a bunch of the rework that already in the next patch
> in the series, plus a "fbno = fblk->blkno + 1;" logic change.

I don't think this is a new logic change, as we start at fbno
already (both in the existing code and with your patch), but we got
here because that block did not contain a suitable free space.

That being said with the reverse search in the next patch the + 1
is pointless as that code changes again. But many of the other changes
in this patch or your next patch (which I hadn't looked at yet when
I did this) should probably be in this one, otherwise we just create
churn.