Re: [PATCH 2/3] fscache/cachefiles: optionally use SEEK_DATA instead of ->bmap.

From: NeilBrown
Date: Tue Apr 21 2015 - 19:07:29 EST


On Mon, 20 Apr 2015 02:45:39 -0700 Christoph Hellwig <hch@xxxxxxxxxxxxx>
wrote:

> On Mon, Apr 20, 2015 at 04:27:00PM +1000, NeilBrown wrote:
> > A worthwhile goal, but I certainly wouldn't consider pursuing it until what I
> > have submitted so far as been accepted - let's not reject "good" while
> > waiting for "perfect".
>
> It's still broken. You add conditional flag for the almost right
> (almost because the flag in the filesystem type needs to go)

Why does it have to go? I suspect you have a reason, but I can't read your
mind.

> while
> leaving the broken option th default.

You say it is broken, and yet people are using it and are having a degree of
success.

Surely the appropriate process is:
- introduce a "better" option
- examine each relevant filesystem and transition over to use the new option.
- remove the "not so good" option.

I'm still at step 1.

> So what you propose here is not
> good, it's at best just as bad as the old version because you don't
> remove broken code but add a lot more clutter at the same time.

What I propose is measurably better because it works with BTRFS now, and
there seems to be a reasonable path towards making to generally better if
someone cares enough to examine each filesystem.

So I still claim you are pushing back against "good" because you want
"perfect".

NeilBrown

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