Freezing (was: Re: fstests generic/441 -- occasional bcachefs failure)

[Kent Overstreet <kent.overstreet@linux.dev>]

On Thu, Feb 02, 2023 at 10:50:23AM -0500, Brian Foster wrote:
> I don't have a public repo atm but I've posted the patch if you have
> somewhere to land it for CI testing..? It survived my regression tests
> so far, FWIW. (I also had posted that random cleanup patch a bit ago if
> you hadn't noticed..).

Must have missed it, sorry. I can host a git repo for you on my server,
or github works fine - I generally prefer git repo links, git am is
always a bit of a hassle.

> Is there a reporting dashboard or something available for the test
> infrastruture for bcachefs?

https://evilpiepirate.org/~testdashboard/ci

I've got a small server farm that watches git branches and runs the
entire test suite on every commit starting from the recent - once you've
got a git branch up I'll add yours to the list it watches.

You'll probably want to get acquainted with ktest, it's what both the CI
uses for running tests, and what we use for local development:

https://evilpiepirate.org/git/ktest.git

> > Freeze definitely needs to happen. It's been _ages_ since I was looking
> > at it so I couldn't say offhand where we'd need to start, but if you're
> > interested I'd be happy to look at what it'd take.
> > 
> 
> Yeah, that would be interesting. Thanks.

Maybe we could get Dave to give us a brief rundown of freezing? It's
been ages since I was thinking about that and it's all fallen out of my
brain, but Dave was the one who was able to explain it to me before :)

I think getting freezing done would up our test coverage by a good bit,
so it's worth prioritizing.

> FWIW, I was reading through the "Journaling" and "Sequential
> consistency" sections of the architecture documentation [1]. It's
> possible I just misinterpreted some wording.
> 
> [1] https://bcachefs.org/Architecture/#Journaling

*nod* Thanks for the link, that's old but not ancient - that's from when
the journal seq blacklist mechanism was how we did sequential
consistency.

Whenever I find the time to work on documentation again, I want to move
more stuff (including that sort of high level developer documentation)
to the principles of operation: https://bcachefs.org/bcachefs-principles-of-operation.pdf

Right now it's more end user documentation, but last I was working on
that I was starting to add documentation centered around on disk data
structures - i.e. btrees and key types, and it seemed to be going in a
useful direction.