From: Jeff King <peff@peff.net>
Date: Wed, 12 Jun 2013 12:52:35 GMT
Subject: Re: [PATCH 00/12] Fix some reference-related races
Message-ID: <20130612125235.GA28876@sigill.intra.peff.net>
In-Reply-To: <1370987312-6761-1-git-send-email-mhagger@alum.mit.edu>

On Tue, Jun 11, 2013 at 11:48:20PM +0200, Michael Haggerty wrote:

> *This patch series must be built on top of mh/reflife.*

Applying on top of what Junio has in mh/reflife seems to create
conflicts at the first patch. I didn't look into it, though, but just
read the patches and looked at the packed-refs-transactions branch at
git://github.com/mhagger/git.git.

> The other problem was that the for_each_ref() functions will die if
> the ref cache that they are iterating over is freed out from under
> them.  This problem is solved by using reference counts to avoid
> freeing the old packed ref cache (even if it is no longer valid) until
> all users are done with it.

I was worried that the reference-counting would end up invasive and
ugly, but it turned out quite nice.

Overall, I think the series goes in the right direction, and I didn't
see any implementation flaws. The core of the race-handling is the same
as in mine, but your "hyperactive repository" patch shows how badly mine
can break under load.

I sent a few comments to specific patches, but I'd be fine with applying
it as-is. Thanks for working on it.

-Peff