From mboxrd@z Thu Jan  1 00:00:00 1970
Date: Sun, 14 Aug 2011 19:55:01 +0200
From: David du Colombier <0intro@gmail.com>
To: 9fans@9fans.net
Message-ID: <20110814195501.74f0f22d@zinc.9fans.fr>
In-Reply-To: <7c79006a18cf3062d910d62a9e0eb893@quintile.net>
References: <069a199a73e794095891a4254e7b765d@orthanc.ca>
	<7c79006a18cf3062d910d62a9e0eb893@quintile.net>
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Subject: Re: [9fans] Fossil fs recovery
Topicbox-Message-UUID: 136ff296-ead7-11e9-9d60-3106f5b1d025

> I certinaly had problems a few years ago with fossil deadlocking,
> since I disabled ephemeral snapshots it has been quite reliable.
>
> My feeling (nothing more than that) was that the deadlocks seemed to
> occur when I receved email just at the time of the snapshot.
>
> the problem seemed to occur at a rate of once per month or two
> for my lightly loaded home server.
>
> I did try to run two file servers for a while, exporting
> /proc from the test machine with snapshots enabled to a seccond one.
> The hope was that I would be able to use acid to debug the test
> machine's fossil when the problem occured. Sadly I never caught the
> problem and had to decomission the old machine (house repairs).

It is pretty easy to reproduce this bug.

When writing a large file, run "snap -a", then "snap" four times.
Fossil should hang.

I just tried and I am able to reproduce it reliably on a new Fossil.

I've uploaded the stack traces on my website.

http://www.9grid.fr/www.9grid.fr/misc/fossil/deadlock1

--
David du Colombier