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Re: [Qemu-devel] [RFC][PATCH 0/7] blkdebug
From: |
Blue Swirl |
Subject: |
Re: [Qemu-devel] [RFC][PATCH 0/7] blkdebug |
Date: |
Mon, 15 Mar 2010 20:17:43 +0200 |
On 3/15/10, Kevin Wolf <address@hidden> wrote:
> Am 15.03.2010 18:40, schrieb Blue Swirl:
>
> > On 3/15/10, Kevin Wolf <address@hidden> wrote:
> >> This patch series introduces a new block driver which acts as a protocol
> and
> >> whose purpose it is to fail requests. To be more precise, I want it to
> fail in
> >> configurable places, so that qemu-iotests can be extended with tests for
> the
> >> error paths (for example for the case when something with metadata
> writes goes
> >> wrong deep in qcow2).
> >
> > Nice. Do you think this could be extended (later) to inject errors
> > also to guest from QEMU?
>
>
> Not sure what you mean by "from QEMU"? To allow injecting errors from
> the monitor instead of based on rules? Sounds certainly doable.
I was thinking rule file, but monitor would be more flexible. Even
better: allow switching rule files from monitor :-).
> Or do you just mean to make it work in qemu as opposed to qemu-io? This
> really doesn't make a difference to the block layer. If it works in one,
> it works in the other one, too.
>
>
> > Then it would be nice to be able to inject
> > errors when reading/writing to a specific guest block range and for
> > other formats (raw etc.) too.
>
>
> Should work with all formats, it's implemented as a protocol (but it's
> untested with everything but qcow2). So you basically stick it between
> the format driver and the image file. The only thing that could be
> needed for other formats is some additional events.
>
> For the block range thing, this would need to implement some more
> conditions instead of just checking the state, but in general this is
> exactly the kind of things that I'd like to see supported eventually.
>
> So I completely agree that this is the right direction for future
> improvements, however I can't tell yet if (or when) I'll get to
> implement it myself. My focus is really the qcow2 error paths for now.
Ok, it's enough to know at this stage that the architecture is
flexible for this.
- Re: [Qemu-devel] [RFC][PATCH 4/7] blkdebug: Inject errors, (continued)