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[Xen-tools] Re: xenbus block device support

To: Christian Limpach <Christian.Limpach@xxxxxxxxxxxx>
Subject: [Xen-tools] Re: xenbus block device support
From: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
Date: Thu, 11 Aug 2005 14:15:36 +1000
Cc: xen-tools@xxxxxxxxxxxxxxxxxxx, Ian Pratt <Ian.Pratt@xxxxxxxxxxxx>
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On Wed, 2005-08-10 at 19:32 +0100, Christian Limpach wrote:
> - store updates from xend don't use transactions and the code in the
>   drivers to handle this short coming is complicated.  On the other
>   hand it should make the drivers more robust.

This is really irritating.  It's so easy to use the C API, and yet the
Python bindings seem to make a mess of it.  I wonder if a
straight-through API would serve xend better?

Kernel code can paper over this for the moment, but in general it will
be unreliable: we will derive some information about the device from
presence or lack of certain nodes.

Only one piece of feedback from reading the patches:
> -int xenbus_register_driver(struct xenbus_driver *drv);
> +int xenbus_register_frontend_driver(struct xenbus_driver *drv);

I left this as "xenbus_register_driver" in my tree, since not every
xenbus driver (think shared LAN driver) is a frontend; a backend implies
a frontend but not vice versa.  Minor nitpick.

A bad analogy is like a leaky screwdriver -- Richard Braakman

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