Re: Disk naming (Was Re: [Xen-devel] [PATCH] Guest boot loadersupport [1/2])

[Adam Heath <doogie@xxxxxxxxxxxxx>]

On Fri, 15 Apr 2005, Anthony Liguori wrote:

> Adam Heath wrote:
>
> >It does.  So, it's the blkback in dom0 that requires a device node.  How 
> >about
> >it the blkback were extended to support files in filesystems?
> >
> >
> I think the hardest thing to deal with is the fact that the control
> messages are limited to 60 bytes meaning that if you changed the
> be_vbd_create message to pass file names instead of device types you'd
> have to support continuations to suport filenames that are > ~40 bytes long.

Er, no.  The blkback allocates it's own id, which is passed around between
them.

The blkback them maps the id into a handle structure, which then has a void
*data(or a union, if you want) that maintains a pointer to a filename, or
reference to a block device, then a function dispatch table that knows how to
handle the requests.


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