Re: [Xen-devel] [PATCH 2 of 6 RESENT] libxl: Accept disk name in libxl_devid_to_device_disk

[Ian Campbell <Ian.Campbell@xxxxxxxxxx>]

On Mon, 2011-06-06 at 12:24 +0100, Ian Campbell wrote:
> On Sun, 2011-06-05 at 17:50 +0100, Marek Marczykowski wrote:
> > # HG changeset patch
> > # User Marek Marczykowski <marmarek@xxxxxxxxxxxx>
> > # Date 1306962929 -7200
> > # Node ID 5231fa19f3e39091ff29e2a6dca057ca54403092
> > # Parent  c32797243a6ba61dd2942a0307151e42fb7bf157
> > libxl: Accept disk name in libxl_devid_to_device_disk
> > 
> > Accept disk name in xl block-detach.
> > 
> > Signed-off-by: Marek Marczykowski <marmarek@xxxxxxxxxxxx>
> 
> Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
> 
> While reviewing I noticed a path out of libxl__device_disk_dev_number
> which would succeed without setting pdisk or ppartition, which would
> surprise a caller which provided them. 
> 
> I wasn't immediately sure from docs/misc/vbd-interface.txt how to parse
> a vdev which is an arbitrary number. Many cases are covered in the
> document but there are others (e.g. NetBSD uses small integers iirc)
> which I was unsure of. (I expect that document needs expanding to cover
> these cases, but I'm not sure what to put...)

Actually the doc does say:
        To cope with guests which predate this specification we preserve the
        existing facility to specify the xenstore numerical value directly by
        putting a single number (hex, decimal or octal) in the domain config
        file instead of the disk identifier; this number is written directly
        to xenstore (after conversion to the canonical decimal format).

so I guess it is explicit that these values cannot be reliably parsed.

Ian.


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