exception looking up device number f,or hda

[Arun Sharma <arun.sharma@intel.com>]

Hi Mike,

I have the following line in my config file:

disk = [ 'file:/var/images/min-el3-i386.img,hda,w' ]

and my host doesn't have a /dev/hda (it has a SATA disk which shows up 
as /dev/sda).

But I would like the guest to see a /dev/hda. Sounds reasonable?

Now, when I try to create this domain, I get:

[2005-08-05 14:40:53 xend] DEBUG (blkif:24) exception looking up device 
number for hda: [Errno 2] No such file or directory: '/dev/hda'
2005-08-05 14:40:53 xend] DEBUG (blkif:449) Destroying blkif domain=1
[2005-08-05 14:40:53 xend] DEBUG (blkif:337) Destroying vbd domain=1 id=0

The code in util/blkif.py that tries to convert name to device number 
doesn't seem to be new, but I don't know why it started showing up suddenly.

I worked around by manually creating /dev/hda, but I don't think it's 
reasonable to expect that host's /dev contains entries for all guest 
devices.

Also, the effect of having a bad "disk=" line in xmdefconfig (such as 
pointing to a non-existent file) results in a xend crash. We probably 
need to add a few checks at the python level so that the user sees a 
more useful stack trace.

	-Arun