Re: [Xen-devel] kpartx for raisin hvm tests

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Wed, 22 Feb 2017, Géza Gémes wrote:
> On 2017-02-21 23:10, Stefano Stabellini wrote:
> > On Tue, 21 Feb 2017, Géza Gémes wrote:
> > > Hi,
> > > 
> > > I've tried to run the raisin test suite, while pv tests pass the hvm tests
> > > fail. I've identified a number of problems, starting with two small disk
> > > size
> > > to formating the whole disk and then being unable to install grub to the
> > > boot
> > > sector. I've trace down these problems into the incorrect invocation of
> > > the
> > > _create_loop_device function in scripts/lopartsetup.
> > > 
> > > My question: Will it be acceptable if I would replace this part of the
> > > code
> > > with a kpartx call? Or introducing kpartx is a too big change in the list
> > > of
> > > dependencies?
> >   I understand that kpartx makes things much easier, but before
> > introducing it as a dependency, I would like to understand this problem
> > a bit better.
> > 
> > Why is _create_loop_device invoked incorrectly? Is it index or offset
> > that is calculate incorrectly?
> 
> Hi Stefano,
> 
> In scripts/lopartsetup:56 unit="`fdisk -lu $filename 2>/dev/null | grep -e
> "^Units = " | cut -d " " -f 9`" . Using ubuntu 16.04 (fdisk coming from
> util-linux-2.27.1-6ubuntu3.2) this yields to an empty variable, as:
> 
> $sudo fdisk -lu /tmp/tmp.x9UN6uxaG2/busybox-vm-disk 2>/dev/null
> 
> Disk /tmp/tmp.x9UN6uxaG2/busybox-vm-disk: 60 MiB, 62914560 bytes, 122880
> sectors
> Units: sectors of 1 * 512 = 512 bytes
> Sector size (logical/physical): 512 bytes / 512 bytes
> I/O size (minimum/optimal): 512 bytes / 512 bytes
> 
> Because of this both unit and offset are wrong ( offset=`echo $i | tr -s " " |
> cut -d " " -f 2`, where i=fdisk -lu $filename 2>/dev/null | grep -e
> "^$filename")
> 
> As I think that different versions of fdisk will produce different results, we
> either introduce an additional logic for the fdisk version, either change this
> part completely.

It doesn't look like fdisk changed output in this case. It looks like
the disk doesn't have any partitions in it. Am I right?

It would be easy to add support to lopartsetup to detect disks without
partitions, and deal with them correctly, without bringing in kpartx.
However, this scenario shouldn't occur, because lopartsetup is only
called by create_one_partition, right after creating a partition on the
disk.

Do you know why create_one_partition doesn't work as expected?

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