openstack team mailing list archive

[Pádraig Brady <P@xxxxxxxxxxxxxx>]

On 06/11/2012 10:16 PM, Scott Moser wrote:
> Without digging around on older versions of OS's and their included
> kernel/udev/kpartx.... i'd have to say that from your message above, and
> my testing that running 'kpartx' is no longer necessary.  That can
> reasonably be expected to be created by the kernel or some other plumbing
> bits automatically.

It would be good to get away from kpartx. I've noticed these issues:

1. The git repo on kernel.org is no longer available.

2. kpartx -l had side effects:
  $ kpartx -l /bin/ls
  $ ls
  text file busy
To fix you need to run losetup -a to find the assigned loopback device
and then losetup -d /dev/loop...

3. On an unconnected loop device we get warnings, but an EXIT_SUCCESS ?
  # kpartx -a /dev/loop1 && echo EXIT_SUCCESS
  read error, sector 0
  llseek error
  llseek error
  llseek error
  EXIT_SUCCESS

4. Also for a loop device that is connected,
I get a "failed" warning, but the EXIT_SUCCESS
is appropriate in that case as the mapped device
is present and usable
  # kpartx -a /dev/loop0
 /dev/mapper/loop0p1: mknod for loop0p1 failed: File exists

That last item is related to the new code for auto parsing partitions.

That's only available since kernel 3.2 I think so we'll have to
be wary on relying on it.

cheers,
Pádraig.