[parted-devel] "linux: use devicemapper task name instead of device node name" causes dmraid breakage

[Phillip Susi]

On 5/17/2010 7:37 AM, Colin Watson wrote:
> IIRC the member of udev upstream who works for us disagrees with this
> naming scheme; Scott, could you comment?

I'm not sure I like the naming scheme either.  The p suffix on dev nodes
normally indicates that the minor number differs from the containing dev
node without the p to indicate it is a partition.  Since the kernel
device mapper does not currently support partitions, dmraid creates new
dm devices to map the partitions.  This means that if dm-0 is the raid
array, then it sounds like with these changes, the partition will be
created as /dev/dm-0p1, though the kernel name of the device is dm-1.
How would udev even know it should name the node dm-0p1 if the kernel
name is dm-1?

>> Likewise kpartx (which one should use rather then dmraid's build
>> in partition code as kpartx can handle gpt labels too and dmraid
>> cannot), also creates partition mappings with a p in the name
>> by default.

I would really like to remove the partition code from the kernel and let
udev handle it with partx.  One thing I've been wondering about is why
it seems others like kpartx instead of the original partx?

> I don't mind resyncing for our development release provided that
> everyone actually agrees.  For a stable update to 10.04, we're probably
> better off making things work with the naming scheme in use elsewhere in
> that release; I don't want to have to go around patching GRUB and the
> like as well.

That's what I was thinking as well.  Revert this upstream change for a
lucid SRU, then drop that and the dmraid patch that removes the p in
maverick.