partman-base and DM multipath

[Guido Guenther <agx@debian.org>]

Hi, 
I'm currently adding multipath support to d-i. In the current setup
multipath device nodes show up as /dev/mapper/mpath[0-9] and the device
nodes on the partitions as /dev/mapper/mpath[0-9]-part[0-9].
Almost everything already works fine, except when it comes to createing
the filesystem:

/lib/partman/commit.d/50format_ext3: IN: PARTITIONS =dev=mapper=mpath0
parted_server: Read command: PARTITIONS
parted_server: command_partitions()
parted_server: Opening outfifo
parted_server: OUT: OK

parted_server: OUT: 1	0-10737418239	10737418240	primary	ext3 /dev/mapper/mpath0	

parted_server: Partitions printed
parted_server: OUT:

Always gives /dev/mapper/mpath0 as device to the commit.d scripts but it
should be /dev/mapper/mpath0-part1. With multipath the
/dev/mapper/mpath0-partX devices are "simple" linear device mapper mappings:
with a table like: "start end linear major:minor offset". So I assume
parted is confused by the fact that the partition itself is a device
mapper device (partmap return "msdos" for mpath0 and "loop" for
mpath0-partX). Any ideas where to start digging?
Cheers,
 -- Guido

p.s.: please cc: me on replies