[dm-devel] fdisk on a multipath device fails kernel partition re-read

["David Strand" <dpstrand gmail com>]

When I perform an fdisk or sfdisk on a /dev/mapper/ multipath device I
get a warning about it failing to re-read the partition information.
With fdisk it warns that I'll need to reboot before using the device,
with sfdisk it just complains about the ioctl that failed:

Re-reading the partition table ...
BLKRRPART: Invalid argument

Is it possible I have something configured wrong? Or is this a problem
with the way /dev/mapper nodes work? I get the same result when using
/dev/dm-* nodes. With the raw device nodes such as /dev/sd* it works
ok.