[dm-devel] What is the deal with the partition separator?

Phillip Susi psusi at cfl.rr.com
Wed Feb 16 19:33:31 UTC 2011

On 2/16/2011 12:19 PM, Curtis Gedak wrote:
> Only newer versions of (lib)parted which link with the dmraid library
> work this way with dmraid devices.  In this situation it is the dmraid
> library that is coming up with the device names.  For all other devices,
> (lib)parted uses the "linux scheme since the dawn of time" mentioned
> below.  Older versions of (lib)parted follow the "linux scheme since the
> dawn of time".

(lib)parted does not link to dmraid; it contains its own code to
generate the name by always adding the 'p' in libparted/arch/linux.c.

> GParted uses (lib)parted to come up with device names, except in the
> case of dmraid devices.  Because dmraid does not follow the "linux
> scheme since the dawn of time", gparted calls dmraid directly to create
> names following the old dmraid standard (only append partition number to
> device name).  If kpartx is available, then GParted will call kpartx to
> ensure that dmraid device names follow the "linux scheme since the dawn
> of time".  This behaviour enables GParted to work with all versions of
> dmraid, and maintain compatibility with (lib)parted versions 1.7.1 and
> higher.

It shouldn't be using both dmraid and kpartx to create the partition
devices.  If dmraid does it, then calling kpartx at best does nothing,
and at worst creates duplicate devices.

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