Am 11.02.2013 09:33, schrieb Michael Tokarev:
> 11.02.2013 04:20, NeilBrown wrote:
>> On Sat,  9 Feb 2013 18:48:38 +0100 Thomas Bächler
>> <thomas@archlinux.org> wrote:
> 
>>> -IMPORT{program}="/sbin/blkid -o udev -p $tempnode"
>>> +IMPORT{builtin}="blkid"
> 
> Does this has additional udev version constrain?
> I mean, which is the minimum udev version to support this properly,
> do we care?

Udev relies on devtmpfs and thus does not create devices since version
176, therefore $tempnode is deprecated and only $devnode should be used
($tempnode seems to be around for compatibility, no idea if/when it will
be dropped).

The blkid builtin is also available since udev 176. In latest
util-linux, the 'blkid -o udev' output is marked as deprecated, although
Karel says it's not entirely going away for now.

Why do we care? We want correct udev rules ($tempnode vs. $devnode), and
the using builtin is faster and less error-prone than calling an
external tool (plus, it is used everywhere else in udev).

As for compatibility: I see no reason why anyone would use a version of
udev that is more than one year old (175) together with a mdadm version
that is to be released in the future (3.2.7). If someone really wants
that, they should be competent enough to adjust the udev rules for their
local build.