[systemd-devel] [systemd-commits] Makefile.am man/udevadm.xml src/libudev src/shared src/test src/udev

[Kay Sievers]

On Mon, Apr 14, 2014 at 8:52 AM, Zbigniew Jędrzejewski-Szmek
<zbyszek at in.waw.pl> wrote:
> On Sun, Apr 13, 2014 at 04:58:31PM -0700, Kay Sievers wrote:
>>  Makefile.am                         |    6
>>  man/udevadm.xml                     |   22 -
>>  src/libudev/libudev-monitor.c       |   17 -
>>  src/libudev/libudev-queue-private.c |  406 ------------------------------------
>>  src/libudev/libudev-queue.c         |  302 ++------------------------
>>  src/libudev/libudev.h               |   10
>>  src/shared/udev-util.h              |    2
>>  src/test/test-libudev.c             |   24 --
>>  src/udev/udev-ctrl.c                |    2
>>  src/udev/udevadm-settle.c           |  131 +----------
>>  src/udev/udevd.c                    |   59 ++---
>>  11 files changed, 84 insertions(+), 897 deletions(-)
>>
>> New commits:
>> commit 9ea28c55a2488e6cd4a44ac5786f12b71ad5bc9f
>> Author: Kay Sievers <kay at vrfy.org>
>> Date:   Sat Apr 12 22:35:50 2014 -0700
>>
>>     udev: remove seqnum API and all assumptions about seqnums
>>
>>     The way the kernel namespaces have been implemented breaks assumptions
>>     udev made regarding uevent sequence numbers. Creating devices in a
>>     namespace "steals" uevents and its sequence numbers from the host. It
>>     confuses the "udevadmin settle" logic, which might block until util a
>>     timeout is reached, even when no uevent is pending.
>>
>>     Remove any assumptions about sequence numbers and deprecate libudev's
>>     API exposing these numbers; none of that can reliably be used anymore
>>     when namespaces are involved.
> Hi Kay,
> maybe we should make the deprecation process a bit gentler: instead of
> ripping out the functionality in one step, instead just deprecate the
> functions, and allow people to use them, with the caveat that launching
> a namespace and creating devices in it will break this functionality.
> Then after a few releases, actually remove the functionality. Not everyone
> uses namespaces, and that'd be a nod towards those poeple. Would
> that be possible?

Not really, because the API relies on the queue tracking data.

But for the queue tracking logic to not break current setups, it would
need to be updated/rewritten to handle holes in the sequence numbers;
with current kernels it is just broken whenever namespaces are
involved. We just did not notice, because we do not use "settle" with
systemd.

I don't think it is worth to try to make the specific queue tracking
logic work again, it is not a useful API and it makes promises we
cannot hold.

Thanks,
Kay