From: Joost Roeleveld <joost@antarean.org>
To: gentoo-user@lists.gentoo.org
Subject: Re: [gentoo-user] udev + /usr
Date: Thu, 15 Sep 2011 16:11:59 +0200 [thread overview]
Message-ID: <1900171.RYZackCgQ3@eve> (raw)
In-Reply-To: <CA+czFiBrfQiBuEUqO106iBDnERSHXeVKsxxLWqbypER1HmCFYQ@mail.gmail.com>
On Thursday, September 15, 2011 09:47:34 AM Michael Mol wrote:
> > The main purpose of udev is to populate the /dev-tree.
> > The running of scripts based on /dev-tree events should be in a seperate
> > tool that starts later in the boot-process.
>
> I'm not entirely convinced this is the case, because it feels like
> some situations like network devices (nbd, iSCSI) or loopback would
> require userland tools to bring up once networking is up.
Yes, but the kernel-events referencing those devices won't appear untill after
the networking is brought up.
The scripts that "udev" starts are run *after* a device-event is created. If
the device itself has not been spotted by the kernel (for instance, the
networking doesn't exist yet), the event won't be triggered yet.
This situation does not require udev to start all these tools when network-
devices appear.
I hope the following would make my thoughts a bit clearer:
1) kernel boots
2) kernel detects network device and places "network-device-event" in the
queue
3) further things happen and kernel places relevant events in the queue (some
other events may also already be in the queue before step 2)
4) udev starts and starts processing the queue
5) For each event, udev creates the corresponding device-entry and places
action-entries in a queue
6) system-init-scripts mount all local filesystems
7) udev-actions starts (I made up this name)
8) udev-actions processes all the entries in the action-queue
From step 4, udev will keep processing further events it gets, which means
that if any action taken by "udev-actions" causes further devices to become
available, "udev" will create the device-entries and place the action in the
action-queue.
If anyone has a setup where /usr can not be mounted easily, it won't work
currently either and a init* would be necessary anyway.
(Am thinking of NFS, CIFS, iSCSI, NBD, special raid-drivers,.... hosting /usr
or other required filesystems)
But anyone with a currently working environment should be able to expect a
currently working environment. If it fails to boot with only updating
versions, it's a regression. And one of the worst kinds of all.
--
Joost
next prev parent reply other threads:[~2011-09-15 14:14 UTC|newest]
Thread overview: 254+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-09-12 15:02 [gentoo-user] udev + /usr Alan Mackenzie
2011-09-12 15:33 ` Michael Schreckenbauer
2011-09-12 17:17 ` Alan Mackenzie
2011-09-12 17:39 ` Michael Mol
2011-09-12 18:08 ` Michael Schreckenbauer
2011-09-12 18:37 ` Canek Peláez Valdés
2011-09-12 19:00 ` Michael Mol
2011-09-12 19:35 ` Canek Peláez Valdés
2011-09-12 19:52 ` Michael Mol
2011-09-12 20:24 ` Alex Schuster
2011-09-13 7:08 ` Joost Roeleveld
2011-09-12 20:31 ` Alan Mackenzie
2011-09-13 3:18 ` Peter Humphrey
2011-09-13 7:15 ` Joost Roeleveld
2011-09-13 7:01 ` Paul Colquhoun
2011-09-13 18:15 ` Dale
2011-09-12 20:16 ` David W Noon
2011-09-12 19:07 ` Michael Schreckenbauer
2011-09-12 19:18 ` Michael Mol
2011-09-12 19:41 ` Michael Schreckenbauer
2011-09-12 20:07 ` Michael Mol
2011-09-12 20:57 ` Alan McKinnon
2011-09-12 22:00 ` Michael Schreckenbauer
2011-09-12 23:31 ` Canek Peláez Valdés
2011-09-13 7:28 ` Joost Roeleveld
2011-09-13 8:52 ` Michael Schreckenbauer
2011-09-12 21:14 ` Pandu Poluan
2011-09-13 2:07 ` Walter Dnes
2011-09-13 7:25 ` Joost Roeleveld
2011-09-12 19:56 ` Dale
2011-09-13 3:28 ` Walter Dnes
2011-09-13 7:04 ` Neil Bothwick
2011-09-13 15:21 ` Walter Dnes
2011-09-13 15:38 ` Michael Schreckenbauer
2011-09-13 15:49 ` Neil Bothwick
2011-09-13 16:56 ` Joost Roeleveld
2011-09-12 17:50 ` Michael Schreckenbauer
2011-09-13 14:40 ` Alan Mackenzie
2011-09-13 14:55 ` Michael Schreckenbauer
2011-09-13 15:38 ` Alan Mackenzie
2011-09-13 16:14 ` Canek Peláez Valdés
2011-09-13 20:35 ` Alan McKinnon
2011-09-13 20:52 ` Canek Peláez Valdés
2011-09-13 20:57 ` Michael Mol
2011-09-13 21:10 ` Canek Peláez Valdés
2011-09-13 21:30 ` Michael Schreckenbauer
2011-09-13 21:53 ` Canek Peláez Valdés
2011-09-13 22:10 ` Michael Schreckenbauer
2011-09-13 22:33 ` Canek Peláez Valdés
2011-09-14 5:52 ` Joost Roeleveld
2011-09-14 14:30 ` Canek Peláez Valdés
2011-09-14 18:36 ` Dale
2011-09-14 18:55 ` Canek Peláez Valdés
2011-09-14 23:06 ` William Kenworthy
2011-09-15 0:00 ` Dale
2011-09-15 20:42 ` Mike Edenfield
2011-09-15 21:01 ` Michael Mol
2011-09-15 21:16 ` Joost Roeleveld
2011-09-15 21:28 ` Canek Peláez Valdés
2011-09-15 22:05 ` Mike Edenfield
2011-09-15 22:26 ` Mark Knecht
2011-09-15 22:44 ` Canek Peláez Valdés
2011-09-16 8:46 ` Joost Roeleveld
2011-09-16 10:00 ` Alan McKinnon
2011-09-16 10:54 ` Joost Roeleveld
2011-09-16 13:03 ` Alan McKinnon
2011-09-15 7:01 ` Joost Roeleveld
2011-09-15 13:47 ` Michael Mol
2011-09-15 14:11 ` Joost Roeleveld [this message]
2011-09-15 14:32 ` Michael Mol
2011-09-15 14:48 ` Joost Roeleveld
2011-09-15 14:58 ` Canek Peláez Valdés
2011-09-15 17:43 ` Canek Peláez Valdés
2011-09-15 21:25 ` Joost Roeleveld
2011-09-15 21:34 ` Canek Peláez Valdés
2011-09-16 8:54 ` Joost Roeleveld
2011-09-18 7:29 ` Walter Dnes
2011-09-15 15:03 ` Michael Mol
2011-09-15 15:16 ` Michael Schreckenbauer
2011-09-15 15:37 ` Michael Mol
2011-09-15 15:43 ` Joost Roeleveld
2011-09-15 16:16 ` Michael Mol
2011-09-15 16:37 ` Joost Roeleveld
2011-09-15 15:13 ` Michael Schreckenbauer
2011-09-15 17:59 ` Mick
2011-09-15 19:04 ` Canek Peláez Valdés
2011-09-15 19:17 ` Neil Bothwick
2011-09-15 21:30 ` Joost Roeleveld
2011-09-15 21:38 ` Canek Peláez Valdés
2011-09-16 8:59 ` Joost Roeleveld
2011-09-16 9:29 ` Pandu Poluan
2011-09-16 14:57 ` Canek Peláez Valdés
2011-09-16 15:57 ` Dale
2011-09-16 16:11 ` Canek Peláez Valdés
2011-09-16 16:20 ` Mark Knecht
2011-09-16 17:09 ` Dale
2011-09-16 16:21 ` Pandu Poluan
2011-09-17 6:06 ` Joost Roeleveld
2011-09-16 18:45 ` Carlos Hendson
2011-09-19 0:58 ` Walter Dnes
2011-09-15 14:57 ` Canek Peláez Valdés
2011-09-15 15:08 ` Michael Mol
2011-09-15 15:37 ` Joost Roeleveld
2011-09-15 18:15 ` Neil Bothwick
2011-09-15 21:32 ` Joost Roeleveld
2011-09-15 17:37 ` pk
2011-09-15 21:34 ` Joost Roeleveld
2011-09-15 20:05 ` Sebastian Beßler
2011-09-15 20:27 ` Canek Peláez Valdés
2011-09-15 20:53 ` Sebastian Beßler
2011-09-15 21:05 ` Canek Peláez Valdés
2011-09-16 9:08 ` Joost Roeleveld
2011-09-16 14:53 ` Canek Peláez Valdés
2011-09-17 6:45 ` Joost Roeleveld
2011-09-17 7:04 ` Joost Roeleveld
2011-09-17 14:59 ` Canek Peláez Valdés
2011-09-17 12:33 ` Alan McKinnon
2011-09-17 14:50 ` Canek Peláez Valdés
2011-09-17 15:41 ` Michael Mol
2011-09-17 18:36 ` Canek Peláez Valdés
2011-09-17 19:24 ` Michael Mol
2011-09-17 21:13 ` Canek Peláez Valdés
2011-09-18 19:13 ` Neil Bothwick
2011-09-17 23:00 ` Alan McKinnon
2011-09-17 23:31 ` Michael Mol
2011-09-17 23:45 ` Canek Peláez Valdés
2011-09-17 23:50 ` Michael Mol
2011-09-18 7:37 ` Alan McKinnon
2011-09-18 9:23 ` [gentoo-user] [OT rant] " pk
2011-09-18 10:03 ` Volker Armin Hemmann
2011-09-18 10:44 ` pk
2011-09-18 12:32 ` Volker Armin Hemmann
2011-09-18 12:56 ` Alan McKinnon
2011-09-18 16:55 ` pk
2011-09-18 17:41 ` Indi
2011-09-18 18:13 ` pk
2011-09-18 19:08 ` Alan McKinnon
2011-09-18 20:48 ` Volker Armin Hemmann
2011-09-20 0:20 ` Walter Dnes
2011-09-20 16:50 ` Volker Armin Hemmann
2011-09-20 17:10 ` Alex Schuster
2011-09-20 17:28 ` Michael Mol
2011-09-20 17:33 ` Mark Knecht
2011-09-20 17:54 ` Alex Schuster
2011-09-20 17:19 ` Thanasis
2011-09-20 17:30 ` Volker Armin Hemmann
2011-09-21 16:54 ` Roman Dobosz
2011-09-18 13:19 ` pk
2011-09-18 13:31 ` Canek Peláez Valdés
2011-09-18 17:43 ` pk
2011-09-18 19:52 ` Michael Mol
2011-09-18 21:06 ` Volker Armin Hemmann
2011-09-19 19:23 ` Alan McKinnon
2011-09-19 16:23 ` pk
2011-09-19 16:37 ` Michael Mol
2011-09-19 17:42 ` Volker Armin Hemmann
2011-09-19 18:02 ` Michael Mol
2011-09-19 19:20 ` Alan McKinnon
2011-09-19 19:42 ` Michael Mol
2011-09-19 20:44 ` Volker Armin Hemmann
2011-09-19 22:13 ` Neil Bothwick
2011-09-19 6:21 ` Paul Colquhoun
2011-09-19 16:28 ` Volker Armin Hemmann
2011-09-18 13:37 ` Volker Armin Hemmann
2011-09-18 13:58 ` Michael Mol
2011-09-18 21:07 ` Volker Armin Hemmann
2011-09-19 17:13 ` Michael Mol
2011-09-18 13:15 ` Canek Peláez Valdés
2011-09-18 13:33 ` Volker Armin Hemmann
2011-09-22 15:06 ` [gentoo-user] " Michael Orlitzky
2011-09-17 21:03 ` pk
2011-09-17 21:25 ` Canek Peláez Valdés
2011-09-19 8:30 ` [gentoo-user] " Nicolas Sebrecht
2011-09-19 14:22 ` Alan McKinnon
2011-09-19 14:41 ` Michael Schreckenbauer
2011-09-19 16:36 ` Volker Armin Hemmann
2011-09-19 17:25 ` Michael Schreckenbauer
2011-09-19 17:43 ` Volker Armin Hemmann
2011-09-19 17:59 ` Michael Schreckenbauer
2011-09-19 18:06 ` Michael Mol
2011-09-19 19:12 ` Alan McKinnon
2011-09-19 20:46 ` Volker Armin Hemmann
2011-09-19 21:22 ` Alan McKinnon
2011-09-20 2:00 ` Indi
2011-09-19 18:28 ` pk
2011-09-20 10:13 ` James Broadhead
2011-09-20 23:12 ` Alan McKinnon
2011-09-20 23:47 ` Dale
2011-09-21 17:55 ` Mick
2011-09-17 18:43 ` [gentoo-user] " Canek Peláez Valdés
2011-09-18 14:47 ` Joost Roeleveld
2011-09-18 15:32 ` Pandu Poluan
2011-09-15 20:26 ` Alan McKinnon
2011-09-14 9:06 ` Neil Bothwick
2011-09-14 14:37 ` Canek Peláez Valdés
2011-09-14 14:49 ` Michael Mol
2011-09-14 15:36 ` Neil Bothwick
2011-09-14 15:43 ` Michael Mol
2011-09-14 16:05 ` Allan Gottlieb
2011-09-14 16:10 ` Canek Peláez Valdés
2011-09-14 18:59 ` Neil Bothwick
2011-09-14 22:37 ` Peter Humphrey
2011-09-14 23:43 ` Neil Bothwick
2011-09-14 23:51 ` Peter Humphrey
2011-09-14 15:35 ` Neil Bothwick
2011-09-14 16:07 ` Canek Peláez Valdés
2011-09-14 16:40 ` Sebastian Beßler
2011-09-15 7:37 ` Joost Roeleveld
2011-09-15 7:26 ` Joost Roeleveld
2011-09-14 10:25 ` Alan Mackenzie
2011-09-14 14:10 ` Mick
2011-09-14 14:19 ` Michael Mol
2011-09-14 14:56 ` Canek Peláez Valdés
2011-09-14 14:50 ` Canek Peláez Valdés
2011-09-14 14:47 ` Canek Peláez Valdés
2011-09-14 15:04 ` Stroller
2011-09-14 21:34 ` Alan Mackenzie
2011-09-14 22:05 ` Really OT now (Re: [gentoo-user] udev + /usr) Michael Schreckenbauer
2011-09-14 22:35 ` Michael Mol
2011-09-15 18:58 ` IDE for C/C++ (Was: " David W Noon
2011-09-15 19:16 ` Michael Mol
2011-09-15 19:47 ` Leonardo Guilherme
2011-09-15 19:59 ` Chris Brennan
2011-09-15 20:05 ` Michael Mol
2011-09-15 21:39 ` Joost Roeleveld
2011-09-16 0:22 ` Michael Mol
2011-09-16 9:43 ` Michael Schreckenbauer
2011-09-16 12:30 ` Mike Edenfield
2011-09-16 12:46 ` Michael Mol
2011-09-16 13:10 ` Alan Mackenzie
2011-09-15 21:37 ` Alexander Tanyukevich
2011-09-15 21:38 ` Alexander Tanyukevich
2011-09-15 20:09 ` [gentoo-user] Re: Really OT now (Re: " Nikos Chantziaras
2011-09-15 14:10 ` [gentoo-user] udev + /usr Stroller
2011-09-13 16:24 ` David W Noon
2011-09-13 23:00 ` Mike Edenfield
2011-09-13 12:38 ` Mike Edenfield
2011-09-13 12:45 ` Neil Bothwick
2011-09-13 15:09 ` Stroller
2011-09-13 15:46 ` Neil Bothwick
2011-09-13 23:10 ` Mike Edenfield
2011-09-13 12:59 ` Michael Mol
2011-09-14 20:41 ` pk
2011-09-12 20:45 ` Alan McKinnon
2011-09-12 15:35 ` Canek Peláez Valdés
2011-09-12 15:59 ` Michael Schreckenbauer
2011-09-13 7:28 ` Paul Colquhoun
2011-09-12 16:21 ` Dale
2011-09-12 16:42 ` Canek Peláez Valdés
2011-09-12 16:52 ` Michael Schreckenbauer
2011-09-12 18:26 ` Canek Peláez Valdés
2011-09-12 18:54 ` Michael Schreckenbauer
2011-09-12 16:55 ` Michael Mol
2011-09-12 20:34 ` Alan McKinnon
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