device_cio_free.conf

[Dan Horák]

Waiki Wright píše v Pá 23. 09. 2011 v 14:16 -0400: 
> On 09/07/2011 05:17 AM, Dan Horák wrote:
> > Waiki Wright píše v Út 06. 09. 2011 v 18:27 -0400:
> >> Hello Dan,
> >> I saw your name in one of the bugs related to device_cio_free.conf and
> >> hope that you may be able to answer my question.  If you prefer me to
> >> send my inquire to a mailing list, please let me know.
> > I'm sending the reply to mailing list, so more people can comment.
> >
> >> I am using s390utils-1.8.2-28.el6.s390x package and I am wondering if
> >> there will be a race condition between rcS and device_cio_free.
> >>
> >> The device_cio_free.conf file said that it will start when rcS.conf is
> >> starting:
> >> #
> >> # free all devices on startup
> >> #
> >>
> >> start on starting rcS
> >>
> >> task
> >>
> >> console output
> >>
> >> exec /sbin/device_cio_free
> >>
> >> However, in the /sbin/device_cio_free script,  it depends on /proc is
> >> mounted before the script is called:
> >>
> >> BLACKLIST=/proc/cio_ignore
> >> .
> >> .
> >> .
> >> if [ ! -f $BLACKLIST ]; then
> >>       echo "Error: $BLACKLIST kernel interface doesn't exist"
> >>       exit 2
> >> fi
> >>
> >> If the file system is mounted later (from rcS), then device_cio_free
> >> script will fail.  So should it be better if
> >> device_cio_free.conf to start on after /proc is mounted?
> >>
> >> Your thought?
> > Your conclusion looks logical. However this upstart job was proposed by
> > our upstart maintainer when I asked him for a solution to the following
> > problem: need to start an action before the system will try to mount
> > non-root filesystem devices or bring network interfaces up. Also it
> > shouldn't interfere with the startup process on primary arches.
> >
> > Staring with Fedora 15 there is a systemd solution, see
> > device_cio_free.service in s390utils-1.14.0-1.fc16 [1]
> >
> >
> > Dan
> >
> > [1] http://s390.koji.fedoraproject.org/koji/buildinfo?buildID=74738
> >
> Hi Dan,
> Even with the systemd implementation, there is still a possibility for 
> the race condition that I mentioned above(let me know if I am wrong).  I 
> haven't seen any response for my question and I wonder if this is a 
> potential problem that worth for a fix.

race conditions are always serious issue and when they can be reproduced
it's definitely worth to open a bugzilla. I'd suggest to fill one
against both RHEL-6 and Fedora.


Dan