probe-storage and addon-storage competing for O_EXCL on cdrom device

[Andrey Borzenkov]

On Thursday 08 March 2007, kareemy wrote:
> I am attaching a quick patch I wrote based on retry code in
> hal-storage-shared.c. This patch appears to solve the problem for me,
> but I've only tested it a few times on my own machine.
>

Confirmed; see Mandriva bug http://qa.mandriva.com/show_bug.cgi?id=29790. The 
attached patch seems to fix it here as well.

-andrey

> On 3/7/07, kareemy <kareemy at gmail.com> wrote:
> > I am trying hal 0.5.9rc1 and have had a problem where most of the times
> > when I insert a new cdrom disk into my cdrom, no volume namespace is
> > created for the cd. I did some debugging and found out this happens when
> > open (device_file, ORDONLY | O_NONBLOCK | O_EXCL) fails and sets EBUSY in
> >  probe-storage.c around line 287.
> >
> > Inside the EBUSY if conditional, hal correctly determines that the device
> > is not mounted and then does a goto out, so it never opens the device and
> > never setups a volume namespace or anything like that.
> >
> > I added some debugging output to probe-storage.c and addon-storage.c that
> > prints when each one successfully opens the device and then closes it
> > again. A lot of times on my system, addon-storage.c does a O_EXCL on the
> > cdrom device, probe-storage attempts an O_EXCL and fails, then
> > addon-storage closes the device.
> >
> > I'm attaching a log of hald --daemon=no --verbose=yes with my additional
> > debugging comments that illustrates this. At the beginning of the file,
> > it shows addon-storage polling the cdrom device every 2 seconds as usual,
> > then once I insert a new media, addon-storage locks the cdrom,
> > probe-storage trys to do an open, it fails, and then addon-storage closes
> > the lock.
> >
> > I figure it is possible to have probe-storage keep trying if it gets an
> > EBUSY error until it can open the device, but I'm not sure if that is the
> > best solution. Ideas?
> >
> > Some more system specs:
> > Linux  2.6.19.2 SMP
> > Hal 0.5.9rc1
> > dbus 1.0.2
> >
> > - Kareem Dana


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