Re: PATCH/FIX for drivers/cdrom/cdrom.c

From: Bodo Eggert
Date: Thu Aug 17 2006 - 08:28:44 EST

Arjan van de Ven <arjan@xxxxxxxxxxxxx> wrote:
> On Wed, 2006-08-16 at 14:37 -0400, Lennart Sorensen wrote:

>> Perhaps the real problem is that some @#$@#$ user space task is
>> constantly trying to mount the disc while something else is trying to
>> write to it.
>> gnome and kde both seem very eager to implement such things.  perhaps
>> there should be a way to prevent any access by such processes while
>> writing to the disc.
> there is. O_EXCL works for this.
> Any sane desktop app and cd burning app use O_EXCL already for this
> purpose...

This was discussed to death:

HAL using O_EXCL will randomly prevent burning/mounting/etc by causing a
race condition, so it can't do that. HAL not using O_EXCL will OTOH succeed
in opening despite of O_EXCL used by the burning process and thereby
prevent burning by opening a busy device. The proposed solution was
introducing O_NONE or O_HARMLESS to prevent side-effects from opening
the device.

This will, however, not prevent other users from maliciously destroying the
CD by not using O_EXCL. Chowning the device is not a real solution, since
users should be able to fusermount the CD.

Maybe it's possible to cache the result and thereby prevent repeated
opening from disturbing the burning process.
Ich danke GMX dafür, die Verwendung meiner Adressen mittels per SPF
verbreiteten Lügen zu sabotieren.
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at