Messages in this thread | | | Date | Tue, 10 May 2011 13:43:53 +0530 | From | Amit Shah <> | Subject | Re: [PATCH 1/2] cdrom: always check_disk_change() on open |
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On (Tue) 10 May 2011 [09:44:28], Jens Axboe wrote: > On 2011-05-10 08:42, Amit Shah wrote: > > On (Fri) 29 Apr 2011 [10:15:50], Jens Axboe wrote: > >> On 2011-04-29 08:57, Amit Shah wrote: > >>> On (Wed) 06 Apr 2011 [05:20:09], Tejun Heo wrote: > >>>> cdrom_open() called check_disk_change() after the rest of open path > >>>> succeeded which leads to the following bizarre behavior. > >>>> > >>>> * After media change, if the device opened without O_NONBLOCK, > >>>> open_for_data() naturally fails with -ENOMEDIA and > >>>> check_disk_change() is never called. The media is known to be gone > >>>> and the open failure makes it obvious to the userland but device > >>>> invalidation never happens. > >>>> > >>>> * But if the device is opened with O_NONBLOCK, all the checks are > >>>> bypassed and cdrom_open() doesn't notice that the media is not there > >>>> and check_disk_change() is called and invalidation happens. > >>>> > >>>> There's nothing to be gained by avoiding calling check_disk_change() > >>>> on open failure. Common cases end up calling check_disk_change() > >>>> anyway. All we get is inconsistent behavior. > >>>> > >>>> Fix it by moving check_disk_change() invocation to the top of > >>>> cdrom_open() so that it always gets called regardless of how the rest > >>>> of open proceeds. > >>>> > >>>> Signed-off-by: Tejun Heo <tj@kernel.org> > >>>> Reported-by: Amit Shah <amit.shah@redhat.com> > >>>> Tested-by: Amit Shah <amit.shah@redhat.com> > >>> > >>> Ping? > >>> > >>> Also, please mark this for stable-2.6.38. > >> > >> Done, added for 2.6.39 and marked stable for 2.6.38. > > > > Ping again. Don't see this yet in Linus's git tree. > > It was added for 2.6.40 and marked for stable.
OK, Thanks.
Amit
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