Re: [PATCH 1/2] cdrom: always check_disk_change() on open

From: Amit Shah
Date: Fri Apr 29 2011 - 02:57:36 EST


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@xxxxxxxxxx>
> Reported-by: Amit Shah <amit.shah@xxxxxxxxxx>
> Tested-by: Amit Shah <amit.shah@xxxxxxxxxx>

Ping?

Also, please mark this for stable-2.6.38.

Thanks,

Amit
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