From: Amit Shah <amit.shah@redhat.com>
To: Jens Axboe <axboe@kernel.dk>
Cc: Tejun Heo <tj@kernel.org>, David Zeuthen <zeuthen@gmail.com>,
Martin Pitt <martin.pitt@ubuntu.com>,
Kay Sievers <kay.sievers@vrfy.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] cdrom: always check_disk_change() on open
Date: Tue, 10 May 2011 12:12:47 +0530 [thread overview]
Message-ID: <20110510064247.GA16436@amit-x200.redhat.com> (raw)
In-Reply-To: <4DBA73B6.6040603@kernel.dk>
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.
Amit
next prev parent reply other threads:[~2011-05-10 6:43 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-06 12:20 Tejun Heo
2011-04-06 12:22 ` [PATCH 2/2] block: rescan partitions on invalidated devices on -ENOMEDIA too Tejun Heo
2011-04-29 6:57 ` [PATCH 1/2] cdrom: always check_disk_change() on open Amit Shah
2011-04-29 8:15 ` Tejun Heo
2011-04-29 8:15 ` Jens Axboe
2011-04-29 8:16 ` Tejun Heo
2011-04-29 8:28 ` Jens Axboe
2011-05-10 6:42 ` Amit Shah [this message]
2011-05-10 7:44 ` Jens Axboe
2011-05-10 8:13 ` Amit Shah
2011-09-03 22:14 ` [regression] CD-ROM polling blocks suspend on some machines (Re: [PATCH 1/2] cdrom: always check_disk_change() on open) Jonathan Nieder
2011-09-04 2:42 ` Tejun Heo
2011-09-04 15:05 ` [regression] CD-ROM polling blocks suspend on some machines Jonathan Nieder
2011-09-05 1:49 ` [regression] CD-ROM polling blocks suspend on some machines (Re: [PATCH 1/2] cdrom: always check_disk_change() on open) Jameson Graef Rollins
2011-09-06 17:45 ` Tejun Heo
2011-09-07 8:50 ` Matthijs Kooijman
2011-09-11 4:08 ` Tejun Heo
2011-10-24 20:25 ` Gaudenz Steinlin
2011-10-26 18:26 ` Matthijs Kooijman - Brevidius
2011-10-26 22:25 ` Tejun Heo
2011-10-28 13:47 ` Matthijs Kooijman
2011-10-30 20:35 ` Tejun Heo
2011-10-31 9:28 ` Matthijs Kooijman
2011-10-31 15:26 ` Tejun Heo
2011-12-19 11:12 ` Matthijs Kooijman
2011-12-19 16:44 ` Tejun Heo
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