Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755810Ab1DFMUW (ORCPT ); Wed, 6 Apr 2011 08:20:22 -0400 Received: from mail-qy0-f174.google.com ([209.85.216.174]:58277 "EHLO mail-qy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750807Ab1DFMUT (ORCPT ); Wed, 6 Apr 2011 08:20:19 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=sender:date:from:to:cc:subject:message-id:mime-version:content-type :content-disposition:user-agent; b=OSGvFAORtGPW1AAluJAGkwt39rxnDRpUPqNxgHNZE4ErnMM9cDgw6+Na9xJKHwrfxz YZG+LKDMuDI/kqXpsSSVwMgYUlUEJiYqNuUnhDKLPJPw4fhEMA/1npZq5L0Lb7KypvA5 RMCRdyyBYxsgrJP59UdV49O7XC9rtXZttxlv8= Date: Wed, 6 Apr 2011 05:20:09 -0700 From: Tejun Heo To: Jens Axboe Cc: Amit Shah , David Zeuthen , Martin Pitt , Kay Sievers , linux-kernel@vger.kernel.org Subject: [PATCH 1/2] cdrom: always check_disk_change() on open Message-ID: <20110406121920.GC4142@mtj.dyndns.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2365 Lines: 57 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 Reported-by: Amit Shah Tested-by: Amit Shah --- drivers/cdrom/cdrom.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/cdrom/cdrom.c b/drivers/cdrom/cdrom.c index e2c48a7..5ade78a 100644 --- a/drivers/cdrom/cdrom.c +++ b/drivers/cdrom/cdrom.c @@ -986,6 +986,9 @@ int cdrom_open(struct cdrom_device_info *cdi, struct block_device *bdev, fmode_t cdinfo(CD_OPEN, "entering cdrom_open\n"); + /* open is event synchronization point, check events first */ + check_disk_change(bdev); + /* if this was a O_NONBLOCK open and we should honor the flags, * do a quick open without drive/disc integrity checks. */ cdi->use_count++; @@ -1012,9 +1015,6 @@ int cdrom_open(struct cdrom_device_info *cdi, struct block_device *bdev, fmode_t cdinfo(CD_OPEN, "Use count for \"/dev/%s\" now %d\n", cdi->name, cdi->use_count); - /* Do this on open. Don't wait for mount, because they might - not be mounting, but opening with O_NONBLOCK */ - check_disk_change(bdev); return 0; err_release: if (CDROM_CAN(CDC_LOCK) && cdi->options & CDO_LOCK) { -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/