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authorTejun Heo <tj@kernel.org>2011-04-29 10:15:14 +0200
committerGreg Kroah-Hartman <gregkh@suse.de>2011-05-21 15:13:33 -0700
commit9f5cc5c89537184cf45a7e069330c85428a7fc09 (patch)
treeee9ab2f23450bd2e8308a89a7d3c915ac5bf7208
parentb106c56573f9656e3cf863781dd5c0895d0f120d (diff)
downloadlinux-2.6.38-lt-ux500-9f5cc5c89537184cf45a7e069330c85428a7fc09.tar.gz
cdrom: always check_disk_change() on open
commit bf2253a6f00e8fea5b026e471e9f0d0a1b3621f2 upstream. 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. Stable: 2.6.38 Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Amit Shah <amit.shah@redhat.com> Tested-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Jens Axboe <jaxboe@fusionio.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--drivers/cdrom/cdrom.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/drivers/cdrom/cdrom.c b/drivers/cdrom/cdrom.c
index e2c48a7eccf..5ade78a01c4 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) {