[PATCH 0/1][SRU][OEM-5.10/H/U] Fix regression for disk media removal

[chris.chiu at canonical.com]

From: Chris Chiu <chris.chiu at canonical.com>

BugLink: https://bugs.launchpad.net/bugs/1920874

[Impact]
Memory card removal event can not be reflected via uevent on some card
readers Ex. Realtek card readers 0bda:0328 and 0bda:0158. Thus the file
browser still see the ghost disk even it's already removed.

[Fix]
Found the commit 6540fbf6b643 in 5.9.0-rc3 introduces this regression.
Make sure the partition scan will never be skipped for each vfs_open
until the partition scan is really done.


[Test]
Verified on the Realtek card reader 0bda:0328 on Dell Precision 7820
and the external Realtek usb interface card reader 0bda:0158.

Insert the SD card in the card reader
  $ udevadm monitor
Remove the SD card and check the udevadm monitor output

KERNEL[188.377042] change /devices/pci0000:00/0000:00:14.0/usb2/2-9/2-9:1.0/host5/target5:0:0/5:0:0:0/block/sdc (block)
UDEV [188.383261] remove /devices/pci0000:00/0000:00:14.0/usb2/2-9/2-9:1.0/host5/target5:0:0/5:0:0:0/block/sdc (block)
KERNEL[188.390887] change /devices/pci0000:00/0000:00:14.0/usb2/2-9/2-9:1.0/host5/target5:0:0/5:0:0:0/block/sdc (block)
UDEV [188.396012] remove /devices/pci0000:00/0000:00:14.0/usb2/2-9/2-9:1.0/host5/target5:0:0/5:0:0:0/block/sdc (block)

The remove event should be observed from the output messages. On the
affected card reader, only change event would be observed.

[Where problem could occur]
These kind of card readers doesn't send remove event of scsi_disk and
scsi_device like others so they only depend on the block subsystem to
detect the media change and relect the removal event by partition scan.
The behavior related to media removal is changed after 5.9.0-rc3.
The remove event is not able to be correcly reflected since then, the
device node of the media will remain there until next card insertion.

Chris Chiu (1):
  block: clear GD_NEED_PART_SCAN later in bdev_disk_changed

 fs/block_dev.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

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2.17.1