2021-03-23 08:54:27

by Chris Chiu

Subject: [PATCH] block: clear GD_NEED_PART_SCAN later in bdev_disk_changed

From: Chris Chiu <[email protected]>

The GD_NEED_PART_SCAN is set by bdev_check_media_change to initiate
a partition scan while removing a block device. It should be cleared
after blk_drop_paritions because blk_drop_paritions could return
-EBUSY and then the consequence __blkdev_get has no chance to do
delete_partition if GD_NEED_PART_SCAN already cleared.

It causes some problems on some card readers. Ex. Realtek card
reader 0bda:0328 and 0bda:0158. The device node of the partition
will not disappear after the memory card removed. Thus the user
applications can not update the device mapping correctly.

BugLink: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1920874
Signed-off-by: Chris Chiu <[email protected]>
---
fs/block_dev.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/block_dev.c b/fs/block_dev.c
index 92ed7d5df677..28d583fcdc2c 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1240,13 +1240,13 @@ int bdev_disk_changed(struct block_device *bdev, bool invalidate)

lockdep_assert_held(&bdev->bd_mutex);

- clear_bit(GD_NEED_PART_SCAN, &bdev->bd_disk->state);
-
rescan:
ret = blk_drop_partitions(bdev);
if (ret)
return ret;

+ clear_bit(GD_NEED_PART_SCAN, &disk->state);
+
/*
* Historically we only set the capacity to zero for devices that
* support partitions (independ of actually having partitions created).
--
2.20.1

2021-03-23 15:52:58

by Christoph Hellwig

Subject: Re: [PATCH] block: clear GD_NEED_PART_SCAN later in bdev_disk_changed

Looks good,

Reviewed-by: Christoph Hellwig <[email protected]>

2021-03-23 16:01:48

by Jens Axboe

Subject: Re: [PATCH] block: clear GD_NEED_PART_SCAN later in bdev_disk_changed

On 3/23/21 2:52 AM, [email protected] wrote:
> From: Chris Chiu <[email protected]>
>
> The GD_NEED_PART_SCAN is set by bdev_check_media_change to initiate
> a partition scan while removing a block device. It should be cleared
> after blk_drop_paritions because blk_drop_paritions could return
> -EBUSY and then the consequence __blkdev_get has no chance to do
> delete_partition if GD_NEED_PART_SCAN already cleared.
>
> It causes some problems on some card readers. Ex. Realtek card
> reader 0bda:0328 and 0bda:0158. The device node of the partition
> will not disappear after the memory card removed. Thus the user
> applications can not update the device mapping correctly.

Applied, thanks.

--
Jens Axboe