Commit 3723091e authored by Yu Kuai's avatar Yu Kuai Committed by Jens Axboe
Browse files

block: don't set GD_NEED_PART_SCAN if scan partition failed 



Currently if disk_scan_partitions() failed, GD_NEED_PART_SCAN will still
set, and partition scan will be proceed again when blkdev_get_by_dev()
is called. However, this will cause a problem that re-assemble partitioned
raid device will creat partition for underlying disk.

Test procedure:

mdadm -CR /dev/md0 -l 1 -n 2 /dev/sda /dev/sdb -e 1.0
sgdisk -n 0:0:+100MiB /dev/md0
blockdev --rereadpt /dev/sda
blockdev --rereadpt /dev/sdb
mdadm -S /dev/md0
mdadm -A /dev/md0 /dev/sda /dev/sdb

Test result: underlying disk partition and raid partition can be
observed at the same time

Note that this can still happen in come corner cases that
GD_NEED_PART_SCAN can be set for underlying disk while re-assemble raid
device.

Fixes: e5cfefa9 ("block: fix scan partition for exclusively open device again")
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Reviewed-by: default avatarMing Lei <ming.lei@redhat.com>
Signed-off-by: default avatarYu Kuai <yukuai3@huawei.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 5b3b9197

block/genhd.c

+7 −1
Original line number Diff line number Diff line
@@ -368,7 +368,6 @@ int disk_scan_partitions(struct gendisk *disk, fmode_t mode) 
	if (disk->open_partitions)

		return -EBUSY;



	set_bit(GD_NEED_PART_SCAN, &disk->state);

	/*

	 * If the device is opened exclusively by current thread already, it's

	 * safe to scan partitons, otherwise, use bd_prepare_to_claim() to
@@ -381,12 +380,19 @@ int disk_scan_partitions(struct gendisk *disk, fmode_t mode) 
			return ret;

	}



	set_bit(GD_NEED_PART_SCAN, &disk->state);

	bdev = blkdev_get_by_dev(disk_devt(disk), mode & ~FMODE_EXCL, NULL);

	if (IS_ERR(bdev))

		ret =  PTR_ERR(bdev);

	else

		blkdev_put(bdev, mode & ~FMODE_EXCL);



	/*

	 * If blkdev_get_by_dev() failed early, GD_NEED_PART_SCAN is still set,

	 * and this will cause that re-assemble partitioned raid device will

	 * creat partition for underlying disk.

	 */

	clear_bit(GD_NEED_PART_SCAN, &disk->state);

	if (!(mode & FMODE_EXCL))

		bd_abort_claiming(disk->part0, disk_scan_partitions);

	return ret;