From: Ming Lei <ming.lei@redhat.com>
Date: Wed, 15 Jul 2020 16:36:19 +0800
Subject: [PATCH] block: always remove partitions from blk_drop_partitions()
Git-commit: d0f0f1b4c55e9e1b10e47399f544be52567d9fc3
Patch-mainline: v5.9-rc1
References: bsc#1175995,jsc#SLE-15608

In theory, when GENHD_FL_NO_PART_SCAN is set, no partitions can be created
on one disk. However, ioctl(BLKPG, BLKPG_ADD_PARTITION) doesn't check
GENHD_FL_NO_PART_SCAN, so partitions still can be added even though
GENHD_FL_NO_PART_SCAN is set.

So far blk_drop_partitions() only removes partitions when disk_part_scan_enabled()
return true. This way can make ghost partition on loop device after changing/clearing
FD in case that PARTSCAN is disabled, such as partitions can be added
via 'parted' on loop disk even though GENHD_FL_NO_PART_SCAN is set.

Fix this issue by always removing partitions in blk_drop_partitions(), and
this way is correct because the current code supposes that no partitions
can be added in case of GENHD_FL_NO_PART_SCAN.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Hannes Reinecke <hare@suse.com>
---
 block/partitions/core.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/block/partitions/core.c b/block/partitions/core.c
index 78951e33b2d7..e62a98a8eeb7 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -619,8 +619,6 @@ int blk_drop_partitions(struct block_device *bdev)
 	struct disk_part_iter piter;
 	struct hd_struct *part;
 
-	if (!disk_part_scan_enabled(bdev->bd_disk))
-		return 0;
 	if (bdev->bd_part_count)
 		return -EBUSY;
 
-- 
2.16.4