block: fix busy device checking in blk_drop_partitions

bd_super is only set by get_tree_bdev and mount_bdev, and thus not by
other openers like btrfs or the XFS realtime and log devices, as well as
block devices directly opened from user space.  Check bd_openers
instead.

Fixes: 77032ca66f86 ("Return EBUSY from BLKRRPART for mounted whole-dev fs")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/partitions/core.c b/block/partitions/core.c
index b79c451..1a0a829 100644 (file)
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -496,7 +496,7 @@ int blk_drop_partitions(struct gendisk *disk, struct block_device *bdev)
 
        if (!disk_part_scan_enabled(disk))
                return 0;
-       if (bdev->bd_part_count || bdev->bd_super)
+       if (bdev->bd_part_count || bdev->bd_openers)
                return -EBUSY;
        res = invalidate_partition(disk, 0);
        if (res)