block: return -EBUSY when there are open partitions in blkdev_reread_part

The switch to go through blkdev_get_by_dev means we now ignore the
return value from bdev_disk_changed in __blkdev_get.  Add a manual
check to restore the old semantics.

Fixes: 4601b4b130de ("block: reopen the device in blkdev_reread_part")
Reported-by: Karel Zak <kzak@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210421160502.447418-1-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/ioctl.c b/block/ioctl.c
index ff241e6..8ba1ed8 100644 (file)
--- a/block/ioctl.c
+++ b/block/ioctl.c
@@ -89,6 +89,8 @@ static int blkdev_reread_part(struct block_device *bdev, fmode_t mode)
                return -EINVAL;
        if (!capable(CAP_SYS_ADMIN))
                return -EACCES;
+       if (bdev->bd_part_count)
+               return -EBUSY;
 
        /*
         * Reopen the device to revalidate the driver state and force a