[PATCH 5.11 11/41] block: return -EBUSY when there are open partitions in blkdev_reread_part

[Greg Kroah-Hartman]

From: Christoph Hellwig <hch@xxxxxx>

[ Upstream commit 68e6582e8f2dc32fd2458b9926564faa1fb4560e ]

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@xxxxxxxxxx>
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Link: https://lore.kernel.org/r/20210421160502.447418-1-hch@xxxxxx
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 block/ioctl.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/block/ioctl.c b/block/ioctl.c
index ff241e663c01..8ba1ed8defd0 100644
--- 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
-- 
2.30.2