block: fix a race between del_gendisk and BLKRRPART

[ Upstream commit bc6a385132601c29a6da1dbf8148c0d3c9ad36dc ]

When BLKRRPART is called concurrently with del_gendisk, the partitions
rescan can create a stale partition that will never be be cleaned up.

Fix this by checking the the disk is up before rescanning partitions
while under bd_mutex.

Signed-off-by: Gulam Mohamed <gulam.mohamed@oracle.com>
[hch: split from a larger patch]
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20210514131842.1600568-3-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/fs/block_dev.c b/fs/block_dev.c
index cacea6bafc22971c081f3cd7621b5619be4a39f0..29f020c4b2d0ddaf758c21ddb339f43cb046a11f 100644 (file)
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1408,6 +1408,9 @@ int bdev_disk_changed(struct block_device *bdev, bool invalidate)
 
        lockdep_assert_held(&bdev->bd_mutex);
 
+       if (!(disk->flags & GENHD_FL_UP))
+               return -ENXIO;
+
 rescan:
        ret = blk_drop_partitions(bdev);
        if (ret)