block: Fix bdi assignment to bdev inode when racing with disk delete

When disk->fops->open() in __blkdev_get() returns -ERESTARTSYS, we
restart the process of opening the block device. However we forget to
switch bdev->bd_bdi back to noop_backing_dev_info and as a result bdev
inode will be pointing to a stale bdi. Fix the problem by setting
bdev->bd_bdi later when __blkdev_get() is already guaranteed to succeed.

Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
Change-Id: I6736ed1aba8732d3146284311c718f48b9c06578
Git-repo:
git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git


Git-commit: 03e262798884b0a5f948b17433afd80606cb3497
Signed-off-by: Ritesh Harjani <riteshh@codeaurora.org>