Re: [RFC PATCH V3 1/1] block: reject I/O for same fd if block size changed

[Christoph Hellwig]

On Mon, Jan 04, 2021 at 06:11:08PM +0100, Christoph Hellwig wrote:
> On Mon, Jan 04, 2021 at 10:06:59PM +0900, Minwoo Im wrote:
> > +	if (q->backing_dev_info && q->backing_dev_info->owner &&
> > +			limits->logical_block_size != size) {
> > +		bdev = blkdev_get_no_open(q->backing_dev_info->owner->devt);
> > +		bdev->bd_disk->flags |= GENHD_FL_BLOCK_SIZE_CHANGED;
> > +		blkdev_put_no_open(bdev);
> > +	}
> 
> We really need the backpointer from the queue to the gendisk I've wanted
> to add for a while.  Can we at least restrict this to a live gendisk?

Alternatively we could make this request_queue QUEUE* flag for now.