On Thu, Oct 29, 2020 at 07:51:49AM +0000, Christoph Hellwig wrote: > On Wed, Oct 28, 2020 at 03:24:34PM +0800, Ming Lei wrote: > > Mounted NBD device can be resized, one use case is rbd-nbd. > > > > Fix the issue by setting up default block size, then not touch it > > in nbd_size_update() any more. This kind of usage is aligned with loop > > which has same use case too. > > I think the only reasonable fix here is to remove the set_blocksize > call entirely. The concept of block size set by it is a file system > construct and nbd has not business setting it at all. I think the idea is reasonable, we have several drivers(loop, nbd, zram, pktcdvd, bcache) which call into set_blocksize(). Also ioctl(BLKBSZSET) which is used by 'blockdev --setbsz', still not understand which kind of use case is served for. Thanks, Ming
