On Wed, Nov 30, 2022 at 10:24:10AM +0800, Sam Li wrote:
> Stefan Hajnoczi <stefa...@gmail.com> 于2022年11月30日周三 10:01写道：
> > On Thu, 27 Oct 2022 at 11:46, Sam Li <faithilike...@gmail.com> wrote:
> > > @@ -1374,9 +1428,11 @@ static int hdev_probe_blocksizes(BlockDriverState
> > > *bs, BlockSizes *bsz)
> > > int ret;
> > >
> > > /* If DASD, get blocksizes */
> > > +#ifndef CONFIG_BLKZONED
> > > if (check_for_dasd(s->fd) < 0) {
> > > return -ENOTSUP;
> > > }
> > > +#endif
> >
> > What is the purpose of this #ifndef? .bdrv_probe_blocksizes() should
> > only return block sizes for s390 DASD devices. I don't think zoned
> > storage needs block size probing here.
>
> Zoned storage needs to be virtualized with the correct physical block
> size and logical block size. And the probing here can guarantee that.
> Or virtio-blk may send wrong block size to the guest. If manually set
> block size in the command line as before, it is somewhat inaccurate.I see. I/O won't work if the guest block size differs from the physical zoned device's block size. However, we must not do this for regular host_device BlockDriverStates. The block size is manually controlled from those devices and defaults to 512B. That way the blocksize doesn't change across live migration and break the guest. Please use a run-time check instead of an #ifdef. Only probe blocksizes for dasd and zoned devices. Stefan
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