On Tue, Sep 13, 2022 at 03:20:23PM +0100, Damien Le Moal wrote: > On 2022/09/13 15:12, Keith Busch wrote: > > On Thu, Sep 08, 2022 at 09:45:26AM -0700, Keith Busch wrote: > >> From: Keith Busch <kbu...@kernel.org> > >> > >> An iov length needs to be aligned to the logical block size, which may > >> be larger than the memory alignment. > > > > [cc'ing some other interested folks] > > > > Any thoughts on this patch? It is fixing an observed IO error when running > > virtio-blk with the default 512b logical block size backed by a drive > > formatted > > with 4k logical block. > > The patch look OK to me, but having virtio expose a 512B LBA size for a > backing > device that has 4K LBAs will break all IOs if caching is turned off (direct > IOs > case), even if this patch is applied. No ?
Yeah, it's just the default. I don't think anyone would do that on purpose since it's so sub-optimal from a performance stand-point. As a follow up patch, perhaps if the logical_block_size parameter is not provided, we should default to the backing device's block size?
