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 ?
>
>> ---
>> block/io.c | 3 ++-
>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/block/io.c b/block/io.c
>> index 0a8cbefe86..296d4b49a7 100644
>> --- a/block/io.c
>> +++ b/block/io.c
>> @@ -3243,13 +3243,14 @@ bool bdrv_qiov_is_aligned(BlockDriverState *bs,
>> QEMUIOVector *qiov)
>> {
>> int i;
>> size_t alignment = bdrv_min_mem_align(bs);
>> + size_t len = bs->bl.request_alignment;
>> IO_CODE();
>>
>> for (i = 0; i < qiov->niov; i++) {
>> if ((uintptr_t) qiov->iov[i].iov_base % alignment) {
>> return false;
>> }
>> - if (qiov->iov[i].iov_len % alignment) {
>> + if (qiov->iov[i].iov_len % len) {
>> return false;
>> }
>> }
>> --
>> 2.30.2
>>
--
Damien Le Moal
Western Digital Research
