Re: [Qemu-block] [PATCH v2 1/1] block/vmdk: Fix the endian problem of buf_len and lba

[Hao QingFeng]

在 2016-11-28 15:56, liujing 写道:
> Hi QingFeng,
>
>
> I just have a question that whether the marker->data
> need convert?
>
> I've no idea, just suddenly realized this question.
nope, the data is type of char * for the compressed data stream, so no 
endian issue.
thanks.
> Jing
>
> On 11/26/2016 01:46 PM, QingFeng Hao wrote:
> > The problem was triggered by qemu-iotests case 055. It failed when it
> > was comparing the compressed vmdk image with original test.img.
> >
> > The cause is that buf_len in vmdk_write_extent wasn't converted to
> > little-endian before it was stored to disk. But later vmdk_read_extent
> > read it and converted it from little-endian to cpu endian.
> > If the cpu is big-endian like s390, the problem will happen and
> > the data length read by vmdk_read_extent will become invalid!
> > The fix is to add the conversion in vmdk_write_extent, meanwhile,
> > repair the endianness problem of lba field which shall also be converted
> > to little-endian before storing to disk.
> >
> > Cc: address@hidden
> > Signed-off-by: QingFeng Hao <address@hidden>
> > Signed-off-by: Jing Liu <address@hidden>
> > Signed-off-by: Kevin Wolf <address@hidden>
> > ---
> >   block/vmdk.c | 4 ++--
> >   1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/block/vmdk.c b/block/vmdk.c
> > index a11c27a..26e5f95 100644
> > --- a/block/vmdk.c
> > +++ b/block/vmdk.c
> > @@ -1354,8 +1354,8 @@ static int vmdk_write_extent(VmdkExtent 
> > *extent, int64_t cluster_offset,
> >               goto out;
> >           }
> >
> > -        data->lba = offset >> BDRV_SECTOR_BITS;
> > -        data->size = buf_len;
> > +        data->lba = cpu_to_le64(offset >> BDRV_SECTOR_BITS);
> > +        data->size = cpu_to_le32(buf_len);
> >
> >           n_bytes = buf_len + sizeof(VmdkGrainMarker);
> >           iov = (struct iovec) {

--
QingFeng Hao(Robin)