在 2016-11-25 18:21, Kevin Wolf 写道:
[ Cc: Fam, qemu-stable ]
Am 25.11.2016 um 11:06 hat QingFeng Hao geschrieben:
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.
Signed-off-by: QingFeng Hao <ha...@linux.vnet.ibm.com>
Signed-off-by: Jing Liu <liuj...@linux.vnet.ibm.com>
Sounds like something that should still be fixed for 2.8 and in the
stable branches.
I didn't find the stable branch on upstream, the latest is 2.6 maybe
it's a private one? :-)
diff --git a/block/vmdk.c b/block/vmdk.c
index a11c27a..bf6667f 100644
--- a/block/vmdk.c
+++ b/block/vmdk.c
@@ -1355,7 +1355,7 @@ static int vmdk_write_extent(VmdkExtent *extent, int64_t
cluster_offset,
}
data->lba = offset >> BDRV_SECTOR_BITS;
- data->size = buf_len;
+ data->size = cpu_to_le32(buf_len);
At least data->lba needs to be fixed, too, both here and in
vmdk_read_extent(). Host endianness in an image file is always wrong.
Good detection!
Maybe we should audit the whole driver for endianness problems.
Good sight! maybe we can encapsulate a suite of endianness functions
for the structures to avoid missing some elements of them like lba?
Also will be better for reuse. When I am checking the endianness calls
in vmdk_create_extent, I am just afraid of missing one. :-)
Thanks!
Kevin
--
QingFeng Hao(Robin)
