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: qemu-sta...@nongnu.org
Signed-off-by: QingFeng Hao 
Signed-off-by: Jing Liu 
Signed-off-by: Kevin Wolf 
---
  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)

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

[liujing]

Hi QingFeng,


I just have a question that whether the marker->data
need convert?

I've no idea, just suddenly realized this question.

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: qemu-sta...@nongnu.org
Signed-off-by: QingFeng Hao 
Signed-off-by: Jing Liu 
Signed-off-by: Kevin Wolf 
---
  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) {

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

[QingFeng Hao]

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: qemu-sta...@nongnu.org
Signed-off-by: QingFeng Hao 
Signed-off-by: Jing Liu 
Signed-off-by: Kevin Wolf 
---
 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) {
-- 
2.8.4