Re: [Qemu-devel] [PATCH v3 1/4] qemu-img: Convert by cluster size if target is compressed

[Stefan Hajnoczi]

On Fri, Apr 25, 2014 at 04:00:49PM +0800, Fam Zheng wrote:
 diff --git a/include/block/block.h b/include/block/block.h
 index b3230a2..8a1cb83 100644
 --- a/include/block/block.h
 +++ b/include/block/block.h
 @@ -34,6 +34,10 @@ typedef struct BlockDriverInfo {
   * opened with BDRV_O_UNMAP flag for this to work.
   */
  bool can_write_zeroes_with_unmap;
 +/*
 + * True if the driver is writing data clusters compressed
 + */
 +bool is_compressed;

is_compressed is more general than what this flag actually
communicates:

/*
 * True if this block driver only supports compressed writes
 */
bool needs_compressed_writes;

[Qemu-devel] [PATCH v3 1/4] qemu-img: Convert by cluster size if target is compressed

[Fam Zheng]

If target block driver forces compression, qemu-img convert needs to
write by cluster size as well as -c option.

Particularly, this applies for converting to VMDK streamOptimized
format.

Signed-off-by: Fam Zheng f...@redhat.com
---
 include/block/block.h | 4 
 qemu-img.c| 1 +
 2 files changed, 5 insertions(+)

diff --git a/include/block/block.h b/include/block/block.h
index b3230a2..8a1cb83 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -34,6 +34,10 @@ typedef struct BlockDriverInfo {
  * opened with BDRV_O_UNMAP flag for this to work.
  */
 bool can_write_zeroes_with_unmap;
+/*
+ * True if the driver is writing data clusters compressed
+ */
+bool is_compressed;
 } BlockDriverInfo;
 
 typedef struct BlockFragInfo {
diff --git a/qemu-img.c b/qemu-img.c
index 8455994..ace4c21 100644
--- a/qemu-img.c
+++ b/qemu-img.c
@@ -1458,6 +1458,7 @@ static int img_convert(int argc, char **argv)
 goto out;
 }
 } else {
+compress = compress || bdi.is_compressed;
 cluster_sectors = bdi.cluster_size / BDRV_SECTOR_SIZE;
 }
 
-- 
1.9.2