Re: [Qemu-block] [PATCH v4 3/5] qcow2: Reduce REFT_OFFSET_MASK

[Alberto Garcia]

On Tue 27 Feb 2018 05:29:42 PM CET, Eric Blake wrote:
> Match our code to the spec change in the previous patch - there's
> no reason for the refcount table to allow larger offsets than the
> L1/L2 tables. In practice, no image has more than 64PB of
> allocated clusters anyways, as anything beyond that can't be
> expressed via L2 mappings to host offsets.
>
> Suggested-by: Alberto Garcia 
> Signed-off-by: Eric Blake 

Reviewed-by: Alberto Garcia 

Berto

[Qemu-block] [PATCH v4 3/5] qcow2: Reduce REFT_OFFSET_MASK

[Eric Blake]

Match our code to the spec change in the previous patch - there's
no reason for the refcount table to allow larger offsets than the
L1/L2 tables. In practice, no image has more than 64PB of
allocated clusters anyways, as anything beyond that can't be
expressed via L2 mappings to host offsets.

Suggested-by: Alberto Garcia 
Signed-off-by: Eric Blake 

---
v4: new patch
---
 block/qcow2.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/block/qcow2.h b/block/qcow2.h
index 883802241fb..afc524ead54 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -442,7 +442,7 @@ typedef enum QCow2MetadataOverlap {
 #define L2E_OFFSET_MASK 0x00fffe00ULL
 #define L2E_COMPRESSED_OFFSET_SIZE_MASK 0x3fffULL

-#define REFT_OFFSET_MASK 0xfe00ULL
+#define REFT_OFFSET_MASK 0x00fffe00ULL

 static inline int64_t start_of_cluster(BDRVQcow2State *s, int64_t offset)
 {
-- 
2.14.3