Re: [Qemu-devel] [PATCH 2/5] vmdk: add support for “zeroed‐grain” GTE

[Stefan Hajnoczi <stefanha@gmail.com>]

On Fri, Apr 19, 2013 at 11:10 AM, Fam Zheng <famz@redhat.com> wrote:
> On Fri, 04/19 10:59, Stefan Hajnoczi wrote:
>> On Fri, Apr 19, 2013 at 11:48:42AM +0800, Fam Zheng wrote:
>> > diff --git a/block/vmdk.c b/block/vmdk.c
>> > index 450a721..5e60940 100644
>> > --- a/block/vmdk.c
>> > +++ b/block/vmdk.c
>> > @@ -33,10 +33,13 @@
>> >  #define VMDK4_MAGIC (('K' << 24) | ('D' << 16) | ('M' << 8) | 'V')
>> >  #define VMDK4_COMPRESSION_DEFLATE 1
>> >  #define VMDK4_FLAG_RGD (1 << 1)
>> > +/* Zeroed-grain enable bit */
>> > +#define VMDK4_FLAG_ZG   (1 << 2)
>>
>> Please use a clear name like VMDK4_FLAG_ZERO_GRAIN.
>>
>> > @@ -81,6 +84,8 @@ typedef struct VmdkExtent {
>> >      bool flat;
>> >      bool compressed;
>> >      bool has_marker;
>> > +    bool has_zero_grain;
>> > +    int version;
>>
>> uint32_t according to the spec.  Please use fixed-size integer types
>> instead of int, long, etc which can change depending on the host
>> architecture.
>
> This is an internal structure holding information for extent, used the
> same way as BDRVVmdkState, there is no direct correspondence to file
> header fields, so I think it should be OK, as `int qcow_version' is also
> found in block/qcow2.h.

What is the benefit of changing the type internally?

Stefan