Re: [Qemu-devel] [PATCH 4/9] block: vhdx - log support struct and defines

[Fam Zheng <famz@redhat.com>]

On Wed, 07/24 13:54, Jeff Cody wrote:
> This adds some magic number defines, and internal structure
> definitions for VHDX log replay support.
> 
> Signed-off-by: Jeff Cody <jcody@redhat.com>
> ---
>  block/vhdx.h | 21 ++++++++++++++++++++-
>  1 file changed, 20 insertions(+), 1 deletion(-)
> 
> diff --git a/block/vhdx.h b/block/vhdx.h
> index c8d8593..2db6615 100644
> --- a/block/vhdx.h
> +++ b/block/vhdx.h
> @@ -151,7 +151,10 @@ typedef struct QEMU_PACKED VHDXRegionTableEntry {
>  
>  
>  /* ---- LOG ENTRY STRUCTURES ---- */
> +#define VHDX_LOG_MIN_SIZE (1024*1024)
> +#define VHDX_LOG_SECTOR_SIZE 4096
>  #define VHDX_LOG_HDR_SIZE 64
> +#define VHDX_LOG_SIGNATURE 0x65676f6c
>  typedef struct QEMU_PACKED VHDXLogEntryHeader {
>      uint32_t    signature;              /* "loge" in ASCII */
>      uint32_t    checksum;               /* CRC-32C hash of the 64KB table */
> @@ -174,7 +177,8 @@ typedef struct QEMU_PACKED VHDXLogEntryHeader {
>  } VHDXLogEntryHeader;
>  
>  #define VHDX_LOG_DESC_SIZE 32
> -
> +#define VHDX_LOG_DESC_SIGNATURE 0x63736564
> +#define VHDX_LOG_ZERO_SIGNATURE 0x6f72657a

Are these macros really used? I see "desc" and "zero" used to compare
signatures.

Thanks

Fam