Re: [Qemu-devel] [PATCH 5/6] qcow2: Add more overlap check bitmask macros

[Kevin Wolf <kwolf@redhat.com>]

Am 20.09.2013 um 10:37 hat Max Reitz geschrieben:
> Introduces the macros QCOW2_OL_CONSTANT and QCOW2_OL_ALL in addition to
> the already existing QCOW2_OL_CACHED, signifying all metadata overlap
> checks that can be performed in constant time (regardless of image size
> etc.) and truly all available overlap checks, respectively.
> 
> Signed-off-by: Max Reitz <mreitz@redhat.com>
> ---
>  block/qcow2.h | 14 +++++++++++---
>  1 file changed, 11 insertions(+), 3 deletions(-)
> 
> diff --git a/block/qcow2.h b/block/qcow2.h
> index 067ed2f..098c14f 100644
> --- a/block/qcow2.h
> +++ b/block/qcow2.h
> @@ -326,11 +326,19 @@ typedef enum QCow2MetadataOverlap {
>      QCOW2_OL_INACTIVE_L2    = (1 << QCOW2_OL_INACTIVE_L2_BITNR),
>  } QCow2MetadataOverlap;
>  
> +/* Perform all overlap checks which can be done in constant time */
> +#define QCOW2_OL_CONSTANT \
> +    (QCOW2_OL_MAIN_HEADER | QCOW2_OL_ACTIVE_L1 | QCOW2_OL_REFCOUNT_TABLE | \
> +     QCOW2_OL_SNAPSHOT_TABLE)
> +
>  /* Perform all overlap checks which don't require disk access */
>  #define QCOW2_OL_CACHED \
> -    (QCOW2_OL_MAIN_HEADER | QCOW2_OL_ACTIVE_L1 | QCOW2_OL_ACTIVE_L2 | \
> -     QCOW2_OL_REFCOUNT_TABLE | QCOW2_OL_REFCOUNT_BLOCK | \
> -     QCOW2_OL_SNAPSHOT_TABLE | QCOW2_OL_INACTIVE_L1)
> +    (QCOW2_OL_CONSTANT | QCOW2_OL_ACTIVE_L2 | QCOW2_OL_REFCOUNT_BLOCK | \
> +     QCOW2_OL_SNAPSHOT_TABLE)

QCOW2_OL_INACTIVE_L1 is lost here.

> +/* Perform all overlap checks */
> +#define QCOW2_OL_ALL \
> +    (QCOW2_OL_CACHED | QCOW2_OL_INACTIVE_L2)

Kevin