Re: [Qemu-devel] [PATCH v2 3/7] docs: add lazy refcounts bit to qcow2 specification

[Kevin Wolf <kwolf@redhat.com>]

Am 25.07.2012 14:21, schrieb Stefan Hajnoczi:
> The lazy refcounts bit indicates that this image can take advantage of
> the dirty bit and that refcount updates can be postponed.
> 
> Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
> ---
>  docs/specs/qcow2.txt |    7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/docs/specs/qcow2.txt b/docs/specs/qcow2.txt
> index 339cdc1..f2f4faa 100644
> --- a/docs/specs/qcow2.txt
> +++ b/docs/specs/qcow2.txt
> @@ -86,7 +86,12 @@ in the description of a field.
>                      Bitmask of compatible features. An implementation can
>                      safely ignore any unknown bits that are set.
>  
> -                    Bits 0-63:  Reserved (set to 0)
> +                    Bit 0:      Lazy refcounts bit.  If this bit is set then
> +                                lazy refcount updates can be used.  This means
> +                                postponing marking the image file dirty and

Not sure what was intended here, but the dirty flag isn't set anywhere
yet, so you can't postpone it either. Maybe s/postponing//?

> +                                postponing refcount metadata updates.
> +
> +                    Bits 1-63:  Reserved (set to 0)
>  
>           88 -  95:  autoclear_features
>                      Bitmask of auto-clear features. An implementation may only

Kevin