Patchwork [RFC,3/7] docs: add lazy refcounts bit to qcow2 specification

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Submitter Stefan Hajnoczi
Date June 22, 2012, 3:08 p.m.
Message ID <1340377726-5896-4-git-send-email-stefanha@linux.vnet.ibm.com>
Download mbox | patch
Permalink /patch/166640/
State New
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Comments

Stefan Hajnoczi - June 22, 2012, 3:08 p.m.
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 |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)
Kevin Wolf - June 25, 2012, 2:35 p.m.
Am 22.06.2012 17:08, 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 |    6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/docs/specs/qcow2.txt b/docs/specs/qcow2.txt
> index 3a789ce..8b2c0eb 100644
> --- a/docs/specs/qcow2.txt
> +++ b/docs/specs/qcow2.txt
> @@ -85,7 +85,11 @@ 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 postponing refcount
> +                           metadata updates.
> +                    Bits 1-63:  Reserved (set to 0)

Please keep the formatting consistent: The description for bit 0 should
be indented to the same level as "Reserved", and an empty line should be
left between each description.

Regarding indentation, the same applies to patch 1.

Kevin
Stefan Hajnoczi - June 25, 2012, 3:53 p.m.
On Mon, Jun 25, 2012 at 3:35 PM, Kevin Wolf <kwolf@redhat.com> wrote:
> Am 22.06.2012 17:08, 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 |    6 +++++-
>>  1 file changed, 5 insertions(+), 1 deletion(-)
>>
>> diff --git a/docs/specs/qcow2.txt b/docs/specs/qcow2.txt
>> index 3a789ce..8b2c0eb 100644
>> --- a/docs/specs/qcow2.txt
>> +++ b/docs/specs/qcow2.txt
>> @@ -85,7 +85,11 @@ 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 postponing refcount
>> +                           metadata updates.
>> +                    Bits 1-63:  Reserved (set to 0)
>
> Please keep the formatting consistent: The description for bit 0 should
> be indented to the same level as "Reserved", and an empty line should be
> left between each description.
>
> Regarding indentation, the same applies to patch 1.

Sorry, the formatting wasn't obvious to me.  Will fix.

Stefan

Patch

diff --git a/docs/specs/qcow2.txt b/docs/specs/qcow2.txt
index 3a789ce..8b2c0eb 100644
--- a/docs/specs/qcow2.txt
+++ b/docs/specs/qcow2.txt
@@ -85,7 +85,11 @@  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 postponing refcount
+                           metadata updates.
+                    Bits 1-63:  Reserved (set to 0)
 
          88 -  95:  autoclear_features
                     Bitmask of auto-clear features. An implementation may only