Patchwork [partial,RFC,1/2] qcow2: modify spec for deduplication

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Submitter Benoît Canet
Date Sept. 27, 2012, 2:29 p.m.
Message ID <1348756198-10845-2-git-send-email-benoit@irqsave.net>
Download mbox | patch
Permalink /patch/187388/
State New
Headers show

Comments

Benoît Canet - Sept. 27, 2012, 2:29 p.m.
---
 docs/specs/qcow2.txt |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)
Eric Blake - Sept. 27, 2012, 3:02 p.m.
On 09/27/2012 08:29 AM, Benoît Canet wrote:
> ---
>  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 36a559d..e8bc189 100644
> --- a/docs/specs/qcow2.txt
> +++ b/docs/specs/qcow2.txt
> @@ -80,7 +80,10 @@ in the description of a field.
>                                  tables to repair refcounts before accessing the
>                                  image.
>  
> -                    Bits 1-63:  Reserved (set to 0)
> +                    Bit 1:      Deduplication bit.  If this bit is set then
> +                                deduplication is used on this image.
> +
> +                    Bits 2-63:  Reserved (set to 0)
>  
>           80 -  87:  compatible_features
>                      Bitmask of compatible features. An implementation can
> @@ -116,6 +119,7 @@ be stored. Each extension has a structure like the following:
>                          0x00000000 - End of the header extension area
>                          0xE2792ACA - Backing file format name
>                          0x6803f857 - Feature name table
> +                        0xCD8E819B - Deduplication table offset and length

Missing a description of what this looks like (see the section on '==
Feature name table ==' for comparison).

Patch

diff --git a/docs/specs/qcow2.txt b/docs/specs/qcow2.txt
index 36a559d..e8bc189 100644
--- a/docs/specs/qcow2.txt
+++ b/docs/specs/qcow2.txt
@@ -80,7 +80,10 @@  in the description of a field.
                                 tables to repair refcounts before accessing the
                                 image.
 
-                    Bits 1-63:  Reserved (set to 0)
+                    Bit 1:      Deduplication bit.  If this bit is set then
+                                deduplication is used on this image.
+
+                    Bits 2-63:  Reserved (set to 0)
 
          80 -  87:  compatible_features
                     Bitmask of compatible features. An implementation can
@@ -116,6 +119,7 @@  be stored. Each extension has a structure like the following:
                         0x00000000 - End of the header extension area
                         0xE2792ACA - Backing file format name
                         0x6803f857 - Feature name table
+                        0xCD8E819B - Deduplication table offset and length
                         other      - Unknown header extension, can be safely
                                      ignored