Message ID | 1350489629-1838-2-git-send-email-benoit@irqsave.net |
---|---|
State | New |
Headers | show |
On 10/17/2012 10:00 AM, Benoît Canet wrote: > --- > docs/specs/qcow2.txt | 16 +++++++++++++++- > 1 file changed, 15 insertions(+), 1 deletion(-) > > diff --git a/docs/specs/qcow2.txt b/docs/specs/qcow2.txt > index 36a559d..013a16b 100644 > --- a/docs/specs/qcow2.txt > +++ b/docs/specs/qcow2.txt > > +== Deduplication == > + > +The deduplication extension contains the offset and size of the deduplication > +table. > + > + Byte 0 - 7: Offset > + > + 8 - 11: Size That's still too sparse for a formal documentation - what is the format of the deduplication table, and what do the bits in that table imply with regards to how the rest of the qcow2 file is used?
> That's still too sparse for a formal documentation - what is the format > of the deduplication table, and what do the bits in that table imply > with regards to how the rest of the qcow2 file is used? I will add this in the next iteration. Best regards Benoît
diff --git a/docs/specs/qcow2.txt b/docs/specs/qcow2.txt index 36a559d..013a16b 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 other - Unknown header extension, can be safely ignored @@ -159,6 +163,16 @@ the header extension data. Each entry look like this: terminated if it has full length) +== Deduplication == + +The deduplication extension contains the offset and size of the deduplication +table. + + Byte 0 - 7: Offset + + 8 - 11: Size + + == Host cluster management == qcow2 manages the allocation of host clusters by maintaining a reference count