docs: add lazy refcounts bit to qcow2 specification

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>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
This commit is contained in:
Stefan Hajnoczi 2012-07-27 09:05:20 +01:00 committed by Kevin Wolf
parent c61d0004bc
commit dae8796d00
1 changed files with 6 additions and 1 deletions

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@ -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
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