From dae8796d009ffc4d980db1f87f26eed0074be4ef Mon Sep 17 00:00:00 2001 From: Stefan Hajnoczi Date: Fri, 27 Jul 2012 09:05:20 +0100 Subject: 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 Signed-off-by: Kevin Wolf --- docs/specs/qcow2.txt | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) (limited to 'docs') diff --git a/docs/specs/qcow2.txt b/docs/specs/qcow2.txt index 339cdc1b58..36a559d886 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 + 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 -- cgit v1.2.3