From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:49403) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SufYQ-0005ea-7X for qemu-devel@nongnu.org; Fri, 27 Jul 2012 04:05:51 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1SufYI-00065t-OT for qemu-devel@nongnu.org; Fri, 27 Jul 2012 04:05:46 -0400 Received: from e06smtp17.uk.ibm.com ([195.75.94.113]:47113) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SufYI-00065G-A9 for qemu-devel@nongnu.org; Fri, 27 Jul 2012 04:05:38 -0400 Received: from /spool/local by e06smtp17.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 27 Jul 2012 09:05:37 +0100 Received: from d06av02.portsmouth.uk.ibm.com (d06av02.portsmouth.uk.ibm.com [9.149.37.228]) by d06nrmr1707.portsmouth.uk.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id q6R85X6W2588672 for ; Fri, 27 Jul 2012 09:05:34 +0100 Received: from d06av02.portsmouth.uk.ibm.com (loopback [127.0.0.1]) by d06av02.portsmouth.uk.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id q6R85WTo031580 for ; Fri, 27 Jul 2012 02:05:33 -0600 From: Stefan Hajnoczi Date: Fri, 27 Jul 2012 09:05:20 +0100 Message-Id: <1343376324-19458-4-git-send-email-stefanha@linux.vnet.ibm.com> In-Reply-To: <1343376324-19458-1-git-send-email-stefanha@linux.vnet.ibm.com> References: <1343376324-19458-1-git-send-email-stefanha@linux.vnet.ibm.com> Subject: [Qemu-devel] [PATCH v3 3/7] docs: add lazy refcounts bit to qcow2 specification List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Kevin Wolf , Khoa Huynh , Anthony Liguori , 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 --- docs/specs/qcow2.txt | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/docs/specs/qcow2.txt b/docs/specs/qcow2.txt index 339cdc1..36a559d 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 -- 1.7.10.4