From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:44348) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XhPEC-0006Sh-Fb for qemu-devel@nongnu.org; Thu, 23 Oct 2014 16:43:30 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XhPE6-0002az-Bi for qemu-devel@nongnu.org; Thu, 23 Oct 2014 16:43:24 -0400 Received: from mx1.redhat.com ([209.132.183.28]:57334) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XhPE6-0002aW-4i for qemu-devel@nongnu.org; Thu, 23 Oct 2014 16:43:18 -0400 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id s9NKhHBm009697 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL) for ; Thu, 23 Oct 2014 16:43:17 -0400 From: Kevin Wolf Date: Thu, 23 Oct 2014 22:42:32 +0200 Message-Id: <1414096959-14682-26-git-send-email-kwolf@redhat.com> In-Reply-To: <1414096959-14682-1-git-send-email-kwolf@redhat.com> References: <1414096959-14682-1-git-send-email-kwolf@redhat.com> Subject: [Qemu-devel] [PULL 25/32] docs/qcow2: Limit refcount_order to [0, 6] List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: kwolf@redhat.com From: Max Reitz Specify the upper limit of refcount_order to be 6 (that is, refcount_bits = 64). Any larger value does not make much sense when all offsets, sizes, cluster counts etc. "only" have a width of 64 bit as well, and very large values would be very difficult to support. Therefore, just cap it at the largest reasonable value. Suggested-by: Eric Blake Signed-off-by: Max Reitz Signed-off-by: Kevin Wolf --- docs/specs/qcow2.txt | 1 + 1 file changed, 1 insertion(+) diff --git a/docs/specs/qcow2.txt b/docs/specs/qcow2.txt index 0a878aa..121dfc8 100644 --- a/docs/specs/qcow2.txt +++ b/docs/specs/qcow2.txt @@ -110,6 +110,7 @@ in the description of a field. in bits: refcount_bits = 1 << refcount_order). For version 2 images, the order is always assumed to be 4 (i.e. refcount_bits = 16). + This value may not exceed 6 (i.e. refcount_bits = 64). 100 - 103: header_length Length of the header structure in bytes. For version 2 -- 1.8.3.1