From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46879) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XgE3s-0001Sz-E7 for qemu-devel@nongnu.org; Mon, 20 Oct 2014 10:35:58 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XgE3i-0005nV-Jf for qemu-devel@nongnu.org; Mon, 20 Oct 2014 10:35:52 -0400 Received: from mx1.redhat.com ([209.132.183.28]:10900) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XgE3i-0005nH-BB for qemu-devel@nongnu.org; Mon, 20 Oct 2014 10:35:42 -0400 From: Max Reitz Date: Mon, 20 Oct 2014 16:35:23 +0200 Message-Id: <1413815733-22829-2-git-send-email-mreitz@redhat.com> In-Reply-To: <1413815733-22829-1-git-send-email-mreitz@redhat.com> References: <1413815733-22829-1-git-send-email-mreitz@redhat.com> Subject: [Qemu-devel] [PATCH v6 01/11] qcow2: Calculate refcount block entry count List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Kevin Wolf , =?UTF-8?q?Beno=C3=AEt=20Canet?= , Stefan Hajnoczi , Max Reitz The size of a refblock entry is (in theory) variable; calculate therefore the number of entries per refblock and the according bit shift (1 << x == entry count) when opening an image. Signed-off-by: Max Reitz Reviewed-by: Eric Blake --- block/qcow2.c | 3 +++ block/qcow2.h | 2 ++ 2 files changed, 5 insertions(+) diff --git a/block/qcow2.c b/block/qcow2.c index 156a219..3c8b881 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -698,6 +698,9 @@ static int qcow2_open(BlockDriverState *bs, QDict *options, int flags, s->l2_bits = s->cluster_bits - 3; /* L2 is always one cluster */ s->l2_size = 1 << s->l2_bits; + /* 2^(s->refcount_order - 3) is the refcount width in bytes */ + s->refcount_block_bits = s->cluster_bits - (s->refcount_order - 3); + s->refcount_block_size = 1 << s->refcount_block_bits; bs->total_sectors = header.size / 512; s->csize_shift = (62 - (s->cluster_bits - 8)); s->csize_mask = (1 << (s->cluster_bits - 8)) - 1; diff --git a/block/qcow2.h b/block/qcow2.h index 7d61e61..47cd4b3 100644 --- a/block/qcow2.h +++ b/block/qcow2.h @@ -223,6 +223,8 @@ typedef struct BDRVQcowState { int l2_size; int l1_size; int l1_vm_state_index; + int refcount_block_bits; + int refcount_block_size; int csize_shift; int csize_mask; uint64_t cluster_offset_mask; -- 2.1.2