From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([140.186.70.92]:45097) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Qe3rH-0006zZ-QW for qemu-devel@nongnu.org; Tue, 05 Jul 2011 07:32:05 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Qe3rG-00020n-8L for qemu-devel@nongnu.org; Tue, 05 Jul 2011 07:32:03 -0400 Received: from mail-iy0-f173.google.com ([209.85.210.173]:32835) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Qe3rF-0001zz-TI for qemu-devel@nongnu.org; Tue, 05 Jul 2011 07:32:02 -0400 Received: by mail-iy0-f173.google.com with SMTP id 3so5889555iyb.4 for ; Tue, 05 Jul 2011 04:32:01 -0700 (PDT) From: Fam Zheng Date: Tue, 5 Jul 2011 19:31:08 +0800 Message-Id: <1309865478-32766-3-git-send-email-famcool@gmail.com> In-Reply-To: <1309865478-32766-1-git-send-email-famcool@gmail.com> References: <1309865478-32766-1-git-send-email-famcool@gmail.com> Subject: [Qemu-devel] [PATCH v8 02/12] VMDK: bugfix, align offset to cluster in get_whole_cluster List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: kwolf@redhat.com, Fam Zheng , hch@lst.de, stefanha@gmail.com In get_whole_cluster, the offset is not aligned to cluster when reading from backing_hd. When the first write to child is not at the cluster boundary, wrong address data from parent is copied to child. Signed-off-by: Fam Zheng --- block/vmdk.c | 8 +++++--- 1 files changed, 5 insertions(+), 3 deletions(-) diff --git a/block/vmdk.c b/block/vmdk.c index 3b78583..03a4619 100644 --- a/block/vmdk.c +++ b/block/vmdk.c @@ -514,21 +514,23 @@ static int get_whole_cluster(BlockDriverState *bs, /* 128 sectors * 512 bytes each = grain size 64KB */ uint8_t whole_grain[extent->cluster_sectors * 512]; - // we will be here if it's first write on non-exist grain(cluster). - // try to read from parent image, if exist + /* we will be here if it's first write on non-exist grain(cluster). + * try to read from parent image, if exist */ if (bs->backing_hd) { int ret; if (!vmdk_is_cid_valid(bs)) return -1; + /* floor offset to cluster */ + offset -= offset % (extent->cluster_sectors * 512); ret = bdrv_read(bs->backing_hd, offset >> 9, whole_grain, extent->cluster_sectors); if (ret < 0) { return -1; } - //Write grain only into the active image + /* Write grain only into the active image */ ret = bdrv_write(extent->file, cluster_offset, whole_grain, extent->cluster_sectors); if (ret < 0) {