From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51100) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VMbUE-0002Qy-6X for qemu-devel@nongnu.org; Thu, 19 Sep 2013 06:29:32 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VMbU8-0001du-7F for qemu-devel@nongnu.org; Thu, 19 Sep 2013 06:29:26 -0400 Received: from mx1.redhat.com ([209.132.183.28]:50688) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VMbU7-0001dk-W9 for qemu-devel@nongnu.org; Thu, 19 Sep 2013 06:29:20 -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 r8JATIou012398 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Thu, 19 Sep 2013 06:29:18 -0400 From: Max Reitz Date: Thu, 19 Sep 2013 12:29:15 +0200 Message-Id: <1379586555-1479-1-git-send-email-mreitz@redhat.com> Subject: [Qemu-devel] [PATCH] qcow2: Correct snapshots size for overlap check List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Kevin Wolf , Stefan Hajnoczi , Max Reitz Using s->snapshots_size instead of snapshots_size for the metadata overlap check in qcow2_write_snapshots leads to the detection of an overlap with the main qcow2 image header when deleting the last snapshot, since s->snapshots_size has not yet been updated and is therefore non-zero. However, the offset returned by qcow2_alloc_clusters will be zero since snapshots_size is zero. Therefore, an overlap is detected albeit no such will occur. This patch fixes this by replacing s->snapshots_size by snapshots_size when calling qcow2_pre_write_overlap_check. Signed-off-by: Max Reitz --- block/qcow2-snapshot.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/block/qcow2-snapshot.c b/block/qcow2-snapshot.c index 7d14420..5e8a779 100644 --- a/block/qcow2-snapshot.c +++ b/block/qcow2-snapshot.c @@ -192,7 +192,7 @@ static int qcow2_write_snapshots(BlockDriverState *bs) /* The snapshot list position has not yet been updated, so these clusters * must indeed be completely free */ ret = qcow2_pre_write_overlap_check(bs, QCOW2_OL_DEFAULT, offset, - s->snapshots_size); + snapshots_size); if (ret < 0) { return ret; } -- 1.8.3.1