From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:35766) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VQw0n-0002cp-HW for qemu-devel@nongnu.org; Tue, 01 Oct 2013 05:13:03 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VQw0h-0002sr-Hw for qemu-devel@nongnu.org; Tue, 01 Oct 2013 05:12:57 -0400 Received: from mx1.redhat.com ([209.132.183.28]:5382) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VQw0h-0002ry-9e for qemu-devel@nongnu.org; Tue, 01 Oct 2013 05:12:51 -0400 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r919CniJ002797 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Tue, 1 Oct 2013 05:12:50 -0400 Date: Tue, 1 Oct 2013 11:12:53 +0200 From: Kevin Wolf Message-ID: <20131001091253.GA3143@dhcp-200-207.str.redhat.com> References: <1380556641-26256-1-git-send-email-mreitz@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1380556641-26256-1-git-send-email-mreitz@redhat.com> Subject: Re: [Qemu-devel] [PATCH] qcow2: Switch L1 table in a single sequence List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Max Reitz Cc: qemu-devel@nongnu.org, Stefan Hajnoczi Am 30.09.2013 um 17:57 hat Max Reitz geschrieben: > Switching the L1 table in memory should be an atomic operation, as far > as possible. Calling qcow2_free_clusters on the old L1 table on disk is > not a good idea when the old L1 table is no longer valid and the address > to the new one hasn't yet been written into the corresponding > BDRVQcowState field. To be more specific, this can lead to segfaults due > to qcow2_check_metadata_overlap trying to access the L1 table during the > free operation. > > Signed-off-by: Max Reitz Reviewed-by: Kevin Wolf