From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60607) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UjJsO-0007xz-F6 for qemu-devel@nongnu.org; Sun, 02 Jun 2013 21:48:03 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UjJsM-0005VS-1p for qemu-devel@nongnu.org; Sun, 02 Jun 2013 21:48:00 -0400 Received: from mx1.redhat.com ([209.132.183.28]:9384) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UjJsL-0005VA-Pv for qemu-devel@nongnu.org; Sun, 02 Jun 2013 21:47:57 -0400 Date: Mon, 3 Jun 2013 09:47:52 +0800 From: Fam Zheng Message-ID: <20130603014752.GA3492@localhost.nay.redhat.com> References: <1369908025-9556-1-git-send-email-wdongxu@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1369908025-9556-1-git-send-email-wdongxu@linux.vnet.ibm.com> Subject: Re: [Qemu-devel] [PATCH V19 0/8] add-cow file format List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Dongxu Wang Cc: kwolf@redhat.com, wdongxu@cn.ibm.com, qemu-devel@nongnu.org, stefanha@redhat.com On Thu, 05/30 18:00, Dongxu Wang wrote: > It will introduce a new file format: add-cow. > > The add-cow file format makes it possible to perform copy-on-write on top of > a raw disk image. When we know that no backing file clusters remain visible > (e.g. we have streamed the entire image and copied all data from the backing > file), then it is possible to discard the add-cow file and use the raw image > file directly. > > This feature adds the copy-on-write feature to raw files (which cannot support > it natively) while allowing us to get full performance again later when we no > longer need copy-on-write. > > add-cow can benefit from other available functions, such as path_has_protocol > and qed_read_string, so we will make them public. > > snapshot_blkdev are not supported now for add-cow. Will add it in futher patches. > > These patches are using QemuOpts parser, former patches could be found here: > http://patchwork.ozlabs.org/patch/247508/ > > > v18->v19: > 1) support parallel aio write. > 2) fix flush method. > 3) other small fix. > v17 -> v18: > 1) remove version field. > 2) header size is maximum value and cluster size value. > 3) fix type. > 4) move struct to source file. > 5) cluster_size->table_size. > 6) use error_report, not fprintf. > 7) remove version field from header. > 8) header_size is MAX(cluster_size, 4096). > 9) introduce s->cluster_sectors. > 10) use BLKDBG_L2_LOAD/UPDATE. > 11) add 037 and 038 tests. > > v16->v17): > 1) Use stringify. > > v15->v16): > 1) Rebased on QEMU upstream source tree. > 2) Judge if opts is null in add_cow_create function. > > v14->v15: > 1) Fix typo and make some sentences more readable in docs. > 2) Introduce STRINGIZER macro. > > v13->v14: > 1) Make some sentences more clear in docs. > 2) Make MAGIC from 8 bytes to 4 bytes. > 3) Fix some bugs. > > v12->v13: > 1) Use QemuOpts, not QEMUOptionParameter > 2) cluster_size configuable > 3) Refactor block-cache.c > 4) Correct qemu-iotests script. > 5) Other bug fix. > > v11->v12: > 1) Removed un-used feature bit. > 2) Share cache code with qcow2.c. > 3) Remove snapshot_blkdev support, will add it in another patch. > 5) COW Bitmap field in add-cow file will be multiple of 65536. > 6) fix grammer and typo. > > Dong Xu Wang (8): > V18: docs: document for add-cow file format Why mention V18 here? -- Fam