From patchwork Fri Nov 30 08:55:21 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrey Shinkevich X-Patchwork-Id: 10705983 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 21E4413A4 for ; Fri, 30 Nov 2018 09:00:14 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 130F82F2CE for ; Fri, 30 Nov 2018 09:00:14 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 0769E2F2EA; Fri, 30 Nov 2018 09:00:14 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 88AE72F2CE for ; Fri, 30 Nov 2018 09:00:13 +0000 (UTC) Received: from localhost ([::1]:58809 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gSeeh-0006ZC-Ue for patchwork-qemu-devel@patchwork.kernel.org; Fri, 30 Nov 2018 04:00:11 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55143) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gSeaI-0001d0-4m for qemu-devel@nongnu.org; Fri, 30 Nov 2018 03:55:40 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gSeaE-0000Ta-Jp for qemu-devel@nongnu.org; Fri, 30 Nov 2018 03:55:37 -0500 Received: from relay.sw.ru ([185.231.240.75]:41914) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gSeaE-0000Rb-5Z; Fri, 30 Nov 2018 03:55:34 -0500 Received: from [172.16.25.136] (helo=localhost.sw.ru) by relay.sw.ru with esmtp (Exim 4.91) (envelope-from ) id 1gSea7-0004HZ-6j; Fri, 30 Nov 2018 11:55:27 +0300 From: Andrey Shinkevich To: qemu-devel@nongnu.org, qemu-block@nongnu.org Date: Fri, 30 Nov 2018 11:55:21 +0300 Message-Id: <1543568126-727235-1-git-send-email-andrey.shinkevich@virtuozzo.com> X-Mailer: git-send-email 1.8.3.1 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [fuzzy] X-Received-From: 185.231.240.75 Subject: [Qemu-devel] [PATCH v4 0/5] Discrad blocks during block-stream operation X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kwolf@redhat.com, vsementsov@virtuozzo.com, armbru@redhat.com, mreitz@redhat.com, andrey.shinkevich@virtuozzo.com, den@openvz.org Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP Dear all, The given feature discards blocks with copy-on-read operation while the streaming process runs. Adding the 'discard' argument to the QMP block-stream command allows dropping a block in the backing chain after it has been copied to the active layer. That will elude the block duplication in the intermediate backing file. It saves the disk space while external snapshots are being merged. The method involves the filter insertion above the active layer to allow write operation in the backing chain. The method is similar to that in the 'commit active' command (mirror.c). The permission to write into an inactive layer can not be obtained due to the existing child permission mechanism. There is a commented up hack in the callback function bdrv_stream_top_pwritev() in block/stream.c that redirects write operations below the filter node. Being uncommented, it enables writing into the inactive layer and passing all the iotests in the 030 file. Otherwise, no WRITE permission is granted after the filter insertion above the target node. Any suggestions to resolve that issue will be appreciated. v4: The targeted version of the release at 'Since' word of the comment to 'discard' argument changed to 4.0 in the file qapi/block-core.json as Eric Blake noticed. v3: [PATCH v3 0/5] Discrad blocks during block-stream operation The series version number and the given changelog were added. 'Signed-off-by' subscription of the patch [PATCH 3/5] amended as Peter Krempa requested. v2: "[PATCH 0/5] Discrad blocks during block-stream operation" The suggestions of Dr. David Alan Gilbert and Alberto Garcia after their first review have been applied. The abort() callback function have been added to the filter driver and some refactoring work done. The test suite for the 'block-stream' command with 'discard' option was added to the 030 file of iotests. v1: "[PATCH 0/2] Discrad blocks during block-stream operation" The initial implementation of the feature. Sincerely, Andrey Shinkevich (5): Discard blocks while copy-on-read The discard flag for block stream operation iotests: allow resume_drive by node name iotests: prepare 030 for graph change iotests: 030 with block-stream discard block/stream.c | 429 ++++++++++++++++++++++++++++++++++++++++-- blockdev.c | 8 +- hmp-commands.hx | 4 +- hmp.c | 4 +- include/block/block_int.h | 2 +- qapi/block-core.json | 5 +- tests/qemu-iotests/030 | 163 +++++++++++----- tests/qemu-iotests/030.out | 4 +- tests/qemu-iotests/iotests.py | 9 +- 9 files changed, 558 insertions(+), 70 deletions(-)