From patchwork Tue Jan 31 11:57:40 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Pavel Dovgalyuk X-Patchwork-Id: 9546993 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 1688B604A0 for ; Tue, 31 Jan 2017 11:58:23 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 08432281C3 for ; Tue, 31 Jan 2017 11:58:23 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id F15B228389; Tue, 31 Jan 2017 11:58:22 +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=-6.9 required=2.0 tests=BAYES_00,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 4D924281C3 for ; Tue, 31 Jan 2017 11:58:22 +0000 (UTC) Received: from localhost ([::1]:37376 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cYX4n-00081V-32 for patchwork-qemu-devel@patchwork.kernel.org; Tue, 31 Jan 2017 06:58:21 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:42332) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cYX4D-0007vg-NW for qemu-devel@nongnu.org; Tue, 31 Jan 2017 06:57:46 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cYX4C-0007ls-Rm for qemu-devel@nongnu.org; Tue, 31 Jan 2017 06:57:45 -0500 Received: from mail.ispras.ru ([83.149.199.45]:58006) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cYX48-0007lF-05; Tue, 31 Jan 2017 06:57:40 -0500 Received: from [10.10.150.12] (unknown [85.142.117.226]) by mail.ispras.ru (Postfix) with ESMTPSA id 2EB015400B1; Tue, 31 Jan 2017 14:57:39 +0300 (MSK) To: qemu-devel@nongnu.org From: Pavel Dovgalyuk Date: Tue, 31 Jan 2017 14:57:40 +0300 Message-ID: <20170131115740.5244.87406.stgit@PASHA-ISP> In-Reply-To: <20170131115728.5244.21690.stgit@PASHA-ISP> References: <20170131115728.5244.21690.stgit@PASHA-ISP> User-Agent: StGit/0.16 MIME-Version: 1.0 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [fuzzy] X-Received-From: 83.149.199.45 Subject: [Qemu-devel] [PATCH 2/3] blkreplay: create temporary overlay for underlaying devices 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, pbonzini@redhat.com, dovgaluk@ispras.ru, qemu-block@nongnu.org, mreitz@redhat.com Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP This patch allows using '-snapshot' behavior in record/replay mode. blkreplay layer creates temporary overlays on top of underlaying disk images. It is needed, because creating an overlay over blkreplay breaks the determinism. Signed-off-by: Pavel Dovgalyuk --- block/blkreplay.c | 76 +++++++++++++++++++++++++++++++++++++++++++++++++++++ stubs/replay.c | 1 + vl.c | 2 + 3 files changed, 78 insertions(+), 1 deletion(-) diff --git a/block/blkreplay.c b/block/blkreplay.c index 8a03d62..172642f 100644 --- a/block/blkreplay.c +++ b/block/blkreplay.c @@ -14,12 +14,76 @@ #include "block/block_int.h" #include "sysemu/replay.h" #include "qapi/error.h" +#include "qapi/qmp/qstring.h" typedef struct Request { Coroutine *co; QEMUBH *bh; } Request; +static BlockDriverState *blkreplay_append_snapshot(BlockDriverState *bs, + Error **errp) +{ + int ret; + BlockDriverState *bs_snapshot; + int64_t total_size; + QemuOpts *opts = NULL; + char tmp_filename[PATH_MAX + 1]; + QDict *snapshot_options = qdict_new(); + + /* Prepare options QDict for the overlay file */ + qdict_put(snapshot_options, "file.driver", + qstring_from_str("file")); + qdict_put(snapshot_options, "driver", + qstring_from_str("qcow2")); + + /* Create temporary file */ + ret = get_tmp_filename(tmp_filename, PATH_MAX + 1); + if (ret < 0) { + error_setg_errno(errp, -ret, "Could not get temporary filename"); + goto out; + } + qdict_put(snapshot_options, "file.filename", + qstring_from_str(tmp_filename)); + + /* Get the required size from the image */ + total_size = bdrv_getlength(bs); + if (total_size < 0) { + error_setg_errno(errp, -total_size, "Could not get image size"); + goto out; + } + + opts = qemu_opts_create(bdrv_qcow2.create_opts, NULL, 0, &error_abort); + qemu_opt_set_number(opts, BLOCK_OPT_SIZE, total_size, &error_abort); + ret = bdrv_create(&bdrv_qcow2, tmp_filename, opts, errp); + qemu_opts_del(opts); + if (ret < 0) { + error_prepend(errp, "Could not create temporary overlay '%s': ", + tmp_filename); + goto out; + } + + bs_snapshot = bdrv_open(NULL, NULL, snapshot_options, + BDRV_O_RDWR | BDRV_O_TEMPORARY, errp); + snapshot_options = NULL; + if (!bs_snapshot) { + ret = -EINVAL; + goto out; + } + + /* bdrv_append() consumes a strong reference to bs_snapshot (i.e. it will + * call bdrv_unref() on it), so in order to be able to return one, we have + * to increase bs_snapshot's refcount here */ + bdrv_ref(bs_snapshot); + bdrv_append(bs_snapshot, bs); + + return bs_snapshot; + +out: + QDECREF(snapshot_options); + return NULL; +} + static int blkreplay_open(BlockDriverState *bs, QDict *options, int flags, Error **errp) { @@ -35,6 +99,14 @@ static int blkreplay_open(BlockDriverState *bs, QDict *options, int flags, goto fail; } + /* Add temporary snapshot to preserve the image */ + if (!replay_snapshot + && !blkreplay_append_snapshot(bs->file->bs, &local_err)) { + ret = -EINVAL; + error_propagate(errp, local_err); + goto fail; + } + ret = 0; fail: if (ret < 0) { @@ -45,6 +117,10 @@ fail: static void blkreplay_close(BlockDriverState *bs) { + if (!replay_snapshot) { + /* Unref created snapshot file */ + bdrv_unref(bs->file->bs); + } } static int64_t blkreplay_getlength(BlockDriverState *bs) diff --git a/stubs/replay.c b/stubs/replay.c index 9c8aa48..9991ee5 100644 --- a/stubs/replay.c +++ b/stubs/replay.c @@ -3,6 +3,7 @@ #include "sysemu/sysemu.h" ReplayMode replay_mode; +char *replay_snapshot; int64_t replay_save_clock(unsigned int kind, int64_t clock) { diff --git a/vl.c b/vl.c index 0b72b12..c6fc5c9 100644 --- a/vl.c +++ b/vl.c @@ -4414,7 +4414,7 @@ int main(int argc, char **argv, char **envp) } /* open the virtual block devices */ - if (snapshot || replay_mode != REPLAY_MODE_NONE) { + if (snapshot) { qemu_opts_foreach(qemu_find_opts("drive"), drive_enable_snapshot, NULL, NULL); }