From patchwork Tue Sep 8 03:28:33 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wen Congyang X-Patchwork-Id: 515266 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 85DF9140134 for ; Tue, 8 Sep 2015 13:29:32 +1000 (AEST) Received: from localhost ([::1]:59793 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZZ9b8-0005Wf-Es for incoming@patchwork.ozlabs.org; Mon, 07 Sep 2015 23:29:30 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54951) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZZ9am-0004uk-JP for qemu-devel@nongnu.org; Mon, 07 Sep 2015 23:29:09 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZZ9ak-00026I-Nd for qemu-devel@nongnu.org; Mon, 07 Sep 2015 23:29:08 -0400 Received: from [59.151.112.132] (port=13270 helo=heian.cn.fujitsu.com) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZZ9ak-00024k-CU; Mon, 07 Sep 2015 23:29:06 -0400 X-IronPort-AV: E=Sophos;i="5.15,520,1432569600"; d="scan'208";a="100454547" Received: from bogon (HELO edo.cn.fujitsu.com) ([10.167.33.5]) by heian.cn.fujitsu.com with ESMTP; 08 Sep 2015 11:31:56 +0800 Received: from G08CNEXCHPEKD01.g08.fujitsu.local (localhost.localdomain [127.0.0.1]) by edo.cn.fujitsu.com (8.14.3/8.13.1) with ESMTP id t883SjT7021881; Tue, 8 Sep 2015 11:28:45 +0800 Received: from G08FNSTD140052.g08.fujitsu.local (10.167.226.52) by G08CNEXCHPEKD01.g08.fujitsu.local (10.167.33.89) with Microsoft SMTP Server (TLS) id 14.3.181.6; Tue, 8 Sep 2015 11:28:57 +0800 From: Wen Congyang To: qemu devel , Paolo Bonzini , Kevin Wolf , Stefan Hajnoczi , qemu block , Jeff Cody Date: Tue, 8 Sep 2015 11:28:33 +0800 Message-ID: <1441682913-14320-3-git-send-email-wency@cn.fujitsu.com> X-Mailer: git-send-email 2.4.3 In-Reply-To: <1441682913-14320-1-git-send-email-wency@cn.fujitsu.com> References: <1441682913-14320-1-git-send-email-wency@cn.fujitsu.com> MIME-Version: 1.0 X-Originating-IP: [10.167.226.52] X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 59.151.112.132 Subject: [Qemu-devel] [PATCH v2 2/2] Backup: don't do copy-on-read in before_write_notifier X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org We will copy data in before_write_notifier to do backup. It is a nested I/O request, so we cannot do copy-on-read. The steps to reproduce it: 1. -drive copy-on-read=on,... // qemu option 2. drive_backup -f disk0 /path_to_backup.img // monitor command Signed-off-by: Wen Congyang Tested-by: Jeff Cody --- block/backup.c | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-) diff --git a/block/backup.c b/block/backup.c index 965654d..5696431 100644 --- a/block/backup.c +++ b/block/backup.c @@ -89,7 +89,8 @@ static void cow_request_end(CowRequest *req) static int coroutine_fn backup_do_cow(BlockDriverState *bs, int64_t sector_num, int nb_sectors, - bool *error_is_read) + bool *error_is_read, + bool is_write_notifier) { BackupBlockJob *job = (BackupBlockJob *)bs->job; CowRequest cow_request; @@ -129,8 +130,14 @@ static int coroutine_fn backup_do_cow(BlockDriverState *bs, iov.iov_len = n * BDRV_SECTOR_SIZE; qemu_iovec_init_external(&bounce_qiov, &iov, 1); - ret = bdrv_co_readv(bs, start * BACKUP_SECTORS_PER_CLUSTER, n, - &bounce_qiov); + if (is_write_notifier) { + ret = bdrv_co_no_copy_on_readv(bs, + start * BACKUP_SECTORS_PER_CLUSTER, + n, &bounce_qiov); + } else { + ret = bdrv_co_readv(bs, start * BACKUP_SECTORS_PER_CLUSTER, n, + &bounce_qiov); + } if (ret < 0) { trace_backup_do_cow_read_fail(job, start, ret); if (error_is_read) { @@ -190,7 +197,7 @@ static int coroutine_fn backup_before_write_notify( assert((req->offset & (BDRV_SECTOR_SIZE - 1)) == 0); assert((req->bytes & (BDRV_SECTOR_SIZE - 1)) == 0); - return backup_do_cow(req->bs, sector_num, nb_sectors, NULL); + return backup_do_cow(req->bs, sector_num, nb_sectors, NULL, true); } static void backup_set_speed(BlockJob *job, int64_t speed, Error **errp) @@ -303,7 +310,8 @@ static int coroutine_fn backup_run_incremental(BackupBlockJob *job) return ret; } ret = backup_do_cow(bs, cluster * BACKUP_SECTORS_PER_CLUSTER, - BACKUP_SECTORS_PER_CLUSTER, &error_is_read); + BACKUP_SECTORS_PER_CLUSTER, &error_is_read, + false); if ((ret < 0) && backup_error_action(job, error_is_read, -ret) == BLOCK_ERROR_ACTION_REPORT) { @@ -408,7 +416,7 @@ static void coroutine_fn backup_run(void *opaque) } /* FULL sync mode we copy the whole drive. */ ret = backup_do_cow(bs, start * BACKUP_SECTORS_PER_CLUSTER, - BACKUP_SECTORS_PER_CLUSTER, &error_is_read); + BACKUP_SECTORS_PER_CLUSTER, &error_is_read, false); if (ret < 0) { /* Depending on error action, fail now or retry cluster */ BlockErrorAction action =