From patchwork Wed Jul 6 05:45:51 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Changlong Xie X-Patchwork-Id: 9215411 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 46435607D9 for ; Wed, 6 Jul 2016 05:50:34 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2BAEB286C3 for ; Wed, 6 Jul 2016 05:50:34 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 1AED7286C7; Wed, 6 Jul 2016 05:50:34 +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 63D2B286C3 for ; Wed, 6 Jul 2016 05:50:33 +0000 (UTC) Received: from localhost ([::1]:59426 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bKfjE-0000x2-MO for patchwork-qemu-devel@patchwork.kernel.org; Wed, 06 Jul 2016 01:50:32 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:54753) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bKfaJ-0000Ds-Oj for qemu-devel@nongnu.org; Wed, 06 Jul 2016 01:41:21 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bKfaI-0005nr-BE for qemu-devel@nongnu.org; Wed, 06 Jul 2016 01:41:19 -0400 Received: from [59.151.112.132] (port=21855 helo=heian.cn.fujitsu.com) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bKfaD-0005iL-6M; Wed, 06 Jul 2016 01:41:13 -0400 X-IronPort-AV: E=Sophos;i="5.22,518,1449504000"; d="scan'208";a="8404729" Received: from unknown (HELO cn.fujitsu.com) ([10.167.33.5]) by heian.cn.fujitsu.com with ESMTP; 06 Jul 2016 13:41:06 +0800 Received: from G08CNEXCHPEKD03.g08.fujitsu.local (unknown [10.167.33.85]) by cn.fujitsu.com (Postfix) with ESMTP id 2427D41C0BBF; Wed, 6 Jul 2016 13:41:03 +0800 (CST) Received: from changlox.g08.fujitsu.local (10.167.225.55) by G08CNEXCHPEKD03.g08.fujitsu.local (10.167.33.89) with Microsoft SMTP Server (TLS) id 14.3.279.2; Wed, 6 Jul 2016 13:41:02 +0800 From: Changlong Xie To: qemu devel , qemu block , Stefan Hajnoczi , Fam Zheng , Max Reitz , Kevin Wolf , Jeff Cody Date: Wed, 6 Jul 2016 13:45:51 +0800 Message-ID: <1467783958-13678-4-git-send-email-xiecl.fnst@cn.fujitsu.com> X-Mailer: git-send-email 1.9.3 In-Reply-To: <1467783958-13678-1-git-send-email-xiecl.fnst@cn.fujitsu.com> References: <1467783958-13678-1-git-send-email-xiecl.fnst@cn.fujitsu.com> MIME-Version: 1.0 X-Originating-IP: [10.167.225.55] X-yoursite-MailScanner-ID: 2427D41C0BBF.A36F0 X-yoursite-MailScanner: Found to be clean X-yoursite-MailScanner-From: xiecl.fnst@cn.fujitsu.com 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 v21 03/10] Backup: export interfaces for extra serialization 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: Changlong Xie , Wang Weiwei , zhanghailiang , Jiang Yunhong , Dong Eddie , Markus Armbruster , "Dr. David Alan Gilbert" , Gonglei , Paolo Bonzini , John Snow Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP Normal backup(sync='none') workflow: step 1. NBD peformance I/O write from client to server qcow2_co_writev bdrv_co_writev ... bdrv_aligned_pwritev notifier_with_return_list_notify -> backup_do_cow bdrv_driver_pwritev // write new contents step 2. drive-backup sync=none backup_do_cow { wait_for_overlapping_requests cow_request_begin for(; start < end; start++) { bdrv_co_readv_no_serialising //read old contents from Secondary disk bdrv_co_writev // write old contents to hidden-disk } cow_request_end } step 3. Then roll back to "step 1" to write new contents to Secondary disk. And for replication, we must make sure that we only read the old contents from Secondary disk in order to keep contents consistent. 1) Replication workflow of Secondary virtio-blk ^ -------> 1 NBD | || server 3 replication || ^ ^ || | backing backing | || Secondary disk 6<-------- hidden-disk 5 <-------- active-disk 4 || | ^ || '-------------------------' || drive-backup sync=none 2 Hence, we need these interfaces to implement coarse-grained serialization between COW of Secondary disk and the read operation of replication. Example codes about how to use them: *#include "block/block_backup.h" static coroutine_fn int xxx_co_readv() { CowRequest req; BlockJob *job = secondary_disk->bs->job; if (job) { backup_wait_for_overlapping_requests(job, start, end); backup_cow_request_begin(&req, job, start, end); ret = bdrv_co_readv(); backup_cow_request_end(&req); goto out; } ret = bdrv_co_readv(); out: return ret; } Signed-off-by: Changlong Xie Signed-off-by: Wen Congyang --- block/backup.c | 41 ++++++++++++++++++++++++++++++++++------- include/block/block_backup.h | 14 ++++++++++++++ 2 files changed, 48 insertions(+), 7 deletions(-) diff --git a/block/backup.c b/block/backup.c index 1964a5a..bc935b4 100644 --- a/block/backup.c +++ b/block/backup.c @@ -28,13 +28,6 @@ #define BACKUP_CLUSTER_SIZE_DEFAULT (1 << 16) #define SLICE_TIME 100000000ULL /* ns */ -typedef struct CowRequest { - int64_t start; - int64_t end; - QLIST_ENTRY(CowRequest) list; - CoQueue wait_queue; /* coroutines blocked on this request */ -} CowRequest; - typedef struct BackupBlockJob { BlockJob common; BlockBackend *target; @@ -271,6 +264,40 @@ void backup_do_checkpoint(BlockJob *job, Error **errp) bitmap_zero(backup_job->done_bitmap, len); } +void backup_wait_for_overlapping_requests(BlockJob *job, int64_t sector_num, + int nb_sectors) +{ + BackupBlockJob *backup_job = container_of(job, BackupBlockJob, common); + int64_t sectors_per_cluster = cluster_size_sectors(backup_job); + int64_t start, end; + + assert(job->driver->job_type == BLOCK_JOB_TYPE_BACKUP); + + start = sector_num / sectors_per_cluster; + end = DIV_ROUND_UP(sector_num + nb_sectors, sectors_per_cluster); + wait_for_overlapping_requests(backup_job, start, end); +} + +void backup_cow_request_begin(CowRequest *req, BlockJob *job, + int64_t sector_num, + int nb_sectors) +{ + BackupBlockJob *backup_job = container_of(job, BackupBlockJob, common); + int64_t sectors_per_cluster = cluster_size_sectors(backup_job); + int64_t start, end; + + assert(job->driver->job_type == BLOCK_JOB_TYPE_BACKUP); + + start = sector_num / sectors_per_cluster; + end = DIV_ROUND_UP(sector_num + nb_sectors, sectors_per_cluster); + cow_request_begin(req, backup_job, start, end); +} + +void backup_cow_request_end(CowRequest *req) +{ + cow_request_end(req); +} + static const BlockJobDriver backup_job_driver = { .instance_size = sizeof(BackupBlockJob), .job_type = BLOCK_JOB_TYPE_BACKUP, diff --git a/include/block/block_backup.h b/include/block/block_backup.h index 3753bcb..e0e7ce6 100644 --- a/include/block/block_backup.h +++ b/include/block/block_backup.h @@ -1,3 +1,17 @@ #include "block/block_int.h" +typedef struct CowRequest { + int64_t start; + int64_t end; + QLIST_ENTRY(CowRequest) list; + CoQueue wait_queue; /* coroutines blocked on this request */ +} CowRequest; + +void backup_wait_for_overlapping_requests(BlockJob *job, int64_t sector_num, + int nb_sectors); +void backup_cow_request_begin(CowRequest *req, BlockJob *job, + int64_t sector_num, + int nb_sectors); +void backup_cow_request_end(CowRequest *req); + void backup_do_checkpoint(BlockJob *job, Error **errp);