From patchwork Thu Feb 4 10:17:31 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Changlong Xie X-Patchwork-Id: 8217031 Return-Path: X-Original-To: patchwork-qemu-devel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 2B22FBEEE5 for ; Thu, 4 Feb 2016 10:16:55 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id A84402010C for ; Thu, 4 Feb 2016 10:16:52 +0000 (UTC) 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.kernel.org (Postfix) with ESMTPS id ACE502038A for ; Thu, 4 Feb 2016 10:16:50 +0000 (UTC) Received: from localhost ([::1]:40665 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aRGy1-0005Ig-L1 for patchwork-qemu-devel@patchwork.kernel.org; Thu, 04 Feb 2016 05:16:49 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:58531) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aRGxs-0005IA-UE for qemu-devel@nongnu.org; Thu, 04 Feb 2016 05:16:42 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aRGxq-0005n2-O5 for qemu-devel@nongnu.org; Thu, 04 Feb 2016 05:16:40 -0500 Received: from [59.151.112.132] (port=30287 helo=heian.cn.fujitsu.com) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aRGxi-0005lV-9s; Thu, 04 Feb 2016 05:16:32 -0500 X-IronPort-AV: E=Sophos;i="5.20,346,1444665600"; d="scan'208";a="3317667" Received: from unknown (HELO cn.fujitsu.com) ([10.167.33.5]) by heian.cn.fujitsu.com with ESMTP; 04 Feb 2016 18:16:20 +0800 Received: from G08CNEXCHPEKD01.g08.fujitsu.local (unknown [10.167.33.80]) by cn.fujitsu.com (Postfix) with ESMTP id A0AD941B720D; Thu, 4 Feb 2016 18:15:19 +0800 (CST) Received: from [10.167.225.55] (10.167.225.55) by G08CNEXCHPEKD01.g08.fujitsu.local (10.167.33.89) with Microsoft SMTP Server id 14.3.181.6; Thu, 4 Feb 2016 18:16:14 +0800 Message-ID: <56B3253B.3030300@cn.fujitsu.com> Date: Thu, 4 Feb 2016 18:17:31 +0800 From: Changlong Xie User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: "Dr. David Alan Gilbert" References: <1451039434-8264-1-git-send-email-xiecl.fnst@cn.fujitsu.com> <20160127110345.GB2394@work-vm> <56AB0C1F.90008@cn.fujitsu.com> <20160129100745.GA2410@work-vm> <56AB3EAD.60609@cn.fujitsu.com> <20160129104754.GB2410@work-vm> <56AEB24C.5080801@cn.fujitsu.com> <56B2B835.2070300@cn.fujitsu.com> <20160204090721.GA2427@work-vm> In-Reply-To: <20160204090721.GA2427@work-vm> X-Originating-IP: [10.167.225.55] X-yoursite-MailScanner-ID: A0AD941B720D.AF4E0 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 Cc: Kevin Wolf , Fam Zheng , qemu block , Jiang Yunhong , Dong Eddie , qemu devel , "Michael R. Hines" , Max Reitz , Gonglei , Stefan Hajnoczi , Paolo Bonzini , zhanghailiang Subject: Re: [Qemu-devel] [PATCH v13 00/10] Block replication for continuous checkpoints 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+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP On 02/04/2016 05:07 PM, Dr. David Alan Gilbert wrote: > * Changlong Xie (xiecl.fnst@cn.fujitsu.com) wrote: >> On 02/01/2016 09:18 AM, Wen Congyang wrote: >>> On 01/29/2016 06:47 PM, Dr. David Alan Gilbert wrote: >>>> * Wen Congyang (wency@cn.fujitsu.com) wrote: >>>>> On 01/29/2016 06:07 PM, Dr. David Alan Gilbert wrote: >>>>>> * Wen Congyang (wency@cn.fujitsu.com) wrote: >>>>>>> On 01/27/2016 07:03 PM, Dr. David Alan Gilbert wrote: >>>>>>>> Hi, >>>>>>>> I've got a block error if I kill the secondary. >>>>>>>> >>>>>>>> Start both primary & secondary >>>>>>>> kill -9 secondary qemu >>>>>>>> x_colo_lost_heartbeat on primary >>>>>>>> >>>>>>>> The guest sees a block error and the ext4 root switches to read-only. >>>>>>>> >>>>>>>> I gdb'd the primary with a breakpoint on quorum_report_bad; see >>>>>>>> backtrace below. >>>>>>>> (This is based on colo-v2.4-periodic-mode of the framework >>>>>>>> code with the block and network proxy merged in; so it could be my >>>>>>>> merging but I don't think so ?) >>>>>>>> >>>>>>>> >>>>>>>> (gdb) where >>>>>>>> #0 quorum_report_bad (node_name=0x7f2946a0892c "node0", ret=-5, acb=0x7f2946cb3910, acb=0x7f2946cb3910) >>>>>>>> at /root/colo/jan-2016/qemu/block/quorum.c:222 >>>>>>>> #1 0x00007f2943b23058 in quorum_aio_cb (opaque=, ret=) >>>>>>>> at /root/colo/jan-2016/qemu/block/quorum.c:315 >>>>>>>> #2 0x00007f2943b311be in bdrv_co_complete (acb=0x7f2946cb3f60) at /root/colo/jan-2016/qemu/block/io.c:2122 >>>>>>>> #3 0x00007f2943ae777d in aio_bh_call (bh=) at /root/colo/jan-2016/qemu/async.c:64 >>>>>>>> #4 aio_bh_poll (ctx=ctx@entry=0x7f2945b771d0) at /root/colo/jan-2016/qemu/async.c:92 >>>>>>>> #5 0x00007f2943af5090 in aio_dispatch (ctx=0x7f2945b771d0) at /root/colo/jan-2016/qemu/aio-posix.c:305 >>>>>>>> #6 0x00007f2943ae756e in aio_ctx_dispatch (source=, callback=, >>>>>>>> user_data=) at /root/colo/jan-2016/qemu/async.c:231 >>>>>>>> #7 0x00007f293b84a79a in g_main_context_dispatch () from /lib64/libglib-2.0.so.0 >>>>>>>> #8 0x00007f2943af3a00 in glib_pollfds_poll () at /root/colo/jan-2016/qemu/main-loop.c:211 >>>>>>>> #9 os_host_main_loop_wait (timeout=) at /root/colo/jan-2016/qemu/main-loop.c:256 >>>>>>>> #10 main_loop_wait (nonblocking=) at /root/colo/jan-2016/qemu/main-loop.c:504 >>>>>>>> #11 0x00007f29438529ee in main_loop () at /root/colo/jan-2016/qemu/vl.c:1945 >>>>>>>> #12 main (argc=, argv=, envp=) at /root/colo/jan-2016/qemu/vl.c:4707 >>>>>>>> >>>>>>>> (gdb) p s->num_children >>>>>>>> $1 = 2 >>>>>>>> (gdb) p acb->success_count >>>>>>>> $2 = 0 >>>>>>>> (gdb) p acb->is_read >>>>>>>> $5 = false >>>>>>> >>>>>>> Sorry for the late reply. >>>>>> >>>>>> No problem. >>>>>> >>>>>>> What it the value of acb->count? >>>>>> >>>>>> (gdb) p acb->count >>>>>> $1 = 1 >>>>> >>>>> Note, the count is 1, not 2. Writing to children.0 is in flight. If writing to children.0 successes, >>>>> the guest doesn't know this error. >>>>>>> If secondary host is down, you should remove quorum's children.1. Otherwise, you will get >>>>>>> I/O error event. >>>>>> >>>>>> Is that safe? If the secondary fails, do you always have time to issue the command to >>>>>> remove the children.1 before the guest sees the error? >>>>> >>>>> We will write to two children, and expect that writing to children.0 will success. If so, >>>>> the guest doesn't know this error. You just get the I/O error event. >>>> >>>> I think children.0 is the disk, and that should be OK - so only the children.1/replication should >>>> be failing - so in that case why do I see the error? >>> >>> I don't know, and I will check the codes. >>> >>>> The 'node0' in the backtrace above is the name of the replication, so it does look like the error >>>> is coming from the replication. >>> >>> No, the backtrace is just report an I/O error events to the management application. >>> >>>> >>>>>> Anyway, I tried removing children.1 but it segfaults now, I guess the replication is unhappy: >>>>>> >>>>>> (qemu) x_block_change colo-disk0 -d children.1 >>>>>> (qemu) x_colo_lost_heartbeat >>>>> >>>>> Hmm, you should not remove the child before failover. I will check it how to avoid it in the codes. >>>> >>>> But you said 'If secondary host is down, you should remove quorum's children.1' - is that not >>>> what you meant? >>> >>> Yes, you should excute 'x_colo_lost_heartbeat' fist, and then excute 'x_block_change ... -d ...'. >>> >> Hi david > > Hi Xie, > Thanks for the response. > >> It seems we missed 'drive_del' command, and will document it in next >> version. Here is the right commands order: >> >> { "execute": "x-colo-lost-heartbeat" } >> { 'execute': 'x-blockdev-change', 'arguments': {'parent': 'colo-disk', >> 'child': 'children.1'}} >> { 'execute': 'human-monitor-command', 'arguments': {'command-line': >> 'drive_del xxxxx'}} > > OK, however, you should fix the seg fault if you don't issue the drive_del; > qemu should never crash. > (Also I still get the IO error in the guest if I do the x-colo-lost-heartbeat). > Here is a quick fix, i just tested for several times. It work well to me. bugfix Signed-off-by: Changlong Xie > Dave > >> Thanks >> -Xie >>>> >>>>>> 12973 Segmentation fault (core dumped) ./try/x86_64-softmmu/qemu-system-x86_64 -enable-kvm $console_param -S -boot c -m 4080 -smp 4 -machine pc-i440fx-2.5,accel=kvm -name debug-threads=on -trace events=trace-file -device virtio-rng-pci $block_param $net_param >>>>>> >>>>>> #0 0x00007f0a398a864c in bdrv_stop_replication (bs=0x7f0a3b0a8430, failover=true, errp=0x7fff6a5c3420) >>>>>> at /root/colo/jan-2016/qemu/block.c:4426 >>>>>> >>>>>> (gdb) p drv >>>>>> $1 = (BlockDriver *) 0x5d2a >>>>>> >>>>>> it looks like the whole of bs is bogus. >>>>>> >>>>>> #1 0x00007f0a398d87f6 in quorum_stop_replication (bs=, failover=, >>>>>> errp=) at /root/colo/jan-2016/qemu/block/quorum.c:1213 >>>>>> >>>>>> (gdb) p s->replication_index >>>>>> $3 = 1 >>>>>> >>>>>> I guess quorum_del_child needs to stop replication before it removes the child? >>>>> >>>>> Yes, but in the newest version, quorum doesn't know the block replication, and I think >>>>> we shoud add an reference to the bs when starting block replication. >>>> >>>> Do you have a new version ready to test? I'm interested to try it (and also interested >>>> to try the latest version of the colo-proxy) >>> >>> I think we can post the newest version this week. >>> >>> Thanks >>> Wen Congyang >>> >>>> >>>> Dave >>>> >>>>> Thanks >>>>> Wen Congyang >>>>> >>>>>> (although it would have to be careful not to block on the dead nbd). >>>>>> >>>>>> #2 0x00007f0a398a8901 in bdrv_stop_replication_all (failover=failover@entry=true, errp=errp@entry=0x7fff6a5c3478) >>>>>> at /root/colo/jan-2016/qemu/block.c:4504 >>>>>> #3 0x00007f0a3984b0af in primary_vm_do_failover () at /root/colo/jan-2016/qemu/migration/colo.c:144 >>>>>> #4 colo_do_failover (s=) at /root/colo/jan-2016/qemu/migration/colo.c:162 >>>>>> #5 0x00007f0a3989d7fd in aio_bh_call (bh=) at /root/colo/jan-2016/qemu/async.c:64 >>>>>> #6 aio_bh_poll (ctx=ctx@entry=0x7f0a3a6c21d0) at /root/colo/jan-2016/qemu/async.c:92 >>>>>> #7 0x00007f0a398ab110 in aio_dispatch (ctx=0x7f0a3a6c21d0) at /root/colo/jan-2016/qemu/aio-posix.c:305 >>>>>> #8 0x00007f0a3989d5ee in aio_ctx_dispatch (source=, callback=, >>>>>> user_data=) at /root/colo/jan-2016/qemu/async.c:231 >>>>>> #9 0x00007f0a3160079a in g_main_context_dispatch () from /lib64/libglib-2.0.so.0 >>>>>> #10 0x00007f0a398a9a80 in glib_pollfds_poll () at /root/colo/jan-2016/qemu/main-loop.c:211 >>>>>> #11 os_host_main_loop_wait (timeout=) at /root/colo/jan-2016/qemu/main-loop.c:256 >>>>>> #12 main_loop_wait (nonblocking=) at /root/colo/jan-2016/qemu/main-loop.c:504 >>>>>> #13 0x00007f0a396089ee in main_loop () at /root/colo/jan-2016/qemu/vl.c:1945 >>>>>> #14 main (argc=, argv=, envp=) at /root/colo/jan-2016/qemu/vl.c:4707 >>>>>> >>>>>> Dave >>>>>> >>>>>>> Thanks >>>>>>> Wen Congyang >>>>>>> >>>>>>>> >>>>>>>> (qemu) info block >>>>>>>> colo-disk0 (#block080): json:{"children": [{"driver": "raw", "file": {"driver": "file", "filename": "/root/colo/bugzilla.raw"}}, {"driver": "replication", "mode": "primary", "file": {"port": "8889", "host": "ibpair", "driver": "nbd", "export": "colo-disk0"}}], "driver": "quorum", "blkverify": false, "rewrite-corrupted": false, "vote-threshold": 1} (quorum) >>>>>>>> Cache mode: writeback, direct >>>>>>>> >>>>>>>> Dave >>>>>>>> >>>>>>>> * Changlong Xie (xiecl.fnst@cn.fujitsu.com) wrote: >>>>>>>>> Block replication is a very important feature which is used for >>>>>>>>> continuous checkpoints(for example: COLO). >>>>>>>>> >>>>>>>>> You can get the detailed information about block replication from here: >>>>>>>>> http://wiki.qemu.org/Features/BlockReplication >>>>>>>>> >>>>>>>>> Usage: >>>>>>>>> Please refer to docs/block-replication.txt >>>>>>>>> >>>>>>>>> This patch series is based on the following patch series: >>>>>>>>> 1. http://lists.nongnu.org/archive/html/qemu-devel/2015-12/msg04570.html >>>>>>>>> >>>>>>>>> You can get the patch here: >>>>>>>>> https://github.com/Pating/qemu/tree/changlox/block-replication-v13 >>>>>>>>> >>>>>>>>> You can get the patch with framework here: >>>>>>>>> https://github.com/Pating/qemu/tree/changlox/colo_framework_v12 >>>>>>>>> >>>>>>>>> TODO: >>>>>>>>> 1. Continuous block replication. It will be started after basic functions >>>>>>>>> are accepted. >>>>>>>>> >>>>>>>>> Changs Log: >>>>>>>>> V13: >>>>>>>>> 1. Rebase to the newest codes >>>>>>>>> 2. Remove redundant marcos and semicolon in replication.c >>>>>>>>> 3. Fix typos in block-replication.txt >>>>>>>>> V12: >>>>>>>>> 1. Rebase to the newest codes >>>>>>>>> 2. Use backing reference to replcace 'allow-write-backing-file' >>>>>>>>> V11: >>>>>>>>> 1. Reopen the backing file when starting blcok replication if it is not >>>>>>>>> opened in R/W mode >>>>>>>>> 2. Unblock BLOCK_OP_TYPE_BACKUP_SOURCE and BLOCK_OP_TYPE_BACKUP_TARGET >>>>>>>>> when opening backing file >>>>>>>>> 3. Block the top BDS so there is only one block job for the top BDS and >>>>>>>>> its backing chain. >>>>>>>>> V10: >>>>>>>>> 1. Use blockdev-remove-medium and blockdev-insert-medium to replace backing >>>>>>>>> reference. >>>>>>>>> 2. Address the comments from Eric Blake >>>>>>>>> V9: >>>>>>>>> 1. Update the error messages >>>>>>>>> 2. Rebase to the newest qemu >>>>>>>>> 3. Split child add/delete support. These patches are sent in another patchset. >>>>>>>>> V8: >>>>>>>>> 1. Address Alberto Garcia's comments >>>>>>>>> V7: >>>>>>>>> 1. Implement adding/removing quorum child. Remove the option non-connect. >>>>>>>>> 2. Simplify the backing refrence option according to Stefan Hajnoczi's suggestion >>>>>>>>> V6: >>>>>>>>> 1. Rebase to the newest qemu. >>>>>>>>> V5: >>>>>>>>> 1. Address the comments from Gong Lei >>>>>>>>> 2. Speed the failover up. The secondary vm can take over very quickly even >>>>>>>>> if there are too many I/O requests. >>>>>>>>> V4: >>>>>>>>> 1. Introduce a new driver replication to avoid touch nbd and qcow2. >>>>>>>>> V3: >>>>>>>>> 1: use error_setg() instead of error_set() >>>>>>>>> 2. Add a new block job API >>>>>>>>> 3. Active disk, hidden disk and nbd target uses the same AioContext >>>>>>>>> 4. Add a testcase to test new hbitmap API >>>>>>>>> V2: >>>>>>>>> 1. Redesign the secondary qemu(use image-fleecing) >>>>>>>>> 2. Use Error objects to return error message >>>>>>>>> 3. Address the comments from Max Reitz and Eric Blake >>>>>>>>> >>>>>>>>> Wen Congyang (10): >>>>>>>>> unblock backup operations in backing file >>>>>>>>> Store parent BDS in BdrvChild >>>>>>>>> Backup: clear all bitmap when doing block checkpoint >>>>>>>>> Allow creating backup jobs when opening BDS >>>>>>>>> docs: block replication's description >>>>>>>>> Add new block driver interfaces to control block replication >>>>>>>>> quorum: implement block driver interfaces for block replication >>>>>>>>> Implement new driver for block replication >>>>>>>>> support replication driver in blockdev-add >>>>>>>>> Add a new API to start/stop replication, do checkpoint to all BDSes >>>>>>>>> >>>>>>>>> block.c | 145 ++++++++++++ >>>>>>>>> block/Makefile.objs | 3 +- >>>>>>>>> block/backup.c | 14 ++ >>>>>>>>> block/quorum.c | 78 +++++++ >>>>>>>>> block/replication.c | 545 +++++++++++++++++++++++++++++++++++++++++++++ >>>>>>>>> blockjob.c | 11 + >>>>>>>>> docs/block-replication.txt | 227 +++++++++++++++++++ >>>>>>>>> include/block/block.h | 9 + >>>>>>>>> include/block/block_int.h | 15 ++ >>>>>>>>> include/block/blockjob.h | 12 + >>>>>>>>> qapi/block-core.json | 33 ++- >>>>>>>>> 11 files changed, 1089 insertions(+), 3 deletions(-) >>>>>>>>> create mode 100644 block/replication.c >>>>>>>>> create mode 100644 docs/block-replication.txt >>>>>>>>> >>>>>>>>> -- >>>>>>>>> 1.9.3 >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>> -- >>>>>>>> Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK >>>>>>>> >>>>>>>> >>>>>>>> . >>>>>>>> >>>>>>> >>>>>>> >>>>>>> >>>>>> -- >>>>>> Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK >>>>>> >>>>>> >>>>>> . >>>>>> >>>>> >>>>> >>>>> >>>> -- >>>> Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK >>>> >>>> >>>> . >>>> >>> >>> . >>> >> >> > -- > Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK > > > . > diff --git a/block/quorum.c b/block/quorum.c index e5a7e4f..f4f1d28 100644 --- a/block/quorum.c +++ b/block/quorum.c @@ -458,6 +458,11 @@ static QuorumVoteVersion *quorum_get_vote_winner(QuorumVotes *votes) if (candidate->vote_count > max) { max = candidate->vote_count; winner = candidate; + continue; + } + if (candidate->vote_count == max && + candidate->value.l > winner->value.l) { + winner = candidate; } }