From patchwork Wed May 22 14:28:53 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Max Reitz X-Patchwork-Id: 1103363 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=redhat.com Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 458FQf1G2dz9s6w for ; Thu, 23 May 2019 00:30:02 +1000 (AEST) Received: from localhost ([127.0.0.1]:44261 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hTSFk-0007bp-3u for incoming@patchwork.ozlabs.org; Wed, 22 May 2019 10:30:00 -0400 Received: from eggs.gnu.org ([209.51.188.92]:53112) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hTSF2-0007Zn-OT for qemu-devel@nongnu.org; Wed, 22 May 2019 10:29:17 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hTSF1-00058o-Nf for qemu-devel@nongnu.org; Wed, 22 May 2019 10:29:16 -0400 Received: from mx1.redhat.com ([209.132.183.28]:48204) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hTSEz-00053S-Eg; Wed, 22 May 2019 10:29:13 -0400 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id C7BDB6378; Wed, 22 May 2019 14:29:06 +0000 (UTC) Received: from localhost (unknown [10.40.205.176]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 34186795A1; Wed, 22 May 2019 14:29:02 +0000 (UTC) From: Max Reitz To: qemu-block@nongnu.org Date: Wed, 22 May 2019 16:28:53 +0200 Message-Id: <20190522142854.22983-2-mreitz@redhat.com> In-Reply-To: <20190522142854.22983-1-mreitz@redhat.com> References: <20190522142854.22983-1-mreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.38]); Wed, 22 May 2019 14:29:12 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH 1/2] block/io: Delay decrementing the quiesce_counter 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: Kevin Wolf , qemu-devel@nongnu.org, Stefan Hajnoczi , Max Reitz Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" When ending a drained section, bdrv_do_drained_end() currently first decrements the quiesce_counter, and only then actually ends the drain. The bdrv_drain_invoke(bs, false) call may cause graph changes. Say the graph change involves replacing an existing BB's ("blk") BDS (blk_bs(blk)) by @bs. Let us introducing the following values: - bs_oqc = old_quiesce_counter (so bs->quiesce_counter == bs_oqc - 1) - obs_qc = blk_bs(blk)->quiesce_counter (before bdrv_drain_invoke()) Let us assume there is no blk_pthread_unthrottled() involved, so blk->quiesce_counter == obs_qc (before bdrv_drain_invoke()). Now replacing blk_bs(blk) by @bs will reduce blk->quiesce_counter by obs_qc (making it 0) and increase it by bs_oqc-1 (making it bs_oqc-1). bdrv_drain_invoke() returns and we invoke bdrv_parent_drained_end(). This will decrement blk->quiesce_counter by one, so it would be -1 -- were there not an assertion against that in blk_root_drained_end(). We therefore have to keep the quiesce_counter up at least until bdrv_drain_invoke() returns, so that bdrv_parent_drained_end() does the right thing for the parents @bs got during bdrv_drain_invoke(). But let us delay it even further, namely until bdrv_parent_drained_end() returns, because then it mirrors bdrv_do_drained_begin(): There, we first increment the quiesce_counter, then begin draining the parents, and then call bdrv_drain_invoke(). It makes sense to let bdrv_do_drained_end() unravel this exactly in reverse. Signed-off-by: Max Reitz --- block/io.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/block/io.c b/block/io.c index 150358c3b1..0f6ebd001c 100644 --- a/block/io.c +++ b/block/io.c @@ -422,11 +422,12 @@ static void bdrv_do_drained_end(BlockDriverState *bs, bool recursive, return; } assert(bs->quiesce_counter > 0); - old_quiesce_counter = atomic_fetch_dec(&bs->quiesce_counter); /* Re-enable things in child-to-parent order */ bdrv_drain_invoke(bs, false); bdrv_parent_drained_end(bs, parent, ignore_bds_parents); + + old_quiesce_counter = atomic_fetch_dec(&bs->quiesce_counter); if (old_quiesce_counter == 1) { aio_enable_external(bdrv_get_aio_context(bs)); } From patchwork Wed May 22 14:28:54 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Max Reitz X-Patchwork-Id: 1103364 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=pass (mailfrom) smtp.mailfrom=nongnu.org (client-ip=209.51.188.17; helo=lists.gnu.org; envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=redhat.com Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 458FQq5bFmz9s6w for ; Thu, 23 May 2019 00:30:11 +1000 (AEST) Received: from localhost ([127.0.0.1]:44265 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hTSFt-0007jK-Ja for incoming@patchwork.ozlabs.org; Wed, 22 May 2019 10:30:09 -0400 Received: from eggs.gnu.org ([209.51.188.92]:53191) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hTSF9-0007fS-GI for qemu-devel@nongnu.org; Wed, 22 May 2019 10:29:24 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hTSF8-0005PV-78 for qemu-devel@nongnu.org; Wed, 22 May 2019 10:29:23 -0400 Received: from mx1.redhat.com ([209.132.183.28]:36272) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1hTSF5-0005GH-8k; Wed, 22 May 2019 10:29:19 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 86B8881E06; Wed, 22 May 2019 14:29:13 +0000 (UTC) Received: from localhost (unknown [10.40.205.176]) by smtp.corp.redhat.com (Postfix) with ESMTPS id E163466D3B; Wed, 22 May 2019 14:29:09 +0000 (UTC) From: Max Reitz To: qemu-block@nongnu.org Date: Wed, 22 May 2019 16:28:54 +0200 Message-Id: <20190522142854.22983-3-mreitz@redhat.com> In-Reply-To: <20190522142854.22983-1-mreitz@redhat.com> References: <20190522142854.22983-1-mreitz@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Wed, 22 May 2019 14:29:13 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH 2/2] iotests: Test cancelling a job and closing the VM 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: Kevin Wolf , qemu-devel@nongnu.org, Stefan Hajnoczi , Max Reitz Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: "Qemu-devel" This patch adds a test where we cancel a throttled mirror job and immediately close the VM before it can be cancelled. Doing so will invoke bdrv_drain_all() while the mirror job tries to drain the throttled node. When bdrv_drain_all_end() tries to lift its drain on the throttle node, the job will exit and replace the current root node of the BB drive0 (which is the job's filter node) by the throttle node. Before the previous patch, this replacement did not increase drive0's quiesce_counter by a sufficient amount, so when bdrv_parent_drained_end() (invoked by bdrv_do_drained_end(), invoked by bdrv_drain_all_end()) tried to end the drain on all of the throttle node's parents, it decreased drive0's quiesce_counter below 0 -- which fails an assertion. Signed-off-by: Max Reitz --- tests/qemu-iotests/255 | 54 ++++++++++++++++++++++++++++++++++++++ tests/qemu-iotests/255.out | 24 +++++++++++++++++ 2 files changed, 78 insertions(+) diff --git a/tests/qemu-iotests/255 b/tests/qemu-iotests/255 index c0bb37a9b0..b1bbe3ff0a 100755 --- a/tests/qemu-iotests/255 +++ b/tests/qemu-iotests/255 @@ -35,6 +35,10 @@ def blockdev_create(vm, options): vm.run_job('job0') iotests.log("") +iotests.log('Finishing a commit job with background reads') +iotests.log('============================================') +iotests.log('') + with iotests.FilePath('t.qcow2') as disk_path, \ iotests.FilePath('t.qcow2.mid') as mid_path, \ iotests.FilePath('t.qcow2.base') as base_path, \ @@ -80,4 +84,54 @@ with iotests.FilePath('t.qcow2') as disk_path, \ vm.run_job('job0', auto_finalize=False, pre_finalize=start_requests, auto_dismiss=True) + #vm.qmp_log('block-job-cancel', device='job0') + + vm.shutdown() + +iotests.log('') +iotests.log('Closing the VM while a job is being cancelled') +iotests.log('=============================================') +iotests.log('') + +with iotests.FilePath('src.qcow2') as src_path, \ + iotests.FilePath('dst.qcow2') as dst_path, \ + iotests.VM() as vm: + + iotests.log('=== Create images and start VM ===') + iotests.log('') + + size = 128 * 1024 * 1024 + size_str = str(size) + + iotests.qemu_img_log('create', '-f', iotests.imgfmt, src_path, size_str) + iotests.qemu_img_log('create', '-f', iotests.imgfmt, dst_path, size_str) + + iotests.log(iotests.qemu_io('-f', iotests.imgfmt, '-c', 'write 0 1M', + src_path), + filters=[iotests.filter_test_dir, iotests.filter_qemu_io]) + + vm.add_object('throttle-group,x-bps-read=4096,id=throttle0') + + vm.add_blockdev('file,node-name=src-file,filename=%s' % (src_path)) + vm.add_blockdev('%s,node-name=src,file=src-file' % (iotests.imgfmt)) + + vm.add_blockdev('file,node-name=dst-file,filename=%s' % (dst_path)) + vm.add_blockdev('%s,node-name=dst,file=dst-file' % (iotests.imgfmt)) + + vm.add_blockdev('throttle,node-name=src-throttled,' + + 'throttle-group=throttle0,file=src') + + vm.add_device('virtio-blk,drive=src-throttled') + + vm.launch() + + iotests.log('=== Start a mirror job ===') + iotests.log('') + + vm.qmp_log('blockdev-mirror', job_id='job0', device='src-throttled', + target='dst', sync='full') + + vm.qmp_log('block-job-cancel', device='job0') + vm.qmp_log('quit') + vm.shutdown() diff --git a/tests/qemu-iotests/255.out b/tests/qemu-iotests/255.out index 9a2d7cbb77..348909fdef 100644 --- a/tests/qemu-iotests/255.out +++ b/tests/qemu-iotests/255.out @@ -1,3 +1,6 @@ +Finishing a commit job with background reads +============================================ + === Create backing chain and start VM === Formatting 'TEST_DIR/PID-t.qcow2.mid', fmt=qcow2 size=134217728 cluster_size=65536 lazy_refcounts=off refcount_bits=16 @@ -14,3 +17,24 @@ Formatting 'TEST_DIR/PID-t.qcow2', fmt=qcow2 size=134217728 cluster_size=65536 l {"return": {}} {"data": {"id": "job0", "type": "commit"}, "event": "BLOCK_JOB_PENDING", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}} {"data": {"device": "job0", "len": 134217728, "offset": 134217728, "speed": 0, "type": "commit"}, "event": "BLOCK_JOB_COMPLETED", "timestamp": {"microseconds": "USECS", "seconds": "SECS"}} + +Closing the VM while a job is being cancelled +============================================= + +=== Create images and start VM === + +Formatting 'TEST_DIR/PID-src.qcow2', fmt=qcow2 size=134217728 cluster_size=65536 lazy_refcounts=off refcount_bits=16 + +Formatting 'TEST_DIR/PID-dst.qcow2', fmt=qcow2 size=134217728 cluster_size=65536 lazy_refcounts=off refcount_bits=16 + +wrote 1048576/1048576 bytes at offset 0 +1 MiB, X ops; XX:XX:XX.X (XXX YYY/sec and XXX ops/sec) + +=== Start a mirror job === + +{"execute": "blockdev-mirror", "arguments": {"device": "src-throttled", "job-id": "job0", "sync": "full", "target": "dst"}} +{"return": {}} +{"execute": "block-job-cancel", "arguments": {"device": "job0"}} +{"return": {}} +{"execute": "quit", "arguments": {}} +{"return": {}}