From nobody Wed Dec 17 05:30:30 2025 Delivered-To: importer@patchew.org Received-SPF: temperror (zoho.com: Error in retrieving data from DNS) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=temperror (zoho.com: Error in retrieving data from DNS) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (208.118.235.17 [208.118.235.17]) by mx.zohomail.com with SMTPS id 1510655979976309.5509677900401; Tue, 14 Nov 2017 02:39:39 -0800 (PST) Received: from localhost ([::1]:58726 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eEYcj-0003KW-Es for importer@patchew.org; Tue, 14 Nov 2017 05:39:21 -0500 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60502) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eEYbC-0002Sh-Jh for qemu-devel@nongnu.org; Tue, 14 Nov 2017 05:37:47 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eEYb6-0004LJ-Ug for qemu-devel@nongnu.org; Tue, 14 Nov 2017 05:37:46 -0500 Received: from mx1.redhat.com ([209.132.183.28]:55590) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eEYb6-0004Ko-Os for qemu-devel@nongnu.org; Tue, 14 Nov 2017 05:37:40 -0500 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id E3CB87EA97; Tue, 14 Nov 2017 10:37:39 +0000 (UTC) Received: from localhost (unknown [10.36.118.2]) by smtp.corp.redhat.com (Postfix) with ESMTP id 13AE7A294A; Tue, 14 Nov 2017 10:37:38 +0000 (UTC) From: Stefan Hajnoczi To: Date: Tue, 14 Nov 2017 10:37:18 +0000 Message-Id: <20171114103721.13869-3-stefanha@redhat.com> In-Reply-To: <20171114103721.13869-1-stefanha@redhat.com> References: <20171114103721.13869-1-stefanha@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Tue, 14 Nov 2017 10:37:39 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PULL for-2.11-rc2 2/5] throttle-groups: drain before detaching ThrottleState 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: Peter Maydell , Stefan Hajnoczi Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_6 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" I/O requests hang after stop/cont commands at least since QEMU 2.10.0 with -drive iops=3D100: (guest)$ dd if=3D/dev/zero of=3D/dev/vdb oflag=3Ddirect count=3D1000 (qemu) stop (qemu) cont ...I/O is stuck... This happens because blk_set_aio_context() detaches the ThrottleState while requests may still be in flight: if (tgm->throttle_state) { throttle_group_detach_aio_context(tgm); throttle_group_attach_aio_context(tgm, new_context); } This patch encloses the detach/attach calls in a drained region so no I/O request is left hanging. Also add assertions so we don't make the same mistake again in the future. Reported-by: Yongxue Hong Signed-off-by: Stefan Hajnoczi Reviewed-by: Alberto Garcia Message-id: 20171110151934.16883-1-stefanha@redhat.com Signed-off-by: Stefan Hajnoczi --- block/block-backend.c | 2 ++ block/throttle-groups.c | 6 ++++++ 2 files changed, 8 insertions(+) diff --git a/block/block-backend.c b/block/block-backend.c index 18e543780d..ab75da32c9 100644 --- a/block/block-backend.c +++ b/block/block-backend.c @@ -1752,8 +1752,10 @@ void blk_set_aio_context(BlockBackend *blk, AioConte= xt *new_context) =20 if (bs) { if (tgm->throttle_state) { + bdrv_drained_begin(bs); throttle_group_detach_aio_context(tgm); throttle_group_attach_aio_context(tgm, new_context); + bdrv_drained_end(bs); } bdrv_set_aio_context(bs, new_context); } diff --git a/block/throttle-groups.c b/block/throttle-groups.c index b291a88481..2587f19ca3 100644 --- a/block/throttle-groups.c +++ b/block/throttle-groups.c @@ -594,6 +594,12 @@ void throttle_group_attach_aio_context(ThrottleGroupMe= mber *tgm, void throttle_group_detach_aio_context(ThrottleGroupMember *tgm) { ThrottleTimers *tt =3D &tgm->throttle_timers; + + /* Requests must have been drained */ + assert(tgm->pending_reqs[0] =3D=3D 0 && tgm->pending_reqs[1] =3D=3D 0); + assert(qemu_co_queue_empty(&tgm->throttled_reqs[0])); + assert(qemu_co_queue_empty(&tgm->throttled_reqs[1])); + throttle_timers_detach_aio_context(tt); tgm->aio_context =3D NULL; } --=20 2.13.6