From nobody Thu Mar 28 15:59:48 2024 Delivered-To: importer@patchew.org Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com ARC-Seal: i=1; a=rsa-sha256; t=1585157074; cv=none; d=zohomail.com; s=zohoarc; b=n+qb9j2ofoNt7jEk5PnJ7cvuzlvJjrfFbTf96ayOXNoJU4k9y1r6Pn9N9b4jinOM1bxp1j/JXhH1Jpdw+4HXND/xMQZ/SM8wjDm/HGh1h0zOuSidfRyrIDmK6ohVS9ac7UojCKaXlHmCu9JJH9OLC/r/zJmNLNyQ3idV4BimtO0= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=zohomail.com; s=zohoarc; t=1585157074; h=Content-Type:Content-Transfer-Encoding:Cc:Date:From:In-Reply-To:List-Subscribe:List-Post:List-Id:List-Archive:List-Help:List-Unsubscribe:MIME-Version:Message-ID:References:Sender:Subject:To; bh=/8wyeUj06KXeS38TLcF04SKwHtzws1PB37ZwA+U4vxc=; b=a2CWGzUExXLmYlyafUnYvpGER60y41lh/PVBkJnwy7EnJuaT7KkhqFXcsCMQwLYZWCyH5LT9cG8XCSLg45jREd+o1rInXGvezuu5uDG5a0m4acwgV1Mtp5Nesc10IWKPb7EILU7S6tpGXDHM/UEbkHkhINkEofHVu03ExHh+ofU= ARC-Authentication-Results: i=1; mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail header.from= (p=none dis=none) header.from= Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1585157074466226.69879095573594; Wed, 25 Mar 2020 10:24:34 -0700 (PDT) Received: from localhost ([::1]:39996 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jH9lY-0008Cn-V3 for importer@patchew.org; Wed, 25 Mar 2020 13:24:32 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:59409) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jH9kk-0006vx-Tv for qemu-devel@nongnu.org; Wed, 25 Mar 2020 13:23:44 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1jH9kj-0002k2-KS for qemu-devel@nongnu.org; Wed, 25 Mar 2020 13:23:42 -0400 Received: from us-smtp-delivery-74.mimecast.com ([63.128.21.74]:24459) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1jH9kj-0002jQ-Gr for qemu-devel@nongnu.org; Wed, 25 Mar 2020 13:23:41 -0400 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-396-FE4D07BMM9GbGoGBHbpZ2Q-1; Wed, 25 Mar 2020 13:23:38 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id A0265107ACC4; Wed, 25 Mar 2020 17:23:37 +0000 (UTC) Received: from linux.fritz.box.com (ovpn-113-184.ams2.redhat.com [10.36.113.184]) by smtp.corp.redhat.com (Postfix) with ESMTP id 5970A6266E; Wed, 25 Mar 2020 17:23:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1585157020; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=/8wyeUj06KXeS38TLcF04SKwHtzws1PB37ZwA+U4vxc=; b=EKxXx2OfZnN0uw6ONUqhym6d4TgGxFKJEtVGL1cjGSai0cuW/9J6apNFZGjLPWqn669o4W 3RsO+kuZX/Ro/hpfQ8QuWNGLo0I+EUhX2W0nP/NUZaEyZClkWIryn7SQpy6iNGtaZv3exL ra4CCpYHZyuTVxjZzzjymVQRT1VTlGw= X-MC-Unique: FE4D07BMM9GbGoGBHbpZ2Q-1 From: Kevin Wolf To: qemu-block@nongnu.org Subject: [PATCH 1/2] Revert "mirror: Don't let an operation wait for itself" Date: Wed, 25 Mar 2020 18:23:25 +0100 Message-Id: <20200325172326.22347-2-kwolf@redhat.com> In-Reply-To: <20200325172326.22347-1-kwolf@redhat.com> References: <20200325172326.22347-1-kwolf@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 63.128.21.74 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kwolf@redhat.com, jsnow@redhat.com, qemu-devel@nongnu.org, mreitz@redhat.com Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) Content-Type: text/plain; charset="utf-8" This reverts commit 7e6c4ff792734e196c8ca82564c56b5e7c6288ca. The fix was incomplete as it only protected against requests waiting for themselves, but not against requests waiting for each other. We need a different solution. Signed-off-by: Kevin Wolf Reviewed-by: Eric Blake --- block/mirror.c | 21 +++++++++------------ 1 file changed, 9 insertions(+), 12 deletions(-) diff --git a/block/mirror.c b/block/mirror.c index 447051dbc6..393131b135 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -283,14 +283,11 @@ static int mirror_cow_align(MirrorBlockJob *s, int64_= t *offset, } =20 static inline void coroutine_fn -mirror_wait_for_any_operation(MirrorBlockJob *s, MirrorOp *self, bool acti= ve) +mirror_wait_for_any_operation(MirrorBlockJob *s, bool active) { MirrorOp *op; =20 QTAILQ_FOREACH(op, &s->ops_in_flight, next) { - if (self =3D=3D op) { - continue; - } /* Do not wait on pseudo ops, because it may in turn wait on * some other operation to start, which may in fact be the * caller of this function. Since there is only one pseudo op @@ -305,10 +302,10 @@ mirror_wait_for_any_operation(MirrorBlockJob *s, Mirr= orOp *self, bool active) } =20 static inline void coroutine_fn -mirror_wait_for_free_in_flight_slot(MirrorBlockJob *s, MirrorOp *self) +mirror_wait_for_free_in_flight_slot(MirrorBlockJob *s) { /* Only non-active operations use up in-flight slots */ - mirror_wait_for_any_operation(s, self, false); + mirror_wait_for_any_operation(s, false); } =20 /* Perform a mirror copy operation. @@ -351,7 +348,7 @@ static void coroutine_fn mirror_co_read(void *opaque) =20 while (s->buf_free_count < nb_chunks) { trace_mirror_yield_in_flight(s, op->offset, s->in_flight); - mirror_wait_for_free_in_flight_slot(s, op); + mirror_wait_for_free_in_flight_slot(s); } =20 /* Now make a QEMUIOVector taking enough granularity-sized chunks @@ -558,7 +555,7 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlo= ckJob *s) =20 while (s->in_flight >=3D MAX_IN_FLIGHT) { trace_mirror_yield_in_flight(s, offset, s->in_flight); - mirror_wait_for_free_in_flight_slot(s, pseudo_op); + mirror_wait_for_free_in_flight_slot(s); } =20 if (s->ret < 0) { @@ -612,7 +609,7 @@ static void mirror_free_init(MirrorBlockJob *s) static void coroutine_fn mirror_wait_for_all_io(MirrorBlockJob *s) { while (s->in_flight > 0) { - mirror_wait_for_free_in_flight_slot(s, NULL); + mirror_wait_for_free_in_flight_slot(s); } } =20 @@ -809,7 +806,7 @@ static int coroutine_fn mirror_dirty_init(MirrorBlockJo= b *s) if (s->in_flight >=3D MAX_IN_FLIGHT) { trace_mirror_yield(s, UINT64_MAX, s->buf_free_count, s->in_flight); - mirror_wait_for_free_in_flight_slot(s, NULL); + mirror_wait_for_free_in_flight_slot(s); continue; } =20 @@ -962,7 +959,7 @@ static int coroutine_fn mirror_run(Job *job, Error **er= rp) /* Do not start passive operations while there are active * writes in progress */ while (s->in_active_write_counter) { - mirror_wait_for_any_operation(s, NULL, true); + mirror_wait_for_any_operation(s, true); } =20 if (s->ret < 0) { @@ -988,7 +985,7 @@ static int coroutine_fn mirror_run(Job *job, Error **er= rp) if (s->in_flight >=3D MAX_IN_FLIGHT || s->buf_free_count =3D= =3D 0 || (cnt =3D=3D 0 && s->in_flight > 0)) { trace_mirror_yield(s, cnt, s->buf_free_count, s->in_flight= ); - mirror_wait_for_free_in_flight_slot(s, NULL); + mirror_wait_for_free_in_flight_slot(s); continue; } else if (cnt !=3D 0) { delay_ns =3D mirror_iteration(s); --=20 2.20.1 From nobody Thu Mar 28 15:59:48 2024 Delivered-To: importer@patchew.org Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; dkim=fail; spf=pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com ARC-Seal: i=1; a=rsa-sha256; t=1585157157; cv=none; d=zohomail.com; s=zohoarc; b=bGXH/0zBkwMjjU0GK+84feTQ6tfCysGh2jCd5RG4+Yjg0rIgiW0MG3FJJ8EIYLiKIR0ibJXKFlL1M3XZ1Vg/E5wNmk1wjDKef2rg8Dt/qPN3I/GvHXmwUaaSIE4k9klNmmjgSrdiHWb/lR1HzrSSABnWrq3ql8shq5JdM8gXIMI= ARC-Message-Signature: i=1; a=rsa-sha256; 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Wed, 25 Mar 2020 17:23:39 +0000 (UTC) Received: from linux.fritz.box.com (ovpn-113-184.ams2.redhat.com [10.36.113.184]) by smtp.corp.redhat.com (Postfix) with ESMTP id E7B3794B57; Wed, 25 Mar 2020 17:23:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1585157021; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=z4GZIoigkEvsVG7WhJxc+xDFAFpTeOM6YrcFeweRdXQ=; b=CXVjCza48p0fYcVB6fFcXYpkFReZDrXolFPcY2txVSIaKvYD1L7TQEZDCKKBcruTXMqFwF f4CjXSJQHyRpMfMyahgJvU4tMu+S8sXAcOmSuIwOOlJme1N/KCSF0b2j8p/TeYnajXUy71 D/1zWpa8Ddh942DuiuKskQw2J/MB9KY= X-MC-Unique: 17tdskvPOwiTcXnycf9HDQ-1 From: Kevin Wolf To: qemu-block@nongnu.org Subject: [PATCH 2/2] mirror: Wait only for in-flight operations Date: Wed, 25 Mar 2020 18:23:26 +0100 Message-Id: <20200325172326.22347-3-kwolf@redhat.com> In-Reply-To: <20200325172326.22347-1-kwolf@redhat.com> References: <20200325172326.22347-1-kwolf@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 63.128.21.74 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kwolf@redhat.com, jsnow@redhat.com, qemu-devel@nongnu.org, mreitz@redhat.com Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) Content-Type: text/plain; charset="utf-8" mirror_wait_for_free_in_flight_slot() just picks a random operation to wait for. However, a MirrorOp is already in s->ops_in_flight when mirror_co_read() waits for free slots, so if not enough slots are immediately available, an operation can end up waiting for itself, or two or more operations can wait for each other to complete, which results in a hang. Fix this by adding a flag to MirrorOp that tells us if the request is already in flight (and therefore occupies slots that it will later free), and picking only such operations for waiting. Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=3D1794692 Signed-off-by: Kevin Wolf Reviewed-by: Eric Blake --- block/mirror.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/block/mirror.c b/block/mirror.c index 393131b135..7fef52ded2 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -102,6 +102,7 @@ struct MirrorOp { =20 bool is_pseudo_op; bool is_active_write; + bool is_in_flight; CoQueue waiting_requests; Coroutine *co; =20 @@ -293,7 +294,9 @@ mirror_wait_for_any_operation(MirrorBlockJob *s, bool a= ctive) * caller of this function. Since there is only one pseudo op * at any given time, we will always find some real operation * to wait on. */ - if (!op->is_pseudo_op && op->is_active_write =3D=3D active) { + if (!op->is_pseudo_op && op->is_in_flight && + op->is_active_write =3D=3D active) + { qemu_co_queue_wait(&op->waiting_requests, NULL); return; } @@ -367,6 +370,7 @@ static void coroutine_fn mirror_co_read(void *opaque) /* Copy the dirty cluster. */ s->in_flight++; s->bytes_in_flight +=3D op->bytes; + op->is_in_flight =3D true; trace_mirror_one_iteration(s, op->offset, op->bytes); =20 ret =3D bdrv_co_preadv(s->mirror_top_bs->backing, op->offset, op->byte= s, @@ -382,6 +386,7 @@ static void coroutine_fn mirror_co_zero(void *opaque) op->s->in_flight++; op->s->bytes_in_flight +=3D op->bytes; *op->bytes_handled =3D op->bytes; + op->is_in_flight =3D true; =20 ret =3D blk_co_pwrite_zeroes(op->s->target, op->offset, op->bytes, op->s->unmap ? BDRV_REQ_MAY_UNMAP : 0); @@ -396,6 +401,7 @@ static void coroutine_fn mirror_co_discard(void *opaque) op->s->in_flight++; op->s->bytes_in_flight +=3D op->bytes; *op->bytes_handled =3D op->bytes; + op->is_in_flight =3D true; =20 ret =3D blk_co_pdiscard(op->s->target, op->offset, op->bytes); mirror_write_complete(op, ret); --=20 2.20.1