From patchwork Tue Jul 28 15:04:06 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Blake X-Patchwork-Id: 277313 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8FA0FC433E3 for ; Tue, 28 Jul 2020 15:09:49 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 5E134204EA for ; Tue, 28 Jul 2020 15:09:49 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="VZ5bPJIn" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5E134204EA Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:32970 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1k0REi-0006ER-Jz for qemu-devel@archiver.kernel.org; Tue, 28 Jul 2020 11:09:48 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:40050) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1k0R9b-0006OV-Hz for qemu-devel@nongnu.org; Tue, 28 Jul 2020 11:04:31 -0400 Received: from us-smtp-2.mimecast.com ([207.211.31.81]:47816 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1k0R9Y-0006uy-MF for qemu-devel@nongnu.org; Tue, 28 Jul 2020 11:04:31 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1595948667; 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=SB4Hc2q6uuPHOSGYKf6pIASqeyKKgufXtcN8atc9kFs=; b=VZ5bPJInfSNvdu2EIvAi1E6SdN/wzte/sdqDfS8q/OujeQAyfsnpE+GwK8RyVm+zI1r+Av NDAW5seWmuGK+nerPh9QbJxjQKTB3IsUdIZoiz6jFmxHFIJkpqt4bdI4p28kblaem6RYPx PmeQnV02PPKslrU8uocV39n1zpIE59s= 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-435-QrHGTC0FONunJbziWCHV0g-1; Tue, 28 Jul 2020 11:04:23 -0400 X-MC-Unique: QrHGTC0FONunJbziWCHV0g-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 2DB9A18A1DFE; Tue, 28 Jul 2020 15:04:22 +0000 (UTC) Received: from blue.redhat.com (ovpn-118-248.rdu2.redhat.com [10.10.118.248]) by smtp.corp.redhat.com (Postfix) with ESMTP id 7EA0E19C71; Tue, 28 Jul 2020 15:04:19 +0000 (UTC) From: Eric Blake To: qemu-devel@nongnu.org Subject: [PULL 8/9] block/nbd: on shutdown terminate connection attempt Date: Tue, 28 Jul 2020 10:04:06 -0500 Message-Id: <20200728150408.291299-9-eblake@redhat.com> In-Reply-To: <20200728150408.291299-1-eblake@redhat.com> References: <20200728150408.291299-1-eblake@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Received-SPF: pass client-ip=207.211.31.81; envelope-from=eblake@redhat.com; helo=us-smtp-delivery-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/07/28 10:31:13 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action 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: Kevin Wolf , Vladimir Sementsov-Ogievskiy , "open list:Network Block Dev..." , Max Reitz Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" From: Vladimir Sementsov-Ogievskiy On shutdown nbd driver may be in a connecting state. We should shutdown it as well, otherwise we may hang in nbd_teardown_connection, waiting for conneciton_co to finish in BDRV_POLL_WHILE(bs, s->connection_co) loop if remote server is down. How to reproduce the dead lock: 1. Create nbd-fault-injector.conf with the following contents: [inject-error "mega1"] event=data io=readwrite when=before 2. In one terminal run nbd-fault-injector in a loop, like this: n=1; while true; do echo $n; ((n++)); ./nbd-fault-injector.py 127.0.0.1:10000 nbd-fault-injector.conf; done 3. In another terminal run qemu-io in a loop, like this: n=1; while true; do echo $n; ((n++)); ./qemu-io -c 'read 0 512' nbd://127.0.0.1:10000; done After some time, qemu-io will hang. Note, that this hang may be triggered by another bug, so the whole case is fixed only together with commit "block/nbd: allow drain during reconnect attempt". Signed-off-by: Vladimir Sementsov-Ogievskiy Reviewed-by: Eric Blake Message-Id: <20200727184751.15704-4-vsementsov@virtuozzo.com> Signed-off-by: Eric Blake --- block/nbd.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/block/nbd.c b/block/nbd.c index ee9ab7512b65..620c97be6ba2 100644 --- a/block/nbd.c +++ b/block/nbd.c @@ -209,11 +209,15 @@ static void nbd_teardown_connection(BlockDriverState *bs) { BDRVNBDState *s = (BDRVNBDState *)bs->opaque; - if (s->state == NBD_CLIENT_CONNECTED) { + if (s->ioc) { /* finish any pending coroutines */ - assert(s->ioc); qio_channel_shutdown(s->ioc, QIO_CHANNEL_SHUTDOWN_BOTH, NULL); + } else if (s->sioc) { + /* abort negotiation */ + qio_channel_shutdown(QIO_CHANNEL(s->sioc), QIO_CHANNEL_SHUTDOWN_BOTH, + NULL); } + s->state = NBD_CLIENT_QUIT; if (s->connection_co) { if (s->connection_co_sleep_ns_state) { @@ -1459,6 +1463,9 @@ static int nbd_client_handshake(BlockDriverState *bs, QIOChannelSocket *sioc, int ret; trace_nbd_client_handshake(s->export); + + s->sioc = sioc; + qio_channel_set_blocking(QIO_CHANNEL(sioc), false, NULL); qio_channel_attach_aio_context(QIO_CHANNEL(sioc), aio_context); @@ -1473,6 +1480,7 @@ static int nbd_client_handshake(BlockDriverState *bs, QIOChannelSocket *sioc, g_free(s->info.name); if (ret < 0) { object_unref(OBJECT(sioc)); + s->sioc = NULL; return ret; } if (s->x_dirty_bitmap && !s->info.base_allocation) { @@ -1498,8 +1506,6 @@ static int nbd_client_handshake(BlockDriverState *bs, QIOChannelSocket *sioc, } } - s->sioc = sioc; - if (!s->ioc) { s->ioc = QIO_CHANNEL(sioc); object_ref(OBJECT(s->ioc)); @@ -1520,6 +1526,7 @@ static int nbd_client_handshake(BlockDriverState *bs, QIOChannelSocket *sioc, nbd_send_request(s->ioc ?: QIO_CHANNEL(sioc), &request); object_unref(OBJECT(sioc)); + s->sioc = NULL; return ret; }