From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lists1p.gnu.org (lists1p.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F19FA606A326 for ; Fri, 6 Nov 2026 19:45:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=RCXRvtoM Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1xPPsD-0000QR-Ql; Fri, 06 Nov 2026 14:45:17 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1xPPsB-0000K5-EE for qemu-devel@nongnu.org; Fri, 06 Nov 2026 14:45:16 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1xPPs6-0002yR-29 for qemu-devel@nongnu.org; Fri, 06 Nov 2026 14:45:11 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1793994309; 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: in-reply-to:in-reply-to:references:references; bh=vcR7lqOr17mWcbq0I6A8LV3Zm+LBQOuQyKftA8nUB2A=; b=RCXRvtoMyTdWJqVroaUkwFB3j5ilkNwOF9Mgf/f/ARjpZo1YGnjT9erWXDMTIlc0coRH30 nyQmraomC4eD5xx9EAQxP6jUDsPaXwQhyiIQNvX4KAiBvo3IBskjpfOjxYQG/wYgbwGwaM TqgL8AybHpGHuR2wh5j6TuCJYXxybvs= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-465-SdlUO_KLOGWSe0mCwnvO-g-1; Fri, 06 Nov 2026 14:45:06 -0500 X-MC-Unique: SdlUO_KLOGWSe0mCwnvO-g-1 X-Mimecast-MFC-AGG-ID: SdlUO_KLOGWSe0mCwnvO-g_1793994305 Received: from mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.12]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id B22001800559; Fri, 6 Nov 2026 19:45:04 +0000 (UTC) Received: from redhat.com (headnet04.pony-001.prod.iad2.dc.redhat.com [10.2.32.116]) by mx-prod-int-03.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 0A71A195608C; Fri, 6 Nov 2026 19:45:02 +0000 (UTC) Date: Fri, 6 Nov 2026 13:45:00 -0600 From: Eric Blake To: Guillaume Vincke Cc: qemu-devel@nongnu.org, qemu-block@nongnu.org, Vladimir Sementsov-Ogievskiy , Kevin Wolf , Hanna Reitz Subject: Re: [PATCH v3 0/2] nbd/client-connection: Fix client returning a closed channel Message-ID: References: <20261105164124.249395-1-guillaume.vincke@ovhcloud.com> X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261105164124.249395-1-guillaume.vincke@ovhcloud.com> User-Agent: NeoMutt/20260616 X-Scanned-By: MIMEDefang 3.0 on 10.30.177.12 Received-SPF: pass client-ip=170.10.129.124; envelope-from=eblake@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H5=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: qemu development List-Archive: List-Post: List-Help: List-Subscribe: , Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org X-Spam-Status: No, score=-7.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On Thu, Nov 05, 2026 at 05:41:22PM +0100, Guillaume Vincke wrote: > NBD client relies on lazy reconnection on error. There is a case where > nbd_co_establish_connection() will hand back a channel disconnected by > its peer. This leads to the request running on the dead channel. When > reconnect-delay is set to 0 (the default), this bug prevents the > nbd-connect thread from running on the first operation. This patch set > addresses this specific case. > > > v3 does not use a more robust method than sleeping to wait for the NBD > client to reach the desired state. An option would be to add a QMP > unstable debug query reporting the NBD client state and whether the > connect thread has a channel ready. The test would poll this instead of > sleeping. Would that be an acceptable follow-up? I think an unstable query for current NBD server state (is the server up, and if so, which exports is it serving and what is the state of all client(s) attached to each server) would indeed make sense. That will probably miss this release, but I still think this series is okay for now. Queueing it up as a bug fix, for my upcoming pull request intended to make it into rc0. -- Eric Blake, Principal Software Engineer Red Hat, Inc. Virtualization: qemu.org | libguestfs.org