From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EC6AAC433EF for ; Fri, 12 Nov 2021 07:41:08 +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 3071660FDA for ; Fri, 12 Nov 2021 07:41:08 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 3071660FDA Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=yandex-team.ru Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:46536 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mlRBL-0000Nl-3v for qemu-devel@archiver.kernel.org; Fri, 12 Nov 2021 02:41:07 -0500 Received: from eggs.gnu.org ([209.51.188.92]:53226) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mlR9a-0007xO-9o; Fri, 12 Nov 2021 02:39:18 -0500 Received: from forwardcorp1p.mail.yandex.net ([77.88.29.217]:57268) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mlR9V-0004ea-BP; Fri, 12 Nov 2021 02:39:16 -0500 Received: from iva8-d2cd82b7433e.qloud-c.yandex.net (iva8-d2cd82b7433e.qloud-c.yandex.net [IPv6:2a02:6b8:c0c:a88e:0:640:d2cd:82b7]) by forwardcorp1p.mail.yandex.net (Yandex) with ESMTP id DFEC42E0B07; Fri, 12 Nov 2021 10:39:08 +0300 (MSK) Received: from iva4-f06c35e68a0a.qloud-c.yandex.net (iva4-f06c35e68a0a.qloud-c.yandex.net [2a02:6b8:c0c:152e:0:640:f06c:35e6]) by iva8-d2cd82b7433e.qloud-c.yandex.net (mxbackcorp/Yandex) with ESMTP id ZbbLIKGWKU-d8sCfUw5; Fri, 12 Nov 2021 10:39:08 +0300 Precedence: bulk DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yandex-team.ru; s=default; t=1636702748; bh=Lt8QaS7rkJ5Szggn8spjr84PEPVWgIjMt+syl8kOpvw=; h=In-Reply-To:Subject:To:From:Message-ID:Cc:References:Date; b=EKfG//ZjCs4lYX27+98QzsEjSZbEstXB4MqJOiD/S3xqyiViNYhco8ech0lKZigRi C1IEBwU1Ap+9bjLuJNu4EEkXSVY5WKu7aly7QY5FwqqBkfSBJTrz0RZKuIzzjqntMF ZuAmqOo5cvAk3NmQ/wcqDL1IXxNCetGMZoSVuxJA= Authentication-Results: iva8-d2cd82b7433e.qloud-c.yandex.net; dkim=pass header.i=@yandex-team.ru Received: from rvkaganb.lan (dynamic-vpn.dhcp.yndx.net [2a02:6b8:b081:14::1:32]) by iva4-f06c35e68a0a.qloud-c.yandex.net (smtpcorp/Yandex) with ESMTPS id iMLHFcLKBQ-d7xeEaAd; Fri, 12 Nov 2021 10:39:08 +0300 (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (Client certificate not present) X-Yandex-Fwd: 2 Date: Fri, 12 Nov 2021 10:39:06 +0300 From: Roman Kagan To: Kevin Wolf Subject: Re: [PATCH 01/10] vhost-user-blk: reconnect on any error during realize Message-ID: Mail-Followup-To: Roman Kagan , Kevin Wolf , qemu-devel@nongnu.org, qemu-block@nongnu.org, "Michael S. Tsirkin" , Hanna Reitz , yc-core@yandex-team.ru, =?iso-8859-1?Q?Marc-Andr=E9?= Lureau , Paolo Bonzini References: <20211111153354.18807-1-rvkagan@yandex-team.ru> <20211111153354.18807-2-rvkagan@yandex-team.ru> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Received-SPF: pass client-ip=77.88.29.217; envelope-from=rvkagan@yandex-team.ru; helo=forwardcorp1p.mail.yandex.net X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: qemu-block@nongnu.org, "Michael S. Tsirkin" , qemu-devel@nongnu.org, Hanna Reitz , yc-core@yandex-team.ru, Paolo Bonzini , =?iso-8859-1?Q?Marc-Andr=E9?= Lureau Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Thu, Nov 11, 2021 at 06:52:30PM +0100, Kevin Wolf wrote: > Am 11.11.2021 um 16:33 hat Roman Kagan geschrieben: > > vhost-user-blk realize only attempts to reconnect if the previous > > connection attempt failed on "a problem with the connection and not an > > error related to the content (which would fail again the same way in the > > next attempt)". > > > > However this distinction is very subtle, and may be inadvertently broken > > if the code changes somewhere deep down the stack and a new error gets > > propagated up to here. > > > > OTOH now that the number of reconnection attempts is limited it seems > > harmless to try reconnecting on any error. > > > > So relax the condition of whether to retry connecting to check for any > > error. > > > > This patch amends a527e312b5 "vhost-user-blk: Implement reconnection > > during realize". > > > > Signed-off-by: Roman Kagan > > It results in less than perfect error messages. With a modified export > that just crashes qemu-storage-daemon during get_features, I get: > > qemu-system-x86_64: -device vhost-user-blk-pci,chardev=c: Failed to read msg header. Read 0 instead of 12. Original request 1. > qemu-system-x86_64: -device vhost-user-blk-pci,chardev=c: Reconnecting after error: vhost_backend_init failed: Protocol error > qemu-system-x86_64: -device vhost-user-blk-pci,chardev=c: Reconnecting after error: Failed to connect to '/tmp/vsock': Connection refused > qemu-system-x86_64: -device vhost-user-blk-pci,chardev=c: Reconnecting after error: Failed to connect to '/tmp/vsock': Connection refused > qemu-system-x86_64: -device vhost-user-blk-pci,chardev=c: Failed to connect to '/tmp/vsock': Connection refused This patch doesn't change any error messages. Which ones specifically became less than perfect as a result of this patch? > I guess this might be tolerable. On the other hand, the patch doesn't > really fix anything either, but just gets rid of possible subtleties. The remaining patches in the series make other errors beside -EPROTO propagate up to this point, and some (most) of them are retryable. This was the reason to include this patch at the beginning of the series (I guess I should've mentioned that in the patch log). Thanks, Roman.