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 X-Spam-Level: X-Spam-Status: No, score=-3.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 6DAA8C10F00 for ; Wed, 27 Mar 2019 10:44:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3E2212075C for ; Wed, 27 Mar 2019 10:44:18 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=nexedi.com header.i=kirr@nexedi.com header.b="VWxiXXnw"; dkim=pass (1024-bit key) header.d=mandrillapp.com header.i=@mandrillapp.com header.b="AH1f0e4B" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732994AbfC0KoR (ORCPT ); Wed, 27 Mar 2019 06:44:17 -0400 Received: from mail177-9.suw61.mandrillapp.com ([198.2.177.9]:58519 "EHLO mail177-9.suw61.mandrillapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731920AbfC0KoR (ORCPT ); Wed, 27 Mar 2019 06:44:17 -0400 X-Greylist: delayed 903 seconds by postgrey-1.27 at vger.kernel.org; Wed, 27 Mar 2019 06:44:15 EDT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; s=mandrill; d=nexedi.com; h=From:Subject:To:Cc:Message-Id:Date:MIME-Version:Content-Type:Content-Transfer-Encoding; i=kirr@nexedi.com; bh=bLuekUlqFzmIMmKwsu2eKGF+DvRjbJugn49IAZaBu1U=; b=VWxiXXnwPpstW87eztkVrNWo4VcQN6zHTreOgoyDkd2iiHcs1yuk6R2GetZHH3ZOPUKllHVWugpU Rjh7YPGugvh4/T3jXa4uX0n2HQgWA8SjupqcvwbAzaaPxKAnfMcGe0capaW44YNKp1uAUy+AeBwh yxRZFeSzVF3+RIhhnn8= Received: from pmta06.mandrill.prod.suw01.rsglab.com (127.0.0.1) by mail177-9.suw61.mandrillapp.com id hjd9vu22rtkl for ; Wed, 27 Mar 2019 10:15:11 +0000 (envelope-from ) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mandrillapp.com; i=@mandrillapp.com; q=dns/txt; s=mandrill; t=1553681710; h=From : Subject : To : Cc : Message-Id : Date : MIME-Version : Content-Type : Content-Transfer-Encoding : From : Subject : Date : X-Mandrill-User : List-Unsubscribe; bh=bLuekUlqFzmIMmKwsu2eKGF+DvRjbJugn49IAZaBu1U=; b=AH1f0e4B+b8NqhkppkfIieo+E4+JTWEtpqWhX7AAJWEu5K2nYZG63rgyGq9EferUqkJtED YRkPxiJi6F5WMLc+OyXuVSPmlgg0mOGtR44mR176MFatajP4ameWJ0Lpc6YhutZAMlSIb9r0 jS3w8VrdO3ZSX52vkh4DatTnPxNGM= From: Kirill Smelkov Subject: [RESEND4, PATCH 0/2] fuse: don't stuck clients on retrieve_notify with size > max_write Received: from [87.98.221.171] by mandrillapp.com id 564054d134c84745a56a85a2885f50b3; Wed, 27 Mar 2019 10:15:10 +0000 X-Mailer: git-send-email 2.21.0.392.gf8f6787159 To: Miklos Szeredi , Miklos Szeredi Cc: Han-Wen Nienhuys , Jakob Unterwurzacher , Kirill Tkhai , Andrew Morton , , , , Kirill Smelkov Message-Id: X-Report-Abuse: Please forward a copy of this message, including all headers, to abuse@mandrill.com X-Report-Abuse: You can also report abuse here: http://mandrillapp.com/contact/abuse?id=31050260.564054d134c84745a56a85a2885f50b3 X-Mandrill-User: md_31050260 Date: Wed, 27 Mar 2019 10:15:10 +0000 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org Miklos, On Thu, Mar 14, 2019 at 01:45:20PM +0300, Kirill Smelkov wrote: > Miklos, > > On Thu, Feb 28, 2019 at 02:47:57PM +0300, Kirill Smelkov wrote: > > On Thu, Feb 28, 2019 at 09:10:15AM +0100, Miklos Szeredi wrote: > > > On Wed, Feb 27, 2019 at 9:39 PM Kirill Smelkov wrote: > > > > > > > I more or less agree with this statement. However can we please make the > > > > breakage to be explicitly visible with an error instead of exhibiting it > > > > via harder to debug stucks/deadlocks? For example sys_read < max_write > > > > -> error instead of getting stuck. And if notify_retrieve requests > > > > buffer larger than max_write -> error or cut to max_write, but don't > > > > return OK when we know we will never send what was requested to > > > > filesystem even if it uses max_write sized reads. What is the point of > > > > breaking in hard to diagnose way when we can make the breakage showing > > > > itself explicitly? Would a patch for such behaviour accepted? > > > > > > Sure, if it's only adds a couple of lines. Adding more than say ten > > > lines for such a non-bug fix is definitely excessive. > > > > Ok, thanks. Please consider applying the following patch. (It's a bit > > pity to hear the problem is not considered to be a bug, but anyway). > > > > I will also send the second patch as another mail, since I could not > > made `git am --scissors` to apply several patched extracted from one > > mail successfully. > > [...] > > On Thu, Mar 07, 2019 at 12:34:21PM +0300, Kirill Smelkov wrote: > > Ping. Miklos, is there anything wrong with this patch and its > > second counterpart? > > As we were talking here are those patches. The first one cuts notify_retrieve > request to max_write and is one line only. The second one returns error to > filesystem server if it is buggy and does sys_read with buffer size < > max_write. It is 2 lines of code and 7 lines of comments. > > I still think that the patches fix real bugs. It is a bug if server behaviour > is a bit non-confirming or simply on an edge of being correct or questionable, > and instead of properly getting plain error from kernel, the whole system gets > stuck. It is a bug because bug amplification factor here is at least one order > of magnitude instead of staying ~1x. > > I'm sending the patches for the third time already, but did not get any > feedback. Could you please have a look? It's been ~ 1 month already since we agreed on the approach and initial postings of the patches that follow the agreed way: https://lwn.net/ml/linux-fsdevel/20190228114757.GA2796@deco.navytux.spb.ru/ Since then the patches were resent several times but without getting any feedback from you. Is there anything wrong with the patches? Could you please have a look? I understand everyone is busy but 1 month seems to be too much and I'm wondering whether maybe my mails got classified as spam or something else on your side. Thanks beforehand, Kirill Kirill Smelkov (2): fuse: retrieve: cap requested size to negotiated max_write fuse: require /dev/fuse reads to have enough buffer capacity as negotiated fs/fuse/dev.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) -- 2.21.0.392.gf8f6787159