From owner-svn-src-head@freebsd.org Thu Jan 21 15:03:27 2016 Return-Path: Delivered-To: svn-src-head@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id C236DA8BA95; Thu, 21 Jan 2016 15:03:27 +0000 (UTC) (envelope-from asomers@gmail.com) Received: from mail-ob0-x22d.google.com (mail-ob0-x22d.google.com [IPv6:2607:f8b0:4003:c01::22d]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 9106519E7; Thu, 21 Jan 2016 15:03:27 +0000 (UTC) (envelope-from asomers@gmail.com) Received: by mail-ob0-x22d.google.com with SMTP id ba1so37306662obb.3; Thu, 21 Jan 2016 07:03:27 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=pJVUr4ZA7JsTZaIuXnwBckT8Y9pT+VJe2kV/Mx0HKXE=; b=cODrBoUCJfcX3c2binrUruHA7IX/1b1Nv/kcbHq1zb6Id4zC0gbm7BscyzKknjniG3 5QRLNb4hadnP8+CBdqWmbFbuY0wqvcIKK38DgGTZ8a1fdT9X/HUE3srrMfMbFFUeD2na 8nISGVaFXoK864jZaOm9ONIuyUwbUC72R6xZ26nRSGbkqSJUo+O1UcOFWCNN6pP1izPq kpLLfvLuO5eF1YoUq4BzbMhnOqAUk4zIHw4xSFNSQ17fMApUq3ZXL9y+vMuHDxlc3jOD vPBr8FRqGIark32WphIEsN1R36bZYhOdQV1EON8bLRgkopZJc6CyIuAxAXhjGHc+kVS2 J4hQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:date :message-id:subject:from:to:cc:content-type; bh=pJVUr4ZA7JsTZaIuXnwBckT8Y9pT+VJe2kV/Mx0HKXE=; b=CX2rTWJJN1xYf5REP3PjmzNpeQo1O3Nqf/o34l9FMrT7gpTw9jfmWLd7OsZV+K7WuS xBDYqVXclsi3D2w84QJG+8MrUiuzPT7Zd2jc9SuAKBaTV9saD+Bcsm7tC5X04g17F1PJ A8Co1TSR5aC1S+wLExKWEohC779UY/20/LPAicE3a0VfwMPtxegRKcoX29bMKZt8KLgS ZSvVWyAmP2HiZKYxhkIOxXTPWBg/svcFNsjHqeq89AXrF7oZIpsmDjczdn6Cdf/IG0fx b6kr/Jq869SeAkUwZwXwaLA3H0zqSzEadNh3p6XoLhRa44oKS7fObdJgMNKSEJombohn IlVw== X-Gm-Message-State: ALoCoQnQ8XT+ZndBT5EXeobeXxif10fraMpe9pI9em2GgpVvEaR03ZDp2hxEb0ij6xlOlPtYnZMYHkLD90dZLsUpXpzYVNH89Q== MIME-Version: 1.0 X-Received: by 10.60.67.34 with SMTP id k2mr32659868oet.67.1453388605707; Thu, 21 Jan 2016 07:03:25 -0800 (PST) Received: by 10.202.69.84 with HTTP; Thu, 21 Jan 2016 07:03:25 -0800 (PST) In-Reply-To: <20160121113813.GG37895@zxy.spb.ru> References: <201601191700.u0JH0P6k061610@repo.freebsd.org> <569E6DA0.9010300@pix.net> <569F516D.80303@FreeBSD.org> <56A019A1.4030900@FreeBSD.org> <20160121113813.GG37895@zxy.spb.ru> Date: Thu, 21 Jan 2016 08:03:25 -0700 Message-ID: Subject: Re: svn commit: r294329 - in head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs: . sys From: alan somers To: Slawa Olhovchenkov Cc: Andriy Gapon , Alan Somers , "svn-src-head@freebsd.org" , "svn-src-all@freebsd.org" , "src-committers@freebsd.org" Content-Type: text/plain; charset=UTF-8 X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 21 Jan 2016 15:03:28 -0000 On Thu, Jan 21, 2016 at 4:38 AM, Slawa Olhovchenkov wrote: > On Thu, Jan 21, 2016 at 01:34:57AM +0200, Andriy Gapon wrote: > >> On 20/01/2016 22:03, Alan Somers wrote: >> > On Wed, Jan 20, 2016 at 2:20 AM, Andriy Gapon wrote: >> >> On 19/01/2016 19:20, Alan Somers wrote: >> >>> The thing is, it never really worked in the first place. Panics and >> >>> deadlocks are so frequent that I don't think the feature was usable >> >>> for anybody. >> >> >> >> The feature is perfectly usable for me. I have never run into the problems that >> >> you describe. Why not fix the real bugs that you've run into? >> > >> > Spectra Logic and iXSystems both experienced many problems with this. >> > The worst is a deadlock that can be triggered simply by pulling a >> > drive from a redundant pool when there exists a zvol anywhere in the >> > system (see https://reviews.freebsd.org/D4998 for a quick way to >> > reproduce). Fixing it correctly would likely require far more time >> > than I have available. I just want the bugs to go away. See that >> > same code review for a change to make the feature optional. >> >> I think that we all want all the bugs to go way. One way to remove bugs is to >> remove (disable) code that contains bugs. That way the perfect bug-free >> software is clearly achievable :-) Unfortunately, that technique is not always >> welcomed. >> >> P.S. >> I think that the real problem here is that a method of a geom must never drop >> topology_lock. In other words, the GEOM management code (like g_xxx() stuff in >> geom_subr.c) expects that a topology can not change underneath it. But >> zvol_geom_access() clearly breaks that contract. > > May be same cause problem with swap on zvol (don't test on latest > -stable)? I'm not familiar with that problem. Is there a PR?