From owner-freebsd-fs@FreeBSD.ORG  Fri Jul 19 19:34:11 2013
Return-Path: <owner-freebsd-fs@FreeBSD.ORG>
Delivered-To: freebsd-fs@FreeBSD.org
Received: from mx1.freebsd.org (mx1.freebsd.org
 [IPv6:2001:1900:2254:206a::19:1])
 by hub.freebsd.org (Postfix) with ESMTP id 83BF578B
 for <freebsd-fs@FreeBSD.org>; Fri, 19 Jul 2013 19:34:11 +0000 (UTC)
 (envelope-from avg@FreeBSD.org)
Received: from citadel.icyb.net.ua (citadel.icyb.net.ua [212.40.38.140])
 by mx1.freebsd.org (Postfix) with ESMTP id CB4BDD76
 for <freebsd-fs@FreeBSD.org>; Fri, 19 Jul 2013 19:34:10 +0000 (UTC)
Received: from porto.starpoint.kiev.ua (porto-e.starpoint.kiev.ua
 [212.40.38.100])
 by citadel.icyb.net.ua (8.8.8p3/ICyb-2.3exp) with ESMTP id WAA12708;
 Fri, 19 Jul 2013 22:34:07 +0300 (EEST)
 (envelope-from avg@FreeBSD.org)
Received: from localhost ([127.0.0.1])
 by porto.starpoint.kiev.ua with esmtp (Exim 4.34 (FreeBSD))
 id 1V0GRL-000AKP-G5; Fri, 19 Jul 2013 22:34:07 +0300
Message-ID: <51E99477.1030308@FreeBSD.org>
Date: Fri, 19 Jul 2013 22:33:11 +0300
From: Andriy Gapon <avg@FreeBSD.org>
User-Agent: Mozilla/5.0 (X11; FreeBSD amd64;
 rv:17.0) Gecko/20130708 Thunderbird/17.0.7
MIME-Version: 1.0
To: Konstantin Belousov <kostikbel@gmail.com>
Subject: Re: Deadlock in nullfs/zfs somewhere
References: <CAJ-VmokR8jJpdRc_kBJzhW4_R1pJnj3UPfsG5ANpq-kEGwCP9g@mail.gmail.com>
 <51E67F54.9080800@FreeBSD.org>
 <CAJ-Vmonk2HAzX38-mbL8hwxiUfL6JyJrMTq0dTBctW=P4dfyEQ@mail.gmail.com>
 <51E7B686.4090509@FreeBSD.org> <20130718112814.GA5991@kib.kiev.ua>
 <51E7F05A.5020609@FreeBSD.org> <20130718185215.GE5991@kib.kiev.ua>
 <51E91277.3070309@FreeBSD.org> <20130719103025.GJ5991@kib.kiev.ua>
 <51E95CDD.7030702@FreeBSD.org> <20130719184243.GM5991@kib.kiev.ua>
In-Reply-To: <20130719184243.GM5991@kib.kiev.ua>
X-Enigmail-Version: 1.5.1
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
Cc: freebsd-fs@FreeBSD.org
X-BeenThere: freebsd-fs@freebsd.org
X-Mailman-Version: 2.1.14
Precedence: list
List-Id: Filesystems <freebsd-fs.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/options/freebsd-fs>,
 <mailto:freebsd-fs-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-fs>
List-Post: <mailto:freebsd-fs@freebsd.org>
List-Help: <mailto:freebsd-fs-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-fs>,
 <mailto:freebsd-fs-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Fri, 19 Jul 2013 19:34:11 -0000

on 19/07/2013 21:42 Konstantin Belousov said the following:
> Then, you cannot use VFS suspension.  Or, in other words, you are directed
> to abuse the VFS interface.  I assure you that any changes to the interface
> would not take into account such abuse and probably break your hack.

So what would be your recommendation about this problem?
Should we add another flavor of VFS suspension?
The one that would mean "all external accesses to this fs must be put on hold",
but would not imply "this fs is frozen".

-- 
Andriy Gapon