From owner-freebsd-stable@FreeBSD.ORG  Wed Mar 10 17:42:47 2010
Return-Path: <owner-freebsd-stable@FreeBSD.ORG>
Delivered-To: freebsd-stable@FreeBSD.org
Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34])
	by hub.freebsd.org (Postfix) with ESMTP id D6E781065670;
	Wed, 10 Mar 2010 17:42:47 +0000 (UTC) (envelope-from avg@icyb.net.ua)
Received: from citadel.icyb.net.ua (citadel.icyb.net.ua [212.40.38.140])
	by mx1.freebsd.org (Postfix) with ESMTP id ACC468FC20;
	Wed, 10 Mar 2010 17:42:46 +0000 (UTC)
Received: from odyssey.starpoint.kiev.ua (alpha-e.starpoint.kiev.ua
	[212.40.38.101])
	by citadel.icyb.net.ua (8.8.8p3/ICyb-2.3exp) with ESMTP id TAA18018;
	Wed, 10 Mar 2010 19:42:44 +0200 (EET) (envelope-from avg@icyb.net.ua)
Message-ID: <4B97DA13.1040900@icyb.net.ua>
Date: Wed, 10 Mar 2010 19:42:43 +0200
From: Andriy Gapon <avg@icyb.net.ua>
User-Agent: Thunderbird 2.0.0.23 (X11/20100211)
MIME-Version: 1.0
To: Pawel Jakub Dawidek <pjd@FreeBSD.org>
References: <864468D4-DCE9-493B-9280-00E5FAB2A05C@lassitu.de>	<20100309122954.GE3155@garage.freebsd.pl>	<EC9BC6B4-8D0E-4FE3-852F-0E3A24569D33@sarenet.es>	<20100309125815.GF3155@garage.freebsd.pl>	<CB854F58-03AF-46DD-8153-85FA96037C21@sarenet.es>	<BFF1E2D6-B48A-4A5E-ACEE-8577FDB07820@sarenet.es>	<20100310110202.GA1715@garage.freebsd.pl>	<E04F91AA-B2C4-4166-A24A-74F1BEF01519@sarenet.es>
	<20100310173143.GD1715@garage.freebsd.pl>
In-Reply-To: <20100310173143.GD1715@garage.freebsd.pl>
X-Enigmail-Version: 0.95.7
Content-Type: text/plain; charset=KOI8-U
Content-Transfer-Encoding: 7bit
Cc: freebsd-fs@FreeBSD.org, FreeBSD Stable <freebsd-stable@FreeBSD.org>,
	Borja Marcos <borjam@sarenet.es>
Subject: Re: Many processes stuck in zfs
X-BeenThere: freebsd-stable@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Production branch of FreeBSD source code <freebsd-stable.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-stable>, 
	<mailto:freebsd-stable-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-stable>
List-Post: <mailto:freebsd-stable@freebsd.org>
List-Help: <mailto:freebsd-stable-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-stable>,
	<mailto:freebsd-stable-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Wed, 10 Mar 2010 17:42:47 -0000

on 10/03/2010 19:31 Pawel Jakub Dawidek said the following:
> This should be impossible. If we are that deep in zfsvfs_teardown(), it means
> that we hold the z_teardown_lock exclusively. And we do as 'show alllocks'
> output confirms. But if we are holding this lock exclusively we shouldn't be
> that deep in create code path, because we need hold this lock as reader.
> It isn't visible in 'show alllocks' output, because this lock is special
> (rrwlock.c).

BTW, it seems that our 'stock' rwlock implements exactly the same thing as
rrwlock.c - recursive readers, etc.

-- 
Andriy Gapon