From owner-freebsd-fs@FreeBSD.ORG Mon Dec 16 15:52:36 2013 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id D8409903; Mon, 16 Dec 2013 15:52:36 +0000 (UTC) Received: from krichy.tvnetwork.hu (unknown [IPv6:2a01:be00:0:2::10]) by mx1.freebsd.org (Postfix) with ESMTP id 9A9631C90; Mon, 16 Dec 2013 15:52:36 +0000 (UTC) Received: by krichy.tvnetwork.hu (Postfix, from userid 1000) id 74237615C; Mon, 16 Dec 2013 16:52:16 +0100 (CET) Received: from localhost (localhost [127.0.0.1]) by krichy.tvnetwork.hu (Postfix) with ESMTP id 7243A615B; Mon, 16 Dec 2013 16:52:16 +0100 (CET) Date: Mon, 16 Dec 2013 16:52:16 +0100 (CET) From: krichy@tvnetwork.hu To: pjd@freebsd.org Subject: Re: kern/184677 (fwd) Message-ID: User-Agent: Alpine 2.10 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Cc: freebsd-fs@freebsd.org X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.17 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 16 Dec 2013 15:52:36 -0000 Dear PJD, I am a happy FreeBSD user, I am sure you've read my previous posts regarding some issues in ZFS. Please give some advice for me, where to look for solutions, or how could I help to resolve those issues. Regards, Kojedzinszky Richard Euronet Magyarorszag Informatikai Zrt. ---------- Forwarded message ---------- Date: Mon, 16 Dec 2013 15:23:06 +0100 (CET) From: krichy@tvnetwork.hu To: freebsd-fs@freebsd.org Subject: Re: kern/184677 Seems that pjd did a change which eliminated the zfsdev_state_lock on Fri Aug 12 07:04:16 2011 +0000, which might introduced a new deadlock situation. Any comments on this? Kojedzinszky Richard Euronet Magyarorszag Informatikai Zrt. On Mon, 16 Dec 2013, krichy@tvnetwork.hu wrote: > Date: Mon, 16 Dec 2013 11:08:11 +0100 (CET) > From: krichy@tvnetwork.hu > To: freebsd-fs@freebsd.org > Subject: kern/184677 > > Dear devs, > > I've attached a patch, which makes the recursive lockmgr disappear, and makes > the reported bug to disappear. I dont know if I followed any guidelines well, > or not, but at least it works for me. Please some ZFS/FreeBSD fs expert > review it, and fix it where it needed. > > But unfortunately, my original problem is still not solved, maybe the same as > Ryan's: > http://lists.freebsd.org/pipermail/freebsd-fs/2013-December/018707.html > > Tracing the problem down is that zfsctl_snapdir_lookup() tries to acquire > spa_namespace_lock while when finishing a zfs send -R does a zfsdev_close(), > and that also holds the same mutex. And this causes a deadlock scenario. I > looked at illumos's code, and for some reason they use another mutex on > zfsdev_close(), which therefore may not deadlock with > zfsctl_snapdir_lookup(). But I am still investigating the problem. > > I would like to help making ZFS more stable on freebsd also with its whole > functionality. I would be very thankful if some expert would give some > advice, how to solve these bugs. PJD, Steven, Xin? > > Thanks in advance, > > > Kojedzinszky Richard > Euronet Magyarorszag Informatikai Zrt.