From mboxrd@z Thu Jan  1 00:00:00 1970
From: Josef Bacik <josef@redhat.com>
Subject: Re: Possible btrfs deadlock coused by commit 660d3f6c
Date: Mon, 16 Jan 2012 09:26:00 -0500
Message-ID: <20120116142540.GB8265@dhcp231-144.rdu.redhat.com>
References: <20120116085322.GB2105@redhat.com>
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Cc: Josef Bacik <josef@redhat.com>, Patrick <ragamuffin@datacomm.ch>,
	linux-btrfs@vger.kernel.org
To: Stanislaw Gruszka <sgruszka@redhat.com>
Return-path: <linux-btrfs-owner@vger.kernel.org>
In-Reply-To: <20120116085322.GB2105@redhat.com>
List-ID: <linux-btrfs.vger.kernel.org>

On Mon, Jan 16, 2012 at 09:53:23AM +0100, Stanislaw Gruszka wrote:
> Hi Josef,
> 
> commit 660d3f6cde552323578b85fc5a09a6742f1fe804
> Author: Josef Bacik <josef@redhat.com>
> Date:   Fri Dec 9 11:18:51 2011 -0500
> 
>     Btrfs: fix how we do delalloc reservations and how we free reservations on error
> 
> introduced possible deadlock. According to comment before
> btrfs_page_mkwrite(), that function is not allowed to take
> node->i_mutex .
> 
> The problem was detected by Patrick (full lockdep info is provided):
> http://bugzilla.kernel.org/attachment.cgi?id=72072
> during investigating of some other issue (kernel.org bug 42576)
> 

It's not a deadlock since you can't mmap a directory, but I posted a fix for
this to linux-btrfs last week, afaik it's headed to -rc1.  Thanks,

Joesf