Date: Mon, 11 Mar 2013 15:41:59 -0400
From: Dave Jones <davej@redhat.com>
To: Markus Trippelsdorf <markus@trippelsdorf.de>
Cc: linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: torrent hash failures since 3.9.0-rc1
Message-ID: <20130311194159.GB3579@redhat.com>
Mail-Followup-To: Dave Jones <davej@redhat.com>,
	Markus Trippelsdorf <markus@trippelsdorf.de>,
	linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20130311171824.GA434@x4>
 <20130311191753.GA439@x4>
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On Mon, Mar 11, 2013 at 08:17:53PM +0100, Markus Trippelsdorf wrote:
 > On 2013.03.11 at 18:18 +0100, Markus Trippelsdorf wrote:
 > > I get hash failures on "completed" torrents since 3.9.0-rc1 (Linux 3.8
 > > seems to be fine). What happens is that the torrents apparently complete
 > > successfully. After reboot however the hash check fails and there are
 > > missing (or corrupted) chunks. I've tested this with two different
 > > clients (rtorrent and aria2c) and both are affected. So I think this
 > > might be a filesystem issue.
 > > 
 > > /dev/sda       ext4      1.4T  666G  640G  51% /var
 > > /dev/sda on /var type ext4 (rw,noatime,data=ordered)
 > > 
 > > I use ECC memory (and there is nothing in the logs).
 > 
 > To reproduce this issue just do the following:
 > 
 >  % wget http://torrents.linuxmint.com/torrents/linuxmint-12-gnome-cd-nocodecs-64bit.iso.torrent
 >  % rtorrent linuxmint-12-gnome-cd-nocodecs-64bit.iso.torrent
 >  (Wait until the torrent finishes)
 >  % sudo echo 3 > /proc/sys/vm/drop_caches
 >  (Rehash the torrent (Ctrl-R))
 >  The torrent doesn't rehash successfully and a few hunks are
 >  missing/corrupted and need to be downloaded again.

Worked fine for me on two separate machines.  Could it be a network problem
perhaps ? If something is mangling the packet before it hits the disk,
that would explain it.  What NIC do you use ?

Or maybe you could isolate it to a filesystem problem using something
like fsx ?

	Dave

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