From: Jens Axboe <jaxboe@fusionio.com>
Subject: Re: fio test triggering bad data on ext4
Date: Fri, 18 Jun 2010 17:13:35 +0200
Message-ID: <4C1B8D1F.3020002@fusionio.com>
References: <4C1B292C.2080205@fusionio.com> <4C1B7C73.505@redhat.com> <4C1B89C1.6090408@redhat.com>
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Cc: "tytso@mit.edu" <tytso@mit.edu>,
	"adilger@sun.com" <adilger@sun.com>,
	"linux-ext4@vger.kernel.org" <linux-ext4@vger.kernel.org>
To: Eric Sandeen <sandeen@redhat.com>
In-Reply-To: <4C1B89C1.6090408@redhat.com>
Sender: linux-ext4-owner@vger.kernel.org

On 18/06/10 16.59, Eric Sandeen wrote:
> Eric Sandeen wrote:
>> Jens Axboe wrote:
>>> Hi,
>>>
>>> I was writing a small fio job file to do writes and read verifies on a
>>> device. It forks 32 processes, each writing randomly to 4 files with a
>>> block size between 4k and 16k. When it has written 1024 of those blocks,
>>> it'll verify the oldest 512 of them. Each block is checksummed for every
>>> 512b. It uses libaio and O_DIRECT.
>>>
>>> It works on ext2 and btrfs. I haven't run it to completion yet, but they
>>> survive 15-20 minutes just fine. ext4 doesn't even go a full minutes
>>> before this triggers:
>>
>> Jens, can you try XFS too?  Since ext3 can't do direct IO to a hole,
>> (and I'm not sure about btrfs in that regard), ext4 may be most similar
>> to xfs's behavior on the test ... wondering how it fares.
>>
>> Thanks,
>> -Eric
> 
> Actually mingming had a patch for direct-io.c which may be related, I'll
> test that out.

OK, I'll try XFS tonight as well.


-- 
Jens Axboe