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From: Goffredo Baroncelli <kreijack@libero.it>
To: Shentino <shentino@gmail.com>
Cc: Michael <mike@draftx.net>, cwillu <cwillu@cwillu.com>,
	linux-btrfs@vger.kernel.org
Subject: Re: rfc: fuzz testing by direct writes to device
Date: Tue, 04 Sep 2012 20:15:08 +0200	[thread overview]
Message-ID: <5046452C.7090804@libero.it> (raw)
In-Reply-To: <CAGDaZ_qD-RHvZk31GYZRTAjUNJ4dTm1wXk1kQELE2p+=xG3yzA@mail.gmail.com>

Hi,

On 09/02/2012 03:03 AM, Shentino wrote:
> This whole subject was also about using sed to corrupt-o-magic a
> file's data on disk.
>
> Is this an acceptable method for testing?


I am not sure that doing "sed </dev/sdX >/dev/sdX ..." is the right 
thing to do, because it rewrites the full disk. This means that:
- it takes a lot of time
- you don't have any control about which part of the disk you change: 
what happens if sed write a block which is update in parallel by BTRFS ?

Anyway I suggest to give a look to the following video [1], which 
explains the automatic repair. Moreover it shows [2] how corrupt a block 
with the "btrfs-corrupt-block" command.

Hoping that this helps you.

BR
G.Baroncelli

[1] http://www.youtube.com/watch?v=hxWuaozpe2I
[2] See minute 17:52 of the video above

>
> On Sat, Sep 1, 2012 at 4:49 PM, Michael<mike@draftx.net>  wrote:
>> It should not. It is always preferred that you dd your drive onto
>> another disk just in case though.
>>
>> On Sat, Sep 1, 2012 at 5:31 PM, Shentino<shentino@gmail.com>  wrote:
>>> On Sat, Sep 1, 2012 at 1:59 PM, cwillu<cwillu@cwillu.com>  wrote:
>>>> You still haven't said which kernel you were running; the thing to do
>>>> is try the very latest rc (if not btrfs-next).
>>>
>>> Sorry about that!
>>>
>>> I thought I included it.
>>>
>>> 3.3.8
>>>
>>> Hmm...seems it's been EOL'ed.  I need to yell at my distro.
>>>
>>> In the meantime, will mounting a btrfs filesystem with a new kernel
>>> render it unmountable by older kernels?
> --
> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
> the body of a message to majordomo@vger.kernel.org
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> .
>


  parent reply	other threads:[~2012-09-04 18:14 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-09-01  6:44 rfc: fuzz testing by direct writes to device Shentino
2012-09-01  8:10 ` Shentino
2012-09-01 15:41   ` Michael
2012-09-01 17:23     ` Shentino
2012-09-01 20:59       ` cwillu
2012-09-01 22:31         ` Shentino
2012-09-01 23:49           ` Michael
2012-09-02  1:03             ` Shentino
2012-09-02  5:44               ` David Sterba
2012-09-02 11:43                 ` Shentino
2012-09-05 15:04                   ` David Sterba
2012-09-05 21:23                     ` Shentino
2012-09-04 18:15               ` Goffredo Baroncelli [this message]
2012-09-05  1:59                 ` Shentino
2012-09-05  5:46                   ` Goffredo Baroncelli

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