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From: Shentino <shentino@gmail.com>
To: dave@jikos.cz, Shentino <shentino@gmail.com>,
	Michael <mike@draftx.net>, cwillu <cwillu@cwillu.com>,
	linux-btrfs@vger.kernel.org
Subject: Re: rfc: fuzz testing by direct writes to device
Date: Sun, 2 Sep 2012 04:43:48 -0700	[thread overview]
Message-ID: <CAGDaZ_r1zZWGh5riLnNnZR8raZZQNwSe0qSNgY3BaBWN-A9Fbg@mail.gmail.com> (raw)
In-Reply-To: <20120902054410.GG17430@twin.jikos.cz>

On Sat, Sep 1, 2012 at 10:44 PM, David Sterba <dave@jikos.cz> wrote:
> On Sat, Sep 01, 2012 at 06:03:32PM -0700, 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?
>
> Starting with kernels 3.4 the error handling has been improved,
> namely for the EIO, so it shouldn't take your box down when you hit one.
> Newer kernels got fixes to the 'transaction abort' cleanup, so it should
> be possible to umount and mount the filesystem without problems.
>
> The filesystem should survive shooting at blocks, the checksums catch
> any change (with respect to it's strength, ie. generating a hash
> collision will lead to crash/abort later).
>
> Expected result for reading blocks after random writes is:
> * EIO for the corrupted block (both data or metadata) provided that
>   there's no other copy
> * transparent and automatic repair from other copies

I assume the same results are expected during a scrub as during a normal read?

> I've tested this on an 2 disk data/raid1, metadata/raid1 with a running
> dd over one of the devices continually and using the filesystem. It was
> slower.
>
>
> david

Would I be correct to assume that a core dump on fsck is an automatic
bug or is using the old 3.3.8 kernel a taint that would invalidate a
report?  Note that this is for the btrfs-progs containing the fsck,
not the actual kernel side code.

  reply	other threads:[~2012-09-02 11:44 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 [this message]
2012-09-05 15:04                   ` David Sterba
2012-09-05 21:23                     ` Shentino
2012-09-04 18:15               ` Goffredo Baroncelli
2012-09-05  1:59                 ` Shentino
2012-09-05  5:46                   ` Goffredo Baroncelli

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