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Message-ID: <2e4afe1e0704230425vb66892la4cc3c2ef14a1470@mail.gmail.com>
Date: Mon, 23 Apr 2007 16:55:52 +0530
From: "Karuna sagar K" <karunasagark@gmail.com>
To: "Kalpak Shah" <kalpak@linsyssoft.com>
Subject: Re: Testing framework
Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
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On 4/23/07, Kalpak Shah <kalpak@linsyssoft.com> wrote:
> On Mon, 2007-04-23 at 02:16 +0530, Karuna sagar K wrote:

.....
>> The file system is looked upon as a set of blocks (more precisely
>> metadata blocks). We randomly choose from this set of blocks to
>> corrupt. Hence we would be able to overcome the deficiency of the
>> previous approach. However this approach makes it difficult to have a
>> replayable corruption. Further thought about this approach has to be
>> given.
>
> Fill a test filesystem with data and save it. Corrupt it by copying a
> chunk of data from random locations A to B. Save positions A and B so
> that you can reproduce the corruption.
>

Hey, thats a nice idea :). But, this woundnt reproduce the same
corruption right? Because, say, on first run of the tool there is
metadata stored at locations A and B and then on the second run there
may be user data present. I mean the allocation may be different.

> Or corrupt random bits (ideally in metadata blocks) and maintain the
> list of the bit numbers for reproducing the corruption.
>

.....
>> The corrupted file system is repaired and recovered with 'fsck' or any
>> other tools; this phase considers the repair and recovery action on
>> the file system as a black box. The time taken to repair by the tool
>> is measured
>
> I see that you are running fsck just once on the test filesystem. It
> might be a good idea to run it twice and if second fsck does not find
> the filesystem to be completely clean that means it is a bug in fsck.

You are right. Will modify that.

>
> <snip>
>

......
>> State of the either file system is stored, which may be huge, time
>> consuming and not necessary. So, we could have better ways of storing
>> the state.
>
> Also, people may want to test with different mount options, so something
> like "mount -t $fstype -o loop,$MOUNT_OPTIONS $imgname $mountpt" may be
> useful. Similarly it may also be useful to have MKFS_OPTIONS while
> formatting the filesystem.
>

Right. I didnt think of that. Will look into it.

> Thanks,
> Kalpak.
>
> >
> > Comments are welcome!!
> >
> > Thanks,
> > Karuna
>
>

Thanks,
Karuna