Ext3 users - Jan 2014 - File System corruption tool

Hi -

I'm searching for file system corruption tool, say it inject disk-errors
like
multiply owned blocks etc. Later an integrity scan process (like e2fsck)
will
verify on-disk layout and fix these errors.

I'd like to read/understand such tools before writing one for an proprietary
on-disk file system.

Do we have such tools for ext{2,3,4}fs ? Thanks for any help or pointers!

-- 
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Cheers,
Lakshmipathi.G
FOSS Programmer.
www.giis.co.in
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On 01/18/2014 07:13 AM, Lakshmipathi.G wrote:
> Hi -
>
> I'm searching for file system corruption tool, say it inject
disk-errors like
> multiply owned blocks etc. Later an integrity scan process (like e2fsck)
will
> verify on-disk layout and fix these errors.
>
> I'd like to read/understand such tools before writing one for an
proprietary
> on-disk file system.
>
> Do we have such tools for ext{2,3,4}fs ? Thanks for any help or pointers!
>
>
For s-ata drives, you can use hdparm to create a bad sector that will cause an 
IO error on read. (Write will fix it)

Ric

We have a script that adds corruption to ext2/3/4 filesystems and runs 
e2fsck on it. It definitely could be improved, but it still catches some
occasional errors:

http://git.whamcloud.com/?p=tools/e2fsprogs.git;a=commit;h=aee44c669bebe29bfdb8a1c86da443234f8bc257

It tries to format the filesystem with different features and options, then
adds corruption from both random data and copying parts of the
filesystem internally to some other part of the filesystem. It might be useful
to corrupt some random bits and bytes in the filesystem also,
but it doesn't do that today.

There is also fsfuzzer, which writes random data to the filesystem and
tries to mount it, but I don't know if that has been tried with e2fsck. 

The other major question I have is why you are trying to create a new
proprietary filesystem?  That is really a ten year effort, and you would
be much better off to use one of the many existing filesystems. If
the current ones don't meet your exact needs, add the missing
features you need instead of creating a whole new one from scratch.

While I'm a big fan of ext4, there are many other good filesystems out
there - XFS, Btrfs, ZFS, and several flash filesystems. 

Cheers, Andreas
> On Jan 18, 2014, at 5:13, "Lakshmipathi.G" <lakshmipathi.g at
gmail.com> wrote:
> 
> Hi - 
> 
> I'm searching for file system corruption tool, say it inject
disk-errors like
> multiply owned blocks etc. Later an integrity scan process (like e2fsck)
will
> verify on-disk layout and fix these errors. 
> 
> I'd like to read/understand such tools before writing one for an
proprietary
> on-disk file system. 
> 
> Do we have such tools for ext{2,3,4}fs ? Thanks for any help or pointers!
> 
> -- 
> ----
> Cheers,
> Lakshmipathi.G
> FOSS Programmer.
> www.giis.co.in
> _______________________________________________
> Ext3-users mailing list
> Ext3-users at redhat.com
> https://www.redhat.com/mailman/listinfo/ext3-users
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> For s-ata drives, you can use hdparm to create a bad sector that will
cause an IO error on read. (Write will fix it)

Thanks Ric Wheeler. Just looked into hdparm, it has nice option to
corrupt sectors but I need to manipulate disk-entries also (like
add invalid nlink value in an inode structure etc).
> We have a script that adds corruption to ext2/3/4 filesystems and runs
> e2fsck on it. It definitely could be improved, but it still catches some
Thanks Andreas. I was going the script, liked idea to create file system
image based on random files. It has minimal option as now of. Will look
into fsfuzzer.
> The other major question I have is why you are trying to create a new
> proprietary filesystem?
Sorry, I should have been clearer. I was assigned with a task of creating a
framework to corrupt disk-layout on an existing FreeBSD based closed source
file system. We have e2fsck like integrity checker, but corrupting disk
script
needs to be added. Thanks!


-- 
----
Cheers,
Lakshmipathi.G
FOSS Programmer.
www.giis.co.in