Re: [PATCH 3/4]ext4: Return exchanged blocks count to user space in failure

[Peng Tao <bergwolf@gmail.com>]

Hi, Greg,

On Thu, Sep 3, 2009 at 4:59 AM, Greg Freemyer<greg.freemyer@gmail.com> wrote:
> Peng,
>
> I have not looked at the code very closely, but can you tell me where
> a file corruption can take place?   Not completing the replacement of
> extents with donor extents is one thing.  Corrupting the original file
> contents is another.
The file corruption is mainly because of the half done replacement.

My test case is here:
http://marc.info/?l=linux-ext4&m=124992522305319&w=2

With Akira's previous patch
(http://marc.info/?l=linux-ext4&m=124937430627867&w=2),
EXT4_IOC_MOVE_EXT does not panic the kernel any more. But it leaves
the orig file's extent tree corrupted.

>
> Clearly we need EXT4_IOC_MOVE_EXT to fail gracefully and not corrupt
> the original file the vast majority of the time.
>
> Greg
>



-- 
Cheers,
Peng Tao
State Key Laboratory of Networking and Switching Technology
Beijing Univ. of Posts and Telecoms.
--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html