Re: [PATCH] Btrfs: relocate csums properly with prealloc extents

[Goffredo Baroncelli <kreijack@libero.it>]

On 2013-11-25 22:01, Greg KH wrote:
> On Mon, Nov 25, 2013 at 05:51:16PM +0100, David Sterba wrote:
>> On Fri, Sep 27, 2013 at 09:37:00AM -0400, Josef Bacik wrote:
>>> A user reported a problem where they were getting csum errors when running a
>>> balance and running systemd's journal.  This is because systemd is awesome and
>>> fallocate()'s its log space and writes into it.  Unfortunately we assume that
>>> when we read in all the csums for an extent that they are sequential starting at
>>> the bytenr we care about.  This obviously isn't the case for prealloc extents,
>>> where we could have written to the middle of the prealloc extent only, which
>>> means the csum would be for the bytenr in the middle of our range and not the
>>> front of our range.  Fix this by offsetting the new bytenr we are logging to
>>> based on the original bytenr the csum was for.  With this patch I no longer see
>>> the csum errors I was seeing.  Thanks,
>>>
>>> Cc: stable@vger.kernel.org
>>
>> The patch had the right CC but I don't see it in the mail's CC list (now
>> added by me). I'm afraid that this never reached stable and explains why
>> the patch did not end up in 3.12.1.
> 
> No, it made it to my list, I was waiting for 3.13-rc1 to come out with
> this patch in it before I could queue it up.  Don't worry, it's not
> lost.
> 
The patch landed in 3.12.2

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