[dm-devel] [GIT PULL] Core block IO bits for 4.2

[Junichi Nomura]

Hi Jens,

On 06/25/15 23:37, Jens Axboe wrote:
>       block, dm: don't copy bios for request clones

this change should not be pushed to mainline yet.

Firstly, Christoph has a newer version of the patch that fixes silent
data corruption problem:
  https://www.redhat.com/archives/dm-devel/2015-May/msg00229.html

And the new version still depends on LLDDs to always complete requests
to the end when error happens, while block API doesn't enforce such a
requirement. If the assumption is ever broken, the inconsistency between
request and bio (e.g. rq->__sector and rq->bio) will cause silent data
corruption:
  https://www.redhat.com/archives/dm-devel/2015-June/msg00022.html

-- 
Jun'ichi Nomura, NEC Corporation