Re: [PATCH 1/2] blkdev: fix merge_bvec_fn return value checks

[Dmitry Monakhov <dmonakhov@openvz.org>]

Jens Axboe <jens.axboe@oracle.com> writes:

> On Wed, Mar 03 2010, Dmitry Monakhov wrote:
>> Jens Axboe <jens.axboe@oracle.com> writes:
>> 
>> > On Sat, Feb 27 2010, Dmitry Monakhov wrote:
>> >> merge_bvec_fn() returns bvec->bv_len on success. So we have to check
>> >> against this value. But in case of fs_optimization merge we compare
>> >> with wrong value. This patch must be included in
>> >>  b428cd6da7e6559aca69aa2e3a526037d3f20403
>> >> But accidentally i've forgot to add this in the initial patch.
>> >> To make things straight let's replace all such checks.
>> >> In fact this makes code easy to understand.
>> >
>> > Agree, applied.
>> Ohh.. as you already know this patch break dm-layer. Sorry.
>> This is because dm->merge may return more than requested. So correct
>> check must test against less what requested. Correct patch attached.
>
> Have you tested this with dm and md (ie actual users of the merge_bvec
> functionality) this time?
Yes. This time both md and dm are ok.