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

From: Jens Axboe
Date: Wed Mar 03 2010 - 02:30:22 EST

On Wed, Mar 03 2010, Dmitry Monakhov wrote:
> Jens Axboe <jens.axboe@xxxxxxxxxx> 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?

Jens Axboe

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