Re: [PATCH v3 07/10] block: Implement bdrv_{pread,pwrite,pwrite_zeroes}() using generated_co_wrapper

[Eric Blake]

On Thu, May 26, 2022 at 08:23:02PM +0100, Alberto Faria wrote:
> On Thu, May 26, 2022 at 9:55 AM Stefan Hajnoczi <stefanha@redhat.com> wrote:
> > The bdrv_pread()/bdrv_pwrite() errno for negative bytes changes from
> > EINVAL to EIO. Did you audit the code to see if it matters?
> 
> I don't believe I had, but I checked all calls now. There's ~140 of
> them, so the probability of me having overlooked something isn't
> exactly low, but it seems callers either cannot pass in negative
> values or don't care about the particular error code returned.
> 
> Another option is to make bdrv_co_pread() and bdrv_co_pwrite() (which
> have much fewer callers) fail with -EINVAL when bytes is negative, but
> perhaps just getting rid of this final inconsistency between
> bdrv_[co_]{pread,pwrite}[v]() now will be worth it in the long run.

Failing with -EINVAL for negative bytes makes more sense at
identifying a programming error (whereas EIO tends to mean hardware
failure), so making that sort of cleanup seems reasonable.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
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