Date:   Mon, 4 Feb 2019 15:11:45 -0500
From:   Bruce Fields <bfields@fieldses.org>
To:     Chuck Lever <chuck.lever@oracle.com>
Cc:     Linux NFS Mailing List <linux-nfs@vger.kernel.org>, simo@redhat.com
Subject: Re: [PATCH RFC 09/10] SUNRPC: Remove xdr_buf_trim()
Message-ID: <20190204201145.GF1816@fieldses.org>
References: <20190201195538.11389.96106.stgit@manet.1015granger.net>
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 <20190204194615.GC1816@fieldses.org>
 <014F38E7-993C-4FD6-A8C6-9FE113A54A03@oracle.com>
 <20190204200044.GD1816@fieldses.org>
 <BB18AC3C-0EAA-4E63-9C87-5377070D1F4E@oracle.com>
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On Mon, Feb 04, 2019 at 03:07:26PM -0500, Chuck Lever wrote:
> 
> 
> > On Feb 4, 2019, at 3:00 PM, Bruce Fields <bfields@fieldses.org> wrote:
> > 
> > On Mon, Feb 04, 2019 at 02:49:11PM -0500, Chuck Lever wrote:
> >> 
> >> 
> >>> On Feb 4, 2019, at 2:46 PM, bfields@fieldses.org wrote:
> >>> 
> >>> On Fri, Feb 01, 2019 at 02:58:14PM -0500, Chuck Lever wrote:
> >>>> The key action of xdr_buf_trim() is that it shortens buf->len, the
> >>>> length of the xdr_buf' content. The other actions -- shortening the
> >>>> head, pages, and tail components -- are actually not necessary. In
> >>>> some cases, changing the size of those components corrupts the RPC
> >>>> message contained in the buffer.
> >>> 
> >>> That's really burying the lede.... Is there an actual user-visible bug
> >>> here?
> >> 
> >> I don't think so. This is more of the form:
> >> 
> >> a) the function does fundamentally the wrong thing, so
> >> 
> >> b) certain changes to this code path result is unexpected and incorrect
> >>   behavior
> >> 
> >> Thus typically only developers hacking on this code run into a problem.
> > 
> > OK, got it.  It'd help just to make it clear in the changelog that that
> > this is an accident waiting to happen rather than a current bug (as far
> > as we know).
> 
> With said improvement to the changelog, can I add your Acked-by
> when I submit this through Anna's tree?

Sure, thanks.

--b.