Re: NFS writes being corrupted?

[Jeff Rizzo <riz%tastylime.net@localhost>]

On 8/3/15 10:15 AM, Martin Husemann wrote:
> On Mon, Aug 03, 2015 at 09:02:19AM -0700, Jeff Rizzo wrote:
> > I'm about 80% sure this was working around 7.99.9, but for a number of
> > reasons it's complicated for me to check older builds, and in any event
> > odroid-c1 support is fairly new.  I noticed some changes to the NFS code
> > on 15 July (
> > http://mail-index.netbsd.org/source-changes/2015/07/15/msg067309.html ),
> > but backing these out does not change the behavior.
> What kind of differences do you see?
>
> Truncation to a multiple of page size? Last partial page filled with zeroes?
> Random corruption? Do you get identical content back when reading on the
> client directly after write?
>
> Typical culprit would be cache ops/pmap issues.
>
> Martin

I need to look deeper, but a quick test writing lines of
ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz

Shows that corruption starts when the file is exactly 65536 bytes long 
(with an 8192 byte page size), with anything that size or longer getting 
corrupted.  It seems to be randomly garbled - same size, same bytes, but 
shuffled around.  When I was narrowing it down, I sometimes saw random 
corruption inserted at larger file sizes - at one point I saw short 
strings of NUL and the string "posix2_upe" (which would appear to be a 
symbol?) inserted at seemingly-random spots.

+j