xfs behaviour on OpenBSD

[Kristaps Johnson]

>> Hello everybody.  I wonder if somebody can shed some light on strange 
>> behahiour (or sloppy thinking on my part).
>>
>> If I mount_xfs on OpenBSD (3.9), and run two versions of a programme, one
>> that read(2)s and one that fread(3)s, the read returns end-of-file while
>> the fread returns correct values.
>
> nnpfs dev will only return untruncted messages, you need to pass in a 
> larger buffer.
>
> fread behavies diffrently because its buffered in libc, ktrace and 
> you'll see that the read(2) is larger then 1 byte.

Problem solved.  I was trying to read a single sizeof struct 
nnpfs_message_header and kept receiving eof.  I'll revert back to 
NNPFS_MSG_MAX_DATASIZE.  Thank you, Kristaps.