negative return value from write to update its position in
a buffer. The patch, courtesy of Andrey Simonenko, also simplifies
a conditional by removing the "i != cnt" clause, since it is
always true at this point in the code. The bug caused problems
for mountd, when it generated a large reply to an exports RPC
request.
Submitted by: simon at comsys.ntu-kpi.kiev.ua
MFC after: 2 weeks
e2c83f74f4