f: Issue found and reported by Lluís; initial investigations by me;
bug finally found and patch by Al; testing by me and Lluís.]

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Tested-by: Lluís Batlle i Rossell <viriketo@gmail.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
ì,`êš