struct pathname is originally from Solaris VFS, and it has been used
in ZoL to merely call VOP from Linux VFS interface without API change,
therefore pathname::pn_path* are unused and unneeded. Technically,
struct pathname is a wrapper for C string in ZoL.
Saves stack a bit on lookup and unlink.
(#if0'd members instead of removing since comments refer to them.)
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Richard Elling <Richard.Elling@RichardElling.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Tomohiro Kusumi <kusumi.tomohiro@gmail.com>
Closes#9025