GFS2: Clean up of glops.c

This cleans up a number of bits of code mostly based in glops.c.
A couple of simple functions have been merged into the callers
to make it more obvious what is going on, the mysterious raising
of i_writecount around the truncate_inode_pages() call has been
removed. The meta_go_* operations have been renamed rgrp_go_*
since that is the only lock type that they are used with.

The unused argument of gfs2_read_sb has been removed. Also
a bug has been fixed where a check for the rindex inode was
in the wrong callback. More comments are added, and the
debugging code is improved too.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

diff --cc fs/gfs2/glops.c
Simple merge

diff --cc fs/gfs2/meta_io.c
Simple merge

diff --cc fs/gfs2/meta_io.h
Simple merge

diff --cc fs/gfs2/ops_file.c
Simple merge

diff --cc fs/gfs2/ops_fstype.c
Simple merge