TAKE - sector fixup

[Nathan Scott <nathans@snort.melbourne.sgi.com>]

Fix up setting up of sector size for the superblock buffer after the
very first read on mount.  Make some of the surrounding code dealing
with buffers consistent.


Date:  Tue Dec 17 19:51:45 PST 2002
Workarea:  snort.melbourne.sgi.com:/home/nathans/pagebuf

The following file(s) were checked into:
  bonnie.engr.sgi.com:/isms/slinx/2.4.x-xfs


Modid:  2.4.x-xfs:slinx:135452a
linux/fs/xfs/xfs_buf.h - 1.102
linux/fs/xfs/xfs_vfsops.c - 1.404
linux/fs/xfs/xfs_mount.c - 1.315
linux/fs/xfs/linux/xfs_super.h - 1.36
linux/fs/xfs/linux/xfs_super.c - 1.237