TAKE - fix unchecked pointer dereferences

[Steve Lord <lord@xxxxxxx>]

Fix regression which came in yesterday, the oops during a freeze call
was this problem.

Date:  Wed Aug 14 11:49:40 PDT 2002
Workarea:  jen.americas.sgi.com:/src/lord/xfs-linux.2.4

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


Modid:  2.4.x-xfs:slinx:125083a
linux/fs/xfs/xfsidbg.c - 1.195
linux/fs/xfs/xfs_rtalloc.c - 1.78
linux/fs/xfs/xfs_vfsops.c - 1.369
linux/fs/xfs/xfs_mount.h - 1.155
linux/fs/xfs/xfs_mount.c - 1.296
linux/fs/xfs/xfs_fsops.c - 1.85
linux/fs/xfs/linux/xfs_lrw.c - 1.165