TAKE - fix some direct I/O corner cases

[Steve Lord <lord@sgi.com>]

Date:  Thu Feb 14 15:40:24 PST 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:111857a
linux/fs/xfs/linux/xfs_iops.c - 1.123
	- Deal with a corner case where we do a mix of buffered and direct I/O to
	  a file. If asking for extents for a direct write and finding delalloc
	  extents there, convert them to real.

linux/fs/xfs/pagebuf/page_buf_io.c - 1.8
	- Fix the direct I/O path for writes from uninitialized malloced memory,
	  basically do not lock the pages around the I/O. We don't need to anyway,
	  so this is also a direct I/O speed up.