TAKE - small fixes for the sync changes

[Christoph Hellwig <hch@xxxxxxxxxxxxxxxxxxxxx>]

Date:  Mon May  5 10:44:11 PDT 2003
Workarea:  lab343.munich.sgi.com:/home/hch/repo/slinx/2.4.x-xfs

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


Modid:  2.4.x-xfs:slinx:147897a
linux/fs/xfs/xfs_iget.c - 1.188
        - remove racy list_empty check

linux/fs/xfs/linux/xfs_super.h - 1.45
        - linvfs_start_syncd returns int now

linux/fs/xfs/linux/xfs_super.c - 1.253
        - check linvfs_start_syncd retval

linux/fs/xfs/linux/xfs_syncd.c - 1.2
        - use wait_event instead of sleep_on
        - use wmb() to protect lockless pointer assignments
        - handle kernel_thread() failure in  linvfs_start_syncd