TAKE - a possible locking hang

[lord@xxxxxxx]

This could fix some soft hangs in XFS, any attempt to directly lock
a pagebuf which has had I/O started on it may require waking up the
driver layer. Replicated code from pagebuf_get_lockable into pagebuf_lock.

Date:  Thu Jul 13 15:44:41 PDT 2000
Workarea:  jen.cray.com:/src/lord/xfs-linux.2.4.0-test1

The following file(s) were checked into:
  bonnie.engr.sgi.com:/isms/slinx/2.4.0-test1-xfs


Modid:  2.4.0-test1-xfs:slinx:66633a
linux/fs/pagebuf/page_buf_locking.c - 1.3
        - When attempting to lock a pagebuf which has I/O outstanding,
          call run_task_queue(&tq_disk);