K 10
svn:author
V 3
pjd
K 8
svn:date
V 27
2007-10-02T14:48:48.000000Z
K 7
svn:log
V 478
Fix sx_try_slock(), so it only fails when there is an exclusive owner.
Before that fix, it was possible for the function to fail if number
of sharers changes between 'x = sx->sx_lock' step and atomic_cmpset_acq_ptr()
call.

This fixes ZFS problem when ZFS returns strange EIO errors under load.
In ZFS there is a code that depends on the fact that sx_try_slock() can
only fail if there is an exclusive owner.

Discussed with:	attilio
Reviewed by:	jhb
Approved by:	re (kensmith)

END