kib 632f1d29f3 Add LK_TRYUPGRADE operation for lockmgr(9), which attempts to
atomically upgrade shared lock to exclusive.  On failure, error is
returned and lock is not dropped in the process.

Tested by:      pho (previous version)
No objections from:     attilio
Sponsored by:   The FreeBSD Foundation
MFC after:      1 week
Approved by:	re (glebius)
2013-09-29 18:02:23 +00:00
..
2013-09-29 15:19:34 +00:00
2013-09-29 01:05:00 +00:00
2013-09-29 15:19:34 +00:00
MFC
2013-09-06 17:42:12 +00:00
2013-08-22 16:39:59 +00:00
2013-09-29 13:09:25 +00:00
2013-09-27 15:17:28 +00:00