K 10 svn:author V 8 mckusick K 8 svn:date V 27 2012-04-08T06:20:21.456594Z K 7 svn:log V 232 Expand locking around identification of filesystem mount point when accounting for I/O counts at completion of I/O operation. Also switch from using global devmtx to vnode mutex to reduce contention. Suggested and reviewed by: kib END