kern/47117: lockstat output doesn't show caller of genfs_lock or vn_lock

[Taylor R Campbell <campbell+netbsd%mumble.net@localhost>]

>Number:         47117
>Category:       kern
>Synopsis:       lockstat output doesn't show caller of genfs_lock or vn_lock
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          change-request
>Submitter-Id:   net
>Arrival-Date:   Tue Oct 23 22:15:00 +0000 2012
>Originator:     Taylor R Campbell <campbell+netbsd%mumble.net@localhost>
>Release:        NetBSD 6.99.14
>Organization:
>Environment:
Architecture: any
Machine: any
>Description:

        The vast majority of the rwlocks in lockstat output are vnode
        locks, for which it only displays genfs_lock as the taker of
        the lock.  It might be nice if it were easier to see who wanted
        the lock in order to get an idea of which operations the
        contention lies in.

>How-To-Repeat:

        Run lockstat while doing file system stuff.  Fail to attain
        enlightenment.  Put on a sad face.

>Fix:

        Yes, please!