panic: vclean: cannot relock.

After updating with your fix from yesterday:

panic: vclean: cannot relock.
cpuid = 2
KDB: enter: panic
[thread pid 48038 tid 100358 ]
Stopped at      kdb_enter+0x30: leave
db> where
Tracing pid 48038 tid 100358 td 0xcef90b80
kdb_enter(c06f4a48,2,c06fd644,ee547b14,cef90b80) at kdb_enter+0x30
panic(c06fd644,12,cef90b80,c06fd21d,904) at panic+0x13e
vgonel(cc10ec30,cef90b80,c06fd21d,839,81b) at vgonel+0x1e4
vflush(c375cc00,1,2,cef90b80,0) at vflush+0x36d
nullfs_unmount(c375cc00,8080000,cef90b80,cef90b80,c06ee579) at nullfs_unmount+0x36
dounmount(c375cc00,8080000,cef90b80,37b,218ffdb) at dounmount+0x2b7
unmount(cef90b80,ee547d14,c070fb7b,3ad,2) at unmount+0x271
syscall(2f,2f,2f,804a619,bfbfe74a) at syscall+0x271
Xint0x80_syscall() at Xint0x80_syscall+0x1f
--- syscall (22, FreeBSD ELF32, unmount), eip = 0x280c5ad3, esp = 0xbfbfe4dc, ebp = 0xbfbfe598 ---
db> show lockedvnods
Locked vnodes
(null)
0xcdb2e4e0: tag ufs, type VDIR
    usecount 6, writecount 0, refcount 2 mountedhere 0
    flags ()
    v_object 0xcde25bdc
     lock type ufs: EXCL (count 1) by thread 0xc3514b80 (pid 48047)
        ino 1130617, on dev da0s1e (235, 8)
(null)
0xc3c03750: tag ufs, type VDIR
    usecount 0, writecount 0, refcount 1 mountedhere 0
    flags ()
    v_object 0
     lock type ufs: EXCL (count 1) by thread 0xc3514b80 (pid 48047)
        ino 1083598, on dev da0s1e (235, 8)
(null)
0xc9e27c30: tag ufs, type VDIR
    usecount 6, writecount 0, refcount 2 mountedhere 0
    flags ()
    v_object 0
     lock type ufs: EXCL (count 1) by thread 0xc3cd5730 (pid 48044)
        ino 662978, on dev da0s1e (235, 8)
(null)
0xccd20c30: tag ufs, type VNON
    usecount 1, writecount 0, refcount 0 mountedhere 0
    flags ()
    v_object 0
     lock type ufs: EXCL (count 1) by thread 0xc3cd5730 (pid 48044)
        ino 768818, on dev da0s1e (235, 8)
(null)
0xcd06f270: tag null, type VDIR
    usecount 1, writecount 0, refcount 0 mountedhere 0
    flags (VV_ROOT)
    v_object 0
     lock type ufs: EXCL (count 1) by thread 0xc3cd5730 (pid 48044)
        vp=0xcd06f270, lowervp=0xc9e27c30
(null)
0xcbc263a8: tag null, type VDIR
    usecount 1, writecount 0, refcount 0 mountedhere 0
    flags (VV_ROOT)
    v_object 0
     lock type ufs: EXCL (count 1) by thread 0xc3514b80 (pid 48047)
        vp=0xcbc263a8, lowervp=0xcdb2e4e0
(null)
0xcd306d68: tag null, type VDIR
    usecount 2, writecount 0, refcount 0 mountedhere 0
    flags (VV_ROOT)
    v_object 0
     lock type ufs: EXCL (count 1) by thread 0xc3cd5730 (pid 48044)
        vp=0xcd306d68, lowervp=0xc9e27c30
(null)
0xcc14ad68: tag null, type VDIR
    usecount 1, writecount 0, refcount 0 mountedhere 0
    flags (VV_ROOT)
    v_object 0
     lock type ufs: EXCL (count 1) by thread 0xc3514b80 (pid 48047)
        vp=0xcc14ad68, lowervp=0xcdb2e4e0
(null)
0xc45ca138: tag null, type VDIR
    usecount 1, writecount 0, refcount 0 mountedhere 0
    flags (VV_ROOT)
    v_object 0
     lock type ufs: EXCL (count 1) by thread 0xc3cd5730 (pid 48044)
        vp=0xc45ca138, lowervp=0xc9e27c30
(null)
0xcc10ec30: tag null, type VDIR
    usecount 2, writecount 0, refcount 0 mountedhere 0
    flags (VV_ROOT|VI_XLOCK)
    v_object 0
     lock type ufs: EXCL (count 1) by thread 0xc3514b80 (pid 48047)
        vp=0xcc10ec30, lowervp=0xcdb2e4e0
db>