ffs_blkfree panic + lockmgr panic

[Matthew Dillon]

    So far I haven't had any luck reproducing the blkfree panic.  I'm doing a
    parallel buildworld and vinum init in a loop.

    I did find at least one issue with the patch set... you have to use
    getpbuf() rather then trypbuf().  You can't have temporary resource 
    failures in the places where trypbuf() is being used.  This is unrelated
    to the bug, though.

    If you could get a crash dump of the blkfree panic onto leaf I'd like 
    to take a look at it.

						-Matt