panic: assertion: layer2->zone == zone in hammer_blockmap_free

[Matthew Dillon]

    I'm readying a commit+MFC for Wednesday if my testing today works out.
    So far so good.  I've been running simultanious buildworld, reblocking,
    and pruning loops all day with no problems.  I believe I have fixed the
    reblocker for good.

    The B-Tree panic is still on my list (a very rare deletion race that
    asserts on a sanity check and does not corrupt the media).  This is
    currently the only known panic.

    During testing I found a directory disconnection issue which can leave
    an inaccessible sub-directory structure on the media if a crash
    occurs during a rm -rf.  The structures don't corrupt the filesystem
    other then eat up some space.  I made one fix that gets most of the
    problem but I think there may be some side cases still present.

    Francois's rmdir-on-regular-file bug will also be in Wednesday's commit.

					-Matt
					Matthew Dillon 
					<dillon at backplane.com>