panic: ffs_blkfree: freeing free block

[Don Bowman]

From: Don Bowman [mailto:don at sandvine.com]
> periodically (once a day or so), i'm getting a panic
> as 'panic: ffs_blkfree: freeing free block'. 

sorry to follow up my own message...
subsequently the machine sometimes goes berserk with:
bad block -1428886735890689256, ino 2049427
bad block 8442294558658211815, ino 2049427

to the serial console.