GEOM_VOL panics when audio CD is present

[Dag-Erling Smørgrav]

g_vol_ffs_taste() tries to taste audio CDs, triggering a KASSERT in
g_io_request() because 65536 is not a valid offset on a medium with
2352-byte sectors.  The exact panic message is "wrong offset 65536 for
sectorsize 2352" (sys/geom/geom_io.c lines 250-251).

None of this code has been touched recently, so I suspect the same bug
is present in 5.3, though I haven't had a chance to test it yet.

DES
-- 
Dag-Erling Smørgrav - des at des.no