panic while reading ntfs partition

Hi,

Not sure if this is useful, but I'm getting a perfectly reproducible
panic when doing 'grep -R foo .' (as normal user) in a read-only
mounted ntfs partition on a -current as of ~3 weeks ago:

Good dump found on device /dev/ad0s2b
  Architecture: i386
  Architecture version: 1
  Dump length: 259461120B (247 MB)
  Blocksize: 512
  Dumptime: Thu Jul 24 13:51:36 2003
  Hostname: phys9911.phys.tue.nl
  Versionstring: FreeBSD 5.1-CURRENT #3: Fri Jul  4 10:56:05 CEST 2003
    root_at_phys9911.phys.tue.nl:/usr/src/sys/i386/compile/KAYJAY
  Panicstring: bundirty: buffer 0xc72d9868 still on queue 2
  Bounds: 3

Since I have no idea whether the ntfs partition is OK because the
Win2000 there does not boot anymore (not even in safe mode), I'm
not sure if it might be due to an unclean ntfs partition. But then,
shouldn't FreeBSD detect this at mount time or is it the user's
responsibility?

Karel.