mount GPT from Windows 7 in FreeBSD 9

[Jeremy Chadwick]

On Fri, Nov 18, 2011 at 10:55:10PM -0200, Nenhum_de_Nos wrote:
> hail,
> 
> I have two disks, and the one holding Windows appears just as ada1 or ad8, despite fdisk shows all
> partitions fine.
> 
> I tried to kldload geom_gpt_something, but it says it was already loaded. I couldn't mount using
> mount_ntfs, so I would use fuse to have ability to write on it :)
> 
> is there a way to solve this ?
> two disks. One just FreeBSD, the other just Windows.

First: to my knowledge, fdisk does not support GPT, so I'm not sure what
you mean when you say "it shows all partitions fine".  You should
probably use gpart(8) instead, e.g. "gpart show" and/or "gpart list".
See the man page for usage.  It will work with all types, and tell you
what scheme is used (MBR, GPT, etc.).

Next item: what do you mean it appears as "ada1 **or** ad8"?  ada1
indicates you're using ahci.ko (not ataahci.ko) which supports AHCI via
CAM(4), while the latter indicates you're using ata(4) (even if AHCI is
in use; that would be ataahci.ko).  Why/how would this change unless you
are messing with cables or enabling/disabling drivers?

Next item: I think you're referring to the geom_part_gpt.ko module,
but you don't need to do that.  GEOM and related kernel bits will load
it automatically, which is why it told you it's already loaded.  You can
use "kldstat" to verify.  Otherwise it's statically-included in your
kernel.

Next item: this sounds like the crux of your issue.  As I understand it,
NTFS support via kernel on FreeBSD is in an extremely bad state on
numerous levels.  You can find complaints about lack-of or badly-done
UTF-8 filename/path support, lack of full write support, and the more
important/major Non-MPSAFE filesystem declaration here:
http://wiki.freebsd.org/NONMPSAFE_DEORBIT_VFS

It looks like attilio at freebsd.org has taken ownership of the NTFS driver
in the kernel at this point.  You may want to ask him if there are any
patches you could try.

However, as I understand it, the fuse-based NTFS is more reliable and
has much higher compatibility.  The trade-offs are added complexity
getting it all to work, and slower speed.

Final item: you sent this mail twice, once to stable at freebsd.org, once to
freebsd-stable at freebsd.org.  The mail ID headers appear to indicate
they were separate/unique and the mail content themselves slightly
differs (extra newlines, etc.).  No need for this; they are the same
list.

3909     11/18 22:55  Nenhum_de_Nos       (0.8K) mount GPT from Windows 7 in FreeBSD 9
         Message-ID: <678178215ed5d725a42eb2b4ae25102c.squirrel at eternamente.info>
3910     11/19 03:20  Nenhum_de_Nos       (1.1K) mount GPT from Windows 7 in FreeBSD 9
         Message-ID: <1c312a399e23d546f05f5e8396763323.squirrel at eternamente.info>

-- 
| Jeremy Chadwick                                jdc at parodius.com |
| Parodius Networking                       http://www.parodius.com/ |
| UNIX Systems Administrator                   Mountain View, CA, US |
| Making life hard for others since 1977.               PGP 4BD6C0CB |