Hi Tony,
I will check it with a debugger and get back to you.
Also, does NTFS have a recognizer or is it being directly loaded? Does that
mean that NTFS will be the first one to be given the opportunity to mount?
Thanks,
Saritha.
-----Original Message-----
*From:* xxxxx@lists.osr.com [mailto:
xxxxx@lists.osr.com]*On Behalf Of *Tony Mason
*Sent:* Tuesday, March 07, 2006 10:48 PM
*To:* Windows File Systems Devs Interest List
*Subject:* RE: FW: [ntfsd] Does windows detects UDF formatted hard disk?If the FS Recognizer’s UDFS objects are in use, the UDFS file system has
not been loaded ? FS Recognizer is a “stand in” driver that is used to defer
loading of the regular file system until it is needed. To determine more
would require a bit of work with the debugger (e.g., check and see if the
recognizer is being called to mount the volume.) If its not being called,
then the next “trick” would be to force the loading of UDFS (which would
then cause registration, which would then mean it gets called prior to
NTFS.) Seriously, this is something that you should be able to figure out
in about 10-15 minutes with a kernel debugger attached (I’ve had to do this
before.) Look at the fs recognizer’s device object, set a break point in
its fs control function and watch to see if it gets called with the UDFS
recognizer object. If it doesn’t then do the same thing to NTFS and watch
its return code ? that’s going to be the key to the whole thing.I’m not sure how the service control manager handles disabled drivers
anymore. If you can’t start it through the SCM, you’ll need to call
ZwLoadDriver directly to accomplish this.Regards,
Tony
Tony Mason
Consulting Partner
OSR Open Systems Resources, Inc.
Looking forward to seeing you at the next OSR File Systems class in Boston,
MA April 18-21, 2006 (note new date - MS scheduled plugfest the same week
again.)Tony Mason
Consulting Partner
OSR Open Systems Resources, Inc.
Looking forward to seeing you at the next OSR File Systems class in Boston,
MA April **18-21, 2006 (note new date - MS scheduled plugfest the same
week again.)*From:* xxxxx@lists.osr.com [mailto:
xxxxx@lists.osr.com] *On Behalf Of *Saritha Vinod
*Sent:* Tuesday, March 07, 2006 1:23 AM
*To:* ntfsd redirect
*Subject:* Re: FW: [ntfsd] Does windows detects UDF formatted hard disk?Hi Tony,
Thanks for the information.
I checked in our Windows 2000 machine also. As you said, the UDFS file
system has two device objects for FILE_DEVICE_DISK_FILE_SYSTEM and
FILE_DEVICE_CD_ROM_FILE_SYSTEM. Hence it would mean that it should be given
the opportunity to mount on disk as well as CD/DVD devices, right?As you said, the last registered file system will be called first. So how
can we change the order in which the registration happens?As far as changing the load order is concerned, what I observed is that, a
file system recognizer is registered with a start type 1(system start) and
group “boot file system”. The fs_rec has device objects
like"UdfsDiskRecognizer" and “UdfsCdromRecognizer”. The actual UDFS file
system driver has a start type of 4(disabled), which will be called by the
recognizer. So in this case how can we make the “UdfsDiskRecognizer” to be
called first to recognize the volume?Also NTFS does not have a recognizer. Hence does it mean that NTFS is
always being called first to mount on a device?Thanks,
Saritha.
-----Original Message-----
*From:* xxxxx@lists.osr.com [mailto:
xxxxx@lists.osr.com]*On Behalf Of *Tony Mason
*Sent:* Tuesday, March 07, 2006 1:14 AM
*To:* Windows File Systems Devs Interest List
*Subject:* RE: [ntfsd] Does windows detects UDF formatted hard disk?Each file system implementation is free to decide how it recognizes its
own file system type. The UDFS file system (at least on my XP box) has
registered for both CD and DISK mount events, so I would assume it can
recognize a UDFS formatted disk drive type. With a tool like objdir or
winobj or the debugger, you should be able to determine what the UDFS driver
has registered as well (the device objects with names have normally been
registered for mount events.)The media type does matter ? Windows only supports mount on four media
types: FILE_DEVICE_DISK, FILE_DEVICE_TAPE, FILE_DEVICE_CD_ROM,
FILE_DEVICE_VIRTUAL_DISK ? with the latter being “lumped into” the same file
system type as the first one. File systems of type
FILE_DEVICE_DISK_FILE_SYSTEM are given the opportunity to mount
FILE_DEVICE_DISK or FILE_DEVICE_VIRTUAL_DISK media. File systems of type
FILE_DEVICE_CD_ROM_FILE_SYSTEM are given the opportunity to mount
FILE_DEVICE_CD_ROM, etc.To achieve this, the file system must create a unique device object and
register that device object with the I/O Manager (IoRegisterFileSystem).
The I/O Manager then maintains a LIFO call table of file systems (last
registered, first called) that are invoked to check a media device and
determine if the volume in question has the right format.One issue I’ve seen interfere with mounting in the past is that the I/O
Manager is very sensitive to errors returned by the mounting file system.
It expects STATUS_UNRECOGNIZED_VOLUME (see FatMountVolume in fsctrl.c for
FAT). Other errors can (and do) cause mounting problems. For example, we
had an FSD that was written to work with WORM media. If NTFS were asked to
mount the volume first and it attempted to read an unrecorded area on the
media it would get an I/O error (indicating that the sector had not yet been
recorded). NTFS would report this error to the I/O Manager and the I/O
Manager would abort the mount processing ? so our file system never was
given an opportunity to mount. Different media, or different load ordering
and the mount proceeded correctly. This was many years ago and at the time
I lobbied for changes to the I/O Manager to be a bit more liberal in its
decision to continue mount processing but was told that this wouldn’t happen
because it only affected a non-MS file system.Bottom line: mount processing is an elaborate dance with multiple players,
each of whom must behave in a proscribed manner. A failure to do so may
lead to cases where a volume may not behave the way that you expect.Regards,
Tony
Tony Mason
Consulting Partner
OSR Open Systems Resources, Inc.
Looking forward to seeing you at the next OSR File Systems class in
Boston, MA April 18-21, 2006 (note new date - MS scheduled plugfest the
same week again.)*From:* xxxxx@lists.osr.com [mailto:
xxxxx@lists.osr.com] *On Behalf Of *Saritha Vinod
*Sent:* Monday, March 06, 2006 7:16 AM
*To:* ntfsd redirect
*Subject:* [ntfsd] Does windows detects UDF formatted hard disk?Hi all,
I am trying to format a hard disk partition using UDF file system. Since
windows 2000 does not have write support for UDF, I formatted using Linux
and was able to read and write to it. The UDF version used was 1.50. I
tried accessing that partition again in Windows. But windows failed to
recognize it and showed that it is not formatted. Can anybody please tell me
the reason for this? Is it that windows will not recognize UDF on hard disk,
since it tries to mount UDF only for CD/DVD devices?Is the media type in anyway related to this behaviour?
Thanks in advance.
Saritha.
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