On Tue, Jul 02, 2019 at 02:14:39PM -0400, Theodore Ts'o wrote:
> On Tue, Jul 02, 2019 at 11:43:34AM +0100, Mike Fleetwood wrote:
> > Hi,
> >
> > Tested with mkntfs from ntfsprogs and blkid and wipefs from util-linux git HEAD.
> > Test case:
> >
> > # mkntfs -Q -F /dev/sdb
> > /dev/sdb is entire device, not just one partition.
> > mkntfs forced anyway.
> > Cluster size has been automatically set to 4096 bytes.
> > Creating NTFS volume structures.
> > mkntfs completed successfully. Have a nice day.
> > # ./blkid --version
> > lt-blkid from util-linux 2.34.24-e3bb9 (libblkid 2.34.24, 14-Jun-2019)
> > # ./blkid /dev/sdb
> > /dev/sdb: UUID="3B64D28A5CF89146" TYPE="ntfs" PTTYPE="dos"
> > # ./wipefs /dev/sdb
> > DEVICE OFFSET TYPE UUID LABEL
> > sdb 0x3 ntfs 3B64D28A5CF89146
> > sdb 0x1fe dos
Thanks for your report Mike.
> So what we call the dos partition table, Microsoft calls the "boot
> sector", and it's not necessarily a partition table at all. (Note
> also that normally, Microsoft won't let you put an ntfs file system on
> the whole disk --- and you had to force this with mkntfs -F. It's
> actually a bad idea, because some versions of Windows will see what it
> thinks is an empty disk, and the contents of that whole disk file
> system can be very easily overwritten by a confused Windows OS.)
>
> You can see this in include/layout.h in the ntfs-3g sources.
>
> This is a pretty broad and general confusion; fdisk will get confused
> and think it is an empty dos partition table, and blkid will as well.
> I suspect the right answer here is if the oem_id is "NTFS ", we should
> not consider it a dos partition table at all, even if there is an "end
> of boot sector" magic value of 0xaa55 at the end of the sector.
Well, our MBR detection is more sophisticated check for 0xaa55 magic
;-) but NTFS is not in the game now. I'll fix it. We need extra check
for NTFS (as we already use for some FATs or GPT+PMBR).
Karel
--
Karel Zak <kzak@xxxxxxxxxx>
http://karelzak.blogspot.com
