Re: NTFS inode ouput from ls -i

[Corinna Vinschen <corinna-cygwin@cygwin.com>]

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On Jul 17 11:44, Harry G McGavran Jr wrote:
> I just had to deal with the output from chkdsk on my Windows 7 pro
> that lists MFT record numbers just like ifind and icat do
> in the Sleuth Kit as summarized in:
> 
> https://cygwin.com/ml/cygwin/2012-11/msg00172.html
> 
> The chkdsk MFT record numbers are exactly what ifind and icat
> display/use. I also discovered when doing "ls -i" on NTFS
> file systems mounted on my Ubuntu 16.04 linux system that
> the "ls -i" numbers reported are the same as the chkdsk, ifind, and icat
> record numbers.  These are all the lower 32 bits of the 64 bit
> numbers reported by "ls -i" with the current cygwin.  Had
> the cygwin "find -inum" and "ls -i" used these 32 bit numbers,
> my task would have been easier.  From the above link, Corinna
> found it odd that ifind and icat would use the 32 bit numbers.
> I would have preferred them when dealing with chkdsk issues.
> 
> What's the current thinking about this?

The descriptions I found describes the NTFS FileID as a combination
of the 16 bit sequence number with the 48 bit file record number(*).
Stripping off 16 bits sequence number would be ok, but stripping the
upper 16 bit from a 48 bit record number sounds bad.

OTOH, the maximum number of files on an NTFS volume is restricted
to the number of clusters, which is 2^32-1.

If it's *safe* to assume that the record number corresponds with
the cluster number, ok, but I'm not sure this is the case.  I never
use really big filesystems with Windows.  This would need testing.

But then there's another problem.  The 64 bit file ID can also be
used to open a file by ID.  Stripping the upper 32 bit from the
value disallows to use the file ID in that way.


Corinna

(*) http://digitalresidue.blogspot.de/2016/02/getting-started-with-sleuth-kit-pt-3.html

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Maintainer                 cygwin AT cygwin DOT com
Red Hat

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