Re: NTFS inode ouput from ls -i

[Harry G McGavran Jr <w5pny@w5pny.com>]

On Jul 18 3:50, Corinna Vinschen wrote:
>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
>

Thanks for the thoughts and info -- based on that info, personally, I'd
go for returning the bottom 48 bit file record number. That is
apparently what ntfs-3g developers felt was appropriate under linux
(Ubuntu 16.04 at least) and would allow people chasing down chkdsk
issues to make using cygwin find and ls easier.

    Harry



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