Re: isofs hardlink bug (inode numbers different)

["H. Peter Anvin" <hpa@zytor.com>]

Kasper Dupont wrote:
>> 
>>Second: If there are files on the CD-ROM *without* RockRidge
>>attributes, you can get collisions with the synthesized inode numbers
>>for non-RR files.
>  
> That can easily be solved. RockRidge inode numbers are multiplied
> by two, and synthesized inode numbers are all odd. Of course if
> the multiplication overflows a fallback to synthesized inode
> numbers would be necesarry. Does any software produce inode
> numbers large enough to make this a problem?
> 

We have no idea, and we will never be able to know.  They certainly 
*CAN*... they are just anonymous 32-bit values.

> 
>>Third: If you actually rely on inode numbers to be able to find your
>>files, like most versions of Unix including old (but not current)
>>versions of Linux, then they are completely meaningless.
> 
> Agreed.
> 
>>There is another way to generate consistent inodes for hard links,
>>which is to use the data block pointer as the "inode number."  This,
>>however, has the problem that *ALL* zero-lenght files become "hard
>>links" to each other.
> 
> That problem can easily be solved. Simply use different methods
> for zero-length files and all other files. But there might be
> other problems with such an approach:
> 
> 1) Could two different files have same data block pointer?
>    (different sizes perhaps?)

Theoretically yes.

> 2) Do we need a way to find metadata from the inode number?

Currently we do, but we could rewrite the code not to.

	-hpa