Re: [PATCH] Linux-2.5 fix/improve get_pid()

[Padraig Brady <padraig.brady@corvil.com>]

Linus Torvalds wrote:
> On 9 Aug 2002, Paul Larson wrote:
> 
>>On Fri, 2002-08-09 at 16:42, Linus Torvalds wrote:
>>
>>>Hmm.. Giving them a quick glance-over, the /proc issues look like they
>>>shouldn't be there in 2.5.x anyway, since the inode number really is
>>>largely just a random number in 2.5 and all the real information is
>>>squirelled away at path open time.
>>
> 
> It looks like the biggest impact on /proc would be that the /proc/<pid> 
> inodes wouldn't be 10%% unique any more, which in turn means that an 
> old-style /bin/pwd that actually walks the tree backwards and checks the 
> inode number would occasionally fail.
> 
> That in turn makes me suspect that we'd better off just biting the bullet 
> and makign the inode numbers almost completely static, and forcing that 
> particular failure mode early rather than hit it randomly due to unlucky 
> timing.
> 
> Doing a simple strace shows that all the systems I have regular access to
> use the "getcwd()" system call anyway, which gets this right on /proc (and
> other filesystems that do not guarantee unique inode numbers)

Anyone care to clarify which filesystems don't
have unique inode numbers. I always thought you
could uniquely identify any file using a device,inode
tuple? Fair enough proc is "special" but can/should
you not assume unique inodes within all other filesystems?

Also why can't you allocate a unique number in /proc?

thanks,
Pádraig.