Re: [PATCH] kill i_dev

[Andries.Brouwer@cwi.nl]

    From torvalds@transmeta.com  Fri Nov 22 00:57:03 2002

    > There is a single side effect: a stat on a socket now sees
    > a nonzero st_dev. There is nothing against that - FreeBSD
    > has a nonzero value as well - but there is at least one
    > utility (fuser) that will need an update.

    Looking at the patch (not testing it), as far as I can tell we'll return a 
    basically random number that is just whatever the anonymous super-block 
    was allocated, right?

Right.

    I'm not convinced that returning random numbers to user space is
    necessarily a great idea.. That said, I think we already do it for unnamed
    pipes anyway, so I'm more wondering if we should have some way to map
    these numbers (in user space) to a valid thing, so that they wouldn't just
    be random numbers.

I don't know. We can try in-kernel to give these well-known services
well-known numbers. Or we can give them essentially random
numbers like today but publish these somewhere, e.g. under /sys.
Both are easy, but seem too heavy for a value used by nobody.
We have process IDs and anonymous fs IDs, and both are just what
they happen to be.


Andries


[If userspace wants to know the present value, then create a socket,
stat, 3! Create a pipe, stat, 7!]