Re: [PATCH] one of $BIGNUM devfs races

Richard Gooch
2001-08-08T23:30:04Z

Alexander Viro writes:
>
> On 8 Aug 2001, H. Peter Anvin wrote:
>
> > Followup to: <Pine.GSO.4.21.0108071510390.18565-100000@weyl.math.psu.edu>
> > By author: Alexander Viro <viro@math.psu.edu>
> > In newsgroup: linux.dev.kernel
> > >
> > > It is not reliable. E.g. on NFS inumbers are not unique - 32 bits is
> > > not enough.
> >
> > Unfortunately there is a whole bunch of other things too that rely on
> > it, and *HAVE* to rely on it -- (st_dev, st_ino) are defined to
> > specify the identity of a file, and if the current types aren't large
> > enough we *HAVE* to go to new types. THERE IS NO OTHER WAY TO TEST
> > FOR FILE IDENTITY IN UNIX, and being able to perform such a test is
> > vital for many things, including security and hard link detection
>
> Indeed, but it still doesn't help libc5 getcwd(3), which uses 32 bit
> values.

FYI: the problem that spawned this sub-thread is fixed. The
devfs-patch-v185 that I released last night fixes this. So the libc5
getcwd(3) is fine with 32 bit inums on devfs.

Filesystems with larger inums are left as an exercise for the reader
:-)

Regards,

Richard....
Permanent: rgooch@atnf.csiro.au
Current: rgooch@ras.ucalgary.ca