Re: [PATCH] ext3: fsid for statvfs

On Tue, Oct 10, 2006 at 01:36:36PM -0700, Andrew Morton wrote:
> On Tue, 10 Oct 2006 11:32:13 +0300 (EEST)
> Pekka J Enberg <[email protected]> wrote:
> 
> > From: Pekka Enberg <[email protected]>
> > 
> > Update ext3_statfs to return an FSID that is a 64 bit XOR of the 128 bit
> > filesystem UUID as suggested by Andreas Dilger.
> 
> Deja vu.  Gosh, has it really been four years?
> 
> Combatants cc'ed ;)

Ha, you have a memory. To me this seems infinitely long ago.
Google turned up some interesting discussions on dev_t, and the below exchange.

No, at first sight I have no objections to the suggested patch.
(Although I think that fsid is used only for doubtful purposes.)

Andries

-----
Andries Brouwer wrote:
> On Mon, Dec 09, 2002 at 02:15:12PM -0800, H. Peter Anvin wrote:
>
> > > The general idea is that f_fsid contains some random stuff such that
> > > the pair (f_fsid,ino) uniquely determines a file.
>
> > This, of course, is the exact POSIX definition of the st_dev part of
> > struct stat: (st_dev, st_ino) uniquely identifies the file.
>
> Yes, but the difference is that (st_dev, st_ino) only identifies
> the file within a single machine, and may stop working when you
> have NFS mounts.