Re: [PATCH] nanosecond resolution for stat(2)

[Kai Henningsen]

[e-mail] (Linus Torvalds)  wrote on 23.09.02 in <[e-mail]>:

> On Mon, 23 Sep 2002, Andi Kleen wrote:
> >
> > Some drivers (like mouse drivers or tty) do dubious inode [mac] time
> > accesses of the on disk inode and without even marking it dirty. This is
> > likely a bug.
>
> No, it is intentional. At least some versions of "w" (maybe all) will use
> the tty access times to judge how long the tty has been idle. The point is
> that this is all information that is interesting (and useful), but not
> worth sending to disk - it is useful only as long as the inode remains
> locked in-core for other reasons, ie being in use.
>
> (It's not only "not worth it" to send to disk, but it would be positively
> wrong to even _try_ updating the disk with the access times, since we want
> these things to work even with a read-only /dev).

Should there perhaps be a special function for this - say  
device_atime_update_nowrite() or something like that, to make it clearer  
what happens? You could put something like you just wrote as a comment  
before that function ...

MfG Kai