Re: [PATCH] vfs: new O_NODE open flag

Dr. David Alan Gilbert
2009-09-25T17:35:27Z

* Valdis.Kletnieks@vt.edu (Valdis.Kletnieks@vt.edu) wrote:
> On Fri, 25 Sep 2009 13:37:47 BST, "Dr. David Alan Gilbert" said:
>
> > Given an fd opened in this way is it possible to reopen it normally and
> > be guarenteed to get the same object?
>
> It's not possible even without this flag. Consider:
>
> fd1 = open("/tmp/foo",flags);
> rc = rename("/tmp/foo","/tmp/bar");
> fd2 = open("/tmp/foo",flags);
>
> Or were you asking if *absent that sort of tomfoolery* if it would work?

I know it's not possible without this flag, my interest is whether
it would be possible WITH this flag to promote an fd opened with the
O_NODE to a normal fd, guaranteeing that it's still operating on the
same object. The case I'm (vaguely) thinking of is open with O_NODE,
fstat it, come to the conslusion it's not a device and then proceed
to open it and read from it.

Dave

--
-----Open up your eyes, open up your mind, open up your code -------
/ Dr. David Alan Gilbert | Running GNU/Linux on Alpha,68K| Happy \
\ gro.gilbert @ treblig.org | MIPS,x86,ARM,SPARC,PPC & HPPA | In Hex /
\ _________________________|_____ http://www.treblig.org |_______/