[PATCH 00/17] [RFC] AFS: Implement OpenAFS pioctls(version)s

[Al Viro]

On Wed, Jun 17, 2009 at 11:44:18AM -0700, Linus Torvalds wrote:
> > O_NOFOLLOW *will* open their mountpoints just fine, without triggering
> > automount.
> 
> That's not the problem with O_NOFOLLOW.
> 
> The problem is that if you want to actually open the symlink itself (say, 
> you do some filesystem cleanup operation on it, like saying "drop the 
> caches of this file"), you can't do it. O_NOFOLLOW won't open the symlink, 
> it will just refuse to follow it, and return an error.

... so we need a syscall that would do that "drop the caches" operation.
_After_ having decided that it's really needed for symlinks.  With decision
made on per-operation basis.  Sure, it will be painful for people proposing
such operations, which is just fine by me - barriers to adding new primitives
shouldn't be low.