Re: [patch 2/3] vfs: fix sys_getcwd for detached mounts

[Al Viro <viro@ZenIV.linux.org.uk>]

On Mon, Jun 23, 2008 at 04:34:00PM +0200, Miklos Szeredi wrote:
> > > After the patch it will give a much saner "/skel" result.
> > 
> > I'm not sure that /skel is much saner, to be honest.
> 
> Just for argument's sake: before the patch getcwd() on detached object
> wasn't consistent with any definition of "absolute path".  After the
> patch it's at least consistent with defining it as the path from the
> ultimate reachable ancestor (which does have at least some historical
> relevance).

Before the patch getcwd() on detached object generated junk, period.
As for the path from ultimate reachable ancestor...  I'm not sure that
this definition actually matches any real-world problem.
 
> >  Existing
> > behaviour is BS, no arguments about that, but I suspect that
> > we want that to be recognizable.  How about doing something
> > like detached:<rest of path> instead (c.f. "pipe:[6969]" and
> > its ilk)?
> 
> OK, obviously current users don't care, otherwise somebody would have
> complained about this issue.  So if we agree on "detached:...", I'm
> fine with that.

Care to resend?  BTW, one more thing - in the 1/3 I'd probably add a
wrapper around prepend() that would take struct qstr * instead of
name/length and used it instead of your locals.  As in
	prepend_name(&end, &buflen, &dentry->d_name)
etc.