[Linux-cachefs] Re: [PATCH 0/7] Permit filesystem local caching and NFS superblock sharing [try #13]

[Ian Kent]

On Tue, 2006-09-05 at 11:37 +0100, David Howells wrote:
> Ian Kent <raven at themaw.net> wrote:
> 
> > > As long as you don't rely on stat...mkdir working.  That can go wrong if the
> > > dentry gets booted from the dcache by memory pressure in the "...".
> > 
> > I'm not clear on your point here.
> 
> I was wondering if you were going to rely on stat() forcing the dentry to be
> correctly initialised before you did mkdir(), but it seems not.
> 
> > If I stat a path and it exists then all is good and I'm done.
> > If I stat a path and I get something other than ENOENT then all is bad
> > and I return fail.
> > Otherwise I can just attempt to create the directory and fail if all is
> > bad with that.
> 
> Okay, I suppose.  But that still doesn't seem to deal with the case of creating
> a directory on the client that then overlays a symlink on the server that you
> can't yet access.

We're largely performing user space actions at this point.
Wouldn't the subsequent call to mount(8) catch that?

> 
> You may also get ENOENT because you stat a symlink, though you'll get EEXIST
> from mkdir, even if there's nothing at the far end.

Don't think this is something I need to care about either.
I can't mount on a symlink so the error return would be the correct way
to deal with it.

Ian