Re: [PATCH 1/6] Add a dentry op to handle automounting rather than abusing follow_link() [ver #2]

[David Howells <dhowells@redhat.com>]

Ian Kent <raven@themaw.net> wrote:

> Is this something others need?

Not as far as I know...  I think autofs is the only one doing out-of-kernel
automounting.

That doesn't mean it shouldn't be provided, though...

> Again, the exists vs not yet exists case for paths within indirect
> autofs mounts. At the moment I can just set the flag on all dentrys in
> the autofs fs and return EXDEV for non-empty directories in order to
> return the dentry as a path component. OTOH if the dentry is a mount
> embeded in the path and the mount fails we get a error return.

Seems redundant, but I'd say go with it for now.  Maybe we can offload
S_AUTOMOUNT to the dentry.

> I could clear the flag on non-root parent dentrys during mkdir if this
> is needed by others.

I'm not sure that would actually matter, since it would come to
follow_automount() at the same place.

Note that someone who tries to stat() with AT_NO_AUTOMOUNT will cause the call
to d_automount() to be suppressed and will see the negative or non-mounted
directory.  That might be okay for you.

David