Re: [RFC][PATCH] Add a dentry op to handle automounting rather than abusing follow_link

[David Howells <dhowells@redhat.com>]

Nick Piggin <npiggin@suse.de> wrote:

> I think you have it the wrong way around. If you wanted to call the
> automount code, you would have incremented d_mounted.

Why?  d_mounted indicates how many things are mounted on a dentry, doesn't it?
Before the automounter is invoked there isn't anything mounted there.

> Those that don't care wouldn't set ->follow_mount though.  Following a mount
> is a fairly heavy operation already, it does take a global lock (before vfs
> scalability patches, anyway).

I wonder if we could do it with a lock on vfsmount instead and use mnt_mounts
to find it.

> I like the flexibility of doing one's own ->follow_mount, although Al might
> object to allowing filesystems to follow mounts in ways that are not
> published to the core namespace structures.

But why would you want to delegate mountpoint traversal to the filesystem?

David