Re: [RFC][PATCH] saner calling conventions for ->d_automount()

[David Howells <dhowells@redhat.com>]

Al Viro <viro@zeniv.linux.org.uk> wrote:

> Currently the calling conventions for ->d_automount() instances have
> an odd wart - returned new mount to be attached is expected to have
> refcount 2.
> 
> That kludge is intended to make sure that mark_mounts_for_expiry() called
> before we get around to attaching that new mount to the tree won't decide
> to take it out.  finish_automount() drops the extra reference after it's
> done with attaching mount to the tree - or drops the reference twice in
> case of error.  ->d_automount() instances have rather counterintuitive
> boilerplate in them.
> 
> There's a much simpler approach: have mark_mounts_for_expiry() skip the
> mounts that are yet to be mounted.  And to hell with grabbing/dropping
> those extra references.  Makes for simpler correctness analysis, at that...
>     
> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

You can test this by installing the kafs-client package, telling systemd to
start afs.mount and then doing "ls /afs/openafs.org/doc", say.

Acked-by: David Howells <dhowells@redhat.com>
Tested-by: David Howells <dhowells@redhat.com>