Re: [PATCH 1/8] vfs: new d_allocate method

[Al Viro]

On Wed, Jun 22, 2016 at 04:35:03PM +0200, Miklos Szeredi wrote:
> Allow filesystem to initialize dentry (->d_fsdata to be explicit) at
> allocation time.

Something similar had been discussed a while ago (I don't remember whether
you'd been on Cc, though).  E.g. ceph and lustre would benefit from having
such method (proposed name was ->d_init(), seeing that it's not always
just an allocation).  The subtle part is barriers and I would really like
to see a proof that you don't need any.