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	Wed, 08 Apr 2026 06:57:19 +0000
Date: Wed, 8 Apr 2026 07:57:19 +0100
From: Al Viro <viro@zeniv.linux.org.uk>
To: Paulo Alcantara <pc@manguebit.org>
Cc: NeilBrown <neil@brown.name>, smfrench@gmail.com,
	David Howells <dhowells@redhat.com>, linux-fsdevel@vger.kernel.org,
	linux-cifs@vger.kernel.org
Subject: Re: [PATCH 2/2] smb: client: add support for O_TMPFILE
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Sender: Al Viro <viro@ftp.linux.org.uk>

On Mon, Apr 06, 2026 at 10:28:51PM -0300, Paulo Alcantara wrote:

> IIUC, this is what we currently have
> 
> * cifs_atomic_open()
> 
>   init state: in-lookup or hashed-negative
>   [d_drop() + d_add()]
>   end state: hashed-positive
> 
> * cifs_tmpfile()
> 
>   init state: unhashed-negative
>   [d_drop() + d_instantiate()]
>   end state: unhashed-positive
> 
> * cifs_create()
> 
>   init state: hashed-negative
>   [d_drop() + d_add()]
>   end state: hashed-positive

IDGI.  Why shouldn't cifs_create() simply do d_instantiate() instead
of that dance, ditto for cifs_tmpfile()?

The only case where you want to change the hashed status is in-lookup
O_CREAT ->atomic_open().  And there it's not d_drop()+d_add() - it's
d_splice_alias().

I'd lift that d_drop() out of cifs_do_create() into the callers and
get rid of it, along with d_add()...