Re: [PATCH 2/2] smb: client: add support for O_TMPFILE

[Paulo Alcantara <pc@manguebit.org>]

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

> 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()?

Yes, makes sense.  Especially d_drop() for cifs_tmpfile() which is
simply a no-op.

> 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().

ACK.

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

Sounds good.  Let me play with it a little bit and, if tests survive,
will send a follow-up patch fixing all that mess.