Re: [PATCH v2 7/7] Use simple_start_creating() in various places.

[Al Viro <viro@zeniv.linux.org.uk>]

On Wed, Sep 10, 2025 at 05:12:49AM +0100, Al Viro wrote:
> On Wed, Sep 10, 2025 at 01:01:49PM +1000, NeilBrown wrote:
> > On Tue, 09 Sep 2025, Al Viro wrote:
> > > On Tue, Sep 09, 2025 at 02:43:21PM +1000, NeilBrown wrote:
> > > 
> > > >  	d_instantiate(dentry, inode);
> > > > -	dget(dentry);
> > > > -fail:
> > > > -	inode_unlock(d_inode(parent));
> > > > -	return dentry;
> > > > +	return simple_end_creating(dentry);
> > > 
> > > No.  This is the wrong model - dget() belongs with d_instantiate()
> > > here; your simple_end_creating() calling conventions are wrong.
> > 
> > I can see that I shouldn't have removed the dget() there - thanks.
> > It is not entirely clear why hypfs_create_file() returns with two
> > references held to the dentry....
> > I see now one is added either to ->update_file or the list at
> > hypfs_last_dentry, and the other is disposed of by kill_litter_super().
> > 
> > But apart from that one error is there something broader wrong with the
> > patch?  You say "the wrong model" but I don't see it.
> 
> See below for hypfs:

... and see viro/vfs.git#work.persistency for the part of the queue that
had order already settled down (I'm reshuffling the tail at the moment;
hypfs commit is still in the leftovers pile - the whole thing used to
have a really messy topology, with most of the prep work that used to
be the cause of that topology already in mainline - e.g. rpc_pipefs
series, securityfs one, etc.)