Re: [PATCH v2 3/3] smb/client: Use d_alloc_trylock() in cifs_prime_dcache()

[NeilBrown]

On Fri, 23 Oct 2026, Paulo Alcantara wrote:
> NeilBrown <neilb@xxxxxxxxxxx> writes:
> 
> > @@ -77,36 +77,34 @@ cifs_prime_dcache(struct dentry *parent, struct qstr *name,
> >  
> >  	cifs_dbg(FYI, "%s: for %s\n", __func__, name->name);
> >  
> > -	dentry = try_lookup_noperm(name, parent);
> > -	if (!dentry) {
> > -		/*
> > -		 * If we know that the inode will need to be revalidated
> > -		 * immediately, then don't create a new dentry for it.
> > -		 * We'll end up doing an on the wire call either way and
> > -		 * this spares us an invalidation.
> > -		 */
> > -retry:
> > -		if (posix) {
> > -			switch (fattr->cf_mode & S_IFMT) {
> > -			case S_IFLNK:
> > -			case S_IFBLK:
> > -			case S_IFCHR:
> > -				reparse_need_reval = true;
> > -				break;
> > -			default:
> > -				break;
> > -			}
> > -		} else if (fattr->cf_cifsattrs & ATTR_REPARSE_POINT) {
> > +	/*
> > +	 * If we know that the inode will need to be revalidated
> > +	 * immediately, then don't create a new dentry for it.
> > +	 * We'll end up doing an on the wire call either way and
> > +	 * this spares us an invalidation.
> > +	 */
> > +	if (posix) {
> > +		switch (fattr->cf_mode & S_IFMT) {
> > +		case S_IFLNK:
> > +		case S_IFBLK:
> > +		case S_IFCHR:
> >  			reparse_need_reval = true;
> > +			break;
> > +		default:
> > +			break;
> >  		}
> > +	} else if (fattr->cf_cifsattrs & ATTR_REPARSE_POINT) {
> > +		reparse_need_reval = true;
> > +	}
> >  
> > -		if (reparse_need_reval ||
> > -		    (fattr->cf_flags & CIFS_FATTR_NEED_REVAL))
> > -			return;
> > +retry:
> > +	if (reparse_need_reval ||
> > +	    (fattr->cf_flags & CIFS_FATTR_NEED_REVAL))
> > +		dentry = try_lookup_noperm(name, parent);
> > +	else
> > +		dentry = d_alloc_trylock(parent, name);
> >  
> > -		dentry = d_alloc_parallel(parent, name);
> > -	}
> > -	if (IS_ERR(dentry))
> > +	if (!dentry || IS_ERR(dentry))
> 
> nit: IS_ERR_OR_NULL(dentry)
> 

I'll fix that thanks.
We should really try to get rid of functions (try_lookup_noperm() in
this case) which return a NULL or an error - but that's for another day.

Thanks,
NeilBrown