From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752684AbcGFDU7 (ORCPT ); Tue, 5 Jul 2016 23:20:59 -0400 Received: from zeniv.linux.org.uk ([195.92.253.2]:48086 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751406AbcGFDU5 (ORCPT ); Tue, 5 Jul 2016 23:20:57 -0400 Date: Wed, 6 Jul 2016 04:20:55 +0100 From: Al Viro To: Oleg Drokin Cc: Mailing List , "" Subject: Re: More parallel atomic_open/d_splice_alias fun with NFS and possibly more FSes. Message-ID: <20160706032055.GQ14480@ZenIV.linux.org.uk> References: <20160703062917.GG14480@ZenIV.linux.org.uk> <94F1587A-7AFC-4B48-A0FC-F4CE152F18CC@linuxhacker.ru> <20160705123110.GL14480@ZenIV.linux.org.uk> <20160705135149.GM14480@ZenIV.linux.org.uk> <6D633478-6B94-465E-84D7-C0BA59C5E5F5@linuxhacker.ru> <20160705180841.GO14480@ZenIV.linux.org.uk> <1C63FC85-848B-486F-8223-F5CEB5C39848@linuxhacker.ru> <20160705200826.GP14480@ZenIV.linux.org.uk> <1587788B-C7F6-4D19-BDAD-29846231CD6C@linuxhacker.ru> <6188A470-DF7F-44CE-89F0-117EC2FA1677@linuxhacker.ru> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <6188A470-DF7F-44CE-89F0-117EC2FA1677@linuxhacker.ru> User-Agent: Mutt/1.6.0 (2016-04-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 05, 2016 at 08:29:37PM -0400, Oleg Drokin wrote: > > + /* Otherwise we just unhash it to be rehashed afresh via > > + * lookup if necessary > > + */ > > + d_drop(dentry); > > So we can even drop this part and retain the top condition as it was. > d_add does not care if the dentry we are feeding it was hashed or not, > so do you see any downsides to doing that I wonder? d_add() on hashed dentry will end up reaching this: static void __d_rehash(struct dentry * entry, struct hlist_bl_head *b) { BUG_ON(!d_unhashed(entry));