Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751988Ab3IKEMl (ORCPT ); Wed, 11 Sep 2013 00:12:41 -0400 Received: from mail-vc0-f171.google.com ([209.85.220.171]:54755 "EHLO mail-vc0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750874Ab3IKEMk (ORCPT ); Wed, 11 Sep 2013 00:12:40 -0400 MIME-Version: 1.0 In-Reply-To: <20130911035636.GI13318@ZenIV.linux.org.uk> References: <522FCC06.3090907@hp.com> <20130911035636.GI13318@ZenIV.linux.org.uk> Date: Tue, 10 Sep 2013 21:12:39 -0700 X-Google-Sender-Auth: SW9xhAAYzA8xIWEBMXxuXBFBJOA Message-ID: Subject: Re: kernel BUG at fs/dcache.c:648! with v3.11-7890-ge5c832d From: Linus Torvalds To: Al Viro Cc: Waiman Long , Mace Moneta , Josh Boyer , "Linux-Kernel@Vger. Kernel. Org" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 903 Lines: 19 On Tue, Sep 10, 2013 at 8:56 PM, Al Viro wrote: > > I do. What we need on the second pass (one where we currently > take seq_writelock()) is exclusion against writers; nothing we are > doing is worth disturbing the readers - we don't change any data > structures. And simple grabbing the spinlock, without touching the > sequence number would achieve exactly that. Writers will have to > wait and won't be able to disturb us, readers won't notice anything > happening. So yes, this extra primitive does make sense here. Ahh. Yes, as a fallback from the reader-side sequence lock that makes perfect sense.. Linus -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/