Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753416AbaBPAD4 (ORCPT ); Sat, 15 Feb 2014 19:03:56 -0500 Received: from mail-ve0-f181.google.com ([209.85.128.181]:56607 "EHLO mail-ve0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752317AbaBPADy (ORCPT ); Sat, 15 Feb 2014 19:03:54 -0500 MIME-Version: 1.0 In-Reply-To: <87a9ds55av.fsf@xmission.com> References: <87a9kkax0j.fsf@xmission.com> <8761v7h2pt.fsf@tw-ebiederman.twitter.com> <87li281wx6.fsf_-_@xmission.com> <87ob28kqks.fsf_-_@xmission.com> <87bny8kqik.fsf_-_@xmission.com> <87a9ds55av.fsf@xmission.com> Date: Sat, 15 Feb 2014 16:03:53 -0800 X-Google-Sender-Auth: e_cqroyEPYq1bb4FB6V1A1DfEx8 Message-ID: Subject: Re: [PATCH 02/11] vfs: More precise tests in d_invalidate From: Linus Torvalds To: "Eric W. Biederman" Cc: Al Viro , "Serge E. Hallyn" , Linux-Fsdevel , Kernel Mailing List , Andy Lutomirski , Rob Landley , Miklos Szeredi , Christoph Hellwig , Karel Zak , "J. Bruce Fields" Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Feb 15, 2014 at 3:23 PM, Eric W. Biederman wrote: > > Except that today d_invalidate drops the dcache lock and > calls shrink_dcache_parent. Which gets you into exactly the same > complex "walk parents and check all siblings" code. Hmm. It only does that for directories that have sub-entries, though. I think you may care just about directories (because that's what your series is about), but d_invalidate() is used for other cases too, notably d_revalidate() (ie things like stale NFS lookups of normal files). That said, I'll have to think about this more. If d_subdir is empty, I guess d_walk() will be fairly cheap. It's very different, but maybe not as disastrous as I thought. 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/