Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751779AbbEQDsY (ORCPT ); Sat, 16 May 2015 23:48:24 -0400 Received: from mail-ig0-f173.google.com ([209.85.213.173]:36483 "EHLO mail-ig0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750849AbbEQDsM (ORCPT ); Sat, 16 May 2015 23:48:12 -0400 MIME-Version: 1.0 In-Reply-To: <20150517131203.7342afc8@notabene.brown> References: <20150514033040.GF7232@ZenIV.linux.org.uk> <20150514112304.GT15721@dastard> <20150516093022.51e1464e@notabene.brown> <20150516112503.2f970573@notabene.brown> <20150516014718.GO7232@ZenIV.linux.org.uk> <20150516144527.20b89194@notabene.brown> <20150516054626.GS7232@ZenIV.linux.org.uk> <20150516141811.GT7232@ZenIV.linux.org.uk> <20150517131203.7342afc8@notabene.brown> Date: Sat, 16 May 2015 20:48:11 -0700 X-Google-Sender-Auth: Ue2nyck0L0u357VT_rH4RD2muLc Message-ID: Subject: Re: [RFC][PATCHSET v3] non-recursive pathname resolution & RCU symlinks From: Linus Torvalds To: NeilBrown Cc: Al Viro , Andreas Dilger , Dave Chinner , Linux Kernel Mailing List , linux-fsdevel , Christoph Hellwig 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: 1245 Lines: 28 On Sat, May 16, 2015 at 8:12 PM, NeilBrown wrote: > > The problem isn't getting intermediates. The problem is that not having > intermediates confuses the dcache. When the dcache is just providing a > caching service, and not providing a consistency service, then it shouldn't > let itself get confused. The dcache is much more than just a cache. It *is* in control. You may not like it, but in the big picture, one odd filesystem not liking it isn't a big deal. Sorry, but that really is how it is. NFS isn't special enough for some badly designed lookup models to matter one whit. And caching si *so* effective, that the actual lookup case isn't the primary thing. Yes, you can find loads where caching doesn't work well. But they are odd and not all that important. The cases where caches dominate are *much* more common. Designing things around the 1% case (or the 0.01%) would be completely insane. The dcache and the vfs is designed for the 99.9% case. 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/