From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755940AbbANIkF (ORCPT ); Wed, 14 Jan 2015 03:40:05 -0500 Received: from bombadil.infradead.org ([198.137.202.9]:48319 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755922AbbANIkA (ORCPT ); Wed, 14 Jan 2015 03:40:00 -0500 Date: Wed, 14 Jan 2015 00:39:51 -0800 From: Christoph Hellwig To: Richard Weinberger Cc: Christoph Hellwig , user-mode-linux-devel@lists.sourceforge.net, dxld@darkboxed.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH] hostfs: Use noop_fsync for directories Message-ID: <20150114083951.GA29714@infradead.org> References: <1421187358-32600-1-git-send-email-richard@nod.at> <20150113221958.GA27739@infradead.org> <54B59B9E.4000806@nod.at> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <54B59B9E.4000806@nod.at> User-Agent: Mutt/1.5.23 (2014-03-12) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 13, 2015 at 11:26:38PM +0100, Richard Weinberger wrote: > hostfs tries do reduce the amount of syscall between guest and host as much > as possible. For file operations it passes everything down to the host but > for directory operations only ->iterate() does. > > It is already horrible slow, if we add an ->open() for directory too it would > get even more slower. :-( This sounds fairlt dangerous. At least add some good documentation explaining these semantics.