Return-Path: linux-nfs-owner@vger.kernel.org Received: from mx2.netapp.com ([216.240.18.37]:28263 "EHLO mx2.netapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752441Ab1KOGeD convert rfc822-to-8bit (ORCPT ); Tue, 15 Nov 2011 01:34:03 -0500 Message-ID: <1321338825.8267.2.camel@lade.trondhjem.org> Subject: Re: [PATCH/RFC 0/7] Volatile Filehandle Client-side Support From: Trond Myklebust To: NeilBrown Cc: "J. Bruce Fields" , Tigran Mkrtchyan , Christoph Hellwig , Matthew Treinish , linux-nfs@vger.kernel.org Date: Tue, 15 Nov 2011 08:33:45 +0200 In-Reply-To: <20111114080745.57083bfe@notabene.brown> References: <1321052673-22171-1-git-send-email-treinish@linux.vnet.ibm.com> <1321056809.8733.2.camel@lade.trondhjem.org> <20111112144953.GA3740@infradead.org> <20111113145400.6c7a9be3@notabene.brown> <20111113163632.GA28574@fieldses.org> <20111114080745.57083bfe@notabene.brown> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Sender: linux-nfs-owner@vger.kernel.org List-ID: On Mon, 2011-11-14 at 08:07 +1100, NeilBrown wrote: > If a server has objects that are never renamed, it can easily use volatile > file handles. > If a server has objects which can be renamed and wants to use volatile file > handles, then if such an object is open and is about to be renamed, it must > first log to stable storage some mapping to allow it to access the file from > the old volatile file handle. And of course it cannot allow renames during > the grace period, but I think we already have that. > Also, if the VFH is such that it will be lost on a reboot, the server must > log it to stable storage before allowing an open. BTW: If the namespace is stable, then the server can easily implement permanent filehandles. Use a hash of the pathname as the filehandle, and set up a hidden directory ('/.filehandles') containing symlinks that map said hash back to the correct pathname. No need for volatile filehandles. -- Trond Myklebust Linux NFS client maintainer NetApp Trond.Myklebust@netapp.com www.netapp.com