From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [RFC] Support for stackable file systems on top of nfs Date: Thu, 10 Nov 2005 20:07:41 +0000 Message-ID: <20051110200741.GA23192@infradead.org> References: <1131643942.9389.17.camel@kleikamp.austin.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: nfsv4 , fsdevel Return-path: Received: from pentafluge.infradead.org ([213.146.154.40]:32734 "EHLO pentafluge.infradead.org") by vger.kernel.org with ESMTP id S1750757AbVKJUHu (ORCPT ); Thu, 10 Nov 2005 15:07:50 -0500 To: Dave Kleikamp Content-Disposition: inline In-Reply-To: <1131643942.9389.17.camel@kleikamp.austin.ibm.com> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On Thu, Nov 10, 2005 at 11:32:22AM -0600, Dave Kleikamp wrote: > The following patch allows stackable file systems, such as ClearCase's > mvfs, to run atop nfs. mvfs has it's own file and inode structures, but > points its inode->i_mapping to the lower file system's mapping. This > causes problems when nfs's address space operations try to extract the > open context from file->private_data. > > The patch adds a small overhead of checking the file structure to see if > it contains an inode that is not the mapping's host. > > I am curious if there are any other stackable file systems that could > benefit from this. A stackable filesystem must never call underlying methods with it's own file structures. Whatever filesystem you use (I suspect the broken piepce of clearcase shit that's always causing trouble) needs to be fixed instead.