Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964798AbWIPWaU (ORCPT ); Sat, 16 Sep 2006 18:30:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964796AbWIPWaT (ORCPT ); Sat, 16 Sep 2006 18:30:19 -0400 Received: from emailer.gwdg.de ([134.76.10.24]:2510 "EHLO emailer.gwdg.de") by vger.kernel.org with ESMTP id S964789AbWIPWaQ (ORCPT ); Sat, 16 Sep 2006 18:30:16 -0400 Date: Sun, 17 Sep 2006 00:26:22 +0200 (MEST) From: Jan Engelhardt To: Josef Sipek cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, hch@infradead.org, akpm@osdl.org, viro@ftp.linux.org.uk Subject: Re: [PATCH 05/22][RFC] Unionfs: Copyup Functionality In-Reply-To: <20060916221341.GB28659@filer.fsl.cs.sunysb.edu> Message-ID: References: <20060901013512.GA5788@fsl.cs.sunysb.edu> <20060901014251.GF5788@fsl.cs.sunysb.edu> <20060904092534.GA19836@filer.fsl.cs.sunysb.edu> <20060916221341.GB28659@filer.fsl.cs.sunysb.edu> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Spam-Report: Content analysis: 0.0 points, 6.0 required _SUMMARY_ Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1513 Lines: 37 >> >> Is BUG the right thing, what do others think? (Using WARN, and set err to >> >> something useful?) >> > >> >Well, it is definitely a condition which Unionfs doesn't expect - if it >> >doesn't know about the type, how could it copy it up? >> >> Other filesystems don't seem to BUG either (at least I have not run into >> that yet) when - for whatever reasons - the statdata of a dentry is >> fubared. `ls` just displays it then, like >> >> ?-w---Sr-T 1 root root 4294967295 date fubared_file > >I was thinking about this, and the difference between "other filesystems" >and unionfs in this case is that the example above is just stat. During >copyup, unionfs has to copy the file to another filesystem. How is it >supposed to do that when it doesn't understand what the file is? > >Sure, when unionfs does stat, fubared statdata is fine, but during >copyup...bad things could potentially happen. > >Any suggestions how to copyup an unknown file type? Return some error value if possible. -EIO, banners, big printk()s, anything. Tell the user the filesytem on some branch is hosed - or too advanced to be understood by unionfs. (There seems to be a variety of file types in other UNIXes according to `man 2 stat`, such as doors, etc.) Jan Engelhardt -- - 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/