Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261733AbVEWPEj (ORCPT ); Mon, 23 May 2005 11:04:39 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261886AbVEWPEd (ORCPT ); Mon, 23 May 2005 11:04:33 -0400 Received: from rev.193.226.233.9.euroweb.hu ([193.226.233.9]:24070 "EHLO dorka.pomaz.szeredi.hu") by vger.kernel.org with ESMTP id S261733AbVEWPCw (ORCPT ); Mon, 23 May 2005 11:02:52 -0400 To: raven@themaw.net CC: linux-fsdevel@vger.kernel.org, autofs@linux.kernel.org, linux-kernel@vger.kernel.org In-reply-to: (raven@themaw.net) Subject: Re: [VFS-RFC] autofs4 and bind, rbind and move mount requests References: Message-Id: From: Miklos Szeredi Date: Mon, 23 May 2005 17:02:36 +0200 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1867 Lines: 42 > I've been investigating a bug report about bind mounting an autofs > controlled mount point. It is indeed disastrous for autofs. It would be > simple enough it to check and fail silently but that won't give sensible > behavior. > > What should the semantics be for these type of mount requests against > autofs? > > First, a move mount doesn't make sense as it places the autofs > filesystem in a location that is not specified in the autofs map to which > it belongs. It looks like the user space daemon would loose contact with > the newly mounted filesystem and so it would become useless and probably > not umountable, not to mention how the daemon would handle it. I believe > that this shouldn't be allowed. What do people think? If we don't treat > these as invalid then how should they behave? Move is very similar to rbind + umount. So if you find sane semantics for the rbind case, that should do for move as well. > Bind mount requests are another question. > > In the case of a bind mount we can find ourselves with a dentry in the > bound filesystem that is marked as mounted but can't be followed > because the parent vfsmount is in the source filesystem. I don't understand this. A bind will just copy a vfsmount and add the copy to some other place in the mount tree. It should not matter if the original mount was automounted or not. What am I missing? > Should the automount functionality go along with the bind mount > filesystem? No. With bind you copy the mount to another place. Now it has nothing to do with the automouter, it becomes a perfectly ordinary mount. Miklos - 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/