Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751726AbZKGL53 (ORCPT ); Sat, 7 Nov 2009 06:57:29 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751682AbZKGL52 (ORCPT ); Sat, 7 Nov 2009 06:57:28 -0500 Received: from out01.mta.xmission.com ([166.70.13.231]:55966 "EHLO out01.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751594AbZKGL51 (ORCPT ); Sat, 7 Nov 2009 06:57:27 -0500 To: Miklos Szeredi Cc: tj@kernel.org, serue@us.ibm.com, gregkh@suse.de, kay.sievers@vrfy.org, greg@kroah.com, linux-kernel@vger.kernel.org, cornelia.huck@de.ibm.com, linux-fsdevel@vger.kernel.org, eric.dumazet@gmail.com, bcrl@lhnet.ca, ebiederm@aristanetworks.com Subject: Re: [PATCH 12/13] sysfs: Propagate renames to the vfs on demand References: <1257249429-12384-12-git-send-email-ebiederm@xmission.com> <20091104214938.GA21033@us.ibm.com> <4AF4D76C.6090008@kernel.org> From: ebiederm@xmission.com (Eric W. Biederman) Date: Sat, 07 Nov 2009 03:57:08 -0800 In-Reply-To: (Miklos Szeredi's message of "Sat\, 07 Nov 2009 12\:12\:40 +0100") Message-ID: User-Agent: Gnus/5.11 (Gnus v5.11) Emacs/22.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-XM-SPF: eid=;;;mid=;;;hst=in02.mta.xmission.com;;;ip=76.21.114.89;;;frm=ebiederm@xmission.com;;;spf=neutral X-SA-Exim-Connect-IP: 76.21.114.89 X-SA-Exim-Mail-From: ebiederm@xmission.com X-SA-Exim-Version: 4.2.1 (built Thu, 25 Oct 2007 00:26:12 +0000) X-SA-Exim-Scanned: No (on in02.mta.xmission.com); Unknown failure Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2001 Lines: 51 Miklos Szeredi writes: > On Fri, 06 Nov 2009, ebiederm@xmission.com (Eric W. Biederman wrote: >> Tejun Heo writes: >> >> > Hello, >> > >> > Eric W. Biederman wrote: >> >> It isn't what I want but it is what the VFS requires. If let the vfs >> >> continue on it's delusional state we will leak the vfs mount and >> >> everything mounted on top of it, with no way to remove the mounts. > > "umount -l" on the whole thing will clear any submounts up too. > >> > >> > This is caused by not having any way to prevent deletion on >> > directories with submounts, right? How does other distributed >> > filesystems deal with directories with submounts going away underneath >> > it? >> >> NFS does exactly the same thing I am doing. > > Yes, this is a problem for NFS too. You cannot tell the NFS server > "this directory is mounted on some client, don't let anything happen > to it!". Basically the remaining choices are: > > a) let the old path leading up to the mount still be accessible, even > though it doesn't exist anymore on the server (or has been replaced > with something different) > > b) automatically dissolve any submounts if the path disappeard on the > server > > I think Al was arguing in favor of b), while Linus said that mounts > must never just disappear, so a) is better. I don't think an > agreement was reached. I haven't seen that conversation. I do know it is non-intutive and if you attempt to delete what is a mount point in another mount namespace and it won't go away. (What we do for non-distributed filesystems). So I would favor mount points dissolving if we had the infrastructure. Regardless the goal for now is to simply catch up with other distributed filesystems. Eric -- 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/