From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Howells Subject: Re: More questions on unionmount Date: Fri, 13 May 2011 14:54:00 +0100 Message-ID: <9194.1305294840@redhat.com> References: <25449.1305223821@redhat.com> Cc: dhowells@redhat.com, linux-fsdevel@vger.kernel.org To: Valerie Aurora , viro@zeniv.linux.org.uk Return-path: Received: from mx1.redhat.com ([209.132.183.28]:63810 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756572Ab1EMNyF (ORCPT ); Fri, 13 May 2011 09:54:05 -0400 In-Reply-To: <25449.1305223821@redhat.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Hmmm... | /** | * clone_union_tree - Clone all union-able mounts at this mountpoint | * @topmost: vfsmount of topmost layer | * @mntpnt: target of union mount | * | * Given the target mountpoint of a union mount, clone all the mounts at that | * mountpoint (well, pathname) that qualify as a union lower layer. ... Is this so that the unionmount can survive MS_BIND and MS_MOVE? | * Returns error if any of the mounts or submounts mounted on or below this | * pathname are unsuitable for union mounting. This means you can't construct | * a union mount at the root of an existing mount without unioning it. If I understand this correctly, I'd rephrase this to be: * Returns an error if any of the stack of mounts or submounts currently * mounted on @mntpnt are unsuitable for union mounting. This means you cannot * construct a union mount over the root of an existing mount without including * it in the union or having it prevent the union. David