Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753481AbZLAE1D (ORCPT ); Mon, 30 Nov 2009 23:27:03 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753474AbZLAE07 (ORCPT ); Mon, 30 Nov 2009 23:26:59 -0500 Received: from filer.fsl.cs.sunysb.edu ([130.245.126.2]:55039 "EHLO filer.fsl.cs.sunysb.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752314AbZLAE06 (ORCPT ); Mon, 30 Nov 2009 23:26:58 -0500 Date: Mon, 30 Nov 2009 23:26:30 -0500 Message-Id: <200912010426.nB14QUt0030633@agora.fsl.cs.sunysb.edu> From: Erez Zadok To: Valerie Aurora Cc: Jan Blunck , Alexander Viro , Christoph Hellwig , Andy Whitcroft , Scott James Remnant , Sandu Popa Marius , Jan Rekorajski , "J. R. Okajima" , Arnd Bergmann , Vladimir Dronnikov , Felix Fietkau , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 38/41] union-mount: Make pivot_root work with union mounts In-reply-to: Your message of "Wed, 21 Oct 2009 12:19:36 PDT." <1256152779-10054-39-git-send-email-vaurora@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1713 Lines: 47 In message <1256152779-10054-39-git-send-email-vaurora@redhat.com>, Valerie Aurora writes: > When moving a union mount, follow it down to the bottom layer and move > that instead of just the top layer. > > Signed-off-by: Valerie Aurora > --- > fs/namespace.c | 9 +++++++++ > 1 files changed, 9 insertions(+), 0 deletions(-) > > diff --git a/fs/namespace.c b/fs/namespace.c > index 9b71743..6ac5fc1 100644 > --- a/fs/namespace.c > +++ b/fs/namespace.c > @@ -2282,6 +2282,15 @@ SYSCALL_DEFINE2(pivot_root, const char __user *, new_root, > if (d_unlinked(old.dentry)) > goto out2; > error = -EBUSY; > + /* > + * follow_union_down() only goes one layer down. We want the > + * bottom-most layer here - if we move that around, all the > + * layers on top move with it. But if we ever allow more than > + * two layers, the below two will both need to be in while() > + * loops. > + */ Given the nature of this comment, I'd stick an "XXX" there for easier ability to grep-the-src-for-issues. > + follow_union_down(&new.mnt, &new.dentry); > + follow_union_down(&root.mnt, &root.dentry); > if (new.mnt == root.mnt || > old.mnt == root.mnt) > goto out2; /* loop, on the same file system */ > -- > 1.6.3.3 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html Erez. -- 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/