From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752662AbbJLNsi (ORCPT ); Mon, 12 Oct 2015 09:48:38 -0400 Received: from mail-wi0-f182.google.com ([209.85.212.182]:34275 "EHLO mail-wi0-f182.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752473AbbJLNsd (ORCPT ); Mon, 12 Oct 2015 09:48:33 -0400 Date: Mon, 12 Oct 2015 15:50:05 +0200 From: Miklos Szeredi To: Alban Crequy Cc: David Howells , sds@tycho.nsa.gov, Alexander Viro , linux-fsdevel@vger.kernel.org, LSM , linux-unionfs@vger.kernel.org, "linux-kernel@vger.kernel.org" , Iago =?utf-8?B?TMOzcGV6?= Galeiras Subject: Re: overlayfs: regression bug from 4bacc9c9 (Make f_path always point to the overlay and f_inode to the underlay) Message-ID: <20151012135005.GA10697@tucsk> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Oct 07, 2015 at 02:23:23PM +0200, Alban Crequy wrote: > Hi, > > I'm reporting an issue in overlay fs that was introduced in v4.2 (it > worked on v4.1): when overlay fs is mounted inside a overlay fs, I get > a "no such device or address" error (ENXIO) during open(). After > adding some debug printks, I found that the ENXIO comes from > fs/inode.c:no_open(). > > The bug was initially reported on: > https://github.com/coreos/rkt/issues/1537 > > The following commands can reproduce the issue: Thanks for the excellent report. See below for a fix. Please let me know if you see any issues. Thanks, Miklos --- Subject: ovl: fix open in stacked overlay From: Miklos Szeredi If two overlayfs filesystems are stacked on top of each other, then we need recursion in ovl_d_select_inode(). I guess d_backing_inode() is supposed to do that. But currently it doesn't and that functionality is open coded in vfs_open(). This is now copied into ovl_d_select_inode() to fix this regression. Reported-by: Alban Crequy Signed-off-by: Miklos Szeredi Fixes: 4bacc9c9234c ("overlayfs: Make f_path always point to the overlay...") Cc: David Howells Cc: # v4.2+ --- fs/overlayfs/inode.c | 3 +++ 1 file changed, 3 insertions(+) --- a/fs/overlayfs/inode.c +++ b/fs/overlayfs/inode.c @@ -363,6 +363,9 @@ struct inode *ovl_d_select_inode(struct ovl_path_upper(dentry, &realpath); } + if (realpath.dentry->d_flags & DCACHE_OP_SELECT_INODE) + return realpath.dentry->d_op->d_select_inode(realpath.dentry, file_flags); + return d_backing_inode(realpath.dentry); }