Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760617AbXFTH6M (ORCPT ); Wed, 20 Jun 2007 03:58:12 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757385AbXFTH55 (ORCPT ); Wed, 20 Jun 2007 03:57:57 -0400 Received: from main.gmane.org ([80.91.229.2]:36615 "EHLO ciao.gmane.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758051AbXFTH54 (ORCPT ); Wed, 20 Jun 2007 03:57:56 -0400 X-Injected-Via-Gmane: http://gmane.org/ To: linux-kernel@vger.kernel.org From: Jan Blunck Subject: Re: [RFC PATCH 2/4] Mount changes to support union mount. Date: Wed, 20 Jun 2007 07:47:11 +0000 (UTC) Organization: SUSE LINUX Products GmbH, GF Markus Rex, HRB 16746 (AG Nuernberg) Message-ID: References: <20070620055050.GB4267@in.ibm.com> <20070620055241.GD4267@in.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Complaints-To: usenet@sea.gmane.org X-Gmane-NNTP-Posting-Host: charybdis-ext.suse.de User-Agent: pan 0.119 (Karma Hunters) Cc: linux-fsdevel@vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1237 Lines: 30 On Wed, 20 Jun 2007 11:22:41 +0530, Bharata B Rao wrote: > +/* > + * When propagating mount events to peer group, this is called under > + * vfsmount_lock. Hence using GFP_ATOMIC for kmalloc here. > + * TODO: Can we use a separate kmem cache for union_mount ? > + */ > +struct union_mount *alloc_union_mount(struct vfsmount *src_mnt, > + struct dentry *src_dentry, struct vfsmount *dst_mnt, > + struct dentry *dst_dentry) > +{ > + struct union_mount *u; > + u = kmalloc(sizeof(struct union_mount), GFP_ATOMIC); > + if (!u) > + return u; > + u->dst_mnt = mntget(dst_mnt); > + u->dst_dentry = dget(dst_dentry); > + u->src_mnt = src_mnt; > + u->src_dentry = dget(src_dentry); > + INIT_LIST_HEAD(&u->hash); > + INIT_LIST_HEAD(&u->list); > + return u; > +} Hmm, you pin the dentries in memory until umount. This isn't good. Besides that this doesn't work with file systems that do invalidate their dentries. The file system must have a chance to replace the dentry in the union structure. Jan - 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/