From: David Howells <dhowells-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Subject: Re: [RFC][PATCH 05/10] cifs: define superblock-level cache index objects and register them
Date: Fri, 25 Jun 2010 14:26:52 +0100
Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley
	Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United
	Kingdom.
	Registered in England and Wales under Company Registration No. 3798903
Lines: 35
Message-ID: <23204.1277472412@redhat.com>
References: <22746.1277470713@redhat.com> <4C24A4A0.90408@suse.de> <1277220206-3559-1-git-send-email-sjayaraman@suse.de> <yes> <9720.1277312290@redhat.com>
Cc: dhowells-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, Suresh Jayaraman <sjayaraman-l3A5Bk7waGM@public.gmane.org>,
	Steve French <smfrench-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>, linux-cifs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
To: unlisted-recipients:; (no To-header on input)
X-From: linux-cifs-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org Fri Jun 25 15:27:01 2010
Return-path: <linux-cifs-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Envelope-to: glkc-linux-cifs-1dZseelyfdZg9hUCZPvPmw@public.gmane.org
Received: from vger.kernel.org ([209.132.180.67])
	by lo.gmane.org with esmtp (Exim 4.69)
	(envelope-from <linux-cifs-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>)
	id 1OS8vt-0000Xv-FL
	for glkc-linux-cifs-1dZseelyfdZg9hUCZPvPmw@public.gmane.org; Fri, 25 Jun 2010 15:27:01 +0200
Received: (majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org) by vger.kernel.org via listexpand
	id S1755944Ab0FYN1A (ORCPT <rfc822;glkc-linux-cifs@m.gmane.org>);
	Fri, 25 Jun 2010 09:27:00 -0400
Received: from mx1.redhat.com ([209.132.183.28]:15634 "EHLO mx1.redhat.com"
	rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
	id S1755398Ab0FYN07 (ORCPT <rfc822;linux-cifs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>);
	Fri, 25 Jun 2010 09:26:59 -0400
Received: from int-mx04.intmail.prod.int.phx2.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.17])
	by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id o5PDQu1D020638
	(version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK);
	Fri, 25 Jun 2010 09:26:56 -0400
Received: from redhat.com (ovpn01.gateway.prod.ext.phx2.redhat.com [10.5.9.1])
	by int-mx04.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id o5PDQruU018472;
	Fri, 25 Jun 2010 09:26:54 -0400
In-Reply-To: <22746.1277470713-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
X-Scanned-By: MIMEDefang 2.67 on 10.5.11.17
Sender: linux-cifs-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Precedence: bulk
List-ID: <linux-cifs.vger.kernel.org>
X-Mailing-List: linux-cifs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Archived-At: <http://permalink.gmane.org/gmane.linux.kernel/1002964>

David Howells <dhowells-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> wrote:

> > > validate the root directory of the share in some way?
> >
> > I don't know if there is a way to do this.
> 
> Is there an inode number or something?  Even the creation time might do.

Looking in cifspdu.h, there are a number of things that it might be possible
to use.

 (1) FILE_ALL_INFO: CreationTime, IndexNumber, IndexNumber1, FileName
     (assuming this isn't flattened to '\' or something for the root of a
     share.

 (2) FILE_UNIX_BASIC_INFO: DevMajor, DevMinor, UniqueId.

 (3) FILE_INFO_STANDARD: CreationDate, CreationTime.

 (4) FILE_INFO_BASIC: CreationTime.

 (5) FILE_DIRECTORY_INFO: FileIndex, CreationTime, FileName.

 (6) SEARCH_ID_FULL_DIR_INFO: FileIndex, CreationTime, UniqueId, FileName.

 (7) FILE_BOTH_DIRECTORY_INFO: FileIndex, CreationTime, ShortName, FileName.

 (8) OPEN_RSP_EXT: Fid, CreationTime, VolumeGUID, FileId.

You may have to choose different sets of things, depending on what the server
has on offer.  Also, don't forget, if you can't work out whether a share is
coherent or not from the above, you can always use LastWriteTime, ChangeTime
and EndOfFile and just discard the whole subtree if they differ.

David