From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 45BDFC77B7A for ; Thu, 25 May 2023 20:22:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241062AbjEYUWO (ORCPT ); Thu, 25 May 2023 16:22:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36594 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241242AbjEYUWN (ORCPT ); Thu, 25 May 2023 16:22:13 -0400 Received: from hr2.samba.org (hr2.samba.org [IPv6:2a01:4f8:192:486::2:0]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5D330E7 for ; Thu, 25 May 2023 13:22:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=samba.org; s=42; h=Message-ID:Cc:To:From:Date; bh=J5YQuBSYJ+Gmm+1sncCCJWxeublLtyJCgvShhMLeZQ8=; b=PukFwWrgaBc5X/SC+g8I8RKpFY xQ3ZLKWtO1NegV2D5D3XRESVApGMsmEmtCNLj0ASZvAkzpLjYF6wA6Z7Xi4DWt/eIS8nesGvt8/ld MrNnRryJtVRxZj+ptcqN68brSf61AubXm8LRMAPcXb2A53tvKH6/B+/iKubRUJNZCu+sxDUQ7dHTG +YgPDFUzfj9dAWPIwDHfe0djx31m92FfoIsfh7910SanGIVz/sZR47XyGYHr4TDTsdusw6o/xwolD zGNQ1KPJS7WyPASaOKY9bX2gnyXPQ+f2FI3gyedWl8EANJFPE1+B9eQvQ+ZsqToRkbucdN6DYGTgD sEPTnRsTzz26zKeB/icG1W50CmZCvlws8SWuz3mn2b4Hau967jn+xVlgAFlkXrCIrOLY94ALVLf5P WwXBcsePWzK0vmXZHRVDGB1jGhXimBs7kj/fFiv3F2aXQggyLxaRJrJZyDK4ltM/jIGVIL1+9uddY b1HtLL4iD+cxQiYwMVvxrNYd; Received: from [127.0.0.2] (localhost [127.0.0.1]) by hr2.samba.org with esmtpsa (TLS1.3:ECDHE_SECP256R1__ECDSA_SECP256R1_SHA256__CHACHA20_POLY1305:256) (Exim) id 1q2HTN-00CCha-0F; Thu, 25 May 2023 20:22:09 +0000 Date: Thu, 25 May 2023 13:22:02 -0700 From: Jeremy Allison To: Steve French Cc: ronnie sahlberg , Christoph Hellwig , =?iso-8859-1?Q?Bj=F6rn?= JACKE , CIFS , samba-technical Subject: Re: Displaying streams as xattrs Message-ID: Reply-To: Jeremy Allison References: <20230525093900.GA261009@sernet.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org On Thu, May 25, 2023 at 03:11:13PM -0500, Steve French wrote: >On Thu, May 25, 2023 at 11:22 AM Jeremy Allison wrote: >> >> On Thu, May 25, 2023 at 08:49:47PM +1000, ronnie sahlberg wrote: >> >> >> >> just took a look at how the ntfs-3g module is handling this. It was an option >> >> streams_interface=value, which allows "windows", which means that the >> >> alternative data streams are accessable as-is like in Windows, with ":" being >> >> the separator. This might be a nice option for cifsfs also. That option would >> >> just be usable if no posix extensions are enabled of course. > >You can already open alternate data streams remotely (from cifs.ko on Linux >as you can from Windows and Macs etc. just open "file:streamname"), but on >Linux you have to disable the reserved character mapping ("nomapposix") >otherwise ":" would get remapped on open in the Unicode conversion. > >There may be a better way to list streams in the future (e.g. to help >backup applications >that need to be able to save files created by Macs or Windows that need these >e.g. Virus checkers etc. use ADS, and looking at my Windows machines, PDFs >can have small "Zone Identifiers" saved in streams), but you can >already list them >with "smbinfo filestreaminfo " > >I was thinking mainly about backup scenarios whether this came up as >listing them >also via a pseudo-xattr (IIRC Macs do something similar). I think cifsfs providing access to ADS remotely on Windows and Samba shares is fine. What I'm scared of is adding ADS as a generic "feature" to the Linux VFS and other filesystems :-).