Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S270480AbTHQS3X (ORCPT ); Sun, 17 Aug 2003 14:29:23 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S270484AbTHQS3W (ORCPT ); Sun, 17 Aug 2003 14:29:22 -0400 Received: from main.gmane.org ([80.91.224.249]:711 "EHLO main.gmane.org") by vger.kernel.org with ESMTP id S270480AbTHQS3P (ORCPT ); Sun, 17 Aug 2003 14:29:15 -0400 X-Injected-Via-Gmane: http://gmane.org/ To: linux-kernel@vger.kernel.org From: Rob North Subject: Re: [RFC] ioctl vs xattr for the filesystem specific attributes Date: Sun, 17 Aug 2003 19:14:28 +0100 Message-ID: References: <8765l67rvc.fsf@devron.myhome.or.jp> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-Complaints-To: usenet@sea.gmane.org User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.4) Gecko/20030624 X-Accept-Language: en, en-us In-Reply-To: <8765l67rvc.fsf@devron.myhome.or.jp> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2796 Lines: 77 OGAWA Hirofumi wrote: > Hi, > > Bastien Roucaries writes: > > >>This patch implement an "extended attributes" (XATTR) hook in aim to read or >>modify specific fatfs flags' like ARCHIVE or SYSTEM. >> >>I believe it's a good idea because : >> - PAX ( GNU replacement of tar) save and restore XATTRs, so you can make more >>exact save of FATfs without use of specific programs. >> - It's an elegant means to avoid use of mattrib. >> - Samba can use this . >>but CONS : >> - use 2 Kb of kernel memory. > > > Bastien Roucaries writes: > > >>Indeed some flags are shared by many namespace for instance immutable is >>shared by xfs,ext2/3,jfs and by the fat ( with a special mount option). >>Compress also is a very common flag >>This flags are in the "common" sub-namespace. >> >>But some are fs specifics for instance notail attr of reiserfs,shortname of >>fat.They are in the the "spec"sub-namespace > > > I received the above email. > > This read/modify the file attributes of filesystem specific via xattr > interface (in this case, ARCHIVE, SYSTEM, HIDDEN flags of fatfs). > > Yes, also we can provide it via ioctl like ext2/ext3 does now. > > But if those flags provides by xattr interfaces and via one namespace > prefix, I guess the app can save/restore easy without dependency of > one fs. > > Which interface would we use for attributes of filesystem specific? > Also if we use xattr, what namepace prefix should be used? > > Any idea? > > Thanks. > I like the ideas that the patch seems to propose. Infact I'd like to see the use of xattr used for non-standard attributes applied to all fs. Specifically, I want to backup all partitions, and attribs from one OS: Linux. I do not want to loose fat attributes during backup. This would also be useful for the Wine developers. If you haven't got a response to your questions, maybe make your own decisions and submit a patch anyway. One question: How does the patch deal with the fact that only some named xattrs are permitted? I see 2 options: 1. all files/dirs in fat mount posess fat-specific xattrs. These xattrs are initialised at file/dir create. No further attribs can be added, none can be deleted. the fat attribute's Boolean value is defined by extended attribute's value. 2. all fat-specific attribs are optional, absence/presence defines boolean value. All operations are permitted, but can only add the fat-specific attributes. I prefer option 1, as it makes clear what attributes are available. - 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/