From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kara Subject: Re: Can someone explain s_xattr field in the superblock? Date: Tue, 31 May 2011 20:47:03 +0200 Message-ID: <20110531184703.GA20905@quack.suse.cz> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-fsdevel@vger.kernel.org To: Sam Gandhi Return-path: Received: from cantor.suse.de ([195.135.220.2]:52175 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758091Ab1EaSrE (ORCPT ); Tue, 31 May 2011 14:47:04 -0400 Content-Disposition: inline In-Reply-To: Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Hello, On Tue 31-05-11 11:23:33, Sam Gandhi wrote: > I have seen some file systems like jffs2/ext4 etc setup the s_xattr > field in the superblock structure. > But there are files systems that do not initialize s_xattr field in > the superblock. Only filesystems that support extended attributes setup s_xattr. > Can someone kindly explain what functionality does s_xattr on super > block provides? What kinds of things file system wouldn't be able to > do if the superblock doesn't have this initialized? It tells VFS what callbacks to call when user tries to obtain/change extended attributes. If s_xattr is left at NULL, user will get EOPNOTSUPP or similar error... Honza -- Jan Kara SUSE Labs, CR