From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752914Ab1AHCyu (ORCPT ); Fri, 7 Jan 2011 21:54:50 -0500 Received: from mail-wy0-f174.google.com ([74.125.82.174]:41467 "EHLO mail-wy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752563Ab1AHCyt (ORCPT ); Fri, 7 Jan 2011 21:54:49 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:date:message-id:subject:from:to:content-type; b=LDCrVQOO19AQu/v0OAX4FvSPferf0krcWQ47LjySGVEpTkXByvwI9XXqk1zDP/2iwZ RvIf4HCsnCsA3MTkn4N1OgNVMIXdPB94ejBKx/gnL+K5WV8uuNBtnVb18TwOciMILhF+ zd54pcXvYg+S++0hxEeZZyLvogVIdW6QnQs2U= MIME-Version: 1.0 Date: Sat, 8 Jan 2011 13:54:47 +1100 Message-ID: Subject: Important for fs devs: rcu-walk merged upstream From: Nick Piggin To: linux-fsdevel , linux-kernel@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The vfs-scale branch is now upstream. If you haven't looked yet, your filesystem is likely to have been touched, so check it out. Also look at Documentation/filesystems/porting and path-lookup.txt. The dcache_lock stuff should have been all done for you (for in-tree filesystems, I can help out of tree fses with conversions there if you ping me offline). The rcu-walk stuff can be more tricky for your filesystem to take advantage of. If you supply a .d_revalidate, .permission, or .check_acl, then path walking is going to be slow and unscalable for you. Out of tree filesystems: you _have_ to at least add a line of code to the above functions in order to specify that you don't want to participate in rcu-walk. Otherwise, you don't have to care about rcu-walk if you have a legacy or special filesystem like configfs then I'd advise against anything fancy. But if you have a userbase and you expect them to actually do any path lookups into your filesystem, please take a look. This is a big and complex change by any measure, so please don't be afraid to ask for help or clarification. I'd also really like to be able to update documentation based on questions from fs maintainers (in and out of tree) who are trying to follow it and bring their code up to speed. Thanks, Nick