From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:58352 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751057AbbIATvS (ORCPT ); Tue, 1 Sep 2015 15:51:18 -0400 Subject: Re: [PATCH 6/6] Btrfs: add free space tree mount option To: Omar Sandoval , References: <508d5b51b22371362ee49047afbfe536bee8ce84.1441131625.git.osandov@fb.com> CC: Omar Sandoval From: Josef Bacik Message-ID: <55E6015A.2070104@fb.com> Date: Tue, 1 Sep 2015 15:49:46 -0400 MIME-Version: 1.0 In-Reply-To: <508d5b51b22371362ee49047afbfe536bee8ce84.1441131625.git.osandov@fb.com> Content-Type: text/plain; charset="windows-1252"; format=flowed Sender: linux-btrfs-owner@vger.kernel.org List-ID: On 09/01/2015 03:05 PM, Omar Sandoval wrote: > From: Omar Sandoval > > Now we can finally hook up everything so we can actually use free space > tree. On the first mount with the free_space_tree mount option, the free > space tree will be created and the FREE_SPACE_TREE read-only compat bit > will be set. Any time the filesystem is mounted from then on, we will > use the free space tree. > > Having both the free space cache and free space trees enabled is > nonsense, so we don't allow that to happen. Since mkfs sets the > superblock cache generation to -1, this means that the filesystem will > have to be mounted with nospace_cache,free_space_tree to create the free > space trees on first mount. Once the FREE_SPACE_TREE bit is set, the > cache generation is ignored when mounting. This is all a little more > complicated than would be ideal, but at some point we can presumably > make the free space tree the default and stop setting the cache > generation in mkfs. > > Signed-off-by: Omar Sandoval Reviewed-by: Josef Bacik Thanks, Josef