From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ud10.udmedia.de ([194.117.254.50]:45555 "EHLO mail.ud10.udmedia.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756462AbcARTMp (ORCPT ); Mon, 18 Jan 2016 14:12:45 -0500 Date: Mon, 18 Jan 2016 20:12:43 +0100 From: Markus Trippelsdorf To: Omar Sandoval Cc: linux-btrfs@vger.kernel.org Subject: Re: space_cache=v2 on root fs Message-ID: <20160118191243.GA321@x4> References: <20160118182717.GA321@x4> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20160118182717.GA321@x4> Sender: linux-btrfs-owner@vger.kernel.org List-ID: On 2016.01.18 at 19:27 +0100, Markus Trippelsdorf wrote: > Hi, > > while testing the new space_cache=v2 mount option it looks like my root fs > doesn't automatically create the new space cache. > > I'm using the following /etc/fstab: > > UUID=7ef56edc-673e-452e-9e05-3fabf074168b / btrfs noatime,compress=lzo,space_cache=v2 0 0 > UUID=6b7d75bf-3d12-409c-88ed-500ac6b78510 /var btrfs compress=lzo,space_cache=v2 0 0 > UUID=24cee7e4-9093-4f86-aa73-d8a59d7f3c6c /var/tmp btrfs compress=lzo,space_cache=v2 0 0 > > During first mount the space cache was created for /var (/dev/sdb2) and > /var/tmp (/dev/sda3), but apparently not for / (/dev/sdc3): > > Jan 18 18:48:18 x4 kernel: BTRFS info (device sdb2): enabling free space tree > Jan 18 18:48:18 x4 kernel: BTRFS info (device sdb2): using free space tree > Jan 18 18:48:18 x4 kernel: BTRFS: creating free space tree > Jan 18 18:48:18 x4 kernel: BTRFS info (device sdb2): setting 1 ro feature flag > Jan 18 18:48:18 x4 kernel: BTRFS: checking UUID tree > Jan 18 18:48:18 x4 kernel: BTRFS info (device sda3): enabling free space tree > Jan 18 18:48:18 x4 kernel: BTRFS info (device sda3): using free space tree > Jan 18 18:48:18 x4 kernel: BTRFS: has skinny extents > Jan 18 18:48:18 x4 kernel: BTRFS: detected SSD devices, enabling SSD mode > Jan 18 18:48:18 x4 kernel: BTRFS: creating free space tree > Jan 18 18:48:18 x4 kernel: BTRFS info (device sda3): setting 1 ro feature flag > Jan 18 18:48:18 x4 kernel: BTRFS: checking UUID tree > Jan 18 18:48:22 x4 kernel: BTRFS info (device sdc3): enabling free space tree > Jan 18 18:48:22 x4 kernel: BTRFS info (device sdc3): using free space tree > > During subsequent boots the "enabling free space tree" message is > repeated every time for the root fs. > > Jan 18 18:53:48 x4 kernel: BTRFS info (device sdb2): using free space tree > Jan 18 18:53:48 x4 kernel: BTRFS info (device sda3): using free space tree > Jan 18 18:53:52 x4 kernel: BTRFS info (device sdc3): enabling free space tree > Jan 18 18:53:52 x4 kernel: BTRFS info (device sdc3): using free space tree To answer my own question. Adding "rw rootflags=space_cache=v2" to the GRUB kernel entry fixes the issue... -- Markus