From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from atl4mhob12.myregisteredsite.com ([209.17.115.50]:57747 "EHLO atl4mhob12.myregisteredsite.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753050Ab3FCCTo (ORCPT ); Sun, 2 Jun 2013 22:19:44 -0400 Received: from mailpod1.hostingplatform.com ([10.30.71.116]) by atl4mhob12.myregisteredsite.com (8.14.4/8.14.4) with ESMTP id r532JgLb020517 for ; Sun, 2 Jun 2013 22:19:42 -0400 Message-ID: <51ABFD46.90601@chinilu.com> Date: Sun, 02 Jun 2013 19:19:50 -0700 From: George Mitchell Reply-To: george@chinilu.com MIME-Version: 1.0 To: bo.li.liu@oracle.com CC: linux-btrfs@vger.kernel.org Subject: Re: Is there a way to flag specific directories "nodatacow"? References: <51AB5974.3080803@chinilu.com> <20130603012848.GA26016@liubo.jp.oracle.com> In-Reply-To: <20130603012848.GA26016@liubo.jp.oracle.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Sender: linux-btrfs-owner@vger.kernel.org List-ID: On 06/02/2013 06:28 PM, Liu Bo wrote: > On Sun, Jun 02, 2013 at 07:40:52AM -0700, George Mitchell wrote: >> I am seeing massive journal corruptions that seem to be unique to >> btrfs and I am suspecting that cow might be causing them. My >> bandaid fix for this will be to mark the /var filesystem "nodatacow" >> at boot. But I am wondering if their is any way to flag a >> particular directory as "nodatacow" outside of the mount process. I >> would like to be able to mark /var/log/journal as "nodatacow" for >> example, without having to declare it a subvolume and mount it >> separately. > Hi George, > > We actually have per-file/directory nodatacow :) > > But please note if you set nodatacow on the particular directory, only > new-created or zero-size files in the directory can follow the nocow rule. > > 'chattr' in the latest e2fsprogs can fit your requirements, > # chattr +C /var/log/journal > > Also, what kind of massive journal corruptions? Does it look like a > btrfs specific bug? > > thanks, > liubo > > I am also assuming that all directories later created under /var/log/journal will inherit the nodatacow profile?