From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from plane.gmane.org ([80.91.229.3]:47618 "EHLO plane.gmane.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750729AbcEPGAh (ORCPT ); Mon, 16 May 2016 02:00:37 -0400 Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1b2BZb-0008Mz-RV for linux-btrfs@vger.kernel.org; Mon, 16 May 2016 08:00:12 +0200 Received: from ip98-167-165-199.ph.ph.cox.net ([98.167.165.199]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Mon, 16 May 2016 08:00:11 +0200 Received: from 1i5t5.duncan by ip98-167-165-199.ph.ph.cox.net with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Mon, 16 May 2016 08:00:11 +0200 To: linux-btrfs@vger.kernel.org From: Duncan <1i5t5.duncan@cox.net> Subject: Re: problems with free space cache Date: Mon, 16 May 2016 05:59:55 +0000 (UTC) Message-ID: References: <85030f6b-b149-ccd2-ea87-42135b9ccd46@cn.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-btrfs-owner@vger.kernel.org List-ID: Qu Wenruo posted on Mon, 16 May 2016 10:24:23 +0800 as excerpted: > IIRC clear_cache option is fs level option. > So the first mount with clear_cache, then all subvolume will have > clear_cache. Question: Does clear_cache work with a read-only mount? I could see it being like the log replay and being done even on ro mounts, particularly since unlike the log replay, clear_cache is a specific mount option so could be seen as specifically requested even if otherwise ro. Or not. So I don't know. He mentioned root, which is normally mounted read-only first. That's what got me thinking about it. Does that complicate things? If root is mounted ro without clear_cache by the initr*, will a subsequent remount,rw,clear_cache do it? And for those like me who keep root mounted ro by default, would clear_cache work at all, or would it not work until such time as I mounted root, or some other subvolume (which I don't have here to worry about, but for those who do...) writable? -- Duncan - List replies preferred. No HTML msgs. "Every nonfree program has a lord, a master -- and if you use the program, he is your master." Richard Stallman