From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-btrfs-owner@vger.kernel.org>
Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:13288 "EHLO
	mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK)
	by vger.kernel.org with ESMTP id S1752766Ab3LJNcX convert rfc822-to-8bit
	(ORCPT <rfc822;linux-btrfs@vger.kernel.org>);
	Tue, 10 Dec 2013 08:32:23 -0500
Content-Type: text/plain; charset="utf-8"
MIME-Version: 1.0
To: <dsterba@suse.cz>, David Sterba <dsterba@suse.cz>,
        Wang Shilong <wangsl.fnst@cn.fujitsu.com>
From: Chris Mason <clm@fb.com>
In-Reply-To: <20131209233245.GF10658@twin.jikos.cz>
CC: <dsterba@suse.cz>, Roman Mamedov <rm@romanrm.net>,
        <linux-btrfs@vger.kernel.org>,
        Alex Lyakas <alex.btrfs@zadarastorage.com>
References: <1385657947-26145-1-git-send-email-dsterba@suse.cz>
 <20131129013638.01ede78a@natsu> <5297F633.8090100@cn.fujitsu.com>
 <20131129173744.GP25312@suse.cz> <529C4CB9.8020403@cn.fujitsu.com>
 <20131209233245.GF10658@twin.jikos.cz>
Message-ID: <20131210131707.16869.32138@ret>
Subject: Re: [PATCH] btrfs-progs: add options to sync filesystem after subvol delete
Date: Tue, 10 Dec 2013 08:17:07 -0500
Sender: linux-btrfs-owner@vger.kernel.org
List-ID: <linux-btrfs.vger.kernel.org>

Quoting David Sterba (2013-12-09 18:32:45)
> On Mon, Dec 02, 2013 at 05:02:49PM +0800, Wang Shilong wrote:
> > >So an enahced interface could look like this:
> > >
> > >subvol delete:
> > >--commit-each - run the ioc sync/wait ioctl after each delete ioctl
> > >--commit-after - dtto but sync/wait after all are deleted
> > >--wait-for-cleanup - wait until all given subvols are cleaned
> > >
> > >'filesystem sync' exteded to wait for subvol cleanup has following
> > >cases:
> > >- wait for a specific subvolume to be cleaned

It may be hard to wait for a specific subvolume from btrfs fi sync.
You'd have to know the id, or have an interface that shows a list of ids
currently under deletion (not a bad idea ;)

> > >- wait for all currently deleted, do not care if more subvols are
> > >   deleted in the meantime
> > >- wait until there are no subvolumes left to clean
> > I think it is unnecessary to add such options for 'filesystem sync'.
> > we may wait a long time until all subvolume deletion are finished as
> > async subvolume deletion is implemented in cleaner thread.:-)
> 
> I mean that 'filesystem sync' will stay as it is now, but will be
> enhanced with a few options to further specify what else should be
> synced.

It's more natural to have the waiting in the subvol delete command, but
I'm not against adding a few ways to wait in btrfs fi sync too, as long
as they share the same core implementation.

-chris