From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx2.suse.de ([195.135.220.15]:42289 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751660AbdATIui (ORCPT ); Fri, 20 Jan 2017 03:50:38 -0500 Date: Fri, 20 Jan 2017 09:50:35 +0100 From: Jan Kara To: Amir Goldstein Cc: Miklos Szeredi , Jan Kara , Al Viro , linux-unionfs@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH 0/2] overlayfs: support freeze/thaw/syncfs Message-ID: <20170120085035.GC14115@quack2.suse.cz> References: <1484828008-27507-1-git-send-email-amir73il@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1484828008-27507-1-git-send-email-amir73il@gmail.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: Hi, On Thu 19-01-17 14:13:26, Amir Goldstein wrote: > I implemented freeze/thaw of overlayfs, because I need it for > overlay snapshots (CoW decision is made before mnt_wat_write(upper) > and I need to serialize it with snapshot take). > > Not sure if there are other use cases for overlayfs freeze?? > > Tested freeze stress with xfstest generic/068 generic/390. > > While staring at the code, I realized that syncfs(2) for overlayfs > seems broken. It looks like only inodes are synced and upper fs > metadata is not being flushed, but I could be wrong. > > Tested sync sanity with -g quick (although no test calls syncfs directly). > Tested the usual unionmount sanity over xfs and over tmpfs. > > I am not sure exactly how to write a test case to verify this alleged > breakage? > > Jan, > > Can you please have a look? So I don't really understand overlayfs but from my 10000 feet view your changes make sense to me... Honza -- Jan Kara SUSE Labs, CR