linux-kernel - 答复: [PATCH V2] ovl: fsync after metadata copy-up via mount option "fsync=strict"

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Message-ID: <4ec356a473294dd3aab94a66c528eb2e@exch01.asrmicro.com>
Date: Fri, 30 Aug 2024 11:52:11 +0000
From: Lv Fei（吕飞） <feilv@...micro.com>
To: Amir Goldstein <amir73il@...il.com>, Miklos Szeredi <miklos@...redi.hu>
CC: "linux-unionfs@...r.kernel.org" <linux-unionfs@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Xu Lianghu（徐良虎） <lianghuxu@...micro.com>
Subject: 答复: [PATCH V2] ovl: fsync after metadata copy-up via mount option "fsync=strict"

> On Thu, Aug 29, 2024 at 6:23 PM Amir Goldstein <amir73il@...il.com> wrote:
> >
> > On Thu, Aug 29, 2024 at 2:51 PM Miklos Szeredi <miklos@...redi.hu> wrote:
> > >
> > > On Thu, 29 Aug 2024 at 12:29, Amir Goldstein <amir73il@...il.com> wrote:
> > >
> > > > But maybe we can ignore crash safety of metacopy on ubifs, because 
> > > > 1. the ubifs users may not be using this feature 2. ubifs may be 
> > > > nice and takes care of ordering O_TMPFILE
> > > >     metadata updates before exposing the link
> > > >
> > > > Then we can do the following:
> > > > IF (metacopy_enabled)
> > > >     fsync only in ovl_copy_up_file() ELSE
> > > >     fsync only in ovl_copy_up_metadata()
> > > >
> > > > Let me know what you think.
> > >
> > > Sounds like a good compromise.
> > >
> >
> > Fei,
> >
> > Could you please test the attached patch and confirm that your use 
> > case does not depend on metacopy enabled?
> >
> > In any case, I am holding on to your patch in case someone reports a 
> > performance regression with this unconditional fsync approach.
> >
> 
> Well, it's a good thing that I took Miklois' advice to make the fsync option implicit, because > the original patch had 2 bugs detected by fstest:
> 1. missing O_LARGEFILE
> 2. trying to fsync special files
> 
> Please see uptodate patch at:
> https://github.com/amir73il/linux/commits/ovl-fsync/
> 
> If there are no complaints, I will queue this up for v6.12.
> Fei, please provide your Tested-by.

We do not enable metacopy.
Tested this patch and it also solved our issue.

Thanks,
Fei