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

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Message-ID: <CAOQ4uxhtoAL43d5HcVEsAH2EtgiT8h6RkjymNhTcP5nnG1h09g@mail.gmail.com>
Date: Thu, 29 Aug 2024 18:23:07 +0200
From: Amir Goldstein <amir73il@...il.com>
To: Miklos Szeredi <miklos@...redi.hu>
Cc: Fei Lv <feilv@...micro.com>, linux-unionfs@...r.kernel.org, 
	linux-kernel@...r.kernel.org, lianghuxu@...micro.com
Subject: Re: [PATCH V2] ovl: fsync after metadata copy-up via mount option "fsync=strict"

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.

Thanks,
Amir.

View attachment "0001-ovl-fsync-after-metadata-copy-up.patch" of type "text/x-patch" (4389 bytes)