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From: Konstantin Khlebnikov <koct9i@gmail.com>
Date: Fri, 11 Nov 2016 12:41:34 +0300
Message-ID: <CALYGNiP9=-FH3Xy5RMjsOg8GbDGDQRSnppuE_UEidehy=fpinA@mail.gmail.com>
Subject: Re: [PATCH 3/3] ovl: redirect on rename-dir
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: Raphael Hertzog <hertzog@debian.org>,
        Miklos Szeredi <mszeredi@redhat.com>,
        "linux-unionfs@vger.kernel.org" <linux-unionfs@vger.kernel.org>,
        Guillem Jover <guillem@debian.org>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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On Fri, Nov 11, 2016 at 1:39 AM, Miklos Szeredi <miklos@szeredi.hu> wrote:
> New version is at:
>
> git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs.git #redirect
>
> News:
> - it actually should work in all cases
> - when rename is not cross directory, just store the new name instead
> of a full path, as suggested by Amir
> - when redirect path is too long fall back to EXDEV (the max length
> should probably be a module param)
>
> About turning the feature on or off.  Yes, maybe the empty checking is
> too complicated.  Going one simpler:
>
>  - default to old behavior, turn on with mount option
>  - add module option and kernel compile option to turn on the feature by default
>
> I guess distros wil simply enable this by default, since back
> compatibility is basically a non-issue.

Looks good.

I suppose module parameter exposed in /sys/module/overlay/parameters/ could be
documented as recommended way for detecting presence of that feature.

--
Konstantin