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Date: Thu, 22 Feb 2024 23:02:16 -0300
From: Thadeu Lima de Souza Cascardo <cascardo@igalia.com>
To: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	Gwendal Grignou <gwendal@chromium.org>, dlunev@chromium.org
Subject: Re: [PATCH] fat: ignore .. subdir and always add a link to dirs
Message-ID: <Zdf8qPN5h74MzCQh@quatroqueijos.cascardo.eti.br>
References: <20240222203013.2649457-1-cascardo@igalia.com>
 <87bk88oskz.fsf@mail.parknet.co.jp>
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On Fri, Feb 23, 2024 at 10:52:12AM +0900, OGAWA Hirofumi wrote:
> Thadeu Lima de Souza Cascardo <cascardo@igalia.com> writes:
> 
> > The tools used for creating images for the Lego Mindstrom EV3 are not
> > adding '.' and '..' entry in the 'Projects' directory.
> >
> > Without this fix, the kernel can not fill the inode structure for
> > 'Projects' directory.
> >
> > See https://github.com/microsoft/pxt-ev3/issues/980
> > And https://github.com/microsoft/uf2-linux/issues/6
> >
> > When counting the number of subdirs, ignore .. subdir and add one when
> > setting the initial link count for directories. This way, when .. is
> > present, it is still accounted for, and when neither . or .. are present, a
> > single link is still done, as it should, since this link would be the one
> > from the parent directory.
> >
> > With this fix applied, we can mount an image with such empty directories,
> > access them, create subdirectories and remove them.
> 
> This looks like the bug of those tools, isn't it?
> 
> Thanks.
> -- 
> OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>

Which they refused to fix, arguing that there are already filesystems out there
in the world like that. Also, there is argument that this works on Windows,
though I haven't been able to test this.

https://github.com/microsoft/pxt-ev3/issues/980
https://github.com/microsoft/uf2-linux/issues/6

Thanks.
Cascardo.