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From: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
To: Thadeu Lima de Souza Cascardo <cascardo@igalia.com>
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
In-Reply-To: <Zd74fjlVJZic8UxI@quatroqueijos.cascardo.eti.br> (Thadeu Lima de
	Souza Cascardo's message of "Wed, 28 Feb 2024 06:10:22 -0300")
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Date: Sun, 10 Mar 2024 14:52:26 +0900
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Thadeu Lima de Souza Cascardo <cascardo@igalia.com> writes:

>> Can you share the image somehow? And fsck (chkdsk, etc.) works without
>> any complain?
>
> Checking the filesystem on Windows runs without any complains, but it turns the
> directory into an useless lump of data. Without checking the filesystem,
> creating and reading files from that directory works just fine.
>
> I tried to use gzip or xz to compress the very sparse filesystem image that I
> got, but they made it larger on disk than it really was. So here is a script
> and pieces of the filesystem that will create a sparse 8GB image.

I tested a your image with some tweaks. Windows's chkdsk complains about
"BADDIR" directory, and it was fixed by converting it to normal
file. Probably, chkdsk thought that "BADDIR" got ATTR_DIR bit by
corruption.  IOW, Windows FATFS driver may accept this image, but
Windows also think this image as corrupt, like chkdsk says.

I think the app that make this should be fixed. Windows accepts more
than linux though, it looks also think as corrupt.

If we really want to accept this image, we have to change the fat driver
without affecting good image.  And your patch affects to good image,
because that patch doesn't count directory correctly, so bad link count.

Thanks.
-- 
OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>