linux-kernel - Re: Linux & FAT32 label

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Message-ID: <20171015065901.GD3916@xo-6d-61-c0.localdomain>
Date:   Sun, 15 Oct 2017 08:59:01 +0200
From:   Pavel Machek <pavel@....cz>
To:     Pali Rohár <pali.rohar@...il.com>
Cc:     Andreas Bombe <aeb@...ian.org>, Karel Zak <kzak@...hat.com>,
        util-linux@...r.kernel.org, linux-kernel@...r.kernel.org,
        Andrius Štikonas <andrius@...konas.eu>,
        Curtis Gedak <gedakc@...il.com>
Subject: Re: Linux & FAT32 label

Hi!

> Based on results I would propose following unification:
> 
...
> 4. Prefer label from the root directory. If there is none entry (means
>    there is also no erased entry), then read label from root sector.
> 
>    --> Reason: Windows XP and mlabel ignores what is written in boot
>        sector. Windows XP even do not update boot sector, so label
>        stored in boot sector is incorrect after any change done by
>        Windows XP.
> 
>        But due to compatibility with older dosfslabel, which stores
>        label only to boot sector, there is need for some fallback. Due
>        to point 1. the best seems to be to process also erased label in
>        root directory (marked with leading 0xE5) and fallback to boot
>        sector only in case label in root directory is missing.
> 
> What do you think about it?

4. seems dangerous. Assume we have "OLD" in boot sector and "0xe5-EW" in the directory
entry. The label will change from <none> to "OLD" when the directory entry is reused by
"FOO.TXT", right? That seems surprising / dangerous.
										Pavel

-- 
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