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From: "Ph. Marek" <philipp.marek@bmlv.gv.at>
To: Andries.Brouwer@cwi.nl
Subject: Re: [PATCH] fs/partitions/msdos.c Guard against negative sizes
Date: Mon, 27 Jan 2003 16:38:47 +0100
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> >             u32 size = NR_SECTS(p)*sector_size;
> > -           if (!size)
> > +           if (size <= 0)
>
> But an unsigned variable cannot be negative, so what you write
> is the same as what was there already.
>
> In other words, your "negative" sizes are just very large positive.
>
> The test should be whether the partition extends beyond the end
> of the disk, but sometimes that is allowed, even necessary, so
> there could be a warning only.
Sorry, didn't pay enough attention.
On second look: it's an u32.
But that brings the next question up: what about overflow? u32 means a max of 
4GB.
	u32 start = START_SECT(p)*sector_size;
	u32 size = NR_SECTS(p)*sector_size;
And this looks as if it was calculated in bytes - but I'm sure that 4GB is not 
the max size! Where am I wrong??

And btw, when can a partition that extends beyond the end be "allowed or even 
necessary"?


Thanks for your answer!


Regards,

Phil


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