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Date: Mon, 10 Jul 2006 21:39:49 +0100
From: Christoph Hellwig <hch@infradead.org>
To: Scott Long <scottl@samsco.org>
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Cc: freebsd-arch@freebsd.org, freebsd-current@freebsd.org,
	Craig Rodrigues <rodrigc@crodrigues.org>
Subject: Re: [RFC] mount can figure out fstype automatically
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On Mon, Jul 10, 2006 at 02:30:20PM -0600, Scott Long wrote:
> >lead to all kinds of funnies.  Linux does this (iterating all filesystem
> >types in kernel) for the special case of the root filesystem where mount(8)
> >is not available, and it showeds various interesting bugs at least in the
> >fat driver.
> >
> 
> How does it resolve situations like with UDF vs iso9660, where both 
> structures can co-exist?

The kernel doesn't do anything fancy.  It just walks the list of filesystem
and the first fs that takes it gets it.  To answer the specific example
iso9660 is registered before udf so if you wanted to use a dual-fs cdrom
as root you would get iso9600 unless you specified the rootfstype=udf
boot option.