[RFC] mount can figure out fstype automatically

[Greg Lewis]

On Mon, Jul 10, 2006 at 09:22:19PM +0100, Christoph Hellwig wrote:
> On Mon, Jul 10, 2006 at 01:06:02PM -0600, Scott Long wrote:
> > So in your opinion and experience, what are the pros and cons of 
> > maintaining a table of magic numbers?
> 
> The feature is imensely useful.  The implementation won't win any
> points for a clean design but works very well in practice.  I think
> it's definitly better than probing in the kernel because letting a filesystem
> driver try to make sense of something that's not it's own format can
> 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.

It also (the root filesystem special case) has a tendency to give
misleading error messages which cost me a number of lost hours and
grey hairs in my previous job.

-- 
Greg Lewis                          Email   : glewis at eyesbeyond.com
Eyes Beyond                         Web     : http://www.eyesbeyond.com
Information Technology              FreeBSD : glewis at FreeBSD.org