tweaking mounted filesystems by fsid

Scott Long scottl at
Sat Jul 3 12:49:39 PDT 2004

Alfred Perlstein wrote:
> Hi.
> The last year or so I spent bringing file system improvements into
> OS X.
> The mechanism I used to tweak filesystems was sysctl.
> I created a node that would route a request to a filesystem based
> on a fsid.  This would allow tweaking of filesystems without entering
> the namespace.
> I realize we have the nmount syscall.  I have several questions
> about it.
> 1) can I muck with it so that it functions like unmount(2) by
> taking the "FSID:val0:val1" parameter in order to properly
> route requests?
> 2) what if i want to pass binary data?  I can do that right?
> I assume by just passing the binary gook via the value of the
> key value pair.
> Any comments?
> On of the issues I have is that I need the call to be callable
> from both inside and outside of the kernel, I'm guessing this can
> be taken care of by the internal options...
> Ideas people?
> Use nmount or sysctl?

Can't comment on your main questions, but there has been talk about
removing nmount since the work was never finished and the benefits
never realized.  If you'd like to breath some life into it, feel free.


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