From owner-freebsd-arch  Tue Jan 23 14:59:21 2001
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Date: Tue, 23 Jan 2001 14:59:02 -0800
From: Alfred Perlstein <bright@wintelcom.net>
To: Adrian Chadd <adrian@FreeBSD.ORG>
Cc: freebsd-arch@FreeBSD.ORG
Subject: Re: mount options
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* Adrian Chadd <adrian@FreeBSD.ORG> [010123 13:06] wrote:
> 
> Hi,
> 
> I'd like to spark a discussion on the mount interface. It seems
> a little evil right now, and I have noted that you can't add
> arbitrary mount options through to an FS since they're passed
> across as binary.
> 
> For an FS porting project I'm doing, the mount interface needs
> to be able to export the mount options back out to userspace,
> and I'd like to tidy the code up instead of just fudge it for
> my needs.
> 
> So, if you have an idea on how the mount interface *should* look,
> now is the time to stand up and tell me what you're thinking.. :-)

I haven't thought about it much except how bad the interface is.

Just some random thoughts on it. :)

I would think that simply using a string passing method given some
helper functions should be enough.  There's really no effeciency
problem as I can see because this wouldn't restrict the VFS from
caching the information in a flags structure.  At the same time it
could allow for extracting some form of the mount options in the
form of strings, perhaps a list of NULL terminated strings as a
large block (sysctl or fetch syscall could specify the block length)?

I also think that passing in each option shouldn't depend on formatting
characters for seperation such as ',', instead it should be a list
of null terminated strings and a length of the block.

Some conventions might be in order, but the current async/noasync
atime/noatime stuff seems to work pretty well.

-- 
-Alfred Perlstein - [bright@wintelcom.net|alfred@freebsd.org]
"I have the heart of a child; I keep it in a jar on my desk."


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