From owner-freebsd-fs  Wed Feb 28 12:54:23 2001
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From: Terry Lambert <tlambert@primenet.com>
Message-Id: <200102282051.NAA05663@usr05.primenet.com>
Subject: Re: mount fixes, part 1
To: adrian@FreeBSD.ORG (Adrian Chadd)
Date: Wed, 28 Feb 2001 20:51:43 +0000 (GMT)
Cc: freebsd-fs@FreeBSD.ORG, freebsd-arch@FreeBSD.ORG
In-Reply-To: <20010228113644.A39251@roaming.cacheboy.net> from "Adrian Chadd" at Feb 28, 2001 11:36:44 AM
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> It is my hope that eventually vfs_mount() and VFS_MOUNT() will not
> use copyin*() at all.
> 
> Comments are welcome. I'd like to commit this in the next couple of days
> so I can continue with my VFS tidyups.

Took a quick peek...

I assume that this is to allow user space and kernel space code
to be equivalent, for developing in user space?

This works particularly well, because of descriptor calling for
VOPs, less so for VFSOPs.

Probably you will want to descriptorize the VFS switch entry
points, and pass descriptors.

Descriptors would have to be internalized, but that would happen
outside the code, so it would eliminate "copyin*()" (I guess that
sopinstr() is the worst of these, which is why you aren't using
uio instead, even though uio in user space would take more work?).

For this to work, you will need to seperate the mount creating
a mounted file system list instance from the vnode covering, or
you will find yourself unable to develop anything other than
"VFS on top, VFS on bottom" modules in user space, and unable
to mount more than one stacking layer deep.


					Terry Lambert
					terry@lambert.org
---
Any opinions in this posting are my own and not those of my present
or previous employers.

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