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From: Terry Lambert <terry@lambert.org>
Message-Id: <199610232054.NAA10399@phaeton.artisoft.com>
Subject: Re: please tell me I'm wrong
To: julian@ref.tfs.com (Julian Elischer)
Date: Wed, 23 Oct 1996 13:54:21 -0700 (MST)
Cc: hackers@FreeBSD.ORG
In-Reply-To: <199610230940.CAA11698@ref.tfs.com> from "Julian Elischer" at Oct 23, 96 02:40:21 am
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> I've been looking at why I can't unmount a filesystem on a device under devfs
> seems that the superblock is stored under the mount point.
> it is saved using the sync function of the filesystem that held the device..
> so if the filesystem that held the device,
> is devfs, it's asked to save the other filesystem private info (superblock)
> but it wouldn't know a superblock if one came up and kicked it
> in the shins!
> 
> I hope I'm reading this wrong, because that would indicate that
> you can only mount a ffs filesystem from a device on a ffs filesystem..
> (and expect it to work)

I think you are missing the "struct fileops" reference, which is different
for devices than it is for non-devices.

I believe the vnode that gets synced on is the vnode of the FS doing
the mounting, not the underlying FS.

You should look in vfs_vnops.c...


Getting rid of the struct fileops nonsense was one of my goals at one
time.


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