Subject: Re: swapfs filesystem design (and mount/umount question)
To: Darren Reed <darrenr@reed.wattle.id.au>
From: Simon Burge <simonb@netbsd.org>
List: tech-kern
Date: 03/20/2000 15:39:54
Darren Reed wrote:
> In some email I received from Simon Burge, sie wrote:
> [...]
> > I've just now got a basic empty filesystem framework working (ie, no vops
> > supported except for mount, umount and statfs, and mount doesn't do
> > anything like creating a filesystem). At the moment I can't unmount the
> > filesystem:
> >
> > wincen:vfs/miscfs/swapfs 1# modload obj.i386/swapfs.o
> > Module loaded as ID 0
> > wincen:vfs/miscfs/swapfs 2# mount_swapfs -s 131072 swapfs /mnt
> > wincen:vfs/miscfs/swapfs 3# df -i
> > Filesystem 1K-blocks Used Avail Capacity iused ifree %iused Mounted on
> > ...
> > swapfs 65404 0 65404 0% 0 523232 0% /mnt
> [...]
>
> What does it look like if you do:
> mkdir /mnt2
> mount_swapfs -s 131072 swapfs /mnt
> mount_swapfs -s 131072 swapfs /mnt2
> df -it swapfs
Not good :-(
wincen:~ 1# modload /NetBSD/src/sys/lkm/vfs/miscfs/swapfs/obj.i386/swapfs.o
Module loaded as ID 0
wincen:~ 2# mount_swapfs -s 131072 swapfs /mnt
wincen:~ 3# mount_swapfs -s 131072 swapfs /mnt2
wincen:~ 4# df | tail -2
swapfs 65404 0 65404 0% /mnt
swapfs 65404 0 65404 0% /mnt2
wincen:~ 5# df -it swapfs
uvm_fault(0xc9bc916c, 0x0, 0, 1) -> 1
kernel: page fault trap, code=0
Stopped in df at sys_statfs+0x4b: movl 0x8(%ebx),%eax
db>
I'm beginning to wonder if I need to at least implement swapfs_lookup()
and a few others :)
Simon.