devfs is alive and well in 2.6. there is a udev(?) scheme i think which accomplishes the same sort of thing via a different mechanism, but that is about the extent of my knowledge on it and is probably wrong anyway!!!
it is the kernel failing to mount /dev/sda7, not userspace. It also fails if I specify root as 0807, so I guess it isn't a devfs issue on dom1. Dom0 also is using devfs, /dev/sda7 is a symlink to /dev/scsi/host0/bus0/target5/lun0/part7, which is in turn of the right major and minor number. Would xen be failing to work out the device numbers because of the symlink?
After my next reboot i'll try making /dev/sda7 a proper device node. After dom1 crashes and burns, I don't seem to be able to kill it (xm destroy 1), or create it again, so I have to reboot. doh.
Also, make menuconfig for xenU flashes an error on the screen but otherwise works unless I try to look in SCSI where I get this message:
Menuconfig has encountered a possible error in one of the kernel's
configuration files and is unable to continue. Here is the error
Q> scripts/Menuconfig: line 832: MCmenu53: command not found
Please indicate the kernel version you are trying to configure and
which menu you were trying to enter when this error occurred.
> Domain1 is now not booting anymore, and the boot console tells me it's because it can't mount /dev/sda7.
> My config files says sda7 maps to /dev/sda7 eg:
> disk = [ 'phy:sda7,sda7,w' ]
> root = "/dev/sda7 ro"
> My only thought is that maybe devfs is confusing the issue... eg there are no scsi devices so sda7 doesn't appear in /dev.
> Can anyone confirm/deny this?
We make no effort to make 'logical' devices appear in devfs --- if
it doesn't happen automatically then code needs to be added to do it
Is devfs still alive in 2.6, or have they moved to some other scheme?