Re: "loopback mount" via vnd feature request

[Brett Lymn <blymn%baesystems.com.au@localhost>]

On Mon, Mar 02, 2009 at 10:03:04PM +0900, Toru Nishimura wrote:
> 
> The issue here is that our vnconfig (vnode-config) is
> unable to show off which file is bound with vnd device alive.
> The addition of -l option is not optimal since showing inode
> number is no better than debug'ng feature.  It'd nice to
> provide a straight-and-easy-to-use way for loopback mounting.
> Possible implementations would vary, I suppose.
>

Well, since we are sharing...
 
> /// mount-iso ///

The problem I see with this script is that you assume the number of
vnd devices configured in the kernel.  You can query for a list of vnd
devices and their status buy using "vnconfig -l".  Here is my script I
use to mount my qemu hard disk images - it uses the vnconfig -l
command to use the first available vnd device for the mount.

#!/bin/sh
#
# Mount the HD for the qemu environment for blymn.
#
QEMUHOME=/home/user/blymn/qemu
QEMUHD=${QEMUHOME}/hda
QEMUMNTPT=/mnt
#
EXIT=0
#
VND=`vnconfig -l | grep 'not in use' | head -1 | cut -d':' -f1`
if [ "${VND}" = "" ]
then
        echo "No available vnd devices.  Exiting."
        exit 1
fi
#
if [ "X$1" != "X" ]
then
        if [ -r "${QEMUHOME}/$1" ]
        then
                QEMUHD=${QEMUHOME}/$1
        else
                QEMUMNTPT=$1
        fi
fi
#
if [ "X$2" != "X" ]
then
        QEMUMNTPT=$2
fi
#
vnconfig ${VND} ${QEMUHD}
if [ $? != 0 ]
then
        echo "vnconfig of ${QEMUHD} failed"
        exit 1
fi
#
fsck -y /dev/r${VND}a
mount /dev/${VND}a ${QEMUMNTPT}
if [ $? != 0 ]
then
        echo "mount of /dev/${VND}a on ${QEMUMNTPT} failed"
        vnconfig -u ${VND}
        EXIT=1
fi
exit ${EXIT}


unfortunately - I have not done the equally clever unmount and vnd
clean up.

-- 
Brett Lymn
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