Edit the qcow2 FreeBSD image file

[Polytropon]

On Wed, 4 Oct 2017 12:02:56 +0200, Johan Hendriks wrote:
> 
> 
> Op 04/10/2017 om 11:29 schreef Polytropon:
> > On Wed, 4 Oct 2017 09:47:47 +0200, Johan Hendriks wrote:
> >> I want to add a script to the default qcow2 file of the FreeBSD qcow2 image.
> >> But how do i mount the qcow2 file on FreeBSD?
> >> There are a lot of howto's how to do it on Linux but i do not always
> >> have a Linux box ready.
> > Without having verified, I'd say something like this will work:
> >
> > 	# mdconfig -a -t vnode -f <flename> -u 0
> > 	# mount -t ufs -o rw /dev/md0s1a /mnt
> >
> > The key is to connect the file to a md device ("memory disk"),
> > and then use it as if it was a real disk. But always check the
> > correct device file name - md0 will reflect the "disk layout"
> > of the image file, so maybe you need to use /dev/md0p1 or
> > /dev/md0a or simply /dev/md0, so check "ls /dev/md0*" to see
> > how the layout is being translated to device files - this
> > depends on the layout that has been constructed within the
> > image file.
> >
> > When you're done, use:
> >
> > 	# umount /mnt
> > 	# mdconfig -d -u 0
> >
> > This will finally sync any changes and disconnect the device.
> > The image file can be used now.
> >
> Thanks, I tried that, but it does not work.
> root at desk:~ # mdconfig -a -t vnode -f FreeBSD-11.1-RELEASE-amd64.qcow2 -u 0
> 
> Then a ls of /dev/md0 only shows md0 and i can not mount that one.
> root at desk:~ # ls -al /dev/md*
> crw-r-----  1 root  operator  0x8c Oct  4 11:48 /dev/md0
> crw-------  1 root  wheel      0xb Sep 21 14:16 /dev/mdctl
> 
> And a mount of /dev/md0 gives an error.
> 
> root at desk:~ # mount -t ufs -o rw /dev/md0 /mnt
> mount: /dev/md0: Invalid argument

Check the file format of md0 if it is recognized as a filesystem
image:

	# file FreeBSD-11.1-RELEASE-amd64.qcow2
	# file -s /dev/md0

it should be recognized as a UFS file system (typically called
"Unix Fast File system [v2]"). Note that you can only mount a
file system which is being recognized correctly.



-- 
Polytropon
Magdeburg, Germany
Happy FreeBSD user since 4.0
Andra moi ennepe, Mousa, ...