Offline Editing Guide
It is often useful to inspect and edit a filesystem image without booting it as a VM. You can mount a filesystem image under a mountpoint on your current filesystem.
Say you have a filesystem image called "ttylinux-xen"
The following makes the filesystem available for editing in your current (Linux) OS, in most cases you're required to be root:
mkdir tempmount mount -o loop ttylinux-xen tempmount
If you encountered a strange error (besides 'only root can do that') you may be missing loopback support from your kernel.
Make sure to un-mount the filesystem!
Note that is 'umount' and not 'unmount'. You can check that it was successfully un-mounted using 'ls' inspections (nothing should be in this 'tempmount' directory anymore) and by checking the currently mounted volumes using the 'df' command.
If you get a message saying the volume is busy, you may have another terminal open whose current directory is under the 'tempmount' mountpoint or perhaps you are editing/viewing a file under this mountpoint? Stopping all use of the volume (including a current terminal directory) will allow the un-mount to succeed.
Always remember to un-mount the filesystems ('umount'). If you boot this file as a VM filesystem while it is still mounted locally, you will have two kernels that think they have control over the same block device. That could, and likely will, lead to filesystem corruption.