You can see what is being used by a loop device with losetup:
# losetup /dev/loop0
/dev/loop0: [fd06]:234921356 (/linux/isos/backtrack.iso)
It is possible to increase the number of available loop devices. Free
all loop devices, and add a line with the following to
/etc/modprobe.conf:
options loop max_loop=64
(maximum is 256)
Then, do:
rmmod loop && modprobe loop
If you get an error that the module couldn't be removed, you still have loop
devices in use.
Newer kernels (2.6.21 or 2.6.22) use a dynamic allocation of loop devices,
so you will only have to create the filesystem representation of the devices:
for ((i=8;i<64;i++)); do
[ -e /dev/loop$i ] || mknod -m 0600 /dev/loop$i b 7 $i
done
