Recent versions of Linux, parted or some other bit of software cause
partition devices, like /dev/loop0p1 to be created when running parted
mkpart. However, these devices are not cleaned up when running
losetup -d to remove /dev/loop0 later, so they linger around and confuse
mkfs (which refuses to make a filesystem, thinking there are partitions):
mkfs.fat 4.1 (2017-01-24)
mkfs.vfat: Partitions or virtual mappings on device '/dev/loop0', not making filesystem (use -I to override)
To prevent this behaviour, pass --partscan to losetup when adding a new
partition, to clean up any lingering partitions. It seems losetup does not
accept --partscan when deleting a loop device, to clean up at that point, but
since binary_hdd mounts the partition last, there should not be any lingering
partition devices after live-build is done.
The --partscan option is available since util-linux 2.21 (released in 2012), so
it should be fairly safe to pass it unconditionally.
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