[OE-core] [PATCHv2 0/4] wic: Further enhance UUID / fstab support

[Tom Rini]

Hey all,

So, per Ed's feedback on my first series, I went and spent some time
trying to figure out how to have wic know what the UUID would be when
updating the fstab.  It turns out the easiest answer here is to have WIC
make the UUID.  Per Otavio's concern last time, I also make sure that
the filesystem UUID can be passed in, for reproducibility.  One thing to
keep in mind here is that FAT filesystem UUIDs are a bit funny to deal
with as mkfs.vfat / mkdosfs / etc want to be given a 32bit hexadecimal
value.  But when we talk mount, it must be split and it must be in
uppercase.  To make the rest of the code easier I'm encoding the '0x'
portion into part.fsuuid rather than doing "-i 0x%s" in a bunch of
places.

While preparing all of this, I found a few minor things such as we did
not test for squashfs and --use-uuid (not supported) and an incorrect
comment around the btrfs support.

Since v1, I've added a testcase into wic.Wic.test_qemu for a UUID mount
and the UUID that we've given. I think this is cleaner than adding a
python function to make a wks file just for this task.

--
Tom