Comment 5 for bug 1670336

Maybe also Ubiquity needs to be patched, I am not sure since I did not have time to test it yet.

I did the following test to isolate the problems.

1) Fresh ubuntu 17.04 installation with no encrypted home (and no encrypted swap). /etc/crypttab is empty, and in /etc/fstab I have the following line:

/swapfile none swap sw 0 0

2) After successfully running ecryptfs-migrate-home, I run ecryptfs-setup-swap (the "original" version, not the one with the above patch) and I get:

INFO: Setting up swap: [/swapfile]
device node not found
WARNING: Commented out your unencrypted swap from /etc/fstab
swapon: cannot open /dev/mapper/cryptswap1: No such file or directory

Now in /etc/fstab I have:

#/swapfile none swap sw 0 0
/dev/mapper/cryptswap1 none swap sw 0 0

and in /etc/crypttab I have:
cryptswap1 UUID=98a3bb25-2c4d-4897-974c-d5dfcc16be8f /dev/urandom swap,offset=1024,cipher=aes-xts-plain64

If I run free, I see that I have no swap:
              total used free shared buff/cache available
Mem: 8084440 1421116 4575096 273228 2088228 6086972
Swap: 0 0 0

3) I reboot, and the system hangs a lot during boot. I see "a start job is running for dev-mapper-cryptswap1.device". After a couple of minutes, the boot process ends and I can login. If I run "systemctl status swapfile.swap" and "free" I see that (unencryted) swapfile has been activated anyway.
THIS IS DIFFERENT FROM WHAT I GOT WHEN DOING A FRESH UBUNTU 17.04 INSTALL WITH THE "ENCRYPT HOME FOLDER" OPTION SELECTED.
In that case, I got the system hanging during boot, too, but when I finally managed to login I got no swap at all ("systemctl status swapfile.swap" returned "failed to activate swap /swapfile").
Looking at ubiquity scripts, I see that if encrypted home option is selected, it runs also ecryptfs-setup-swap (so ubiquity is actually affected by the bug described above); but the fact that system fails also to activate unencrypted swap seems to suggest that Ubiquity may need to be patched too.

4)