UUID base RESUME always wait 5 seconds for activating LVM swap

[Hiroo MATSUMOTO]

Ubuntu 16.04 with LVM have delay around LVM mount.

  $ dmesg
  <snip>
  [ 1.126338] FDC 0 is a S82078B
  [ 1.830136] tsc: Refined TSC clocksource calibration: 3392.321 MHz
  [ 1.830140] clocksource: tsc: mask: 0xffffffffffffffff max_cycles:
  0x30e5f904771, max_idle_ns: 440795373543 ns
  [ 6.984151] EXT4-fs (dm-0): mounted filesystem with ordered data
  mode. Opts: (null)
  [ 10.421370] systemd[1]: systemd 229 running in system mode.
  (+PAM +AUDIT +SELINUX +IMA +APPARMOR +SMACK +SYSVINIT +UTMP
  +LIBCRYPTSETUP +GCRYPT +GNUTLS +ACL +XZ -LZ4 +SECCOMP +BLKID
  +ELFUTILS +KMOD -IDN)
  [ 10.421397] systemd[1]: Detected virtualization kvm.
  <snip>

LVM partition will be activated by scripts/local-top/lvm2 in initrd.
But scripts/local-top/lvm2 does not take care of resume variable which
is set from UUID base RESUME.

  $ cat /usr/share/initramfs-tools/scripts/local-top/lvm2
  <snip>
  activate() {
  <snip>
    /dev/mapper/*)
    <snip>
  }

  activate "$ROOT"
  activate "$resume"
  <snip>

And then, scripts/local-premount/resume in initrd will always wait 5
seconds for activating LVM swap.
After mounting root filesystem, systemd will activate LVM swap.

  $ cat /usr/share/initramfs-tools/scripts/local-premount/resume
  <snip>
  SWAPTYPE=$(wait-for-root "${resume}" ${RESUMEDELAY:-5})
  <snip>

RESUME is defined at /etc/initramfs-tools/conf.d/resume which is
created by plugininstall.py.
So plugininstall.py needs to support non-UUID base RESUME,
e.g. RESUME=/dev/mapper/ubuntu--vg-swap_1.

  $ sudo su -c 'echo RESUME=/dev/mapper/ubuntu--vg-swap_1 \
  > /etc/initramfs-tools/conf.d/resume'
  $ sudo update-initramfs -u && sudo reboot

  $ dmesg # after boot
  <snip>
  [ 1.095876] FDC 0 is a S82078B
  [ 1.507060] EXT4-fs (dm-0): mounted filesystem with ordered data
  mode. Opts: (null)
  [ 1.807522] tsc: Refined TSC clocksource calibration: 3392.321 MHz
  [ 1.807526] clocksource: tsc: mask: 0xffffffffffffffff max_cycles:
  0x30e5f904771, max_idle_ns: 440795373543 ns
  [ 2.648513] systemd[1]: systemd 229 running in system mode.
  (+PAM +AUDIT +SELINUX +IMA +APPARMOR +SMACK +SYSVINIT +UTMP
  +LIBCRYPTSETUP +GCRYPT +GNUTLS +ACL +XZ -LZ4 +SECCOMP +BLKID
  +ELFUTILS +KMOD -IDN)
  [ 2.648542] systemd[1]: Detected virtualization kvm.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.