udev: start grow service automatically

Grow continue via service or fork is started during raid assembly.
If raid was assembled in initrd it will be newer restarted after
switch root.
Add udev support for starting mdadm-grow-continue service.

Signed-off-by: Mariusz Tkaczyk <mariusz.tkaczyk@intel.com>

udev-md-raid-arrays.rules

diff --git a/udev-md-raid-arrays.rules b/udev-md-raid-arrays.rules
index c8fa8e8..13c9076 100644
--- a/udev-md-raid-arrays.rules
+++ b/udev-md-raid-arrays.rules
@@ -15,6 +15,7 @@
 ATTR{md/metadata_version}=="external:[A-Za-z]*", ATTR{md/array_state}=="inactive", GOTO="md_ignore_state"
 TEST!="md/array_state", ENV{SYSTEMD_READY}="0", GOTO="md_end"
 ATTR{md/array_state}=="clear*|inactive", ENV{SYSTEMD_READY}="0", GOTO="md_end"
+ATTR{md/sync_action}=="reshape", ENV{RESHAPE_ACTIVE}="yes"
 LABEL="md_ignore_state"
 
 IMPORT{program}="BINDIR/mdadm --detail --no-devices --export $devnode"
@@ -38,5 +39,6 @@
 # Tell systemd to run mdmon for our container, if we need it.
 ENV{MD_LEVEL}=="raid[1-9]*", ENV{MD_CONTAINER}=="?*", PROGRAM="/usr/bin/readlink $env{MD_CONTAINER}", ENV{MD_MON_THIS}="%c"
 ENV{MD_MON_THIS}=="?*", PROGRAM="/usr/bin/basename $env{MD_MON_THIS}", ENV{SYSTEMD_WANTS}+="mdmon@%c.service"
+ENV{RESHAPE_ACTIVE}=="yes", PROGRAM="/usr/bin/basename $env{MD_MON_THIS}", ENV{SYSTEMD_WANTS}+="mdadm-grow-continue@%c.service"
 
 LABEL="md_end"