How to update a git repo containing a submodule?

mblsha@siruba:~/src/psi/ $ git status
iris: needs merge
# On branch master
# Changes to be committed:
#   (use "git reset HEAD <file>..." to unstage)
#
#   modified:   src/common.cpp
#
# Changed but not updated:
#   (use "git add <file>..." to update what will be committed)
#
#   unmerged:   iris
#
# Untracked files:
#   (use "git add <file>..." to include in what will be committed)
#
#   gupdate.sh
mblsha@siruba:~/src/psi/ $ git submodule status
+cf237ef8f3d9dc058dbde47e6973e6388608ce60 iris (heads/master)
+cf237ef8f3d9dc058dbde47e6973e6388608ce60 iris (heads/master)
+cf237ef8f3d9dc058dbde47e6973e6388608ce60 iris (heads/master)
mblsha@siruba:~/src/psi/ $ cd iris
mblsha@siruba:~/src/psi/iris/ $ cat .git/HEAD
cf237ef8f3d9dc058dbde47e6973e6388608ce60

1. deleting the submodule (rm -r iris)
2. recreating it again (git submodule update)