LUKS: make /usr writable

Since systemd commit ffc1ec73b3 ("pid1: add ProtectSystem= as system-wide
configuration, and default it to true in the initrd"), systemd makes
/usr read-only by default and it will cause dracut to not wait for the
LUKS-encrypted devices to be unlocked,

    dracut-cmdline[296]: mv: inter-device move failed: '/tmp/294-daemon-reload.sh' to '/lib/dracut/hooks/initqueue/daemon-reload.sh'; unable to remove target: Read-only file syste

    dracut-cmdline[294]: /sbin/initqueue: line 71: /lib/dracut/hooks/initqueue/work: Read-only file system
    dracut-cmdline[221]: /lib/dracut-dev-lib.sh: line 118: /lib/dracut/hooks/initqueue/finished/devexists-\x2fdev\x2fmyvg\x2fluks_lv.sh: Read-only file system
    dracut-cmdline[221]: /lib/dracut-dev-lib.sh: line 103: /lib/dracut/hooks/emergency/80-\x2fdev\x2fmyvg\x2fluks_lv.sh: Read-only file system

Fix the above issue by making /usr writable.

Signed-off-by: Coiby Xu <[email protected]>

Author: coiby

dracut/99kdumpbase/module-setup.sh

@@ -1135,6 +1135,13 @@ $CRYPTSETUP_PATH luksOpen --volume-key-keyring \
 EOF
     done
 
+    # latest systemd makes /usr read-only by default
+    mkdir -p "${initdir}/etc/systemd/system.conf.d"
+    cat << EOF > "${initdir}/etc/systemd/system.conf.d/kdump_luks.conf"
+[Manager]
+ProtectSystem=false
+EOF
+
     dracut_need_initqueue
 }