--- /etc/init/mysql.conf.ori	2013-08-09 09:44:12.000000000 +0200
+++ /etc/init/mysql.conf	2013-08-09 10:40:52.000000000 +0200
@@ -12,10 +12,21 @@
 env HOME=/etc/mysql
 umask 007
 
-# The default of 5 seconds is too low for mysql which needs to flush buffers
 kill timeout 300
 
 pre-start script
+    ## Fetch a particular option from mysql's invocation.
+    #
+    # Usage: void mysqld_get_param option
+    mysqld_get_param() {
+	    /usr/sbin/mysqld --print-defaults \
+  		  | tr " " "\n" \
+  		  | grep -- "--$1" \
+	    	| tail -n 1 \
+	  	  | cut -d= -f2
+    }
+
+    # The default of 5 seconds is too low for mysql which needs to flush buffers
 
     # priority can be overriden and "-s" adds output to stderr
     ERR_LOGGER="logger -p daemon.err -t /etc/init/mysql.conf -i"
@@ -26,7 +37,8 @@
     /lib/init/apparmor-profile-load usr.sbin.mysqld
     # check for diskspace shortage
     datadir=`mysqld_get_param datadir`
-    if LC_ALL=C BLOCKSIZE= df --portability $datadir/. | tail -n 1 | awk '{ exit ($4<4096) }'; then
+    LC_ALL=C BLOCKSIZE=`df --portability $datadir/. | tail -n 1 | awk '{ print $4 }'`
+    if [ $BLOCKSIZE -lt 4096 ]; then
       echo "$0: ERROR: The partition with $datadir is too full!" >&2
       echo                "ERROR: The partition with $datadir is too full!" | $ERR_LOGGER
       exit 1