this version on the pi2 seems to clean up on reboot. from pi2

[ 2.474555] mmcblk0: p1 p2
[ 2.499110] EXT4-fs (mmcblk0p2): INFO: recovery required on readonly filesystem
[ 2.508125] EXT4-fs (mmcblk0p2): write access will be enabled during recovery
[ 3.213253] EXT4-fs (mmcblk0p2): recovery complete
[ 3.227194] EXT4-fs (mmcblk0p2): mounted filesystem with ordered data mode. Opts: (null)
[ 15.604242] EXT4-fs (mmcblk0p2): re-mounted. Opts: (null)
[ 15.855481] EXT4-fs (mmcblk0p2): re-mounted. Opts: (null)

root@raspberrypi2:~# uname -a
Linux raspberrypi2 3.18.11-v7+ #781 SMP PREEMPT Tue Apr 21 18:07:59 BST 2015 armv7l GNU/Linux

on the b+ pi the FAT partition often needs cleanup. Not on ups due to location of weather station.

[ 2.520520] EXT4-fs (mmcblk0p2): INFO: recovery required on readonly filesystem
[ 2.529772] EXT4-fs (mmcblk0p2): write access will be enabled during recovery
[ 2.971006] EXT4-fs (mmcblk0p2): orphan cleanup on readonly fs
[ 3.030760] EXT4-fs (mmcblk0p2): 5 orphan inodes deleted
[ 3.038370] EXT4-fs (mmcblk0p2): recovery complete
[ 3.076741] EXT4-fs (mmcblk0p2): mounted filesystem with ordered data mode. Opts: (null)
[ 8.902682] EXT4-fs (mmcblk0p2): re-mounted. Opts: (null)
[ 11.672354] FAT-fs (mmcblk0p1): Volume was not properly unmounted. Some data may be corrupt. Please run fsck.

root@weather:~# uname -a
Linux weather 3.18.3+ #739 PREEMPT Tue Jan 20 17:45:32 GMT 2015 armv6l GNU/Linux