[Desire Android Development] foobar66:
Well, I have been testing sibere's original DATA2SD using the following 01data script:

/system/bin/logwrapper echo "Starting DATA2SD"

/system/bin/logwrapper echo "Unmounting /data"

/system/xbin/busybox umount /data

/system/bin/logwrapper echo "Listing filesystem superblock"

/system/bin/tune2fs -l dev/block/mmcblk0p2

/system/bin/logwrapper echo "Checking ext4 file system on sdcard"

/system/bin/e2fsck -yf /dev/block/mmcblk0p2

/system/bin/logwrapper echo "Mounting ext4 file system on /data"

/system/xbin/busybox mount -t ext4 -o rw,noatime,nodiratime,nosuid,nodev,nobh,nouser_xattr /dev/block/mmcblk0p2 /data

/system/bin/logwrapper echo "Changing ownership of /data"

chown 1000.1000 /data

/system/bin/logwrapper echo "Changing permissions of /data"

chmod 771 /data

Now, even with a normal phone shutdown (which is supposed to be clean), I always get upon boot:

I//system/xbin/busybox( 54): Filesystem volume name: userdata

I//system/xbin/busybox( 54): Last mounted on: /data

I//system/xbin/busybox( 54): Filesystem UUID: bc4658cc-0e1f-463f-93cb-97bd4998fb17

I//system/xbin/busybox( 54): Filesystem magic number: 0xEF53

I//system/xbin/busybox( 54): Filesystem revision #: 1 (dynamic)

I//system/xbin/busybox( 54): Filesystem features: ext_attr resize_inode dir_index filetype extent flex_bg sparse_super large_file uninit_bg dir_nlink extra_isize

I//system/xbin/busybox( 54): Filesystem flags: unsigned_directory_hash

I//system/xbin/busybox( 54): Default mount options: (none)

I//system/xbin/busybox( 54): Filesystem state: not clean

I//system/xbin/busybox( 54): Errors behavior: Continue

I//system/xbin/busybox( 54): Filesystem OS type: Linux

I//system/xbin/busybox( 54): Inode count: 65536

I//system/xbin/busybox( 54): Block count: 262144

I//system/xbin/busybox( 54): Reserved block count: 0

I//system/xbin/busybox( 54): Free blocks: 232497

I//system/xbin/busybox( 54): Free inodes: 63762

I//system/xbin/busybox( 54): First block: 0

I//system/xbin/busybox( 54): Block size: 4096

I//system/xbin/busybox( 54): Fragment size: 4096

I//system/xbin/busybox( 54): Reserved GDT blocks: 63

I//system/xbin/busybox( 54): Blocks per group: 32768

I//system/xbin/busybox( 54): Fragments per group: 32768

I//system/xbin/busybox( 54): Inodes per group: 8192

I//system/xbin/busybox( 54): Inode blocks per group: 512

I//system/xbin/busybox( 54): RAID stride: 64

I//system/xbin/busybox( 54): RAID stripe width: 64

I//system/xbin/busybox( 54): Flex block group size: 16

I//system/xbin/busybox( 54): Filesystem created: Mon Feb 7 17:53:10 2011

I//system/xbin/busybox( 54): Last mount time: Tue Feb 8 16:05:30 2011

I//system/xbin/busybox( 54): Last write time: Tue Feb 8 16:07:33 2011

I//system/xbin/busybox( 54): Mount count: 1

I//system/xbin/busybox( 54): Maximum mount count: 37

I//system/xbin/busybox( 54): Last checked: Tue Feb 8 16:05:30 2011

I//system/xbin/busybox( 54): Check interval: 15552000 (6 months)

I//system/xbin/busybox( 54): Next check after: Sun Aug 7 17:05:30 2011

I//system/xbin/busybox( 54): Reserved blocks uid: 0 (user root)

I//system/xbin/busybox( 54): Reserved blocks gid: 0 (group root)

I//system/xbin/busybox( 54): First inode: 11

I//system/xbin/busybox( 54): Inode size:	256

I//system/xbin/busybox( 54): Required extra isize: 28

I//system/xbin/busybox( 54): Desired extra isize: 28

I//system/xbin/busybox( 54): Default directory hash: half_md4

I//system/xbin/busybox( 54): Directory Hash Seed: 03d677b9-0505-42c5-938f-bbb4fb738544

I always get "non clean". I have tried 20 reboots or so ... always "not clean".

Sometimes the file system checks then shows repairs at boot time:

I//system/xbin/busybox( 54): e2fsck 1.41.3 (12-Oct-2008)

I//system/xbin/busybox( 54): Pass 1: Checking inodes, blocks, and sizes

I//system/xbin/busybox( 54): Pass 2: Checking directory structure

I//system/xbin/busybox( 54): Pass 3: Checking directory connectivity

I//system/xbin/busybox( 54): Pass 4: Checking reference counts

I//system/xbin/busybox( 54): Pass 5: Checking group summary information

I//system/xbin/busybox( 54): Block bitmap differences: +(48053--48058)

I//system/xbin/busybox( 54): Fix? yes

I//system/xbin/busybox( 54): Free blocks count wrong for group #1 (8644, counted=8638).

I//system/xbin/busybox( 54): Fix? yes

I//system/xbin/busybox( 54): Free blocks count wrong (232508, counted=232502).

I//system/xbin/busybox( 54): Fix? yes

I//system/xbin/busybox( 54): userdata: ***** FILE SYSTEM WAS MODIFIED *****

I//system/xbin/busybox( 54): userdata: 1773/65536 files (2.0non-contiguous), 29642/262144 blocks

You can see the "Fix? yes" in here.

So ... hmmm ... sibere, maybe I have missed something, but I do not think that /data get cleanly unmounted.