[Nexus One Android Development] BakaPhoenix:
Looking in the m2sd debug log i found out 2 strange thing

--------- beginning of /dev/log/main
V/sysinit ( 81): Executing /system/etc/init.d/01sysctl...
I/01sysctl( 84): vm.swappiness = 20
I/01sysctl( 84): vm.min_free_kbytes = 8192
I/01sysctl( 84): vm.dirty_ratio = 60
I/01sysctl( 84): vm.dirty_background_ratio = 20
V/sysinit ( 87): Executing /system/etc/init.d/05hostname...
I/01sysctl( 84): vm.vfs_cache_pressure = 40
V/sysinit ( 116): Executing /system/etc/init.d/09mkloops...
V/sysinit ( 156): Executing /system/etc/init.d/10mounts2sd...
V/mounts2sd( 209): Initiating Mounts2SD (v:4.2.0) [Sat Apr 21 11:56:23 CEST 2012]
D/mounts2sd( 230): doCreateFile: Writing to file /system/etc/m2sd.log...
D/mounts2sd( 235): doCreateFile: Setting permissions on /system/etc/m2sd.log, mod(0661), own(1000.1000)...
V/mounts2sd( 254): Checking configurations...
D/mounts2sd( 372): Checking device /dev/block/mtdblock3 to prepare for Optimization...
V/mounts2sd( 382): Optimizing /system readahead...
V/mounts2sd( 387): Disabling /system atime & diratime...
D/mounts2sd( 392): Checking device /dev/block/mtdblock5 to prepare for Optimization...
V/mounts2sd( 402): Optimizing /data readahead...
V/mounts2sd( 408): Waiting for sdcard to initiate...
D/mounts2sd( 414): Checking /sys/block/mmcblk0/device/type for sdcard flag...
V/mounts2sd( 420): sdcard found at /dev/block/mmcblk0...
D/mounts2sd( 431): Checking device 179:0 to prepare for Optimization...
V/mounts2sd( 435): Setting sdcard readahead to 2048kb...
D/mounts2sd( 440): Checking file system type on /dev/block/mmcblk0p1...
D/mounts2sd( 456): Found sdcard (FAT32) partition...
D/mounts2sd( 460): Checking file system type on /dev/block/mmcblk0p2...
D/mounts2sd( 479): Found sd-ext (ext3) partition...
D/mounts2sd( 484): Checking file system type on /dev/block/mmcblk0p3...
D/mounts2sd( 496): Found swap partition...
V/mounts2sd( 506): Activating SWAP partition...
V/mounts2sd( 545): Running e2fsck on sd-ext...
I/10mounts2sd( 159): e2fsck 1.41.10 (10-Feb-2009)
I/10mounts2sd( 159): /dev/block/mmcblk0p2: clean, 126/131328 files, 87758/524288 blocks
V/mounts2sd( 568): The sd-ext partition was mounted successfully at /sd-ext forced as ext4!
D/mounts2sd( 609): Looking in /data/dalvik-cache for any content to move to /sd-ext/dalvik-cache...
V/mounts2sd( 616): Creating link between /data/dalvik-cache and /sd-ext/dalvik-cache...
D/mounts2sd( 634): Looking in /data/app for any content to move to /sd-ext/app...
V/mounts2sd( 641): Creating link between /data/app and /sd-ext/app...
D/mounts2sd( 659): Looking in /data/app-private for any content to move to /sd-ext/app-private...
V/mounts2sd( 666): Creating link between /data/app-private and /sd-ext/app-private...
D/mounts2sd( 682): Looking in /data/app-system for any content to move to /sd-ext/app-system...
V/mounts2sd( 689): Creating link between /data/app-system and /sd-ext/app-system...
D/mounts2sd( 704): Looking in /sd-ext/dontpanic for any content to revert back to /data/dontpanic...
D/mounts2sd( 712): Looking in /sd-ext/resource-cache for any content to revert back to /data/resource-cache...
D/mounts2sd( 720): Looking in /sd-ext/lost+found for any content to revert back to /data/lost+found...
D/mounts2sd( 732): Looking in /sd-ext/drm for any content to revert back to /data/drm...
D/mounts2sd( 740): Looking in /sd-ext/local for any content to revert back to /data/local...
D/mounts2sd( 748): Looking in /sd-ext/misc for any content to revert back to /data/misc...
D/mounts2sd( 756): Looking in /sd-ext/system for any content to revert back to /data/system...
D/mounts2sd( 764): Looking in /sd-ext/tombstones for any content to revert back to /data/tombstones...
D/mounts2sd( 772): Looking in /sd-ext/data for any content to revert back to /data/data...
D/mounts2sd( 780): Looking in /sd-ext/property for any content to revert back to /data/property...
D/mounts2sd( 788): Checking if sub-directory /data/misc/bluetoothd exists...
D/mounts2sd( 794): Checking if sub-directory /data/misc/bluetooth exists...
D/mounts2sd( 800): Checking if sub-directory /data/misc/keystore exists...
D/mounts2sd( 806): Checking if sub-directory /data/misc/keychain exists...
D/mounts2sd( 812): Checking if sub-directory /data/misc/vpn exists...
D/mounts2sd( 818): Checking if sub-directory /data/misc/systemkeys exists...
D/mounts2sd( 824): Checking if sub-directory /data/misc/wifi exists...
D/mounts2sd( 830): Checking if sub-directory /data/local/tmp exists...
V/mounts2sd( 950): Linking apps from /data/app-system to /system/app...
D/mounts2sd( 1016): doCreateFolder: Creating new folder /cache/download...
D/mounts2sd( 1028): doCreateFolder: Setting permissions on /cache/download, mod(0771), own(1000.2001)...
V/mounts2sd( 1037): Mounting /cache/download at tmpfs...
D/mounts2sd( 1063): Connecting /cache/dalvik-cache with /data/dalvik-cache...
V/mounts2sd( 1070): Creating link between /cache/dalvik-cache and /data/dalvik-cache...
V/mounts2sd( 1080): Mounts2SD has been loaded!

1. It recognise my ext4 partition as ext3 (i even reformatted it in ext4 with gparted so i'm pretty sure that is an ext4 partition XD) so it force is as ext 4 since i selected ext4, but now i put it on auto.

2. It disable atime and diratime even though i didn't enabled that feature

I hope this helped :D