Problem using JFFS2 on flash

[Kor]

I am trying to mount flash memory as jffs2, mounting result is ok, but I
cannot use it for data storage (even can't create any subdirectory - result
is "Segmentation fault").

After commands:
eraseall /dev/mtd2
mount -t jffs2 /dev/mtdblock2 /mnt
there are no error messages, everything seems to be ok.
Mount returns row:
/dev/mtdblock2 on /mnt type jffs2 (rw)
but df returns:
/dev/mtdblock2 4096 used=640 (16%) /mnt which seems to be wrong - flash
should be empty, shouldn't it?
So could anyone tell me what to check - is there some problem with eraseall or
jffs2 driver or something else?


Here is the solution from SSV:
steps for setup a flash disk in linux:

1) boot linux system
2) login as root
3) erase flash -> eraseall /dev/mtd2
4) create filesystem -> mount -t jffs2 /dev/mtdblock2 /mnt
5) finalize filesystem (take a long time) -> umount /mnt
6) reboot/reset system

I will try it ....