[Yaffs] umount YAFFS2 block: the used NAND space was increas…

I utilized yaffs2 to K9F2G08(1Page=2K+64Bytes), the kernel was linux2.6.12. All seemed OK except the command, umount, was executed, the used space would be increased, each time, when a umount command followed by the mount command. What's wrong with it.

The following was the infoes.

Thanks!

[root@INTUM /]$mount
/dev/mtdblock/5 on /mnt/database type yaffs2 (rw,noatime)
[root@INTUM /]$df
Filesystem           1k-blocks      Used Available Use% Mounted on
/dev/mtdblock/5         208896      1292    207604   1% /mnt/database               //the used space was 1292K

[root@INTUM /]$umount /mnt/database/
save exit: isCheckpointed 1
[root@INTUM /]$mount -t yaffs2 /dev/mtdblock/5 /mnt/database/
yaffs: dev is 32505861 name is "mtdblock5"
yaffs: passed flags ""
yaffs: Attempting MTD mount on 31.5, "mtdblock5"
[root@INTUM /]$df
Filesystem           1k-blocks      Used Available Use% Mounted on
/dev/mtdblock/5         208896      1420    207476   1% /mnt/database                //the used space increased to 1420K