mount nand jffs2 take more time

I am using PowerPC and 512MB NAND flash (2k Page size). Linux version
I was trying to mount the NAND Flash as jffs2 file system. During the
initial stage (NAND was empty) it takes less time to mount. After that
I wrote the data into NAND flash.
After that I rebooted and mounted the NAND flash again but now it
takes nearly 4 min.
If I type “ls” after mounting it also takes nearly 5 min.
Can any one help me how to fix this problem?
Is there any configuration change which needs to be made in JFFS2 file
system to reduce the mount time?

Thanks in advance.

Thangavadivel K