Chunhong,
Try with applying all the UBIFS/NAND related patches from:
http://arago-project.org/git/projects/?p=linux-dvr-rdk-dm81xx.git;a=summary
http://arago-project.org/git/projects/?p=linux-dvr-rdk-dm81xx.git;a=shortlog;h=refs/heads/dvrrdk_kernel_int_branch
http://arago-project.org/git/projects/?p=linux-omap3.git;a=shortlog;h=refs/heads/ti81xx-master
BR
Pavel