[Yaffs] YAFFS2 and OneNAND bad blocks

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Author: Sudeep K N
Date:  
To: yaffs
CC: manningc2
Subject: [Yaffs] YAFFS2 and OneNAND bad blocks
Hi,

I am facing a strange behavior on OneNAND device with YAFFS2 file system.

Setup: Eclair release, Linux 2.6.29 from Google Repo, ARM11EJFS,
Samsung OneNAND device
Description of steps followed as below:

1. Created a yaffs2 image of Android rootfs using mkyaffs2image tool
2. Flashed the image to a MTD partition on OneNAND device using fastboot
3. Verified the image flashed using fastboot in bootloader and also
   using MTD utilities in Linux and found to fine. (Bad blocks are skipped
   while flashing as well as reading)
4. Mount that MTD partition and found few files corrupted.
5. When compared mounted contents with the rootfs directory flashed,
   the files that are corrupted differ exactly by 4KB. That 4KB data
is all zero.
  Further, I observed that 4KB data that has been zeroed falls exactly in
  first two pages of the blocks following a bad block.

I am not able to understand why is this behavior seen for 4KB data
following a bad block.
Please let me know if I am not clear in explain the issue.

--
Regards,
Sudeep