My cat /proc/yaffs shows 
cat /proc/yaffs
YAFFS built:Oct 29 2004 16:26:29
$Id: yaffs_fs.c,v 1.35 2004/10/20 20:12:43 charles Exp $
$Id: yaffs_guts.c,v 1.37 2004/10/20 20:12:43 charles Exp $

Device yaffs
startBlock......... 1
endBlock........... 1023
chunkGroupBits..... 0
chunkGroupSize..... 1
nErasedBlocks...... 1017
nTnodesCreated..... 100
nFreeTnodes........ 86
nObjectsCreated.... 100
nFreeObjects....... 91
nFreeChunks........ 32570
nPageWrites........ 4
nPageReads......... 4
nBlockErasures..... 0
nGCCopies.......... 0
garbageCollections. 0
passiveGCs......... 0
nRetriedWrites..... 0
nRetireBlocks...... 0
eccFixed........... 0
eccUnfixed......... 0
tagsEccFixed....... 0
tagsEccUnfixed..... 1024
cacheHits.......... 0
nDeletedFiles...... 0
nUnlinkedFiles..... 0
nBackgroudDeletions 0
useNANDECC......... 1
[root@manav yaffs]#cd /

and a very weird erro message comes when we unmount the nand file system .
umount /mnt/yaffs/
VFS: Busy inodes after unmount. Self-destruct in 5 seconds.  Have a nice day...

???? 

On Fri, 29 Oct 2004 12:37:47 +0530, bandwidthcrunch
<bandwidthcrunch@gmail.com> wrote:
> Hi All,
>         Have got yaffs running on a 2.6.8-1 kernel , It mounts
> perfectly but when i try to copy a file or write a file to the mounted
> partion it gives a lot of
> 
> **>>yaffs chunk 1 was not erased
> ...................
> **>> yaffs chunk 32567 was not erased
> **>> yaffs chunk 32568 was not erased
> **>> yaffs chunk 32569 was not erased
> **>> yaffs chunk 32570 was not erased
> **>> yaffs chunk 32571 was not erased
> **>> yaffs chunk 32572 was not erased
> **>> yaffs chunk 32573 was not erased
> **>> yaffs chunk 32574 was not erased
> **>> yaffs chunk 32575 was not erased
> **>> Block 1017 retired
> **>> yaffs write required 32544 attempts
> cp: unable to open `/mnt/yaffs/startup': Cannot allocate memory
> 
> and df will show me full usage
> Filesystem           1k-blocks      Used Available Use% Mounted on
> rootfs                   31488      8944     22544  28% /
> /dev/mtdblock2           31488      8944     22544  28% /
> /dev/mtdblock3           16368     16368         0 100% /mnt/yaffs
> 
> after the failed attemp to copy.
> I have tried enabling and disabling both IGNORE_CHUNK_ERASED =
> -DCONFIG_YAFFS_DISABLE_CHUNK_ERASED_CHECK in the Makefile but to no
> avail.
> 
> I am  erasing the nand device like this
> [root@manav /root]#./mkyaffs /dev/mtd3
> Erasing and programming NAND
> Erasing block at 0x080
> Block at 0x084000 is damaged and is not being formatted
> Erasingnand_erase: attempt to erase a bad block at page 0x00000060
>  block at 0x088000
> Erasing block at 0x08c000
> 
> MTD Erase failure
> : Input/output error
> 
> Any clues or suggestions are welcome ?
> 
> regards,
> Manav
>