On Thursday 03 March 2011 05:26:03 Yoann Sculo wrote:
> Hello,
>
> I'm using a yaffs partition on a EABI arm920t platform and having strange
> problems while umounting my partition.
> In this case I'm using BusyBox v1.17.4 with the uClibC 0.9.31 for my umount
> binary.
> I'm looking for help, I can't find the possible reasons... I suppose it
> could comes from my yaffs partition or busybox umount applet. I have asked
> them for help.
> Meantime, I'm exploring the possibility my yaffs is corrupted.
>
> I have the following command in my linuxrc, that mounts my yaffs system
>
> /bin/mount -t yaffs /dev/mtdblock6 /usr
>
> which gets me the following system messages :
>
> yaffs: dev is 32505862 name is "mtdblock6"
> yaffs: passed flags ""
> yaffs: Attempting MTD mount on 31.6, "mtdblock6"
> yaffs: auto selecting yaffs2
> yaffs: restored from checkpoint
> yaffs_read_super: isCheckpointed 1
>
> In my case (a few seconds later) one of my scripts starts the following
> command :
>
> /bin/umount /usr || return 1
>
> For the record, in this particular case, I just want to umount my yaffs
> filesystem to flash erase it and get something brand new :)
> And before I have the time to flash erase it, that returns these errors :
>
> umount: can't umount /usr: Device or resource busy

This typically indicates that files in the file system are in use.

> save exit: isCheckpointed 1
> umount: /dev/mtdblock6 busy - remounted read-only
> umount: none busy - remounted read-only
>
> "isCheckpointed 1" rings a bell actually. 

I doubt very much that this is having an impact.

> But I can't really find specs 
> that explain checkpointing. Except here :
> http://www.yaffs.net/lurker/message/20070327.193931.32818f24.pl.html But It
> doesn't really help me.
> Could someone explain to me what the purpose of checkpointing flag ? 

Have you read HowYaffsWorks.pdf? 

> I 
> could imagine there is something wrong with my partition. But I don't
> really understand what happened here.
>
> The problem is quite embarrassing because I can't change my system here. I
> just want to understand what could have happened :/
>
> Last thing I could add is that I have the following system message while
> creating my mtd partitions :
>
> mtd: partition "yaffs" extends beyond the end of device "NAND 256MiB 3,3V
> 8-bit" -- size truncated to 0xeac0000
>
> Could this be related ?

Possibly. This indicates that your partition table has been set up 
incorrectly.