If you set yaffs_auto_checkpoint to 0 it sounds like it'll write a checkpoint on unmount, so it wouldn't need to check the whole NAND on boot (if you do clean unmounts on shutdown). If you're aiming to save space, it might be worth trying 0 instead of the default 1, sounds like you'll get fewer checkpoints that way.

There's also this, from the link I posted:

skipCheckpointWrite

Yaffs2 only: Flag to skip writing checkpoint on sync or unmount.

That should probably get rid of all checkpoints if that's what you want, but since it's only listed under "Initialisation Parameters", maybe you have to set this on file system creation. Not even sure how, though.

Sorry I can't be more specific, but my knowledge of yaffs2 is very theoretical, I have little practical experience using it. Charles would be the authority on this stuff.

Regards, Ketil


On 9 April 2014 11:47, albhuang <albhuang@hotmail.com> wrote:
Hi Ketil,
A global variable, yaffs_auto_checkpoint, control the checkpoint action, just like:
 If 0 only checkpoint on unmount.
 If 1 checkpoint on sync.
 If 2 checkpoint on write_super and sync.
 Default is 1.
I'd like to know what would happen if it was set to zero(yaffs_auto_checkpoint = 0), only a little slow during booting because it would check the whole NAND, was it?
 
Thanks!
 
albhuang
 
Date: 2014-04-09 13:53
Subject: Re: Re: [Yaffs] umount YAFFS2 block: the used NAND space was increased

Not sure how it can be disabled, but looking at http://www.yaffs.net/yaffs-tuning-and-configuration#Initialisation_Parameters it seems possible.

If you redo the math I think you will find that the difference was 128k after all, but perhaps you did that already. :)

On 9 Apr 2014 04:05, "albhuang" <albhuang@hotmail.com> wrote:
Ketil,
It seemed the checkpoint action caused the error,could i abandon it, or anything could i do?
 
Best Regards!
 
albhuang
 
Date: 2014-04-08 17:42
CC: yaffs
Subject: Re: [Yaffs] umount YAFFS2 block: the used NAND space was increased
Could it perhaps be a yaffs2 checkpoint that was written on unmount so that it'll mount quickly next time?

Cheers, Ketil


On 8 April 2014 10:07, albhuang <albhuang@hotmail.com> wrote:
Hi,
I utilized yaffs2 to K9F2G08(1Page=2K+64Bytes), the kernel was linux2.6.12. All seemed OK except the command, umount, was executed, the used space would be increased, each time, when a umount command followed by the mount command. What's wrong with it.
 
The following was the infoes.
 
Thanks!
 
[root@INTUM /]$mount
/dev/mtdblock/5 on /mnt/database type yaffs2 (rw,noatime)
[root@INTUM /]$df
Filesystem           1k-blocks      Used Available Use% Mounted on
/dev/mtdblock/5         208896      1292    207604   1% /mnt/database               //the used space was 1292K
 
[root@INTUM /]$umount /mnt/database/
save exit: isCheckpointed 1
[root@INTUM /]$mount -t yaffs2 /dev/mtdblock/5 /mnt/database/
yaffs: dev is 32505861 name is "mtdblock5"
yaffs: passed flags ""
yaffs: Attempting MTD mount on 31.5, "mtdblock5"
[root@INTUM /]$df
Filesystem           1k-blocks      Used Available Use% Mounted on
/dev/mtdblock/5         208896      1420    207476   1% /mnt/database                //the used space increased to 1420K
 
 
 
 
 

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-Ketil



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-Ketil