JFFS2 mount time

Artem B. Bityuckiy abityuckiy at yandex.ru
Wed Oct 20 11:53:20 EDT 2004


Ferenc Havasi wrote:
> The reason is the following: the summary node is at the end of the erase 
> block, and it has not fixed size (its size depends on the information it 
> stores).
> 
> The main advantage of using summary node is to avoid the original 
> scanning method. So we cannot use the original full-scanning method to 
> determine  the begining of the summary node (using only 
> JFFS2_NODETYPE_INODE_SUM).
> 
> Our method is the following:
> - read some bytes at the end of the erase block
> - if the last word is JFFS2_SUM_MAGIC than we will almost sure that it 
> is an erase block which has summary
> - the word before this magic is the length of the node
> - using this length we can check that it is really a 
> JFFS2_NODETYPE_INODE_SUM node, and process it
> 
> I can't image more effective method to determine the begining of the 
> summary node. (if you have better suggestion...) And because the magic 
> is inside of the summary node I think it is fit to the philosophy of 
> JFFS2 - but a little bit tricky.
Ok, I got it. I was wrong, sorry.

-- 
Best Regards,
Artem B. Bityuckiy,
St.-Petersburg, Russia.




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