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CLEANMARKER obsolete, last-ic cache.



I've committed code to the trunk to remember the last inode_cache looked 
up, and to mark CLEANMARKER nodes obsolete in jffs2_do_reserve_space() when 
we first start to allocate from a new block.

What I think I'll do next is preread the whole erase block at the beginning 
of jffs2_scan_eraseblock() instead of reading it all in little pieces to 
little buffers. In jffs2_scan_medium() we can vmalloc() an eraseblock-sized 
space for this. I don't think that's too evil.

Next optimisation will be to lock the flash chip down and just use a 
pointer into the chip itself, of course - once all the actual scan code is 
set up to deal with the fact that it's just dealing with a pointer to the 
data.

Your optimisation of checking for a cleanmarker and avoiding the scan for 
0xFF will still be possible, if you can work out a way to make it reliable 
with older filesystems that didn't obsolete the cleanmarker. You just put 
that check before the large read at the beginning of jffs2_scan_eraseblock().

Btw, there's now an IRC channel on irc.openprojects.net - #mtd. 
Semi-intelligent conversation has been known to occur there, between Thomas
and I who are the only people on it so far.

--
dwmw2



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