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RE: New jffs2 files stay uncompressed?
> email@example.com said:
> > In my tree, the most time is spent scanning empty flash and doing CRC
> > on the inodes data part. If there were a way to avoid scanning the
> > empty nodes(that is, play with the ACCURATE bit in the CLEANMARKER
> > node) and avoid CRC(CRC is checked at every read request anyway so
> > maybe we could just skip the extra CRC check at mount) at mount on
> > every files data, the mount would be very fast.
> If we can make that work, I'd prefer it to the special case in
> jffs2_mark_node_obsolete(). Until now, the ACCURATE bit has been strictly
> an optimisation - you can't do it on NAND flash or even some NOR chips.
> That situation has to work too.
How? I figure that iff ACCURATE bit is set in a CLEANMARKER, then
that erase block is empty. On first write to such a EB, clear ACCURATE bit in the
CLEANMARKER node and then write you data to flash. Can't see how to do that
> > BTW, today the CLEANMARKER is optional, is that intentional? If it was
> > mandatory it would make life simpler when playing with the erase
> > blocks.
> It wasn't implemented in the beginning. Making it mandatory would have
> involved a break in compatibility. And mkfs.jffs2 still doesn't emit them.
Changing from CRC32 to Adler32 would also break compatibility, but we
could at least have it as an compile option?
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