Re: data loss on jffs2 filesystem on dataflash

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Jörn Engel wrote:
Still can't.  Block devices have the attribute that writing AAA... to
a block containing BBB... gives you one of three possible results in
case of power failure:

1. BBB...BBB all written
2. AAA...AAA nothing written
3. AAA...BBB partially written.

Flash doesn't have 3, but two more cases:
4. FFF...FFF erased, nothing written
5. AAA...FFF erased, partially written

Plus the really obnoxious
6. FFF...FFF partially erased.  Looks fine but some bits may flip
   randomly, writes may not stick, etc.

Now try finding a filesystem that is robust if 4-6 happens. ;)
Don't underastand this. If you mean the atomicity, CRC may help here. And no problems. Or may be you missed the the fact that we have eraseblock size = writeblock size?

JFFS2 orients to "classical" flashes. They have no "write page with built-in erase" operation.
What does this thing do?
It erases individual page, then writes there. To put it differently, in your terminology, eraseblock size = writeblock size.

P.S. I actually missed the mailing list, this should have gone to the MTD ML. So let's move there please.

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

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