JFFS2 SUMMARY nodes aren't working
joakim.tjernlund at transmode.se
Mon Mar 26 11:09:20 EDT 2007
On Mon, 2007-03-26 at 09:02 -0500, Josh Boyer wrote:
> On Mon, 2007-03-26 at 15:16 +0200, Joakim Tjernlund wrote:
> > On Mon, 2007-03-26 at 07:37 -0500, Josh Boyer wrote:
> > > On Fri, 2007-03-23 at 18:24 +0100, Joakim Tjernlund wrote:
> > > >
> > > > I found that an all empty FS took about the same time to mount
> > > > which I find very strange.
> > > >
> > > > Looking into the code in scan.c I found that even though I have
> > > > cleanmarkers in all EB:s, JFFS2 still scans the whole EB. Do
> > > > you really need to scan the whole area after the cleanmarker?
> > > > Should be enough to only check a few words after the clean marker
> > > > and if that is 0xffffffff then assume that the EB is clean
> > > > since it had a valid clean marker at the beginning.
> > >
> > > No, you can't just read a few words. On some flash, the cleanmarker
> > > cannot be marked invalid in place so you still need to scan the rest of
> > > the block. Sucks.
> > Not quite true, for the non XIP case you don't read more than
> > EMPTY_SCAN_SIZE(c->sector_size) before declaring it free.
> > JFFS2 has relied on this behavior in 2.4 and I see no reason to
> > change that.
> Well, yes you're right. Too early in the morning for me to be emailing.
> But now I'm confused. Are you running with XIP or no? If not, then you
> shouldn't be hitting this issue from what I can tell. The check below
> the code you quoted earlier explicitly looks to see if the first node
> found is a cleanmarker and then returns.
> I'm confused how you're hitting this issue unless you have XIP turned on
I don't run XIP, but I use cfi_cmdset_0001 flash driver and that one
has support for the point/unpoint methods.
XIP needs point but point is also an optimization that has
its own use and cfi_cmdset_0001 enables them by default.
This means that all users of above flashdriver(Intel flashes)
will use point if the flash mapping is linear.
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