[Yaffs] CVS updates

Nick Bane nick@cecomputing.co.uk
Thu, 28 Apr 2005 17:38:35 +0100


> Hi YAFFSers
>=20
> I have just done some YAFFS and YAFFS2 updates in CVS.
>=20
> Some of these are patching in some older stuff that I should have done =
a=20
> while ago and include the fixes to kill_block_super and the handling =
of=20
> special inodes in 2.6.  I have been delaying these waiting to set=20
> up a new=20
> 2.6 box, but have not done this and so checked them in anyway. If=20
> any of this=20
> breaks you, please scream.
>=20
>=20
> The major change has been adding the two scanning speed-ups to YAFFS2:
> * Backward scanning
> * Stuffing extra information into the tags for object headers.
> Some people have tried these and get **huge** speedups in mounting.
>=20
> -- Charles

Charles, a rambling implementation report (sorry its taken so long)=20
that may be of help to others.

I am testing yaffs2 using a standard 8-bit interface 512 bytes=20
per page nand plus an 8-bit interface 2K bytes per page nand (1GBit).
Is there a missing yaffs_tagsvalidiy.h in the CVS? It looks like it.
I faked one up with a couple of #defines and it now compile ok.

Mounting the first chip using yaffs is unremarkable.
Mounting the second gives unexpected results using df -h
Size: 16M Used: 16T(!) Available: 29.2M Use% -82%

I also got a load of erase failures and bad block warnings when deleting =
files.
Part of the problem may have been that I am not using NANDECC (for =
compatability reasons) with the files on the first nand device. I note =
that yaffs2 always passes a NULL in the place of the oobinfo so is =
effectively always in NANDECC mode. I suspect I was therfore getting a =
double ECC calculation effects. When the second nand chip was reduced to =
all bad blocks, df reported that its size was 16MB, 16MB was used, 0 was =
free and use% was 100%. /proc/mtd thinks its 128MB though.

I fully erased the second nand and patched yaffs_fs.h so that if =
yaffsVersion =3D=3D 2 , dev->useNANDECC is always asserted.

Now all seems well except for the df anomaly.

Nick Bane

--=20
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