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Date: Wed, 26 Jan 2011 15:20:23 +0100
From: Holger Brunck <holger.brunck@keymile.com>
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Subject: UBIFS incompatibilities due to min_io_size adaptions?
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Cc: Andreas Huber <andreas.huber@keymile.com>
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Hi all,
we use UBI and UBIFS on NOR and NAND based systems and kernel 2.6.33. In the
last days we applied the latest UBI and MTD patches for the min I/O size.

Due to commit  a121f643993474548fe98144514c50dd4f3dbe76 UBI: use
mtd->writebufsize to set minimal I/O unit size
now the min I/O size is equal to the writebuffersize of the flash.

This caused incompatibilites in the UBIFS. We have an UBIFS on a board on a NOR
flash created in the past without the patches. Now with a newer SW and a newer
kernel which has the latest fixes we can't mount the old UBIFS anymore.

UBIFS error (pid 865): validate_sb: min. I/O unit mismatch: 8 in superblock, 64 real
UBIFS error (pid 865): validate_sb: bad superblock, error 1
mount: wrong fs type, bad option, bad superblock on ubi0:cfg,
        missing codepage or other error

If we reformate the UBIFS everything is ok, but we got a problem with the older
SW image:
UBIFS error (pid 865): validate_sb: min. I/O unit mismatch: 64 in
superblock, 8 real
UBIFS error (pid 865): validate_sb: bad superblock, error 1
mount: wrong fs type, bad option, bad superblock on ubi0:cfg,
        missing codepage or other error

Is there a way to solve this problem? I do not hope that the only solution is to
remove these patch.

Any help is appreciated.

Best regards
Holger Brunck