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Commit 3a0592b1 authored by Artem Bityutskiy's avatar Artem Bityutskiy
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Revert "UBI: use mtd->writebufsize to set minimal I/O unit size" 



This reverts commit a121f643.

Unfortunately, this commit breaks UBIFS backward compatibility and
makes new UBIFS refuse older UBIFS-formatted media:

UBIFS error: validate_sb: min. I/O unit mismatch: 8 in superblock, 64 real

Thus, we have to revert this patch and work on a better solution.

Reported-by: default avatarHolger Brunck <holger.brunck@keymile.com>
Signed-off-by: default avatarArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
parent 1bae4ce2

drivers/mtd/ubi/build.c

+1 −27
Original line number Diff line number Diff line
@@ -672,33 +672,7 @@ static int io_init(struct ubi_device *ubi) 
		ubi->nor_flash = 1;

	}



	/*

	 * Set UBI min. I/O size (@ubi->min_io_size). We use @mtd->writebufsize

	 * for these purposes, not @mtd->writesize. At the moment this does not

	 * matter for NAND, because currently @mtd->writebufsize is equivalent to

	 * @mtd->writesize for all NANDs. However, some CFI NOR flashes may

	 * have @mtd->writebufsize which is multiple of @mtd->writesize.

	 *

	 * The reason we use @mtd->writebufsize for @ubi->min_io_size is that

	 * UBI and UBIFS recovery algorithms rely on the fact that if there was

	 * an unclean power cut, then we can find offset of the last corrupted

	 * node, align the offset to @ubi->min_io_size, read the rest of the

	 * eraseblock starting from this offset, and check whether there are

	 * only 0xFF bytes. If yes, then we are probably dealing with a

	 * corruption caused by a power cut, if not, then this is probably some

	 * severe corruption.

	 *

	 * Thus, we have to use the maximum write unit size of the flash, which

	 * is @mtd->writebufsize, because @mtd->writesize is the minimum write

	 * size, not the maximum.

	 */

	if (ubi->mtd->type == MTD_NANDFLASH)

		ubi_assert(ubi->mtd->writebufsize == ubi->mtd->writesize);

	else if (ubi->mtd->type == MTD_NORFLASH)

		ubi_assert(ubi->mtd->writebufsize % ubi->mtd->writesize == 0);



	ubi->min_io_size = ubi->mtd->writebufsize;



	ubi->min_io_size = ubi->mtd->writesize;

	ubi->hdrs_min_io_size = ubi->mtd->writesize >> ubi->mtd->subpage_sft;



	/*