vtbl.c

uboot200903最新版本的通用uboot

			err = create_vtbl(ubi, si, 1, leb[0]);
			if (err)
				goto out_free;
			ubi_msg("volume table was restored");
		}

		/* Both LEB 1 and LEB 2 are OK and consistent */
		vfree(leb[1]);
		return leb[0];
	} else {
		/* LEB 0 is corrupted or does not exist */
		if (leb[1]) {
			leb_corrupted[1] = vtbl_check(ubi, leb[1]);
			if (leb_corrupted[1] < 0)
				goto out_free;
		}
		if (leb_corrupted[1]) {
			/* Both LEB 0 and LEB 1 are corrupted */
			ubi_err("both volume tables are corrupted");
			goto out_free;
		}

		ubi_warn("volume table copy #1 is corrupted");
		err = create_vtbl(ubi, si, 0, leb[1]);
		if (err)
			goto out_free;
		ubi_msg("volume table was restored");

		vfree(leb[0]);
		return leb[1];
	}

out_free:
	vfree(leb[0]);
	vfree(leb[1]);
	return ERR_PTR(err);
}

/**
 * create_empty_lvol - create empty layout volume.
 * @ubi: UBI device description object
 * @si: scanning information
 *
 * This function returns volume table contents in case of success and a
 * negative error code in case of failure.
 */
static struct ubi_vtbl_record *create_empty_lvol(struct ubi_device *ubi,
						 struct ubi_scan_info *si)
{
	int i;
	struct ubi_vtbl_record *vtbl;

	vtbl = vmalloc(ubi->vtbl_size);
	if (!vtbl)
		return ERR_PTR(-ENOMEM);
	memset(vtbl, 0, ubi->vtbl_size);

	for (i = 0; i < ubi->vtbl_slots; i++)
		memcpy(&vtbl[i], &empty_vtbl_record, UBI_VTBL_RECORD_SIZE);

	for (i = 0; i < UBI_LAYOUT_VOLUME_EBS; i++) {
		int err;

		err = create_vtbl(ubi, si, i, vtbl);
		if (err) {
			vfree(vtbl);
			return ERR_PTR(err);
		}
	}

	return vtbl;
}

/**
 * init_volumes - initialize volume information for existing volumes.
 * @ubi: UBI device description object
 * @si: scanning information
 * @vtbl: volume table
 *
 * This function allocates volume description objects for existing volumes.
 * Returns zero in case of success and a negative error code in case of
 * failure.
 */
static int init_volumes(struct ubi_device *ubi, const struct ubi_scan_info *si,
			const struct ubi_vtbl_record *vtbl)
{
	int i, reserved_pebs = 0;
	struct ubi_scan_volume *sv;
	struct ubi_volume *vol;

	for (i = 0; i < ubi->vtbl_slots; i++) {
		cond_resched();

		if (be32_to_cpu(vtbl[i].reserved_pebs) == 0)
			continue; /* Empty record */

		vol = kzalloc(sizeof(struct ubi_volume), GFP_KERNEL);
		if (!vol)
			return -ENOMEM;

		vol->reserved_pebs = be32_to_cpu(vtbl[i].reserved_pebs);
		vol->alignment = be32_to_cpu(vtbl[i].alignment);
		vol->data_pad = be32_to_cpu(vtbl[i].data_pad);
		vol->vol_type = vtbl[i].vol_type == UBI_VID_DYNAMIC ?
					UBI_DYNAMIC_VOLUME : UBI_STATIC_VOLUME;
		vol->name_len = be16_to_cpu(vtbl[i].name_len);
		vol->usable_leb_size = ubi->leb_size - vol->data_pad;
		memcpy(vol->name, vtbl[i].name, vol->name_len);
		vol->name[vol->name_len] = '\0';
		vol->vol_id = i;

		if (vtbl[i].flags & UBI_VTBL_AUTORESIZE_FLG) {
			/* Auto re-size flag may be set only for one volume */
			if (ubi->autoresize_vol_id != -1) {
				ubi_err("more then one auto-resize volume (%d "
					"and %d)", ubi->autoresize_vol_id, i);
				kfree(vol);
				return -EINVAL;
			}

			ubi->autoresize_vol_id = i;
		}

		ubi_assert(!ubi->volumes[i]);
		ubi->volumes[i] = vol;
		ubi->vol_count += 1;
		vol->ubi = ubi;
		reserved_pebs += vol->reserved_pebs;

		/*
		 * In case of dynamic volume UBI knows nothing about how many
		 * data is stored there. So assume the whole volume is used.
		 */
		if (vol->vol_type == UBI_DYNAMIC_VOLUME) {
			vol->used_ebs = vol->reserved_pebs;
			vol->last_eb_bytes = vol->usable_leb_size;
			vol->used_bytes =
				(long long)vol->used_ebs * vol->usable_leb_size;
			continue;
		}

		/* Static volumes only */
		sv = ubi_scan_find_sv(si, i);
		if (!sv) {
			/*
			 * No eraseblocks belonging to this volume found. We
			 * don't actually know whether this static volume is
			 * completely corrupted or just contains no data. And
			 * we cannot know this as long as data size is not
			 * stored on flash. So we just assume the volume is
			 * empty. FIXME: this should be handled.
			 */
			continue;
		}

		if (sv->leb_count != sv->used_ebs) {
			/*
			 * We found a static volume which misses several
			 * eraseblocks. Treat it as corrupted.
			 */
			ubi_warn("static volume %d misses %d LEBs - corrupted",
				 sv->vol_id, sv->used_ebs - sv->leb_count);
			vol->corrupted = 1;
			continue;
		}

		vol->used_ebs = sv->used_ebs;
		vol->used_bytes =
			(long long)(vol->used_ebs - 1) * vol->usable_leb_size;
		vol->used_bytes += sv->last_data_size;
		vol->last_eb_bytes = sv->last_data_size;
	}

	/* And add the layout volume */
	vol = kzalloc(sizeof(struct ubi_volume), GFP_KERNEL);
	if (!vol)
		return -ENOMEM;

	vol->reserved_pebs = UBI_LAYOUT_VOLUME_EBS;
	vol->alignment = 1;
	vol->vol_type = UBI_DYNAMIC_VOLUME;
	vol->name_len = sizeof(UBI_LAYOUT_VOLUME_NAME) - 1;
	memcpy(vol->name, UBI_LAYOUT_VOLUME_NAME, vol->name_len + 1);
	vol->usable_leb_size = ubi->leb_size;
	vol->used_ebs = vol->reserved_pebs;
	vol->last_eb_bytes = vol->reserved_pebs;
	vol->used_bytes =
		(long long)vol->used_ebs * (ubi->leb_size - vol->data_pad);
	vol->vol_id = UBI_LAYOUT_VOLUME_ID;
	vol->ref_count = 1;

	ubi_assert(!ubi->volumes[i]);
	ubi->volumes[vol_id2idx(ubi, vol->vol_id)] = vol;
	reserved_pebs += vol->reserved_pebs;
	ubi->vol_count += 1;
	vol->ubi = ubi;

	if (reserved_pebs > ubi->avail_pebs)
		ubi_err("not enough PEBs, required %d, available %d",
			reserved_pebs, ubi->avail_pebs);
	ubi->rsvd_pebs += reserved_pebs;
	ubi->avail_pebs -= reserved_pebs;

	return 0;
}

/**
 * check_sv - check volume scanning information.
 * @vol: UBI volume description object
 * @sv: volume scanning information
 *
 * This function returns zero if the volume scanning information is consistent
 * to the data read from the volume tabla, and %-EINVAL if not.
 */
static int check_sv(const struct ubi_volume *vol,
		    const struct ubi_scan_volume *sv)
{
	int err;

	if (sv->highest_lnum >= vol->reserved_pebs) {
		err = 1;
		goto bad;
	}
	if (sv->leb_count > vol->reserved_pebs) {
		err = 2;
		goto bad;
	}
	if (sv->vol_type != vol->vol_type) {
		err = 3;
		goto bad;
	}
	if (sv->used_ebs > vol->reserved_pebs) {
		err = 4;
		goto bad;
	}
	if (sv->data_pad != vol->data_pad) {
		err = 5;
		goto bad;
	}
	return 0;

bad:
	ubi_err("bad scanning information, error %d", err);
	ubi_dbg_dump_sv(sv);
	ubi_dbg_dump_vol_info(vol);
	return -EINVAL;
}

/**
 * check_scanning_info - check that scanning information.
 * @ubi: UBI device description object
 * @si: scanning information
 *
 * Even though we protect on-flash data by CRC checksums, we still don't trust
 * the media. This function ensures that scanning information is consistent to
 * the information read from the volume table. Returns zero if the scanning
 * information is OK and %-EINVAL if it is not.
 */
static int check_scanning_info(const struct ubi_device *ubi,
			       struct ubi_scan_info *si)
{
	int err, i;
	struct ubi_scan_volume *sv;
	struct ubi_volume *vol;

	if (si->vols_found > UBI_INT_VOL_COUNT + ubi->vtbl_slots) {
		ubi_err("scanning found %d volumes, maximum is %d + %d",
			si->vols_found, UBI_INT_VOL_COUNT, ubi->vtbl_slots);
		return -EINVAL;
	}

	if (si->highest_vol_id >= ubi->vtbl_slots + UBI_INT_VOL_COUNT &&
	    si->highest_vol_id < UBI_INTERNAL_VOL_START) {
		ubi_err("too large volume ID %d found by scanning",
			si->highest_vol_id);
		return -EINVAL;
	}

	for (i = 0; i < ubi->vtbl_slots + UBI_INT_VOL_COUNT; i++) {
		cond_resched();

		sv = ubi_scan_find_sv(si, i);
		vol = ubi->volumes[i];
		if (!vol) {
			if (sv)
				ubi_scan_rm_volume(si, sv);
			continue;
		}

		if (vol->reserved_pebs == 0) {
			ubi_assert(i < ubi->vtbl_slots);

			if (!sv)
				continue;

			/*
			 * During scanning we found a volume which does not
			 * exist according to the information in the volume
			 * table. This must have happened due to an unclean
			 * reboot while the volume was being removed. Discard
			 * these eraseblocks.
			 */
			ubi_msg("finish volume %d removal", sv->vol_id);
			ubi_scan_rm_volume(si, sv);
		} else if (sv) {
			err = check_sv(vol, sv);
			if (err)
				return err;
		}
	}

	return 0;
}

/**
 * ubi_read_volume_table - read volume table.
 * information.
 * @ubi: UBI device description object
 * @si: scanning information
 *
 * This function reads volume table, checks it, recover from errors if needed,
 * or creates it if needed. Returns zero in case of success and a negative
 * error code in case of failure.
 */
int ubi_read_volume_table(struct ubi_device *ubi, struct ubi_scan_info *si)
{
	int i, err;
	struct ubi_scan_volume *sv;

	empty_vtbl_record.crc = cpu_to_be32(0xf116c36b);

	/*
	 * The number of supported volumes is limited by the eraseblock size
	 * and by the UBI_MAX_VOLUMES constant.
	 */
	ubi->vtbl_slots = ubi->leb_size / UBI_VTBL_RECORD_SIZE;
	if (ubi->vtbl_slots > UBI_MAX_VOLUMES)
		ubi->vtbl_slots = UBI_MAX_VOLUMES;

	ubi->vtbl_size = ubi->vtbl_slots * UBI_VTBL_RECORD_SIZE;
	ubi->vtbl_size = ALIGN(ubi->vtbl_size, ubi->min_io_size);

	sv = ubi_scan_find_sv(si, UBI_LAYOUT_VOLUME_ID);
	if (!sv) {
		/*
		 * No logical eraseblocks belonging to the layout volume were
		 * found. This could mean that the flash is just empty. In
		 * this case we create empty layout volume.
		 *
		 * But if flash is not empty this must be a corruption or the
		 * MTD device just contains garbage.
		 */
		if (si->is_empty) {
			ubi->vtbl = create_empty_lvol(ubi, si);
			if (IS_ERR(ubi->vtbl))
				return PTR_ERR(ubi->vtbl);
		} else {
			ubi_err("the layout volume was not found");
			return -EINVAL;
		}
	} else {
		if (sv->leb_count > UBI_LAYOUT_VOLUME_EBS) {
			/* This must not happen with proper UBI images */
			dbg_err("too many LEBs (%d) in layout volume",
				sv->leb_count);
			return -EINVAL;
		}

		ubi->vtbl = process_lvol(ubi, si, sv);
		if (IS_ERR(ubi->vtbl))
			return PTR_ERR(ubi->vtbl);
	}

	ubi->avail_pebs = ubi->good_peb_count;

	/*
	 * The layout volume is OK, initialize the corresponding in-RAM data
	 * structures.
	 */
	err = init_volumes(ubi, si, ubi->vtbl);
	if (err)
		goto out_free;

	/*
	 * Get sure that the scanning information is consistent to the
	 * information stored in the volume table.
	 */
	err = check_scanning_info(ubi, si);
	if (err)
		goto out_free;

	return 0;

out_free:
	vfree(ubi->vtbl);
	for (i = 0; i < ubi->vtbl_slots + UBI_INT_VOL_COUNT; i++)
		if (ubi->volumes[i]) {
			kfree(ubi->volumes[i]);
			ubi->volumes[i] = NULL;
		}
	return err;
}

#ifdef CONFIG_MTD_UBI_DEBUG_PARANOID

/**
 * paranoid_vtbl_check - check volume table.
 * @ubi: UBI device description object
 */
static void paranoid_vtbl_check(const struct ubi_device *ubi)
{
	if (vtbl_check(ubi, ubi->vtbl)) {
		ubi_err("paranoid check failed");
		BUG();
	}
}

#endif /* CONFIG_MTD_UBI_DEBUG_PARANOID */